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:: SEQ - Set On Equal
483 dst.x = (src0.x == src1.x) ? 1.0F : 0.0F
485 dst.y = (src0.y == src1.y) ? 1.0F : 0.0F
487 dst.z = (src0.z == src1.z) ? 1.0F : 0.0F
489 dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
492 .. opcode:: SGT - Set On Greater Than
496 dst.x = (src0.x > src1.x) ? 1.0F : 0.0F
498 dst.y = (src0.y > src1.y) ? 1.0F : 0.0F
500 dst.z = (src0.z > src1.z) ? 1.0F : 0.0F
502 dst.w = (src0.w > src1.w) ? 1.0F : 0.0F
505 .. opcode:: SIN - Sine
507 This instruction replicates its result.
514 .. opcode:: SLE - Set On Less Equal Than
518 dst.x = (src0.x <= src1.x) ? 1.0F : 0.0F
520 dst.y = (src0.y <= src1.y) ? 1.0F : 0.0F
522 dst.z = (src0.z <= src1.z) ? 1.0F : 0.0F
524 dst.w = (src0.w <= src1.w) ? 1.0F : 0.0F
527 .. opcode:: SNE - Set On Not Equal
531 dst.x = (src0.x != src1.x) ? 1.0F : 0.0F
533 dst.y = (src0.y != src1.y) ? 1.0F : 0.0F
535 dst.z = (src0.z != src1.z) ? 1.0F : 0.0F
537 dst.w = (src0.w != src1.w) ? 1.0F : 0.0F
540 .. opcode:: STR - Set On True
542 This instruction replicates its result.
549 .. opcode:: TEX - Texture Lookup
551 for array textures src0.y contains the slice for 1D,
552 and src0.z contain the slice for 2D.
554 for shadow textures with no arrays (and not cube map),
555 src0.z contains the reference value.
557 for shadow textures with arrays, src0.z contains
558 the reference value for 1D arrays, and src0.w contains
559 the reference value for 2D arrays and cube maps.
561 for cube map array shadow textures, the reference value
562 cannot be passed in src0.w, and TEX2 must be used instead.
568 shadow_ref = src0.z or src0.w (optional)
572 dst = texture\_sample(unit, coord, shadow_ref)
575 .. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only)
577 this is the same as TEX, but uses another reg to encode the
588 dst = texture\_sample(unit, coord, shadow_ref)
593 .. opcode:: TXD - Texture Lookup with Derivatives
605 dst = texture\_sample\_deriv(unit, coord, ddx, ddy)
608 .. opcode:: TXP - Projective Texture Lookup
612 coord.x = src0.x / src0.w
614 coord.y = src0.y / src0.w
616 coord.z = src0.z / src0.w
622 dst = texture\_sample(unit, coord)
625 .. opcode:: UP2H - Unpack Two 16-Bit Floats
631 Considered for removal.
633 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
639 Considered for removal.
641 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
647 Considered for removal.
649 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
655 Considered for removal.
658 .. opcode:: ARR - Address Register Load With Round
671 .. opcode:: SSG - Set Sign
675 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
677 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
679 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
681 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
684 .. opcode:: CMP - Compare
688 dst.x = (src0.x < 0) ? src1.x : src2.x
690 dst.y = (src0.y < 0) ? src1.y : src2.y
692 dst.z = (src0.z < 0) ? src1.z : src2.z
694 dst.w = (src0.w < 0) ? src1.w : src2.w
697 .. opcode:: KILL_IF - Conditional Discard
699 Conditional discard. Allowed in fragment shaders only.
703 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
708 .. opcode:: KILL - Discard
710 Unconditional discard. Allowed in fragment shaders only.
713 .. opcode:: SCS - Sine Cosine
726 .. opcode:: TXB - Texture Lookup With Bias
728 for cube map array textures and shadow cube maps, the bias value
729 cannot be passed in src0.w, and TXB2 must be used instead.
731 if the target is a shadow texture, the reference value is always
732 in src.z (this prevents shadow 3d and shadow 2d arrays from
733 using this instruction, but this is not needed).
749 dst = texture\_sample(unit, coord, bias)
752 .. opcode:: TXB2 - Texture Lookup With Bias (some cube maps only)
754 this is the same as TXB, but uses another reg to encode the
755 lod bias value for cube map arrays and shadow cube maps.
756 Presumably shadow 2d arrays and shadow 3d targets could use
757 this encoding too, but this is not legal.
759 shadow cube map arrays are neither possible nor required.
769 dst = texture\_sample(unit, coord, bias)
772 .. opcode:: DIV - Divide
776 dst.x = \frac{src0.x}{src1.x}
778 dst.y = \frac{src0.y}{src1.y}
780 dst.z = \frac{src0.z}{src1.z}
782 dst.w = \frac{src0.w}{src1.w}
785 .. opcode:: DP2 - 2-component Dot Product
787 This instruction replicates its result.
791 dst = src0.x \times src1.x + src0.y \times src1.y
794 .. opcode:: TXL - Texture Lookup With explicit LOD
796 for cube map array textures, the explicit lod value
797 cannot be passed in src0.w, and TXL2 must be used instead.
799 if the target is a shadow texture, the reference value is always
800 in src.z (this prevents shadow 3d / 2d array / cube targets from
801 using this instruction, but this is not needed).
817 dst = texture\_sample(unit, coord, lod)
820 .. opcode:: TXL2 - Texture Lookup With explicit LOD (for cube map arrays only)
822 this is the same as TXL, but uses another reg to encode the
824 Presumably shadow 3d / 2d array / cube targets could use
825 this encoding too, but this is not legal.
827 shadow cube map arrays are neither possible nor required.
837 dst = texture\_sample(unit, coord, lod)
840 .. opcode:: PUSHA - Push Address Register On Stack
849 Considered for cleanup.
853 Considered for removal.
855 .. opcode:: POPA - Pop Address Register From Stack
864 Considered for cleanup.
868 Considered for removal.
871 .. opcode:: BRA - Branch
877 Considered for removal.
880 .. opcode:: CALLNZ - Subroutine Call If Not Zero
886 Considered for cleanup.
890 Considered for removal.
894 ^^^^^^^^^^^^^^^^^^^^^^^^
896 These opcodes are primarily provided for special-use computational shaders.
897 Support for these opcodes indicated by a special pipe capability bit (TBD).
899 XXX doesn't look like most of the opcodes really belong here.
901 .. opcode:: CEIL - Ceiling
905 dst.x = \lceil src.x\rceil
907 dst.y = \lceil src.y\rceil
909 dst.z = \lceil src.z\rceil
911 dst.w = \lceil src.w\rceil
914 .. opcode:: TRUNC - Truncate
927 .. opcode:: MOD - Modulus
931 dst.x = src0.x \bmod src1.x
933 dst.y = src0.y \bmod src1.y
935 dst.z = src0.z \bmod src1.z
937 dst.w = src0.w \bmod src1.w
940 .. opcode:: UARL - Integer Address Register Load
942 Moves the contents of the source register, assumed to be an integer, into the
943 destination register, which is assumed to be an address (ADDR) register.
