4 TGSI, Tungsten Graphics Shader Infrastructure, is an intermediate language
5 for describing shaders. Since Gallium is inherently shaderful, shaders are
6 an important part of the API. TGSI is the only intermediate representation
12 All TGSI instructions, known as *opcodes*, operate on arbitrary-precision
13 floating-point four-component vectors. An opcode may have up to one
14 destination register, known as *dst*, and between zero and three source
15 registers, called *src0* through *src2*, or simply *src* if there is only
18 Some instructions, like :opcode:`I2F`, permit re-interpretation of vector
19 components as integers. Other instructions permit using registers as
20 two-component vectors with double precision; see :ref:`doubleopcodes`.
22 When an instruction has a scalar result, the result is usually copied into
23 each of the components of *dst*. When this happens, the result is said to be
24 *replicated* to *dst*. :opcode:`RCP` is one such instruction.
29 TGSI supports modifiers on inputs (as well as saturate modifier on instructions).
31 For inputs which have a floating point type, both absolute value and negation
32 modifiers are supported (with absolute value being applied first).
33 TGSI_OPCODE_MOV is considered to have float input type for applying modifiers.
35 For inputs which have signed or unsigned type only the negate modifier is
42 ^^^^^^^^^^^^^^^^^^^^^^^^^
44 These opcodes are guaranteed to be available regardless of the driver being
47 .. opcode:: ARL - Address Register Load
51 dst.x = \lfloor src.x\rfloor
53 dst.y = \lfloor src.y\rfloor
55 dst.z = \lfloor src.z\rfloor
57 dst.w = \lfloor src.w\rfloor
60 .. opcode:: MOV - Move
73 .. opcode:: LIT - Light Coefficients
78 dst.y &= max(src.x, 0) \\
79 dst.z &= (src.x > 0) ? max(src.y, 0)^{clamp(src.w, -128, 128))} : 0 \\
83 .. opcode:: RCP - Reciprocal
85 This instruction replicates its result.
92 .. opcode:: RSQ - Reciprocal Square Root
94 This instruction replicates its result. The results are undefined for src <= 0.
98 dst = \frac{1}{\sqrt{src.x}}
101 .. opcode:: SQRT - Square Root
103 This instruction replicates its result. The results are undefined for src < 0.
110 .. opcode:: EXP - Approximate Exponential Base 2
114 dst.x &= 2^{\lfloor src.x\rfloor} \\
115 dst.y &= src.x - \lfloor src.x\rfloor \\
116 dst.z &= 2^{src.x} \\
120 .. opcode:: LOG - Approximate Logarithm Base 2
124 dst.x &= \lfloor\log_2{|src.x|}\rfloor \\
125 dst.y &= \frac{|src.x|}{2^{\lfloor\log_2{|src.x|}\rfloor}} \\
126 dst.z &= \log_2{|src.x|} \\
130 .. opcode:: MUL - Multiply
134 dst.x = src0.x \times src1.x
136 dst.y = src0.y \times src1.y
138 dst.z = src0.z \times src1.z
140 dst.w = src0.w \times src1.w
143 .. opcode:: ADD - Add
147 dst.x = src0.x + src1.x
149 dst.y = src0.y + src1.y
151 dst.z = src0.z + src1.z
153 dst.w = src0.w + src1.w
156 .. opcode:: DP3 - 3-component Dot Product
158 This instruction replicates its result.
162 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
165 .. opcode:: DP4 - 4-component Dot Product
167 This instruction replicates its result.
171 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
174 .. opcode:: DST - Distance Vector
179 dst.y &= src0.y \times src1.y\\
184 .. opcode:: MIN - Minimum
188 dst.x = min(src0.x, src1.x)
190 dst.y = min(src0.y, src1.y)
192 dst.z = min(src0.z, src1.z)
194 dst.w = min(src0.w, src1.w)
197 .. opcode:: MAX - Maximum
201 dst.x = max(src0.x, src1.x)
203 dst.y = max(src0.y, src1.y)
205 dst.z = max(src0.z, src1.z)
207 dst.w = max(src0.w, src1.w)
210 .. opcode:: SLT - Set On Less Than
214 dst.x = (src0.x < src1.x) ? 1.0F : 0.0F
216 dst.y = (src0.y < src1.y) ? 1.0F : 0.0F
218 dst.z = (src0.z < src1.z) ? 1.0F : 0.0F
220 dst.w = (src0.w < src1.w) ? 1.0F : 0.0F
223 .. opcode:: SGE - Set On Greater Equal Than
227 dst.x = (src0.x >= src1.x) ? 1.0F : 0.0F
229 dst.y = (src0.y >= src1.y) ? 1.0F : 0.0F
231 dst.z = (src0.z >= src1.z) ? 1.0F : 0.0F
233 dst.w = (src0.w >= src1.w) ? 1.0F : 0.0F
236 .. opcode:: MAD - Multiply And Add
240 dst.x = src0.x \times src1.x + src2.x
242 dst.y = src0.y \times src1.y + src2.y
244 dst.z = src0.z \times src1.z + src2.z
246 dst.w = src0.w \times src1.w + src2.w
249 .. opcode:: SUB - Subtract
253 dst.x = src0.x - src1.x
255 dst.y = src0.y - src1.y
257 dst.z = src0.z - src1.z
259 dst.w = src0.w - src1.w
262 .. opcode:: LRP - Linear Interpolate
266 dst.x = src0.x \times src1.x + (1 - src0.x) \times src2.x
268 dst.y = src0.y \times src1.y + (1 - src0.y) \times src2.y
270 dst.z = src0.z \times src1.z + (1 - src0.z) \times src2.z
272 dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
275 .. opcode:: CND - Condition
279 dst.x = (src2.x > 0.5) ? src0.x : src1.x
281 dst.y = (src2.y > 0.5) ? src0.y : src1.y
283 dst.z = (src2.z > 0.5) ? src0.z : src1.z
285 dst.w = (src2.w > 0.5) ? src0.w : src1.w
288 .. opcode:: DP2A - 2-component Dot Product And Add
292 dst.x = src0.x \times src1.x + src0.y \times src1.y + src2.x
294 dst.y = src0.x \times src1.x + src0.y \times src1.y + src2.x
296 dst.z = src0.x \times src1.x + src0.y \times src1.y + src2.x
298 dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x
301 .. opcode:: FRC - Fraction
305 dst.x = src.x - \lfloor src.x\rfloor
307 dst.y = src.y - \lfloor src.y\rfloor
309 dst.z = src.z - \lfloor src.z\rfloor
311 dst.w = src.w - \lfloor src.w\rfloor
314 .. opcode:: CLAMP - Clamp
318 dst.x = clamp(src0.x, src1.x, src2.x)
320 dst.y = clamp(src0.y, src1.y, src2.y)
322 dst.z = clamp(src0.z, src1.z, src2.z)
324 dst.w = clamp(src0.w, src1.w, src2.w)
327 .. opcode:: FLR - Floor
329 This is identical to :opcode:`ARL`.
333 dst.x = \lfloor src.x\rfloor
335 dst.y = \lfloor src.y\rfloor
337 dst.z = \lfloor src.z\rfloor
339 dst.w = \lfloor src.w\rfloor
342 .. opcode:: ROUND - Round
355 .. opcode:: EX2 - Exponential Base 2
357 This instruction replicates its result.
364 .. opcode:: LG2 - Logarithm Base 2
366 This instruction replicates its result.
373 .. opcode:: POW - Power
375 This instruction replicates its result.
379 dst = src0.x^{src1.x}
381 .. opcode:: XPD - Cross Product
385 dst.x = src0.y \times src1.z - src1.y \times src0.z
387 dst.y = src0.z \times src1.x - src1.z \times src0.x
389 dst.z = src0.x \times src1.y - src1.x \times src0.y
394 .. opcode:: ABS - Absolute
407 .. opcode:: DPH - Homogeneous Dot Product
409 This instruction replicates its result.
413 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
416 .. opcode:: COS - Cosine
418 This instruction replicates its result.
425 .. opcode:: DDX, DDX_FINE - Derivative Relative To X
427 The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
428 advertised. When it is, the fine version guarantees one derivative per row
429 while DDX is allowed to be the same for the entire 2x2 quad.