946 .. opcode:: SAD - Sum Of Absolute Differences
950 dst.x = |src0.x - src1.x| + src2.x
952 dst.y = |src0.y - src1.y| + src2.y
954 dst.z = |src0.z - src1.z| + src2.z
956 dst.w = |src0.w - src1.w| + src2.w
959 .. opcode:: TXF - Texel Fetch
961 As per NV_gpu_shader4, extract a single texel from a specified texture
962 image. The source sampler may not be a CUBE or SHADOW. src 0 is a
963 four-component signed integer vector used to identify the single texel
964 accessed. 3 components + level. Just like texture instructions, an optional
965 offset vector is provided, which is subject to various driver restrictions
966 (regarding range, source of offsets).
967 TXF(uint_vec coord, int_vec offset).
970 .. opcode:: TXQ - Texture Size Query
972 As per NV_gpu_program4, retrieve the dimensions of the texture depending on
973 the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
974 depth), 1D array (width, layers), 2D array (width, height, layers).
975 Also return the number of accessible levels (last_level - first_level + 1)
978 For components which don't return a resource dimension, their value
986 dst.x = texture\_width(unit, lod)
988 dst.y = texture\_height(unit, lod)
990 dst.z = texture\_depth(unit, lod)
992 dst.w = texture\_levels(unit)
994 .. opcode:: TG4 - Texture Gather
996 As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
997 filtering operation and packs them into a single register. Only works with
998 2D, 2D array, cubemaps, and cubemaps arrays. For 2D textures, only the
999 addressing modes of the sampler and the top level of any mip pyramid are
1000 used. Set W to zero. It behaves like the TEX instruction, but a filtered
1001 sample is not generated. The four samples that contribute to filtering are
1002 placed into xyzw in clockwise order, starting with the (u,v) texture
1003 coordinate delta at the following locations (-, +), (+, +), (+, -), (-, -),
1004 where the magnitude of the deltas are half a texel.
1006 PIPE_CAP_TEXTURE_SM5 enhances this instruction to support shadow per-sample
1007 depth compares, single component selection, and a non-constant offset. It
1008 doesn't allow support for the GL independent offset to get i0,j0. This would
1009 require another CAP is hw can do it natively. For now we lower that before
1018 dst = texture\_gather4 (unit, coord, component)
1020 (with SM5 - cube array shadow)
1028 dst = texture\_gather (uint, coord, compare)
1030 .. opcode:: LODQ - level of detail query
1032 Compute the LOD information that the texture pipe would use to access the
1033 texture. The Y component contains the computed LOD lambda_prime. The X
1034 component contains the LOD that will be accessed, based on min/max lod's
1041 dst.xy = lodq(uint, coord);
1044 ^^^^^^^^^^^^^^^^^^^^^^^^
1045 These opcodes are used for integer operations.
1046 Support for these opcodes indicated by PIPE_SHADER_CAP_INTEGERS (all of them?)
1049 .. opcode:: I2F - Signed Integer To Float
1051 Rounding is unspecified (round to nearest even suggested).
1055 dst.x = (float) src.x
1057 dst.y = (float) src.y
1059 dst.z = (float) src.z
1061 dst.w = (float) src.w
1064 .. opcode:: U2F - Unsigned Integer To Float
1066 Rounding is unspecified (round to nearest even suggested).
1070 dst.x = (float) src.x
1072 dst.y = (float) src.y
1074 dst.z = (float) src.z
1076 dst.w = (float) src.w
1079 .. opcode:: F2I - Float to Signed Integer
1081 Rounding is towards zero (truncate).
1082 Values outside signed range (including NaNs) produce undefined results.
1095 .. opcode:: F2U - Float to Unsigned Integer
1097 Rounding is towards zero (truncate).
1098 Values outside unsigned range (including NaNs) produce undefined results.
1102 dst.x = (unsigned) src.x
1104 dst.y = (unsigned) src.y
1106 dst.z = (unsigned) src.z
1108 dst.w = (unsigned) src.w
1111 .. opcode:: UADD - Integer Add
1113 This instruction works the same for signed and unsigned integers.
1114 The low 32bit of the result is returned.
1118 dst.x = src0.x + src1.x
1120 dst.y = src0.y + src1.y
1122 dst.z = src0.z + src1.z
1124 dst.w = src0.w + src1.w
1127 .. opcode:: UMAD - Integer Multiply And Add
1129 This instruction works the same for signed and unsigned integers.
1130 The multiplication returns the low 32bit (as does the result itself).
1134 dst.x = src0.x \times src1.x + src2.x
1136 dst.y = src0.y \times src1.y + src2.y
1138 dst.z = src0.z \times src1.z + src2.z
1140 dst.w = src0.w \times src1.w + src2.w
1143 .. opcode:: UMUL - Integer Multiply
1145 This instruction works the same for signed and unsigned integers.
1146 The low 32bit of the result is returned.
1150 dst.x = src0.x \times src1.x
1152 dst.y = src0.y \times src1.y
1154 dst.z = src0.z \times src1.z
1156 dst.w = src0.w \times src1.w
1159 .. opcode:: IMUL_HI - Signed Integer Multiply High Bits
1161 The high 32bits of the multiplication of 2 signed integers are returned.
1165 dst.x = (src0.x \times src1.x) >> 32
1167 dst.y = (src0.y \times src1.y) >> 32
1169 dst.z = (src0.z \times src1.z) >> 32
1171 dst.w = (src0.w \times src1.w) >> 32
1174 .. opcode:: UMUL_HI - Unsigned Integer Multiply High Bits
1176 The high 32bits of the multiplication of 2 unsigned integers are returned.
1180 dst.x = (src0.x \times src1.x) >> 32
1182 dst.y = (src0.y \times src1.y) >> 32
1184 dst.z = (src0.z \times src1.z) >> 32
1186 dst.w = (src0.w \times src1.w) >> 32
1189 .. opcode:: IDIV - Signed Integer Division
1191 TBD: behavior for division by zero.
1195 dst.x = src0.x \ src1.x
1197 dst.y = src0.y \ src1.y
1199 dst.z = src0.z \ src1.z
1201 dst.w = src0.w \ src1.w
1204 .. opcode:: UDIV - Unsigned Integer Division
1206 For division by zero, 0xffffffff is returned.
1210 dst.x = src0.x \ src1.x
1212 dst.y = src0.y \ src1.y
1214 dst.z = src0.z \ src1.z
1216 dst.w = src0.w \ src1.w
1219 .. opcode:: UMOD - Unsigned Integer Remainder
1221 If second arg is zero, 0xffffffff is returned.
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:: NOT - Bitwise Not
1247 .. opcode:: AND - Bitwise And
1251 dst.x = src0.x \& src1.x
1253 dst.y = src0.y \& src1.y
1255 dst.z = src0.z \& src1.z
1257 dst.w = src0.w \& src1.w
1260 .. opcode:: OR - Bitwise Or
1264 dst.x = src0.x | src1.x
1266 dst.y = src0.y | src1.y
1268 dst.z = src0.z | src1.z
1270 dst.w = src0.w | src1.w
1273 .. opcode:: XOR - Bitwise Xor
1277 dst.x = src0.x \oplus src1.x
1279 dst.y = src0.y \oplus src1.y
1281 dst.z = src0.z \oplus src1.z
1283 dst.w = src0.w \oplus src1.w
1286 .. opcode:: IMAX - Maximum of Signed Integers
1290 dst.x = max(src0.x, src1.x)
1292 dst.y = max(src0.y, src1.y)
1294 dst.z = max(src0.z, src1.z)
1296 dst.w = max(src0.w, src1.w)
1299 .. opcode:: UMAX - Maximum of Unsigned Integers
1303 dst.x = max(src0.x, src1.x)
1305 dst.y = max(src0.y, src1.y)
1307 dst.z = max(src0.z, src1.z)
1309 dst.w = max(src0.w, src1.w)
1312 .. opcode:: IMIN - Minimum of Signed Integers
1316 dst.x = min(src0.x, src1.x)
1318 dst.y = min(src0.y, src1.y)
1320 dst.z = min(src0.z, src1.z)
1322 dst.w = min(src0.w, src1.w)
1325 .. opcode:: UMIN - Minimum of Unsigned Integers
1329 dst.x = min(src0.x, src1.x)
1331 dst.y = min(src0.y, src1.y)
1333 dst.z = min(src0.z, src1.z)
1335 dst.w = min(src0.w, src1.w)
1338 .. opcode:: SHL - Shift Left
1340 The shift count is masked with 0x1f before the shift is applied.
1344 dst.x = src0.x << (0x1f \& src1.x)
1346 dst.y = src0.y << (0x1f \& src1.y)
1348 dst.z = src0.z << (0x1f \& src1.z)
1350 dst.w = src0.w << (0x1f \& src1.w)
1353 .. opcode:: ISHR - Arithmetic Shift Right (of Signed Integer)
1355 The shift count is masked with 0x1f before the shift is applied.
1359 dst.x = src0.x >> (0x1f \& src1.x)
1361 dst.y = src0.y >> (0x1f \& src1.y)
1363 dst.z = src0.z >> (0x1f \& src1.z)
1365 dst.w = src0.w >> (0x1f \& src1.w)
1368 .. opcode:: USHR - Logical Shift Right
1370 The shift count is masked with 0x1f before the shift is applied.
1374 dst.x = src0.x >> (unsigned) (0x1f \& src1.x)
1376 dst.y = src0.y >> (unsigned) (0x1f \& src1.y)
1378 dst.z = src0.z >> (unsigned) (0x1f \& src1.z)
1380 dst.w = src0.w >> (unsigned) (0x1f \& src1.w)
1383 .. opcode:: UCMP - Integer Conditional Move
1387 dst.x = src0.x ? src1.x : src2.x
1389 dst.y = src0.y ? src1.y : src2.y
1391 dst.z = src0.z ? src1.z : src2.z
1393 dst.w = src0.w ? src1.w : src2.w
1397 .. opcode:: ISSG - Integer Set Sign
1401 dst.x = (src0.x < 0) ? -1 : (src0.x > 0) ? 1 : 0
1403 dst.y = (src0.y < 0) ? -1 : (src0.y > 0) ? 1 : 0
1405 dst.z = (src0.z < 0) ? -1 : (src0.z > 0) ? 1 : 0
1407 dst.w = (src0.w < 0) ? -1 : (src0.w > 0) ? 1 : 0
1411 .. opcode:: FSLT - Float Set On Less Than (ordered)
1413 Same comparison as SLT but returns integer instead of 1.0/0.0 float
1417 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1419 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1421 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1423 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1426 .. opcode:: ISLT - Signed Integer Set On Less Than
1430 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1432 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1434 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1436 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1439 .. opcode:: USLT - Unsigned Integer Set On Less Than
1443 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1445 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1447 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1449 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1452 .. opcode:: FSGE - Float Set On Greater Equal Than (ordered)
1454 Same comparison as SGE but returns integer instead of 1.0/0.0 float
1458 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1460 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1462 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1464 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1467 .. opcode:: ISGE - Signed Integer Set On Greater Equal Than
1471 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1473 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1475 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1477 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1480 .. opcode:: USGE - Unsigned Integer Set On Greater Equal Than
1484 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1486 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1488 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1490 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1493 .. opcode:: FSEQ - Float Set On Equal (ordered)
1495 Same comparison as SEQ but returns integer instead of 1.0/0.0 float
1499 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1501 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1503 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1505 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1508 .. opcode:: USEQ - Integer Set On Equal
1512 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1514 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1516 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1518 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1521 .. opcode:: FSNE - Float Set On Not Equal (unordered)
1523 Same comparison as SNE but returns integer instead of 1.0/0.0 float
1527 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1529 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1531 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1533 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1536 .. opcode:: USNE - Integer Set On Not Equal
1540 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1542 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1544 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1546 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1549 .. opcode:: INEG - Integer Negate
1564 .. opcode:: IABS - Integer Absolute Value
1578 These opcodes are used for bit-level manipulation of integers.
1580 .. opcode:: IBFE - Signed Bitfield Extract
1582 See SM5 instruction of the same name. Extracts a set of bits from the input,
1583 and sign-extends them if the high bit of the extracted window is set.
1587 def ibfe(value, offset, bits):
1588 offset = offset & 0x1f
1590 if bits == 0: return 0
1591 # Note: >> sign-extends
1592 if width + offset < 32:
1593 return (value << (32 - offset - bits)) >> (32 - bits)
1595 return value >> offset
1597 .. opcode:: UBFE - Unsigned Bitfield Extract
1599 See SM5 instruction of the same name. Extracts a set of bits from the input,
1600 without any sign-extension.
1604 def ubfe(value, offset, bits):
1605 offset = offset & 0x1f
1607 if bits == 0: return 0
1608 # Note: >> does not sign-extend
1609 if width + offset < 32:
1610 return (value << (32 - offset - bits)) >> (32 - bits)
1612 return value >> offset
1614 .. opcode:: BFI - Bitfield Insert
1616 See SM5 instruction of the same name. Replaces a bit region of 'base' with
1617 the low bits of 'insert'.
1621 def bfi(base, insert, offset, bits):
1622 offset = offset & 0x1f
1624 mask = ((1 << bits) - 1) << offset
1625 return ((insert << offset) & mask) | (base & ~mask)
1627 .. opcode:: BREV - Bitfield Reverse
1629 See SM5 instruction BFREV. Reverses the bits of the argument.
1631 .. opcode:: POPC - Population Count
1633 See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
1635 .. opcode:: LSB - Index of lowest set bit
1637 See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
1638 bit of the argument. Returns -1 if none are set.