433 dst.x = partialx(src.x)
435 dst.y = partialx(src.y)
437 dst.z = partialx(src.z)
439 dst.w = partialx(src.w)
442 .. opcode:: DDY, DDY_FINE - Derivative Relative To Y
444 The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
445 advertised. When it is, the fine version guarantees one derivative per column
446 while DDY is allowed to be the same for the entire 2x2 quad.
450 dst.x = partialy(src.x)
452 dst.y = partialy(src.y)
454 dst.z = partialy(src.z)
456 dst.w = partialy(src.w)
459 .. opcode:: PK2H - Pack Two 16-bit Floats
464 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
469 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
474 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
479 .. opcode:: RFL - Reflection Vector
483 dst.x = 2 \times (src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z) / (src0.x \times src0.x + src0.y \times src0.y + src0.z \times src0.z) \times src0.x - src1.x
485 dst.y = 2 \times (src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z) / (src0.x \times src0.x + src0.y \times src0.y + src0.z \times src0.z) \times src0.y - src1.y
487 dst.z = 2 \times (src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z) / (src0.x \times src0.x + src0.y \times src0.y + src0.z \times src0.z) \times src0.z - src1.z
493 Considered for removal.
496 .. opcode:: SEQ - Set On Equal
500 dst.x = (src0.x == src1.x) ? 1.0F : 0.0F
502 dst.y = (src0.y == src1.y) ? 1.0F : 0.0F
504 dst.z = (src0.z == src1.z) ? 1.0F : 0.0F
506 dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
509 .. opcode:: SFL - Set On False
511 This instruction replicates its result.
519 Considered for removal.
522 .. opcode:: SGT - Set On Greater Than
526 dst.x = (src0.x > src1.x) ? 1.0F : 0.0F
528 dst.y = (src0.y > src1.y) ? 1.0F : 0.0F
530 dst.z = (src0.z > src1.z) ? 1.0F : 0.0F
532 dst.w = (src0.w > src1.w) ? 1.0F : 0.0F
535 .. opcode:: SIN - Sine
537 This instruction replicates its result.
544 .. opcode:: SLE - Set On Less Equal Than
548 dst.x = (src0.x <= src1.x) ? 1.0F : 0.0F
550 dst.y = (src0.y <= src1.y) ? 1.0F : 0.0F
552 dst.z = (src0.z <= src1.z) ? 1.0F : 0.0F
554 dst.w = (src0.w <= src1.w) ? 1.0F : 0.0F
557 .. opcode:: SNE - Set On Not Equal
561 dst.x = (src0.x != src1.x) ? 1.0F : 0.0F
563 dst.y = (src0.y != src1.y) ? 1.0F : 0.0F
565 dst.z = (src0.z != src1.z) ? 1.0F : 0.0F
567 dst.w = (src0.w != src1.w) ? 1.0F : 0.0F
570 .. opcode:: STR - Set On True
572 This instruction replicates its result.
579 .. opcode:: TEX - Texture Lookup
581 for array textures src0.y contains the slice for 1D,
582 and src0.z contain the slice for 2D.
584 for shadow textures with no arrays (and not cube map),
585 src0.z contains the reference value.
587 for shadow textures with arrays, src0.z contains
588 the reference value for 1D arrays, and src0.w contains
589 the reference value for 2D arrays and cube maps.
591 for cube map array shadow textures, the reference value
592 cannot be passed in src0.w, and TEX2 must be used instead.
598 shadow_ref = src0.z or src0.w (optional)
602 dst = texture\_sample(unit, coord, shadow_ref)
605 .. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only)
607 this is the same as TEX, but uses another reg to encode the
618 dst = texture\_sample(unit, coord, shadow_ref)
623 .. opcode:: TXD - Texture Lookup with Derivatives
635 dst = texture\_sample\_deriv(unit, coord, ddx, ddy)
638 .. opcode:: TXP - Projective Texture Lookup
642 coord.x = src0.x / src0.w
644 coord.y = src0.y / src0.w
646 coord.z = src0.z / src0.w
652 dst = texture\_sample(unit, coord)
655 .. opcode:: UP2H - Unpack Two 16-Bit Floats
661 Considered for removal.
663 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
669 Considered for removal.
671 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
677 Considered for removal.
679 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
685 Considered for removal.
688 .. opcode:: ARR - Address Register Load With Round
701 .. opcode:: SSG - Set Sign
705 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
707 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
709 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
711 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
714 .. opcode:: CMP - Compare
718 dst.x = (src0.x < 0) ? src1.x : src2.x
720 dst.y = (src0.y < 0) ? src1.y : src2.y
722 dst.z = (src0.z < 0) ? src1.z : src2.z
724 dst.w = (src0.w < 0) ? src1.w : src2.w
727 .. opcode:: KILL_IF - Conditional Discard
729 Conditional discard. Allowed in fragment shaders only.
733 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
738 .. opcode:: KILL - Discard
740 Unconditional discard. Allowed in fragment shaders only.
743 .. opcode:: SCS - Sine Cosine
756 .. opcode:: TXB - Texture Lookup With Bias
758 for cube map array textures and shadow cube maps, the bias value
759 cannot be passed in src0.w, and TXB2 must be used instead.
761 if the target is a shadow texture, the reference value is always
762 in src.z (this prevents shadow 3d and shadow 2d arrays from
763 using this instruction, but this is not needed).
779 dst = texture\_sample(unit, coord, bias)
782 .. opcode:: TXB2 - Texture Lookup With Bias (some cube maps only)
784 this is the same as TXB, but uses another reg to encode the
785 lod bias value for cube map arrays and shadow cube maps.
786 Presumably shadow 2d arrays and shadow 3d targets could use
787 this encoding too, but this is not legal.
789 shadow cube map arrays are neither possible nor required.
799 dst = texture\_sample(unit, coord, bias)
802 .. opcode:: DIV - Divide
806 dst.x = \frac{src0.x}{src1.x}
808 dst.y = \frac{src0.y}{src1.y}
810 dst.z = \frac{src0.z}{src1.z}
812 dst.w = \frac{src0.w}{src1.w}
815 .. opcode:: DP2 - 2-component Dot Product
817 This instruction replicates its result.
821 dst = src0.x \times src1.x + src0.y \times src1.y
824 .. opcode:: TXL - Texture Lookup With explicit LOD
826 for cube map array textures, the explicit lod value
827 cannot be passed in src0.w, and TXL2 must be used instead.
829 if the target is a shadow texture, the reference value is always
830 in src.z (this prevents shadow 3d / 2d array / cube targets from
831 using this instruction, but this is not needed).
847 dst = texture\_sample(unit, coord, lod)
850 .. opcode:: TXL2 - Texture Lookup With explicit LOD (for cube map arrays only)
852 this is the same as TXL, but uses another reg to encode the
854 Presumably shadow 3d / 2d array / cube targets could use
855 this encoding too, but this is not legal.
857 shadow cube map arrays are neither possible nor required.
867 dst = texture\_sample(unit, coord, lod)
870 .. opcode:: PUSHA - Push Address Register On Stack
879 Considered for cleanup.
883 Considered for removal.
885 .. opcode:: POPA - Pop Address Register From Stack
894 Considered for cleanup.
898 Considered for removal.
901 .. opcode:: BRA - Branch
907 Considered for removal.
910 .. opcode:: CALLNZ - Subroutine Call If Not Zero
916 Considered for cleanup.
920 Considered for removal.
924 ^^^^^^^^^^^^^^^^^^^^^^^^
926 These opcodes are primarily provided for special-use computational shaders.
927 Support for these opcodes indicated by a special pipe capability bit (TBD).
929 XXX doesn't look like most of the opcodes really belong here.
931 .. opcode:: CEIL - Ceiling
935 dst.x = \lceil src.x\rceil
937 dst.y = \lceil src.y\rceil
939 dst.z = \lceil src.z\rceil
941 dst.w = \lceil src.w\rceil
944 .. opcode:: TRUNC - Truncate
957 .. opcode:: MOD - Modulus
961 dst.x = src0.x \bmod src1.x
963 dst.y = src0.y \bmod src1.y
965 dst.z = src0.z \bmod src1.z
967 dst.w = src0.w \bmod src1.w
970 .. opcode:: UARL - Integer Address Register Load
972 Moves the contents of the source register, assumed to be an integer, into the
973 destination register, which is assumed to be an address (ADDR) register.