1640 .. opcode:: IMSB - Index of highest non-sign bit
1642 See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
1643 non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
1644 highest 1 bit for positive numbers). Returns -1 if all bits are the same
1645 (i.e. for inputs 0 and -1).
1647 .. opcode:: UMSB - Index of highest set bit
1649 See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
1650 set bit of the argument. Returns -1 if none are set.
1653 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1655 These opcodes are only supported in geometry shaders; they have no meaning
1656 in any other type of shader.
1658 .. opcode:: EMIT - Emit
1660 Generate a new vertex for the current primitive into the specified vertex
1661 stream using the values in the output registers.
1664 .. opcode:: ENDPRIM - End Primitive
1666 Complete the current primitive in the specified vertex stream (consisting of
1667 the emitted vertices), and start a new one.
1673 These opcodes are part of :term:`GLSL`'s opcode set. Support for these
1674 opcodes is determined by a special capability bit, ``GLSL``.
1675 Some require glsl version 1.30 (UIF/BREAKC/SWITCH/CASE/DEFAULT/ENDSWITCH).
1677 .. opcode:: CAL - Subroutine Call
1683 .. opcode:: RET - Subroutine Call Return
1688 .. opcode:: CONT - Continue
1690 Unconditionally moves the point of execution to the instruction after the
1691 last bgnloop. The instruction must appear within a bgnloop/endloop.
1695 Support for CONT is determined by a special capability bit,
1696 ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
1699 .. opcode:: BGNLOOP - Begin a Loop
1701 Start a loop. Must have a matching endloop.
1704 .. opcode:: BGNSUB - Begin Subroutine
1706 Starts definition of a subroutine. Must have a matching endsub.
1709 .. opcode:: ENDLOOP - End a Loop
1711 End a loop started with bgnloop.
1714 .. opcode:: ENDSUB - End Subroutine
1716 Ends definition of a subroutine.
1719 .. opcode:: NOP - No Operation
1724 .. opcode:: BRK - Break
1726 Unconditionally moves the point of execution to the instruction after the
1727 next endloop or endswitch. The instruction must appear within a loop/endloop
1728 or switch/endswitch.
1731 .. opcode:: BREAKC - Break Conditional
1733 Conditionally moves the point of execution to the instruction after the
1734 next endloop or endswitch. The instruction must appear within a loop/endloop
1735 or switch/endswitch.
1736 Condition evaluates to true if src0.x != 0 where src0.x is interpreted
1737 as an integer register.
1741 Considered for removal as it's quite inconsistent wrt other opcodes
1742 (could emulate with UIF/BRK/ENDIF).
1745 .. opcode:: IF - Float If
1747 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
1751 where src0.x is interpreted as a floating point register.
1754 .. opcode:: UIF - Bitwise If
1756 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
1760 where src0.x is interpreted as an integer register.
1763 .. opcode:: ELSE - Else
1765 Starts an else block, after an IF or UIF statement.
1768 .. opcode:: ENDIF - End If
1770 Ends an IF or UIF block.
1773 .. opcode:: SWITCH - Switch
1775 Starts a C-style switch expression. The switch consists of one or multiple
1776 CASE statements, and at most one DEFAULT statement. Execution of a statement
1777 ends when a BRK is hit, but just like in C falling through to other cases
1778 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
1779 just as last statement, and fallthrough is allowed into/from it.
1780 CASE src arguments are evaluated at bit level against the SWITCH src argument.
1786 (some instructions here)
1789 (some instructions here)
1792 (some instructions here)
1797 .. opcode:: CASE - Switch case
1799 This represents a switch case label. The src arg must be an integer immediate.
1802 .. opcode:: DEFAULT - Switch default
1804 This represents the default case in the switch, which is taken if no other
1808 .. opcode:: ENDSWITCH - End of switch
1810 Ends a switch expression.
1816 The interpolation instructions allow an input to be interpolated in a
1817 different way than its declaration. This corresponds to the GLSL 4.00
1818 interpolateAt* functions. The first argument of each of these must come from
1819 ``TGSI_FILE_INPUT``.
1821 .. opcode:: INTERP_CENTROID - Interpolate at the centroid
1823 Interpolates the varying specified by src0 at the centroid
1825 .. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
1827 Interpolates the varying specified by src0 at the sample id specified by
1828 src1.x (interpreted as an integer)
1830 .. opcode:: INTERP_OFFSET - Interpolate at the specified offset
1832 Interpolates the varying specified by src0 at the offset src1.xy from the
1833 pixel center (interpreted as floats)
1841 The double-precision opcodes reinterpret four-component vectors into
1842 two-component vectors with doubled precision in each component.
1844 Support for these opcodes is XXX undecided. :T
1846 .. opcode:: DADD - Add
1850 dst.xy = src0.xy + src1.xy
1852 dst.zw = src0.zw + src1.zw
1855 .. opcode:: DDIV - Divide
1859 dst.xy = src0.xy / src1.xy
1861 dst.zw = src0.zw / src1.zw
1863 .. opcode:: DSEQ - Set on Equal
1867 dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
1869 dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
1871 .. opcode:: DSLT - Set on Less than
1875 dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
1877 dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
1879 .. opcode:: DFRAC - Fraction
1883 dst.xy = src.xy - \lfloor src.xy\rfloor
1885 dst.zw = src.zw - \lfloor src.zw\rfloor
1888 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1890 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1891 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1892 :math:`dst1 \times 2^{dst0} = src` .
1896 dst0.xy = exp(src.xy)
1898 dst1.xy = frac(src.xy)
1900 dst0.zw = exp(src.zw)
1902 dst1.zw = frac(src.zw)
1904 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1906 This opcode is the inverse of :opcode:`DFRACEXP`.
1910 dst.xy = src0.xy \times 2^{src1.xy}
1912 dst.zw = src0.zw \times 2^{src1.zw}
1914 .. opcode:: DMIN - Minimum
1918 dst.xy = min(src0.xy, src1.xy)
1920 dst.zw = min(src0.zw, src1.zw)
1922 .. opcode:: DMAX - Maximum
1926 dst.xy = max(src0.xy, src1.xy)
1928 dst.zw = max(src0.zw, src1.zw)
1930 .. opcode:: DMUL - Multiply
1934 dst.xy = src0.xy \times src1.xy
1936 dst.zw = src0.zw \times src1.zw
1939 .. opcode:: DMAD - Multiply And Add
1943 dst.xy = src0.xy \times src1.xy + src2.xy
1945 dst.zw = src0.zw \times src1.zw + src2.zw
1948 .. opcode:: DRCP - Reciprocal
1952 dst.xy = \frac{1}{src.xy}
1954 dst.zw = \frac{1}{src.zw}
1956 .. opcode:: DSQRT - Square Root
1960 dst.xy = \sqrt{src.xy}
1962 dst.zw = \sqrt{src.zw}
1965 .. _samplingopcodes:
1967 Resource Sampling Opcodes
1968 ^^^^^^^^^^^^^^^^^^^^^^^^^
1970 Those opcodes follow very closely semantics of the respective Direct3D
1971 instructions. If in doubt double check Direct3D documentation.
1972 Note that the swizzle on SVIEW (src1) determines texel swizzling
1977 Using provided address, sample data from the specified texture using the
1978 filtering mode identified by the gven sampler. The source data may come from
1979 any resource type other than buffers.
1981 Syntax: ``SAMPLE dst, address, sampler_view, sampler``
1983 Example: ``SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]``
1985 .. opcode:: SAMPLE_I
1987 Simplified alternative to the SAMPLE instruction. Using the provided
1988 integer address, SAMPLE_I fetches data from the specified sampler view
1989 without any filtering. The source data may come from any resource type
1992 Syntax: ``SAMPLE_I dst, address, sampler_view``
1994 Example: ``SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]``
1996 The 'address' is specified as unsigned integers. If the 'address' is out of
1997 range [0...(# texels - 1)] the result of the fetch is always 0 in all
1998 components. As such the instruction doesn't honor address wrap modes, in
1999 cases where that behavior is desirable 'SAMPLE' instruction should be used.
2000 address.w always provides an unsigned integer mipmap level. If the value is
2001 out of the range then the instruction always returns 0 in all components.
2002 address.yz are ignored for buffers and 1d textures. address.z is ignored
2003 for 1d texture arrays and 2d textures.
2005 For 1D texture arrays address.y provides the array index (also as unsigned
2006 integer). If the value is out of the range of available array indices
2007 [0... (array size - 1)] then the opcode always returns 0 in all components.
2008 For 2D texture arrays address.z provides the array index, otherwise it
2009 exhibits the same behavior as in the case for 1D texture arrays. The exact
2010 semantics of the source address are presented in the table below:
2012 +---------------------------+----+-----+-----+---------+
2013 | resource type | X | Y | Z | W |
2014 +===========================+====+=====+=====+=========+
2015 | ``PIPE_BUFFER`` | x | | | ignored |
2016 +---------------------------+----+-----+-----+---------+
2017 | ``PIPE_TEXTURE_1D`` | x | | | mpl |
2018 +---------------------------+----+-----+-----+---------+
2019 | ``PIPE_TEXTURE_2D`` | x | y | | mpl |
2020 +---------------------------+----+-----+-----+---------+
2021 | ``PIPE_TEXTURE_3D`` | x | y | z | mpl |
2022 +---------------------------+----+-----+-----+---------+
2023 | ``PIPE_TEXTURE_RECT`` | x | y | | mpl |
2024 +---------------------------+----+-----+-----+---------+
2025 | ``PIPE_TEXTURE_CUBE`` | not allowed as source |
2026 +---------------------------+----+-----+-----+---------+
2027 | ``PIPE_TEXTURE_1D_ARRAY`` | x | idx | | mpl |
2028 +---------------------------+----+-----+-----+---------+
2029 | ``PIPE_TEXTURE_2D_ARRAY`` | x | y | idx | mpl |
2030 +---------------------------+----+-----+-----+---------+
2032 Where 'mpl' is a mipmap level and 'idx' is the array index.
2034 .. opcode:: SAMPLE_I_MS
2036 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2038 Syntax: ``SAMPLE_I_MS dst, address, sampler_view, sample``
2040 .. opcode:: SAMPLE_B
2042 Just like the SAMPLE instruction with the exception that an additional bias
2043 is applied to the level of detail computed as part of the instruction
2046 Syntax: ``SAMPLE_B dst, address, sampler_view, sampler, lod_bias``
2048 Example: ``SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2050 .. opcode:: SAMPLE_C
2052 Similar to the SAMPLE instruction but it performs a comparison filter. The
2053 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2054 additional float32 operand, reference value, which must be a register with
2055 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2056 current samplers compare_func (in pipe_sampler_state) to compare reference
2057 value against the red component value for the surce resource at each texel
2058 that the currently configured texture filter covers based on the provided
2061 Syntax: ``SAMPLE_C dst, address, sampler_view.r, sampler, ref_value``
2063 Example: ``SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2065 .. opcode:: SAMPLE_C_LZ
2067 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2070 Syntax: ``SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value``
2072 Example: ``SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2075 .. opcode:: SAMPLE_D
2077 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2078 the source address in the x direction and the y direction are provided by
2081 Syntax: ``SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y``
2083 Example: ``SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]``
2085 .. opcode:: SAMPLE_L
2087 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2088 directly as a scalar value, representing no anisotropy.
2090 Syntax: ``SAMPLE_L dst, address, sampler_view, sampler, explicit_lod``
2092 Example: ``SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2096 Gathers the four texels to be used in a bi-linear filtering operation and
2097 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2098 and cubemaps arrays. For 2D textures, only the addressing modes of the
2099 sampler and the top level of any mip pyramid are used. Set W to zero. It
2100 behaves like the SAMPLE instruction, but a filtered sample is not
2101 generated. The four samples that contribute to filtering are placed into
2102 xyzw in counter-clockwise order, starting with the (u,v) texture coordinate
2103 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2104 magnitude of the deltas are half a texel.
2107 .. opcode:: SVIEWINFO
2109 Query the dimensions of a given sampler view. dst receives width, height,
2110 depth or array size and number of mipmap levels as int4. The dst can have a
2111 writemask which will specify what info is the caller interested in.
2113 Syntax: ``SVIEWINFO dst, src_mip_level, sampler_view``
2115 Example: ``SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]``
2117 src_mip_level is an unsigned integer scalar. If it's out of range then
2118 returns 0 for width, height and depth/array size but the total number of
2119 mipmap is still returned correctly for the given sampler view. The returned
2120 width, height and depth values are for the mipmap level selected by the
2121 src_mip_level and are in the number of texels. For 1d texture array width
2122 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2123 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2124 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2125 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2126 resinfo allowing swizzling dst values is ignored (due to the interaction
2127 with rcpfloat modifier which requires some swizzle handling in the state
2130 .. opcode:: SAMPLE_POS
2132 Query the position of a given sample. dst receives float4 (x, y, 0, 0)
2133 indicated where the sample is located. If the resource is not a multi-sample
2134 resource and not a render target, the result is 0.
2136 .. opcode:: SAMPLE_INFO
2138 dst receives number of samples in x. If the resource is not a multi-sample
2139 resource and not a render target, the result is 0.
2142 .. _resourceopcodes:
2144 Resource Access Opcodes
2145 ^^^^^^^^^^^^^^^^^^^^^^^
2147 .. opcode:: LOAD - Fetch data from a shader resource
2149 Syntax: ``LOAD dst, resource, address``
2151 Example: ``LOAD TEMP[0], RES[0], TEMP[1]``
2153 Using the provided integer address, LOAD fetches data
2154 from the specified buffer or texture without any
2157 The 'address' is specified as a vector of unsigned
2158 integers. If the 'address' is out of range the result
2161 Only the first mipmap level of a resource can be read
2162 from using this instruction.