976 .. opcode:: SAD - Sum Of Absolute Differences
980 dst.x = |src0.x - src1.x| + src2.x
982 dst.y = |src0.y - src1.y| + src2.y
984 dst.z = |src0.z - src1.z| + src2.z
986 dst.w = |src0.w - src1.w| + src2.w
989 .. opcode:: TXF - Texel Fetch
991 As per NV_gpu_shader4, extract a single texel from a specified texture
992 image. The source sampler may not be a CUBE or SHADOW. src 0 is a
993 four-component signed integer vector used to identify the single texel
994 accessed. 3 components + level. Just like texture instructions, an optional
995 offset vector is provided, which is subject to various driver restrictions
996 (regarding range, source of offsets).
997 TXF(uint_vec coord, int_vec offset).
1000 .. opcode:: TXQ - Texture Size Query
1002 As per NV_gpu_program4, retrieve the dimensions of the texture depending on
1003 the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
1004 depth), 1D array (width, layers), 2D array (width, height, layers).
1005 Also return the number of accessible levels (last_level - first_level + 1)
1008 For components which don't return a resource dimension, their value
1016 dst.x = texture\_width(unit, lod)
1018 dst.y = texture\_height(unit, lod)
1020 dst.z = texture\_depth(unit, lod)
1022 dst.w = texture\_levels(unit)
1024 .. opcode:: TG4 - Texture Gather
1026 As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
1027 filtering operation and packs them into a single register. Only works with
1028 2D, 2D array, cubemaps, and cubemaps arrays. For 2D textures, only the
1029 addressing modes of the sampler and the top level of any mip pyramid are
1030 used. Set W to zero. It behaves like the TEX instruction, but a filtered
1031 sample is not generated. The four samples that contribute to filtering are
1032 placed into xyzw in clockwise order, starting with the (u,v) texture
1033 coordinate delta at the following locations (-, +), (+, +), (+, -), (-, -),
1034 where the magnitude of the deltas are half a texel.
1036 PIPE_CAP_TEXTURE_SM5 enhances this instruction to support shadow per-sample
1037 depth compares, single component selection, and a non-constant offset. It
1038 doesn't allow support for the GL independent offset to get i0,j0. This would
1039 require another CAP is hw can do it natively. For now we lower that before
1048 dst = texture\_gather4 (unit, coord, component)
1050 (with SM5 - cube array shadow)
1058 dst = texture\_gather (uint, coord, compare)
1060 .. opcode:: LODQ - level of detail query
1062 Compute the LOD information that the texture pipe would use to access the
1063 texture. The Y component contains the computed LOD lambda_prime. The X
1064 component contains the LOD that will be accessed, based on min/max lod's
1071 dst.xy = lodq(uint, coord);
1074 ^^^^^^^^^^^^^^^^^^^^^^^^
1075 These opcodes are used for integer operations.
1076 Support for these opcodes indicated by PIPE_SHADER_CAP_INTEGERS (all of them?)
1079 .. opcode:: I2F - Signed Integer To Float
1081 Rounding is unspecified (round to nearest even suggested).
1085 dst.x = (float) src.x
1087 dst.y = (float) src.y
1089 dst.z = (float) src.z
1091 dst.w = (float) src.w
1094 .. opcode:: U2F - Unsigned Integer To Float
1096 Rounding is unspecified (round to nearest even suggested).
1100 dst.x = (float) src.x
1102 dst.y = (float) src.y
1104 dst.z = (float) src.z
1106 dst.w = (float) src.w
1109 .. opcode:: F2I - Float to Signed Integer
1111 Rounding is towards zero (truncate).
1112 Values outside signed range (including NaNs) produce undefined results.
1125 .. opcode:: F2U - Float to Unsigned Integer
1127 Rounding is towards zero (truncate).
1128 Values outside unsigned range (including NaNs) produce undefined results.
1132 dst.x = (unsigned) src.x
1134 dst.y = (unsigned) src.y
1136 dst.z = (unsigned) src.z
1138 dst.w = (unsigned) src.w
1141 .. opcode:: UADD - Integer Add
1143 This instruction works the same for signed and unsigned integers.
1144 The low 32bit of the result is returned.
1148 dst.x = src0.x + src1.x
1150 dst.y = src0.y + src1.y
1152 dst.z = src0.z + src1.z
1154 dst.w = src0.w + src1.w
1157 .. opcode:: UMAD - Integer Multiply And Add
1159 This instruction works the same for signed and unsigned integers.
1160 The multiplication returns the low 32bit (as does the result itself).
1164 dst.x = src0.x \times src1.x + src2.x
1166 dst.y = src0.y \times src1.y + src2.y
1168 dst.z = src0.z \times src1.z + src2.z
1170 dst.w = src0.w \times src1.w + src2.w
1173 .. opcode:: UMUL - Integer Multiply
1175 This instruction works the same for signed and unsigned integers.
1176 The low 32bit of the result is returned.
1180 dst.x = src0.x \times src1.x
1182 dst.y = src0.y \times src1.y
1184 dst.z = src0.z \times src1.z
1186 dst.w = src0.w \times src1.w
1189 .. opcode:: IMUL_HI - Signed Integer Multiply High Bits
1191 The high 32bits of the multiplication of 2 signed integers are returned.
1195 dst.x = (src0.x \times src1.x) >> 32
1197 dst.y = (src0.y \times src1.y) >> 32
1199 dst.z = (src0.z \times src1.z) >> 32
1201 dst.w = (src0.w \times src1.w) >> 32
1204 .. opcode:: UMUL_HI - Unsigned Integer Multiply High Bits
1206 The high 32bits of the multiplication of 2 unsigned integers are returned.
1210 dst.x = (src0.x \times src1.x) >> 32
1212 dst.y = (src0.y \times src1.y) >> 32
1214 dst.z = (src0.z \times src1.z) >> 32
1216 dst.w = (src0.w \times src1.w) >> 32
1219 .. opcode:: IDIV - Signed Integer Division
1221 TBD: behavior for division by zero.
1225 dst.x = src0.x \ src1.x
1227 dst.y = src0.y \ src1.y
1229 dst.z = src0.z \ src1.z
1231 dst.w = src0.w \ src1.w
1234 .. opcode:: UDIV - Unsigned Integer Division
1236 For division by zero, 0xffffffff is returned.
1240 dst.x = src0.x \ src1.x
1242 dst.y = src0.y \ src1.y
1244 dst.z = src0.z \ src1.z
1246 dst.w = src0.w \ src1.w
1249 .. opcode:: UMOD - Unsigned Integer Remainder
1251 If second arg is zero, 0xffffffff is returned.
1255 dst.x = src0.x \ src1.x
1257 dst.y = src0.y \ src1.y
1259 dst.z = src0.z \ src1.z
1261 dst.w = src0.w \ src1.w
1264 .. opcode:: NOT - Bitwise Not
1277 .. opcode:: AND - Bitwise And
1281 dst.x = src0.x \& src1.x
1283 dst.y = src0.y \& src1.y
1285 dst.z = src0.z \& src1.z
1287 dst.w = src0.w \& src1.w
1290 .. opcode:: OR - Bitwise Or
1294 dst.x = src0.x | src1.x
1296 dst.y = src0.y | src1.y
1298 dst.z = src0.z | src1.z
1300 dst.w = src0.w | src1.w
1303 .. opcode:: XOR - Bitwise Xor
1307 dst.x = src0.x \oplus src1.x
1309 dst.y = src0.y \oplus src1.y
1311 dst.z = src0.z \oplus src1.z
1313 dst.w = src0.w \oplus src1.w
1316 .. opcode:: IMAX - Maximum of Signed Integers
1320 dst.x = max(src0.x, src1.x)
1322 dst.y = max(src0.y, src1.y)
1324 dst.z = max(src0.z, src1.z)
1326 dst.w = max(src0.w, src1.w)
1329 .. opcode:: UMAX - Maximum of Unsigned Integers
1333 dst.x = max(src0.x, src1.x)
1335 dst.y = max(src0.y, src1.y)
1337 dst.z = max(src0.z, src1.z)
1339 dst.w = max(src0.w, src1.w)
1342 .. opcode:: IMIN - Minimum of Signed Integers
1346 dst.x = min(src0.x, src1.x)
1348 dst.y = min(src0.y, src1.y)
1350 dst.z = min(src0.z, src1.z)
1352 dst.w = min(src0.w, src1.w)
1355 .. opcode:: UMIN - Minimum of Unsigned Integers
1359 dst.x = min(src0.x, src1.x)
1361 dst.y = min(src0.y, src1.y)
1363 dst.z = min(src0.z, src1.z)
1365 dst.w = min(src0.w, src1.w)
1368 .. opcode:: SHL - Shift Left
1370 The shift count is masked with 0x1f before the shift is applied.
1374 dst.x = src0.x << (0x1f \& src1.x)
1376 dst.y = src0.y << (0x1f \& src1.y)
1378 dst.z = src0.z << (0x1f \& src1.z)
1380 dst.w = src0.w << (0x1f \& src1.w)
1383 .. opcode:: ISHR - Arithmetic Shift Right (of Signed Integer)
1385 The shift count is masked with 0x1f before the shift is applied.
1389 dst.x = src0.x >> (0x1f \& src1.x)
1391 dst.y = src0.y >> (0x1f \& src1.y)
1393 dst.z = src0.z >> (0x1f \& src1.z)
1395 dst.w = src0.w >> (0x1f \& src1.w)
1398 .. opcode:: USHR - Logical Shift Right
1400 The shift count is masked with 0x1f before the shift is applied.
1404 dst.x = src0.x >> (unsigned) (0x1f \& src1.x)
1406 dst.y = src0.y >> (unsigned) (0x1f \& src1.y)
1408 dst.z = src0.z >> (unsigned) (0x1f \& src1.z)
1410 dst.w = src0.w >> (unsigned) (0x1f \& src1.w)
1413 .. opcode:: UCMP - Integer Conditional Move
1417 dst.x = src0.x ? src1.x : src2.x
1419 dst.y = src0.y ? src1.y : src2.y
1421 dst.z = src0.z ? src1.z : src2.z
1423 dst.w = src0.w ? src1.w : src2.w
1427 .. opcode:: ISSG - Integer Set Sign
1431 dst.x = (src0.x < 0) ? -1 : (src0.x > 0) ? 1 : 0
1433 dst.y = (src0.y < 0) ? -1 : (src0.y > 0) ? 1 : 0
1435 dst.z = (src0.z < 0) ? -1 : (src0.z > 0) ? 1 : 0
1437 dst.w = (src0.w < 0) ? -1 : (src0.w > 0) ? 1 : 0
1441 .. opcode:: FSLT - Float Set On Less Than (ordered)
1443 Same comparison as SLT but returns integer instead of 1.0/0.0 float
1447 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1449 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1451 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1453 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1456 .. opcode:: ISLT - Signed Integer Set On Less Than
1460 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1462 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1464 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1466 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1469 .. opcode:: USLT - Unsigned Integer Set On Less Than
1473 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1475 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1477 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1479 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1482 .. opcode:: FSGE - Float Set On Greater Equal Than (ordered)
1484 Same comparison as SGE but returns integer instead of 1.0/0.0 float
1488 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1490 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1492 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1494 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1497 .. opcode:: ISGE - Signed Integer Set On Greater Equal Than
1501 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1503 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1505 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1507 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1510 .. opcode:: USGE - Unsigned Integer Set On Greater Equal Than
1514 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1516 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1518 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1520 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1523 .. opcode:: FSEQ - Float Set On Equal (ordered)
1525 Same comparison as SEQ but returns integer instead of 1.0/0.0 float
1529 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1531 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1533 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1535 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1538 .. opcode:: USEQ - Integer Set On Equal
1542 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1544 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1546 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1548 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1551 .. opcode:: FSNE - Float Set On Not Equal (unordered)
1553 Same comparison as SNE but returns integer instead of 1.0/0.0 float
1557 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1559 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1561 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1563 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1566 .. opcode:: USNE - Integer Set On Not Equal
1570 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1572 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1574 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1576 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1579 .. opcode:: INEG - Integer Negate
1594 .. opcode:: IABS - Integer Absolute Value
1608 These opcodes are used for bit-level manipulation of integers.
1610 .. opcode:: IBFE - Signed Bitfield Extract
1612 See SM5 instruction of the same name. Extracts a set of bits from the input,
1613 and sign-extends them if the high bit of the extracted window is set.
1617 def ibfe(value, offset, bits):
1618 offset = offset & 0x1f
1620 if bits == 0: return 0
1621 # Note: >> sign-extends
1622 if width + offset < 32:
1623 return (value << (32 - offset - bits)) >> (32 - bits)
1625 return value >> offset
1627 .. opcode:: UBFE - Unsigned Bitfield Extract
1629 See SM5 instruction of the same name. Extracts a set of bits from the input,
1630 without any sign-extension.
1634 def ubfe(value, offset, bits):
1635 offset = offset & 0x1f
1637 if bits == 0: return 0
1638 # Note: >> does not sign-extend
1639 if width + offset < 32:
1640 return (value << (32 - offset - bits)) >> (32 - bits)
1642 return value >> offset
1644 .. opcode:: BFI - Bitfield Insert
1646 See SM5 instruction of the same name. Replaces a bit region of 'base' with
1647 the low bits of 'insert'.
1651 def bfi(base, insert, offset, bits):
1652 offset = offset & 0x1f
1654 mask = ((1 << bits) - 1) << offset
1655 return ((insert << offset) & mask) | (base & ~mask)
1657 .. opcode:: BREV - Bitfield Reverse
1659 See SM5 instruction BFREV. Reverses the bits of the argument.
1661 .. opcode:: POPC - Population Count
1663 See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
1665 .. opcode:: LSB - Index of lowest set bit
1667 See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
1668 bit of the argument. Returns -1 if none are set.
1670 .. opcode:: IMSB - Index of highest non-sign bit
1672 See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
1673 non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
1674 highest 1 bit for positive numbers). Returns -1 if all bits are the same
1675 (i.e. for inputs 0 and -1).
1677 .. opcode:: UMSB - Index of highest set bit
1679 See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
1680 set bit of the argument. Returns -1 if none are set.
1683 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1685 These opcodes are only supported in geometry shaders; they have no meaning
1686 in any other type of shader.
1688 .. opcode:: EMIT - Emit
1690 Generate a new vertex for the current primitive into the specified vertex
1691 stream using the values in the output registers.
1694 .. opcode:: ENDPRIM - End Primitive
1696 Complete the current primitive in the specified vertex stream (consisting of
1697 the emitted vertices), and start a new one.
1703 These opcodes are part of :term:`GLSL`'s opcode set. Support for these
1704 opcodes is determined by a special capability bit, ``GLSL``.
1705 Some require glsl version 1.30 (UIF/BREAKC/SWITCH/CASE/DEFAULT/ENDSWITCH).
1707 .. opcode:: CAL - Subroutine Call
1713 .. opcode:: RET - Subroutine Call Return
1718 .. opcode:: CONT - Continue
1720 Unconditionally moves the point of execution to the instruction after the
1721 last bgnloop. The instruction must appear within a bgnloop/endloop.
1725 Support for CONT is determined by a special capability bit,
1726 ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
1729 .. opcode:: BGNLOOP - Begin a Loop
1731 Start a loop. Must have a matching endloop.
1734 .. opcode:: BGNSUB - Begin Subroutine
1736 Starts definition of a subroutine. Must have a matching endsub.
1739 .. opcode:: ENDLOOP - End a Loop
1741 End a loop started with bgnloop.
1744 .. opcode:: ENDSUB - End Subroutine
1746 Ends definition of a subroutine.
1749 .. opcode:: NOP - No Operation
1754 .. opcode:: BRK - Break
1756 Unconditionally moves the point of execution to the instruction after the
1757 next endloop or endswitch. The instruction must appear within a loop/endloop
1758 or switch/endswitch.
1761 .. opcode:: BREAKC - Break Conditional
1763 Conditionally moves the point of execution to the instruction after the
1764 next endloop or endswitch. The instruction must appear within a loop/endloop
1765 or switch/endswitch.
1766 Condition evaluates to true if src0.x != 0 where src0.x is interpreted
1767 as an integer register.