2164 For 1D or 2D texture arrays, the array index is
2165 provided as an unsigned integer in address.y or
2166 address.z, respectively. address.yz are ignored for
2167 buffers and 1D textures. address.z is ignored for 1D
2168 texture arrays and 2D textures. address.w is always
2171 .. opcode:: STORE - Write data to a shader resource
2173 Syntax: ``STORE resource, address, src``
2175 Example: ``STORE RES[0], TEMP[0], TEMP[1]``
2177 Using the provided integer address, STORE writes data
2178 to the specified buffer or texture.
2180 The 'address' is specified as a vector of unsigned
2181 integers. If the 'address' is out of range the result
2184 Only the first mipmap level of a resource can be
2185 written to using this instruction.
2187 For 1D or 2D texture arrays, the array index is
2188 provided as an unsigned integer in address.y or
2189 address.z, respectively. address.yz are ignored for
2190 buffers and 1D textures. address.z is ignored for 1D
2191 texture arrays and 2D textures. address.w is always
2195 .. _threadsyncopcodes:
2197 Inter-thread synchronization opcodes
2198 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2200 These opcodes are intended for communication between threads running
2201 within the same compute grid. For now they're only valid in compute
2204 .. opcode:: MFENCE - Memory fence
2206 Syntax: ``MFENCE resource``
2208 Example: ``MFENCE RES[0]``
2210 This opcode forces strong ordering between any memory access
2211 operations that affect the specified resource. This means that
2212 previous loads and stores (and only those) will be performed and
2213 visible to other threads before the program execution continues.
2216 .. opcode:: LFENCE - Load memory fence
2218 Syntax: ``LFENCE resource``
2220 Example: ``LFENCE RES[0]``
2222 Similar to MFENCE, but it only affects the ordering of memory loads.
2225 .. opcode:: SFENCE - Store memory fence
2227 Syntax: ``SFENCE resource``
2229 Example: ``SFENCE RES[0]``
2231 Similar to MFENCE, but it only affects the ordering of memory stores.
2234 .. opcode:: BARRIER - Thread group barrier
2238 This opcode suspends the execution of the current thread until all
2239 the remaining threads in the working group reach the same point of
2240 the program. Results are unspecified if any of the remaining
2241 threads terminates or never reaches an executed BARRIER instruction.
2249 These opcodes provide atomic variants of some common arithmetic and
2250 logical operations. In this context atomicity means that another
2251 concurrent memory access operation that affects the same memory
2252 location is guaranteed to be performed strictly before or after the
2253 entire execution of the atomic operation.
2255 For the moment they're only valid in compute programs.
2257 .. opcode:: ATOMUADD - Atomic integer addition
2259 Syntax: ``ATOMUADD dst, resource, offset, src``
2261 Example: ``ATOMUADD TEMP[0], RES[0], TEMP[1], TEMP[2]``
2263 The following operation is performed atomically on each component:
2267 dst_i = resource[offset]_i
2269 resource[offset]_i = dst_i + src_i
2272 .. opcode:: ATOMXCHG - Atomic exchange
2274 Syntax: ``ATOMXCHG dst, resource, offset, src``
2276 Example: ``ATOMXCHG TEMP[0], RES[0], TEMP[1], TEMP[2]``
2278 The following operation is performed atomically on each component:
2282 dst_i = resource[offset]_i
2284 resource[offset]_i = src_i
2287 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2289 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
2291 Example: ``ATOMCAS TEMP[0], RES[0], TEMP[1], TEMP[2], TEMP[3]``
2293 The following operation is performed atomically on each component:
2297 dst_i = resource[offset]_i
2299 resource[offset]_i = (dst_i == cmp_i ? src_i : dst_i)
2302 .. opcode:: ATOMAND - Atomic bitwise And
2304 Syntax: ``ATOMAND dst, resource, offset, src``
2306 Example: ``ATOMAND 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 = dst_i \& src_i
2317 .. opcode:: ATOMOR - Atomic bitwise Or
2319 Syntax: ``ATOMOR dst, resource, offset, src``
2321 Example: ``ATOMOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2323 The following operation is performed atomically on each component:
2327 dst_i = resource[offset]_i
2329 resource[offset]_i = dst_i | src_i
2332 .. opcode:: ATOMXOR - Atomic bitwise Xor
2334 Syntax: ``ATOMXOR dst, resource, offset, src``
2336 Example: ``ATOMXOR 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 \oplus src_i
2347 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2349 Syntax: ``ATOMUMIN dst, resource, offset, src``
2351 Example: ``ATOMUMIN 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 ? dst_i : src_i)
2362 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2364 Syntax: ``ATOMUMAX dst, resource, offset, src``
2366 Example: ``ATOMUMAX 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 > src_i ? dst_i : src_i)
2377 .. opcode:: ATOMIMIN - Atomic signed minimum
2379 Syntax: ``ATOMIMIN dst, resource, offset, src``
2381 Example: ``ATOMIMIN 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:: ATOMIMAX - Atomic signed maximum
2394 Syntax: ``ATOMIMAX dst, resource, offset, src``
2396 Example: ``ATOMIMAX 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)
2408 Explanation of symbols used
2409 ------------------------------
2416 :math:`|x|` Absolute value of `x`.
2418 :math:`\lceil x \rceil` Ceiling of `x`.
2420 clamp(x,y,z) Clamp x between y and z.
2421 (x < y) ? y : (x > z) ? z : x
2423 :math:`\lfloor x\rfloor` Floor of `x`.
2425 :math:`\log_2{x}` Logarithm of `x`, base 2.
2427 max(x,y) Maximum of x and y.
2430 min(x,y) Minimum of x and y.
2433 partialx(x) Derivative of x relative to fragment's X.
2435 partialy(x) Derivative of x relative to fragment's Y.
2437 pop() Pop from stack.
2439 :math:`x^y` `x` to the power `y`.
2441 push(x) Push x on stack.
2445 trunc(x) Truncate x, i.e. drop the fraction bits.
2452 discard Discard fragment.
2456 target Label of target instruction.
2467 Declares a register that is will be referenced as an operand in Instruction
2470 File field contains register file that is being declared and is one
2473 UsageMask field specifies which of the register components can be accessed
2474 and is one of TGSI_WRITEMASK.
2476 The Local flag specifies that a given value isn't intended for
2477 subroutine parameter passing and, as a result, the implementation
2478 isn't required to give any guarantees of it being preserved across
2479 subroutine boundaries. As it's merely a compiler hint, the
2480 implementation is free to ignore it.
2482 If Dimension flag is set to 1, a Declaration Dimension token follows.
2484 If Semantic flag is set to 1, a Declaration Semantic token follows.
2486 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
2488 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
2490 If Array flag is set to 1, a Declaration Array token follows.
2493 ^^^^^^^^^^^^^^^^^^^^^^^^
2495 Declarations can optional have an ArrayID attribute which can be referred by
2496 indirect addressing operands. An ArrayID of zero is reserved and treaded as
2497 if no ArrayID is specified.
2499 If an indirect addressing operand refers to a specific declaration by using
2500 an ArrayID only the registers in this declaration are guaranteed to be
2501 accessed, accessing any register outside this declaration results in undefined
2502 behavior. Note that for compatibility the effective index is zero-based and
2503 not relative to the specified declaration
2505 If no ArrayID is specified with an indirect addressing operand the whole
2506 register file might be accessed by this operand. This is strongly discouraged
2507 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
2509 Declaration Semantic
2510 ^^^^^^^^^^^^^^^^^^^^^^^^
2512 Vertex and fragment shader input and output registers may be labeled
2513 with semantic information consisting of a name and index.
2515 Follows Declaration token if Semantic bit is set.
2517 Since its purpose is to link a shader with other stages of the pipeline,
2518 it is valid to follow only those Declaration tokens that declare a register
2519 either in INPUT or OUTPUT file.
2521 SemanticName field contains the semantic name of the register being declared.
2522 There is no default value.
2524 SemanticIndex is an optional subscript that can be used to distinguish
2525 different register declarations with the same semantic name. The default value
2528 The meanings of the individual semantic names are explained in the following
2531 TGSI_SEMANTIC_POSITION
2532 """"""""""""""""""""""
2534 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
2535 output register which contains the homogeneous vertex position in the clip
2536 space coordinate system. After clipping, the X, Y and Z components of the
2537 vertex will be divided by the W value to get normalized device coordinates.
2539 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
2540 fragment shader input contains the fragment's window position. The X
2541 component starts at zero and always increases from left to right.
2542 The Y component starts at zero and always increases but Y=0 may either
2543 indicate the top of the window or the bottom depending on the fragment
2544 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
2545 The Z coordinate ranges from 0 to 1 to represent depth from the front
2546 to the back of the Z buffer. The W component contains the reciprocol
2547 of the interpolated vertex position W component.
2549 Fragment shaders may also declare an output register with
2550 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
2551 the fragment shader to change the fragment's Z position.
2558 For vertex shader outputs or fragment shader inputs/outputs, this
2559 label indicates that the resister contains an R,G,B,A color.
2561 Several shader inputs/outputs may contain colors so the semantic index
2562 is used to distinguish them. For example, color[0] may be the diffuse
2563 color while color[1] may be the specular color.
2565 This label is needed so that the flat/smooth shading can be applied
2566 to the right interpolants during rasterization.
2570 TGSI_SEMANTIC_BCOLOR
2571 """"""""""""""""""""
2573 Back-facing colors are only used for back-facing polygons, and are only valid
2574 in vertex shader outputs. After rasterization, all polygons are front-facing
2575 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
2576 so all BCOLORs effectively become regular COLORs in the fragment shader.
2582 Vertex shader inputs and outputs and fragment shader inputs may be
2583 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
2584 a fog coordinate. Typically, the fragment shader will use the fog coordinate
2585 to compute a fog blend factor which is used to blend the normal fragment color
2586 with a constant fog color. But fog coord really is just an ordinary vec4
2587 register like regular semantics.
2593 Vertex shader input and output registers may be labeled with
2594 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
2595 in the form (S, 0, 0, 1). The point size controls the width or diameter
2596 of points for rasterization. This label cannot be used in fragment
2599 When using this semantic, be sure to set the appropriate state in the
2600 :ref:`rasterizer` first.
2603 TGSI_SEMANTIC_TEXCOORD
2604 """"""""""""""""""""""
2606 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2608 Vertex shader outputs and fragment shader inputs may be labeled with
2609 this semantic to make them replaceable by sprite coordinates via the
2610 sprite_coord_enable state in the :ref:`rasterizer`.
2611 The semantic index permitted with this semantic is limited to <= 7.
2613 If the driver does not support TEXCOORD, sprite coordinate replacement
2614 applies to inputs with the GENERIC semantic instead.
2616 The intended use case for this semantic is gl_TexCoord.
2619 TGSI_SEMANTIC_PCOORD
2620 """"""""""""""""""""
2622 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2624 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
2625 that the register contains sprite coordinates in the form (x, y, 0, 1), if
2626 the current primitive is a point and point sprites are enabled. Otherwise,
2627 the contents of the register are undefined.
2629 The intended use case for this semantic is gl_PointCoord.
2632 TGSI_SEMANTIC_GENERIC
2633 """""""""""""""""""""
2635 All vertex/fragment shader inputs/outputs not labeled with any other
2636 semantic label can be considered to be generic attributes. Typical
2637 uses of generic inputs/outputs are texcoords and user-defined values.
2640 TGSI_SEMANTIC_NORMAL
2641 """"""""""""""""""""
2643 Indicates that a vertex shader input is a normal vector. This is
2644 typically only used for legacy graphics APIs.
2650 This label applies to fragment shader inputs only and indicates that
2651 the register contains front/back-face information of the form (F, 0,
2652 0, 1). The first component will be positive when the fragment belongs
2653 to a front-facing polygon, and negative when the fragment belongs to a
2654 back-facing polygon.
2657 TGSI_SEMANTIC_EDGEFLAG
2658 """"""""""""""""""""""
2660 For vertex shaders, this sematic label indicates that an input or
2661 output is a boolean edge flag. The register layout is [F, x, x, x]
2662 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
2663 simply copies the edge flag input to the edgeflag output.
2665 Edge flags are used to control which lines or points are actually
2666 drawn when the polygon mode converts triangles/quads/polygons into
2670 TGSI_SEMANTIC_STENCIL
2671 """""""""""""""""""""
2673 For fragment shaders, this semantic label indicates that an output
2674 is a writable stencil reference value. Only the Y component is writable.
2675 This allows the fragment shader to change the fragments stencilref value.
2678 TGSI_SEMANTIC_VIEWPORT_INDEX
2679 """"""""""""""""""""""""""""
2681 For geometry shaders, this semantic label indicates that an output
2682 contains the index of the viewport (and scissor) to use.
2683 Only the X value is used.
2689 For geometry shaders, this semantic label indicates that an output
2690 contains the layer value to use for the color and depth/stencil surfaces.
2691 Only the X value is used. (Also known as rendertarget array index.)
2694 TGSI_SEMANTIC_CULLDIST
2695 """"""""""""""""""""""
2697 Used as distance to plane for performing application-defined culling
2698 of individual primitives against a plane. When components of vertex
2699 elements are given this label, these values are assumed to be a
2700 float32 signed distance to a plane. Primitives will be completely
2701 discarded if the plane distance for all of the vertices in the
2702 primitive are < 0. If a vertex has a cull distance of NaN, that
2703 vertex counts as "out" (as if its < 0);
2704 The limits on both clip and cull distances are bound
2705 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2706 the maximum number of components that can be used to hold the
2707 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2708 which specifies the maximum number of registers which can be
2709 annotated with those semantics.
2712 TGSI_SEMANTIC_CLIPDIST
2713 """"""""""""""""""""""
2715 When components of vertex elements are identified this way, these
2716 values are each assumed to be a float32 signed distance to a plane.