1771 Considered for removal as it's quite inconsistent wrt other opcodes
1772 (could emulate with UIF/BRK/ENDIF).
1775 .. opcode:: IF - Float If
1777 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
1781 where src0.x is interpreted as a floating point register.
1784 .. opcode:: UIF - Bitwise If
1786 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
1790 where src0.x is interpreted as an integer register.
1793 .. opcode:: ELSE - Else
1795 Starts an else block, after an IF or UIF statement.
1798 .. opcode:: ENDIF - End If
1800 Ends an IF or UIF block.
1803 .. opcode:: SWITCH - Switch
1805 Starts a C-style switch expression. The switch consists of one or multiple
1806 CASE statements, and at most one DEFAULT statement. Execution of a statement
1807 ends when a BRK is hit, but just like in C falling through to other cases
1808 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
1809 just as last statement, and fallthrough is allowed into/from it.
1810 CASE src arguments are evaluated at bit level against the SWITCH src argument.
1816 (some instructions here)
1819 (some instructions here)
1822 (some instructions here)
1827 .. opcode:: CASE - Switch case
1829 This represents a switch case label. The src arg must be an integer immediate.
1832 .. opcode:: DEFAULT - Switch default
1834 This represents the default case in the switch, which is taken if no other
1838 .. opcode:: ENDSWITCH - End of switch
1840 Ends a switch expression.
1846 The interpolation instructions allow an input to be interpolated in a
1847 different way than its declaration. This corresponds to the GLSL 4.00
1848 interpolateAt* functions. The first argument of each of these must come from
1849 ``TGSI_FILE_INPUT``.
1851 .. opcode:: INTERP_CENTROID - Interpolate at the centroid
1853 Interpolates the varying specified by src0 at the centroid
1855 .. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
1857 Interpolates the varying specified by src0 at the sample id specified by
1858 src1.x (interpreted as an integer)
1860 .. opcode:: INTERP_OFFSET - Interpolate at the specified offset
1862 Interpolates the varying specified by src0 at the offset src1.xy from the
1863 pixel center (interpreted as floats)
1871 The double-precision opcodes reinterpret four-component vectors into
1872 two-component vectors with doubled precision in each component.
1874 Support for these opcodes is XXX undecided. :T
1876 .. opcode:: DADD - Add
1880 dst.xy = src0.xy + src1.xy
1882 dst.zw = src0.zw + src1.zw
1885 .. opcode:: DDIV - Divide
1889 dst.xy = src0.xy / src1.xy
1891 dst.zw = src0.zw / src1.zw
1893 .. opcode:: DSEQ - Set on Equal
1897 dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
1899 dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
1901 .. opcode:: DSLT - Set on Less than
1905 dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
1907 dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
1909 .. opcode:: DFRAC - Fraction
1913 dst.xy = src.xy - \lfloor src.xy\rfloor
1915 dst.zw = src.zw - \lfloor src.zw\rfloor
1918 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1920 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1921 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1922 :math:`dst1 \times 2^{dst0} = src` .
1926 dst0.xy = exp(src.xy)
1928 dst1.xy = frac(src.xy)
1930 dst0.zw = exp(src.zw)
1932 dst1.zw = frac(src.zw)
1934 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1936 This opcode is the inverse of :opcode:`DFRACEXP`.
1940 dst.xy = src0.xy \times 2^{src1.xy}
1942 dst.zw = src0.zw \times 2^{src1.zw}
1944 .. opcode:: DMIN - Minimum
1948 dst.xy = min(src0.xy, src1.xy)
1950 dst.zw = min(src0.zw, src1.zw)
1952 .. opcode:: DMAX - Maximum
1956 dst.xy = max(src0.xy, src1.xy)
1958 dst.zw = max(src0.zw, src1.zw)
1960 .. opcode:: DMUL - Multiply
1964 dst.xy = src0.xy \times src1.xy
1966 dst.zw = src0.zw \times src1.zw
1969 .. opcode:: DMAD - Multiply And Add
1973 dst.xy = src0.xy \times src1.xy + src2.xy
1975 dst.zw = src0.zw \times src1.zw + src2.zw
1978 .. opcode:: DRCP - Reciprocal
1982 dst.xy = \frac{1}{src.xy}
1984 dst.zw = \frac{1}{src.zw}
1986 .. opcode:: DSQRT - Square Root
1990 dst.xy = \sqrt{src.xy}
1992 dst.zw = \sqrt{src.zw}
1995 .. _samplingopcodes:
1997 Resource Sampling Opcodes
1998 ^^^^^^^^^^^^^^^^^^^^^^^^^
2000 Those opcodes follow very closely semantics of the respective Direct3D
2001 instructions. If in doubt double check Direct3D documentation.
2002 Note that the swizzle on SVIEW (src1) determines texel swizzling
2007 Using provided address, sample data from the specified texture using the
2008 filtering mode identified by the gven sampler. The source data may come from
2009 any resource type other than buffers.
2011 Syntax: ``SAMPLE dst, address, sampler_view, sampler``
2013 Example: ``SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]``
2015 .. opcode:: SAMPLE_I
2017 Simplified alternative to the SAMPLE instruction. Using the provided
2018 integer address, SAMPLE_I fetches data from the specified sampler view
2019 without any filtering. The source data may come from any resource type
2022 Syntax: ``SAMPLE_I dst, address, sampler_view``
2024 Example: ``SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]``
2026 The 'address' is specified as unsigned integers. If the 'address' is out of
2027 range [0...(# texels - 1)] the result of the fetch is always 0 in all
2028 components. As such the instruction doesn't honor address wrap modes, in
2029 cases where that behavior is desirable 'SAMPLE' instruction should be used.
2030 address.w always provides an unsigned integer mipmap level. If the value is
2031 out of the range then the instruction always returns 0 in all components.
2032 address.yz are ignored for buffers and 1d textures. address.z is ignored
2033 for 1d texture arrays and 2d textures.
2035 For 1D texture arrays address.y provides the array index (also as unsigned
2036 integer). If the value is out of the range of available array indices
2037 [0... (array size - 1)] then the opcode always returns 0 in all components.
2038 For 2D texture arrays address.z provides the array index, otherwise it
2039 exhibits the same behavior as in the case for 1D texture arrays. The exact
2040 semantics of the source address are presented in the table below:
2042 +---------------------------+----+-----+-----+---------+
2043 | resource type | X | Y | Z | W |
2044 +===========================+====+=====+=====+=========+
2045 | ``PIPE_BUFFER`` | x | | | ignored |
2046 +---------------------------+----+-----+-----+---------+
2047 | ``PIPE_TEXTURE_1D`` | x | | | mpl |
2048 +---------------------------+----+-----+-----+---------+
2049 | ``PIPE_TEXTURE_2D`` | x | y | | mpl |
2050 +---------------------------+----+-----+-----+---------+
2051 | ``PIPE_TEXTURE_3D`` | x | y | z | mpl |
2052 +---------------------------+----+-----+-----+---------+
2053 | ``PIPE_TEXTURE_RECT`` | x | y | | mpl |
2054 +---------------------------+----+-----+-----+---------+
2055 | ``PIPE_TEXTURE_CUBE`` | not allowed as source |
2056 +---------------------------+----+-----+-----+---------+
2057 | ``PIPE_TEXTURE_1D_ARRAY`` | x | idx | | mpl |
2058 +---------------------------+----+-----+-----+---------+
2059 | ``PIPE_TEXTURE_2D_ARRAY`` | x | y | idx | mpl |
2060 +---------------------------+----+-----+-----+---------+
2062 Where 'mpl' is a mipmap level and 'idx' is the array index.
2064 .. opcode:: SAMPLE_I_MS
2066 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2068 Syntax: ``SAMPLE_I_MS dst, address, sampler_view, sample``
2070 .. opcode:: SAMPLE_B
2072 Just like the SAMPLE instruction with the exception that an additional bias
2073 is applied to the level of detail computed as part of the instruction
2076 Syntax: ``SAMPLE_B dst, address, sampler_view, sampler, lod_bias``
2078 Example: ``SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2080 .. opcode:: SAMPLE_C
2082 Similar to the SAMPLE instruction but it performs a comparison filter. The
2083 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2084 additional float32 operand, reference value, which must be a register with
2085 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2086 current samplers compare_func (in pipe_sampler_state) to compare reference
2087 value against the red component value for the surce resource at each texel
2088 that the currently configured texture filter covers based on the provided
2091 Syntax: ``SAMPLE_C dst, address, sampler_view.r, sampler, ref_value``
2093 Example: ``SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2095 .. opcode:: SAMPLE_C_LZ
2097 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2100 Syntax: ``SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value``
2102 Example: ``SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2105 .. opcode:: SAMPLE_D
2107 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2108 the source address in the x direction and the y direction are provided by
2111 Syntax: ``SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y``
2113 Example: ``SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]``
2115 .. opcode:: SAMPLE_L
2117 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2118 directly as a scalar value, representing no anisotropy.
2120 Syntax: ``SAMPLE_L dst, address, sampler_view, sampler, explicit_lod``
2122 Example: ``SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2126 Gathers the four texels to be used in a bi-linear filtering operation and
2127 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2128 and cubemaps arrays. For 2D textures, only the addressing modes of the
2129 sampler and the top level of any mip pyramid are used. Set W to zero. It
2130 behaves like the SAMPLE instruction, but a filtered sample is not
2131 generated. The four samples that contribute to filtering are placed into
2132 xyzw in counter-clockwise order, starting with the (u,v) texture coordinate
2133 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2134 magnitude of the deltas are half a texel.
2137 .. opcode:: SVIEWINFO
2139 Query the dimensions of a given sampler view. dst receives width, height,
2140 depth or array size and number of mipmap levels as int4. The dst can have a
2141 writemask which will specify what info is the caller interested in.
2143 Syntax: ``SVIEWINFO dst, src_mip_level, sampler_view``
2145 Example: ``SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]``
2147 src_mip_level is an unsigned integer scalar. If it's out of range then
2148 returns 0 for width, height and depth/array size but the total number of
2149 mipmap is still returned correctly for the given sampler view. The returned
2150 width, height and depth values are for the mipmap level selected by the
2151 src_mip_level and are in the number of texels. For 1d texture array width
2152 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2153 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2154 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2155 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2156 resinfo allowing swizzling dst values is ignored (due to the interaction
2157 with rcpfloat modifier which requires some swizzle handling in the state
2160 .. opcode:: SAMPLE_POS
2162 Query the position of a given sample. dst receives float4 (x, y, 0, 0)
2163 indicated where the sample is located. If the resource is not a multi-sample
2164 resource and not a render target, the result is 0.
2166 .. opcode:: SAMPLE_INFO
2168 dst receives number of samples in x. If the resource is not a multi-sample
2169 resource and not a render target, the result is 0.
2172 .. _resourceopcodes:
2174 Resource Access Opcodes
2175 ^^^^^^^^^^^^^^^^^^^^^^^
2177 .. opcode:: LOAD - Fetch data from a shader resource
2179 Syntax: ``LOAD dst, resource, address``
2181 Example: ``LOAD TEMP[0], RES[0], TEMP[1]``
2183 Using the provided integer address, LOAD fetches data
2184 from the specified buffer or texture without any
2187 The 'address' is specified as a vector of unsigned
2188 integers. If the 'address' is out of range the result
2191 Only the first mipmap level of a resource can be read
2192 from using this instruction.
2194 For 1D or 2D texture arrays, the array index is
2195 provided as an unsigned integer in address.y or
2196 address.z, respectively. address.yz are ignored for
2197 buffers and 1D textures. address.z is ignored for 1D
2198 texture arrays and 2D textures. address.w is always
2201 .. opcode:: STORE - Write data to a shader resource
2203 Syntax: ``STORE resource, address, src``
2205 Example: ``STORE RES[0], TEMP[0], TEMP[1]``
2207 Using the provided integer address, STORE writes data
2208 to the specified buffer or texture.
2210 The 'address' is specified as a vector of unsigned
2211 integers. If the 'address' is out of range the result
2214 Only the first mipmap level of a resource can be
2215 written to using this instruction.
2217 For 1D or 2D texture arrays, the array index is
2218 provided as an unsigned integer in address.y or
2219 address.z, respectively. address.yz are ignored for
2220 buffers and 1D textures. address.z is ignored for 1D
2221 texture arrays and 2D textures. address.w is always
2225 .. _threadsyncopcodes:
2227 Inter-thread synchronization opcodes
2228 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2230 These opcodes are intended for communication between threads running
2231 within the same compute grid. For now they're only valid in compute
2234 .. opcode:: MFENCE - Memory fence
2236 Syntax: ``MFENCE resource``
2238 Example: ``MFENCE RES[0]``
2240 This opcode forces strong ordering between any memory access
2241 operations that affect the specified resource. This means that
2242 previous loads and stores (and only those) will be performed and
2243 visible to other threads before the program execution continues.
2246 .. opcode:: LFENCE - Load memory fence
2248 Syntax: ``LFENCE resource``
2250 Example: ``LFENCE RES[0]``
2252 Similar to MFENCE, but it only affects the ordering of memory loads.
2255 .. opcode:: SFENCE - Store memory fence
2257 Syntax: ``SFENCE resource``
2259 Example: ``SFENCE RES[0]``
2261 Similar to MFENCE, but it only affects the ordering of memory stores.
2264 .. opcode:: BARRIER - Thread group barrier
2268 This opcode suspends the execution of the current thread until all
2269 the remaining threads in the working group reach the same point of
2270 the program. Results are unspecified if any of the remaining
2271 threads terminates or never reaches an executed BARRIER instruction.
2279 These opcodes provide atomic variants of some common arithmetic and
2280 logical operations. In this context atomicity means that another
2281 concurrent memory access operation that affects the same memory
2282 location is guaranteed to be performed strictly before or after the
2283 entire execution of the atomic operation.
2285 For the moment they're only valid in compute programs.
2287 .. opcode:: ATOMUADD - Atomic integer addition
2289 Syntax: ``ATOMUADD dst, resource, offset, src``
2291 Example: ``ATOMUADD TEMP[0], RES[0], TEMP[1], TEMP[2]``
2293 The following operation is performed atomically on each component:
2297 dst_i = resource[offset]_i
2299 resource[offset]_i = dst_i + src_i
2302 .. opcode:: ATOMXCHG - Atomic exchange
2304 Syntax: ``ATOMXCHG dst, resource, offset, src``
2306 Example: ``ATOMXCHG TEMP[0], RES[0], TEMP[1], TEMP[2]``
2308 The following operation is performed atomically on each component:
2312 dst_i = resource[offset]_i
2314 resource[offset]_i = src_i
2317 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2319 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
2321 Example: ``ATOMCAS TEMP[0], RES[0], TEMP[1], TEMP[2], TEMP[3]``
2323 The following operation is performed atomically on each component:
2327 dst_i = resource[offset]_i
2329 resource[offset]_i = (dst_i == cmp_i ? src_i : dst_i)
2332 .. opcode:: ATOMAND - Atomic bitwise And
2334 Syntax: ``ATOMAND dst, resource, offset, src``
2336 Example: ``ATOMAND TEMP[0], RES[0], TEMP[1], TEMP[2]``
2338 The following operation is performed atomically on each component:
2342 dst_i = resource[offset]_i
2344 resource[offset]_i = dst_i \& src_i
2347 .. opcode:: ATOMOR - Atomic bitwise Or
2349 Syntax: ``ATOMOR dst, resource, offset, src``
2351 Example: ``ATOMOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2353 The following operation is performed atomically on each component:
2357 dst_i = resource[offset]_i
2359 resource[offset]_i = dst_i | src_i
2362 .. opcode:: ATOMXOR - Atomic bitwise Xor
2364 Syntax: ``ATOMXOR dst, resource, offset, src``
2366 Example: ``ATOMXOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2368 The following operation is performed atomically on each component:
2372 dst_i = resource[offset]_i
2374 resource[offset]_i = dst_i \oplus src_i
2377 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2379 Syntax: ``ATOMUMIN dst, resource, offset, src``
2381 Example: ``ATOMUMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
2383 The following operation is performed atomically on each component:
2387 dst_i = resource[offset]_i
2389 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
2392 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2394 Syntax: ``ATOMUMAX dst, resource, offset, src``
2396 Example: ``ATOMUMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
2398 The following operation is performed atomically on each component:
2402 dst_i = resource[offset]_i
2404 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
2407 .. opcode:: ATOMIMIN - Atomic signed minimum
2409 Syntax: ``ATOMIMIN dst, resource, offset, src``
2411 Example: ``ATOMIMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
2413 The following operation is performed atomically on each component:
2417 dst_i = resource[offset]_i
2419 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
2422 .. opcode:: ATOMIMAX - Atomic signed maximum
2424 Syntax: ``ATOMIMAX dst, resource, offset, src``
2426 Example: ``ATOMIMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
2428 The following operation is performed atomically on each component:
2432 dst_i = resource[offset]_i
2434 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
2438 Explanation of symbols used
2439 ------------------------------
2446 :math:`|x|` Absolute value of `x`.