2717 Primitive setup only invokes rasterization on pixels for which
2718 the interpolated plane distances are >= 0. Multiple clip planes
2719 can be implemented simultaneously, by annotating multiple
2720 components of one or more vertex elements with the above specified
2721 semantic. The limits on both clip and cull distances are bound
2722 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2723 the maximum number of components that can be used to hold the
2724 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2725 which specifies the maximum number of registers which can be
2726 annotated with those semantics.
2728 TGSI_SEMANTIC_SAMPLEID
2729 """"""""""""""""""""""
2731 For fragment shaders, this semantic label indicates that a system value
2732 contains the current sample id (i.e. gl_SampleID). Only the X value is used.
2734 TGSI_SEMANTIC_SAMPLEPOS
2735 """""""""""""""""""""""
2737 For fragment shaders, this semantic label indicates that a system value
2738 contains the current sample's position (i.e. gl_SamplePosition). Only the X
2739 and Y values are used.
2741 TGSI_SEMANTIC_SAMPLEMASK
2742 """"""""""""""""""""""""
2744 For fragment shaders, this semantic label indicates that an output contains
2745 the sample mask used to disable further sample processing
2746 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
2748 TGSI_SEMANTIC_INVOCATIONID
2749 """"""""""""""""""""""""""
2751 For geometry shaders, this semantic label indicates that a system value
2752 contains the current invocation id (i.e. gl_InvocationID). Only the X value is
2755 Declaration Interpolate
2756 ^^^^^^^^^^^^^^^^^^^^^^^
2758 This token is only valid for fragment shader INPUT declarations.
2760 The Interpolate field specifes the way input is being interpolated by
2761 the rasteriser and is one of TGSI_INTERPOLATE_*.
2763 The Location field specifies the location inside the pixel that the
2764 interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
2765 when per-sample shading is enabled, the implementation may choose to
2766 interpolate at the sample irrespective of the Location field.
2768 The CylindricalWrap bitfield specifies which register components
2769 should be subject to cylindrical wrapping when interpolating by the
2770 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
2771 should be interpolated according to cylindrical wrapping rules.
2774 Declaration Sampler View
2775 ^^^^^^^^^^^^^^^^^^^^^^^^
2777 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
2779 DCL SVIEW[#], resource, type(s)
2781 Declares a shader input sampler view and assigns it to a SVIEW[#]
2784 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
2786 type must be 1 or 4 entries (if specifying on a per-component
2787 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
2790 Declaration Resource
2791 ^^^^^^^^^^^^^^^^^^^^
2793 Follows Declaration token if file is TGSI_FILE_RESOURCE.
2795 DCL RES[#], resource [, WR] [, RAW]
2797 Declares a shader input resource and assigns it to a RES[#]
2800 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
2803 If the RAW keyword is not specified, the texture data will be
2804 subject to conversion, swizzling and scaling as required to yield
2805 the specified data type from the physical data format of the bound
2808 If the RAW keyword is specified, no channel conversion will be
2809 performed: the values read for each of the channels (X,Y,Z,W) will
2810 correspond to consecutive words in the same order and format
2811 they're found in memory. No element-to-address conversion will be
2812 performed either: the value of the provided X coordinate will be
2813 interpreted in byte units instead of texel units. The result of
2814 accessing a misaligned address is undefined.
2816 Usage of the STORE opcode is only allowed if the WR (writable) flag
2821 ^^^^^^^^^^^^^^^^^^^^^^^^
2823 Properties are general directives that apply to the whole TGSI program.
2828 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
2829 The default value is UPPER_LEFT.
2831 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
2832 increase downward and rightward.
2833 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
2834 increase upward and rightward.
2836 OpenGL defaults to LOWER_LEFT, and is configurable with the
2837 GL_ARB_fragment_coord_conventions extension.
2839 DirectX 9/10 use UPPER_LEFT.
2841 FS_COORD_PIXEL_CENTER
2842 """""""""""""""""""""
2844 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
2845 The default value is HALF_INTEGER.
2847 If HALF_INTEGER, the fractionary part of the position will be 0.5
2848 If INTEGER, the fractionary part of the position will be 0.0
2850 Note that this does not affect the set of fragments generated by
2851 rasterization, which is instead controlled by half_pixel_center in the
2854 OpenGL defaults to HALF_INTEGER, and is configurable with the
2855 GL_ARB_fragment_coord_conventions extension.
2857 DirectX 9 uses INTEGER.
2858 DirectX 10 uses HALF_INTEGER.
2860 FS_COLOR0_WRITES_ALL_CBUFS
2861 """"""""""""""""""""""""""
2862 Specifies that writes to the fragment shader color 0 are replicated to all
2863 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
2864 fragData is directed to a single color buffer, but fragColor is broadcast.
2867 """"""""""""""""""""""""""
2868 If this property is set on the program bound to the shader stage before the
2869 fragment shader, user clip planes should have no effect (be disabled) even if
2870 that shader does not write to any clip distance outputs and the rasterizer's
2871 clip_plane_enable is non-zero.
2872 This property is only supported by drivers that also support shader clip
2874 This is useful for APIs that don't have UCPs and where clip distances written
2875 by a shader cannot be disabled.
2880 Specifies the number of times a geometry shader should be executed for each
2881 input primitive. Each invocation will have a different
2882 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
2885 VS_WINDOW_SPACE_POSITION
2886 """"""""""""""""""""""""""
2887 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
2888 is assumed to contain window space coordinates.
2889 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
2890 directly taken from the 4-th component of the shader output.
2891 Naturally, clipping is not performed on window coordinates either.
2892 The effect of this property is undefined if a geometry or tessellation shader
2895 Texture Sampling and Texture Formats
2896 ------------------------------------
2898 This table shows how texture image components are returned as (x,y,z,w) tuples
2899 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
2900 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
2903 +--------------------+--------------+--------------------+--------------+
2904 | Texture Components | Gallium | OpenGL | Direct3D 9 |
2905 +====================+==============+====================+==============+
2906 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
2907 +--------------------+--------------+--------------------+--------------+
2908 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
2909 +--------------------+--------------+--------------------+--------------+
2910 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
2911 +--------------------+--------------+--------------------+--------------+
2912 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
2913 +--------------------+--------------+--------------------+--------------+
2914 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
2915 +--------------------+--------------+--------------------+--------------+
2916 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
2917 +--------------------+--------------+--------------------+--------------+
2918 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
2919 +--------------------+--------------+--------------------+--------------+
2920 | I | (i, i, i, i) | (i, i, i, i) | N/A |
2921 +--------------------+--------------+--------------------+--------------+
2922 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
2923 | | | [#envmap-bumpmap]_ | |
2924 +--------------------+--------------+--------------------+--------------+
2925 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
2926 | | | [#depth-tex-mode]_ | |
2927 +--------------------+--------------+--------------------+--------------+
2928 | S | (s, s, s, s) | unknown | unknown |
2929 +--------------------+--------------+--------------------+--------------+
2931 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
2932 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
2933 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.