2448 :math:`\lceil x \rceil` Ceiling of `x`.
2450 clamp(x,y,z) Clamp x between y and z.
2451 (x < y) ? y : (x > z) ? z : x
2453 :math:`\lfloor x\rfloor` Floor of `x`.
2455 :math:`\log_2{x}` Logarithm of `x`, base 2.
2457 max(x,y) Maximum of x and y.
2460 min(x,y) Minimum of x and y.
2463 partialx(x) Derivative of x relative to fragment's X.
2465 partialy(x) Derivative of x relative to fragment's Y.
2467 pop() Pop from stack.
2469 :math:`x^y` `x` to the power `y`.
2471 push(x) Push x on stack.
2475 trunc(x) Truncate x, i.e. drop the fraction bits.
2482 discard Discard fragment.
2486 target Label of target instruction.
2497 Declares a register that is will be referenced as an operand in Instruction
2500 File field contains register file that is being declared and is one
2503 UsageMask field specifies which of the register components can be accessed
2504 and is one of TGSI_WRITEMASK.
2506 The Local flag specifies that a given value isn't intended for
2507 subroutine parameter passing and, as a result, the implementation
2508 isn't required to give any guarantees of it being preserved across
2509 subroutine boundaries. As it's merely a compiler hint, the
2510 implementation is free to ignore it.
2512 If Dimension flag is set to 1, a Declaration Dimension token follows.
2514 If Semantic flag is set to 1, a Declaration Semantic token follows.
2516 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
2518 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
2520 If Array flag is set to 1, a Declaration Array token follows.
2523 ^^^^^^^^^^^^^^^^^^^^^^^^
2525 Declarations can optional have an ArrayID attribute which can be referred by
2526 indirect addressing operands. An ArrayID of zero is reserved and treaded as
2527 if no ArrayID is specified.
2529 If an indirect addressing operand refers to a specific declaration by using
2530 an ArrayID only the registers in this declaration are guaranteed to be
2531 accessed, accessing any register outside this declaration results in undefined
2532 behavior. Note that for compatibility the effective index is zero-based and
2533 not relative to the specified declaration
2535 If no ArrayID is specified with an indirect addressing operand the whole
2536 register file might be accessed by this operand. This is strongly discouraged
2537 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
2539 Declaration Semantic
2540 ^^^^^^^^^^^^^^^^^^^^^^^^
2542 Vertex and fragment shader input and output registers may be labeled
2543 with semantic information consisting of a name and index.
2545 Follows Declaration token if Semantic bit is set.
2547 Since its purpose is to link a shader with other stages of the pipeline,
2548 it is valid to follow only those Declaration tokens that declare a register
2549 either in INPUT or OUTPUT file.
2551 SemanticName field contains the semantic name of the register being declared.
2552 There is no default value.
2554 SemanticIndex is an optional subscript that can be used to distinguish
2555 different register declarations with the same semantic name. The default value
2558 The meanings of the individual semantic names are explained in the following
2561 TGSI_SEMANTIC_POSITION
2562 """"""""""""""""""""""
2564 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
2565 output register which contains the homogeneous vertex position in the clip
2566 space coordinate system. After clipping, the X, Y and Z components of the
2567 vertex will be divided by the W value to get normalized device coordinates.
2569 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
2570 fragment shader input contains the fragment's window position. The X
2571 component starts at zero and always increases from left to right.
2572 The Y component starts at zero and always increases but Y=0 may either
2573 indicate the top of the window or the bottom depending on the fragment
2574 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
2575 The Z coordinate ranges from 0 to 1 to represent depth from the front
2576 to the back of the Z buffer. The W component contains the reciprocol
2577 of the interpolated vertex position W component.
2579 Fragment shaders may also declare an output register with
2580 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
2581 the fragment shader to change the fragment's Z position.
2588 For vertex shader outputs or fragment shader inputs/outputs, this
2589 label indicates that the resister contains an R,G,B,A color.
2591 Several shader inputs/outputs may contain colors so the semantic index
2592 is used to distinguish them. For example, color[0] may be the diffuse
2593 color while color[1] may be the specular color.
2595 This label is needed so that the flat/smooth shading can be applied
2596 to the right interpolants during rasterization.
2600 TGSI_SEMANTIC_BCOLOR
2601 """"""""""""""""""""
2603 Back-facing colors are only used for back-facing polygons, and are only valid
2604 in vertex shader outputs. After rasterization, all polygons are front-facing
2605 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
2606 so all BCOLORs effectively become regular COLORs in the fragment shader.
2612 Vertex shader inputs and outputs and fragment shader inputs may be
2613 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
2614 a fog coordinate. Typically, the fragment shader will use the fog coordinate
2615 to compute a fog blend factor which is used to blend the normal fragment color
2616 with a constant fog color. But fog coord really is just an ordinary vec4
2617 register like regular semantics.
2623 Vertex shader input and output registers may be labeled with
2624 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
2625 in the form (S, 0, 0, 1). The point size controls the width or diameter
2626 of points for rasterization. This label cannot be used in fragment
2629 When using this semantic, be sure to set the appropriate state in the
2630 :ref:`rasterizer` first.
2633 TGSI_SEMANTIC_TEXCOORD
2634 """"""""""""""""""""""
2636 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2638 Vertex shader outputs and fragment shader inputs may be labeled with
2639 this semantic to make them replaceable by sprite coordinates via the
2640 sprite_coord_enable state in the :ref:`rasterizer`.
2641 The semantic index permitted with this semantic is limited to <= 7.
2643 If the driver does not support TEXCOORD, sprite coordinate replacement
2644 applies to inputs with the GENERIC semantic instead.
2646 The intended use case for this semantic is gl_TexCoord.
2649 TGSI_SEMANTIC_PCOORD
2650 """"""""""""""""""""
2652 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2654 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
2655 that the register contains sprite coordinates in the form (x, y, 0, 1), if
2656 the current primitive is a point and point sprites are enabled. Otherwise,
2657 the contents of the register are undefined.
2659 The intended use case for this semantic is gl_PointCoord.
2662 TGSI_SEMANTIC_GENERIC
2663 """""""""""""""""""""
2665 All vertex/fragment shader inputs/outputs not labeled with any other
2666 semantic label can be considered to be generic attributes. Typical
2667 uses of generic inputs/outputs are texcoords and user-defined values.
2670 TGSI_SEMANTIC_NORMAL
2671 """"""""""""""""""""
2673 Indicates that a vertex shader input is a normal vector. This is
2674 typically only used for legacy graphics APIs.
2680 This label applies to fragment shader inputs only and indicates that
2681 the register contains front/back-face information of the form (F, 0,
2682 0, 1). The first component will be positive when the fragment belongs
2683 to a front-facing polygon, and negative when the fragment belongs to a
2684 back-facing polygon.
2687 TGSI_SEMANTIC_EDGEFLAG
2688 """"""""""""""""""""""
2690 For vertex shaders, this sematic label indicates that an input or
2691 output is a boolean edge flag. The register layout is [F, x, x, x]
2692 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
2693 simply copies the edge flag input to the edgeflag output.
2695 Edge flags are used to control which lines or points are actually
2696 drawn when the polygon mode converts triangles/quads/polygons into
2700 TGSI_SEMANTIC_STENCIL
2701 """""""""""""""""""""
2703 For fragment shaders, this semantic label indicates that an output
2704 is a writable stencil reference value. Only the Y component is writable.
2705 This allows the fragment shader to change the fragments stencilref value.
2708 TGSI_SEMANTIC_VIEWPORT_INDEX
2709 """"""""""""""""""""""""""""
2711 For geometry shaders, this semantic label indicates that an output
2712 contains the index of the viewport (and scissor) to use.
2713 Only the X value is used.
2719 For geometry shaders, this semantic label indicates that an output
2720 contains the layer value to use for the color and depth/stencil surfaces.
2721 Only the X value is used. (Also known as rendertarget array index.)
2724 TGSI_SEMANTIC_CULLDIST
2725 """"""""""""""""""""""
2727 Used as distance to plane for performing application-defined culling
2728 of individual primitives against a plane. When components of vertex
2729 elements are given this label, these values are assumed to be a
2730 float32 signed distance to a plane. Primitives will be completely
2731 discarded if the plane distance for all of the vertices in the
2732 primitive are < 0. If a vertex has a cull distance of NaN, that
2733 vertex counts as "out" (as if its < 0);
2734 The limits on both clip and cull distances are bound
2735 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2736 the maximum number of components that can be used to hold the
2737 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2738 which specifies the maximum number of registers which can be
2739 annotated with those semantics.
2742 TGSI_SEMANTIC_CLIPDIST
2743 """"""""""""""""""""""
2745 When components of vertex elements are identified this way, these
2746 values are each assumed to be a float32 signed distance to a plane.
2747 Primitive setup only invokes rasterization on pixels for which
2748 the interpolated plane distances are >= 0. Multiple clip planes
2749 can be implemented simultaneously, by annotating multiple
2750 components of one or more vertex elements with the above specified
2751 semantic. The limits on both clip and cull distances are bound
2752 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2753 the maximum number of components that can be used to hold the
2754 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2755 which specifies the maximum number of registers which can be
2756 annotated with those semantics.
2758 TGSI_SEMANTIC_SAMPLEID
2759 """"""""""""""""""""""
2761 For fragment shaders, this semantic label indicates that a system value
2762 contains the current sample id (i.e. gl_SampleID). Only the X value is used.
2764 TGSI_SEMANTIC_SAMPLEPOS
2765 """""""""""""""""""""""
2767 For fragment shaders, this semantic label indicates that a system value
2768 contains the current sample's position (i.e. gl_SamplePosition). Only the X
2769 and Y values are used.
2771 TGSI_SEMANTIC_SAMPLEMASK
2772 """"""""""""""""""""""""
2774 For fragment shaders, this semantic label indicates that an output contains
2775 the sample mask used to disable further sample processing
2776 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
2778 TGSI_SEMANTIC_INVOCATIONID
2779 """"""""""""""""""""""""""
2781 For geometry shaders, this semantic label indicates that a system value
2782 contains the current invocation id (i.e. gl_InvocationID). Only the X value is
2785 Declaration Interpolate
2786 ^^^^^^^^^^^^^^^^^^^^^^^
2788 This token is only valid for fragment shader INPUT declarations.
2790 The Interpolate field specifes the way input is being interpolated by
2791 the rasteriser and is one of TGSI_INTERPOLATE_*.
2793 The Location field specifies the location inside the pixel that the
2794 interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
2795 when per-sample shading is enabled, the implementation may choose to
2796 interpolate at the sample irrespective of the Location field.
2798 The CylindricalWrap bitfield specifies which register components
2799 should be subject to cylindrical wrapping when interpolating by the
2800 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
2801 should be interpolated according to cylindrical wrapping rules.
2804 Declaration Sampler View
2805 ^^^^^^^^^^^^^^^^^^^^^^^^
2807 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
2809 DCL SVIEW[#], resource, type(s)
2811 Declares a shader input sampler view and assigns it to a SVIEW[#]
2814 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
2816 type must be 1 or 4 entries (if specifying on a per-component
2817 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
2820 Declaration Resource
2821 ^^^^^^^^^^^^^^^^^^^^
2823 Follows Declaration token if file is TGSI_FILE_RESOURCE.
2825 DCL RES[#], resource [, WR] [, RAW]
2827 Declares a shader input resource and assigns it to a RES[#]
2830 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
2833 If the RAW keyword is not specified, the texture data will be
2834 subject to conversion, swizzling and scaling as required to yield
2835 the specified data type from the physical data format of the bound
2838 If the RAW keyword is specified, no channel conversion will be
2839 performed: the values read for each of the channels (X,Y,Z,W) will
2840 correspond to consecutive words in the same order and format
2841 they're found in memory. No element-to-address conversion will be
2842 performed either: the value of the provided X coordinate will be
2843 interpreted in byte units instead of texel units. The result of
2844 accessing a misaligned address is undefined.
2846 Usage of the STORE opcode is only allowed if the WR (writable) flag
2851 ^^^^^^^^^^^^^^^^^^^^^^^^
2853 Properties are general directives that apply to the whole TGSI program.
2858 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
2859 The default value is UPPER_LEFT.
2861 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
2862 increase downward and rightward.
2863 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
2864 increase upward and rightward.
2866 OpenGL defaults to LOWER_LEFT, and is configurable with the
2867 GL_ARB_fragment_coord_conventions extension.
2869 DirectX 9/10 use UPPER_LEFT.
2871 FS_COORD_PIXEL_CENTER
2872 """""""""""""""""""""
2874 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
2875 The default value is HALF_INTEGER.
2877 If HALF_INTEGER, the fractionary part of the position will be 0.5
2878 If INTEGER, the fractionary part of the position will be 0.0
2880 Note that this does not affect the set of fragments generated by
2881 rasterization, which is instead controlled by half_pixel_center in the
2884 OpenGL defaults to HALF_INTEGER, and is configurable with the
2885 GL_ARB_fragment_coord_conventions extension.
2887 DirectX 9 uses INTEGER.
2888 DirectX 10 uses HALF_INTEGER.
2890 FS_COLOR0_WRITES_ALL_CBUFS
2891 """"""""""""""""""""""""""
2892 Specifies that writes to the fragment shader color 0 are replicated to all
2893 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
2894 fragData is directed to a single color buffer, but fragColor is broadcast.
2897 """"""""""""""""""""""""""
2898 If this property is set on the program bound to the shader stage before the
2899 fragment shader, user clip planes should have no effect (be disabled) even if
2900 that shader does not write to any clip distance outputs and the rasterizer's
2901 clip_plane_enable is non-zero.
2902 This property is only supported by drivers that also support shader clip
2904 This is useful for APIs that don't have UCPs and where clip distances written
2905 by a shader cannot be disabled.
2910 Specifies the number of times a geometry shader should be executed for each
2911 input primitive. Each invocation will have a different
2912 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
2915 VS_WINDOW_SPACE_POSITION
2916 """"""""""""""""""""""""""
2917 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
2918 is assumed to contain window space coordinates.
2919 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
2920 directly taken from the 4-th component of the shader output.
2921 Naturally, clipping is not performed on window coordinates either.
2922 The effect of this property is undefined if a geometry or tessellation shader
2925 Texture Sampling and Texture Formats
2926 ------------------------------------
2928 This table shows how texture image components are returned as (x,y,z,w) tuples
2929 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
2930 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
2933 +--------------------+--------------+--------------------+--------------+
2934 | Texture Components | Gallium | OpenGL | Direct3D 9 |
2935 +====================+==============+====================+==============+
2936 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
2937 +--------------------+--------------+--------------------+--------------+
2938 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
2939 +--------------------+--------------+--------------------+--------------+
2940 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
2941 +--------------------+--------------+--------------------+--------------+
2942 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
2943 +--------------------+--------------+--------------------+--------------+
2944 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
2945 +--------------------+--------------+--------------------+--------------+
2946 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
2947 +--------------------+--------------+--------------------+--------------+
2948 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
2949 +--------------------+--------------+--------------------+--------------+
2950 | I | (i, i, i, i) | (i, i, i, i) | N/A |
2951 +--------------------+--------------+--------------------+--------------+
2952 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
2953 | | | [#envmap-bumpmap]_ | |
2954 +--------------------+--------------+--------------------+--------------+
2955 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
2956 | | | [#depth-tex-mode]_ | |
2957 +--------------------+--------------+--------------------+--------------+
2958 | S | (s, s, s, s) | unknown | unknown |
2959 +--------------------+--------------+--------------------+--------------+
2961 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
2962 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
2963 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.