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:: DP2A - 2-component Dot Product And Add
279 dst.x = src0.x \times src1.x + src0.y \times src1.y + src2.x
281 dst.y = src0.x \times src1.x + src0.y \times src1.y + src2.x
283 dst.z = src0.x \times src1.x + src0.y \times src1.y + src2.x
285 dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x
288 .. opcode:: FRC - Fraction
292 dst.x = src.x - \lfloor src.x\rfloor
294 dst.y = src.y - \lfloor src.y\rfloor
296 dst.z = src.z - \lfloor src.z\rfloor
298 dst.w = src.w - \lfloor src.w\rfloor
301 .. opcode:: CLAMP - Clamp
305 dst.x = clamp(src0.x, src1.x, src2.x)
307 dst.y = clamp(src0.y, src1.y, src2.y)
309 dst.z = clamp(src0.z, src1.z, src2.z)
311 dst.w = clamp(src0.w, src1.w, src2.w)
314 .. opcode:: FLR - Floor
316 This is identical to :opcode:`ARL`.
320 dst.x = \lfloor src.x\rfloor
322 dst.y = \lfloor src.y\rfloor
324 dst.z = \lfloor src.z\rfloor
326 dst.w = \lfloor src.w\rfloor
329 .. opcode:: ROUND - Round
342 .. opcode:: EX2 - Exponential Base 2
344 This instruction replicates its result.
351 .. opcode:: LG2 - Logarithm Base 2
353 This instruction replicates its result.
360 .. opcode:: POW - Power
362 This instruction replicates its result.
366 dst = src0.x^{src1.x}
368 .. opcode:: XPD - Cross Product
372 dst.x = src0.y \times src1.z - src1.y \times src0.z
374 dst.y = src0.z \times src1.x - src1.z \times src0.x
376 dst.z = src0.x \times src1.y - src1.x \times src0.y
381 .. opcode:: ABS - Absolute
394 .. opcode:: DPH - Homogeneous Dot Product
396 This instruction replicates its result.
400 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
403 .. opcode:: COS - Cosine
405 This instruction replicates its result.
412 .. opcode:: DDX, DDX_FINE - Derivative Relative To X
414 The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
415 advertised. When it is, the fine version guarantees one derivative per row
416 while DDX is allowed to be the same for the entire 2x2 quad.
420 dst.x = partialx(src.x)
422 dst.y = partialx(src.y)
424 dst.z = partialx(src.z)
426 dst.w = partialx(src.w)
429 .. opcode:: DDY, DDY_FINE - Derivative Relative To Y
431 The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
432 advertised. When it is, the fine version guarantees one derivative per column
433 while DDY is allowed to be the same for the entire 2x2 quad.
437 dst.x = partialy(src.x)
439 dst.y = partialy(src.y)
441 dst.z = partialy(src.z)
443 dst.w = partialy(src.w)
446 .. opcode:: PK2H - Pack Two 16-bit Floats
451 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
456 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
461 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
466 .. opcode:: SEQ - Set On Equal
470 dst.x = (src0.x == src1.x) ? 1.0F : 0.0F
472 dst.y = (src0.y == src1.y) ? 1.0F : 0.0F
474 dst.z = (src0.z == src1.z) ? 1.0F : 0.0F
476 dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
479 .. opcode:: SGT - Set On Greater Than
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:: SIN - Sine
494 This instruction replicates its result.
501 .. opcode:: SLE - Set On Less Equal Than
505 dst.x = (src0.x <= src1.x) ? 1.0F : 0.0F
507 dst.y = (src0.y <= src1.y) ? 1.0F : 0.0F
509 dst.z = (src0.z <= src1.z) ? 1.0F : 0.0F
511 dst.w = (src0.w <= src1.w) ? 1.0F : 0.0F
514 .. opcode:: SNE - Set On Not Equal
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:: STR - Set On True
529 This instruction replicates its result.
536 .. opcode:: TEX - Texture Lookup
538 for array textures src0.y contains the slice for 1D,
539 and src0.z contain the slice for 2D.
541 for shadow textures with no arrays (and not cube map),
542 src0.z contains the reference value.
544 for shadow textures with arrays, src0.z contains
545 the reference value for 1D arrays, and src0.w contains
546 the reference value for 2D arrays and cube maps.
548 for cube map array shadow textures, the reference value
549 cannot be passed in src0.w, and TEX2 must be used instead.
555 shadow_ref = src0.z or src0.w (optional)
559 dst = texture\_sample(unit, coord, shadow_ref)
562 .. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only)
564 this is the same as TEX, but uses another reg to encode the
575 dst = texture\_sample(unit, coord, shadow_ref)
580 .. opcode:: TXD - Texture Lookup with Derivatives
592 dst = texture\_sample\_deriv(unit, coord, ddx, ddy)
595 .. opcode:: TXP - Projective Texture Lookup
599 coord.x = src0.x / src0.w
601 coord.y = src0.y / src0.w
603 coord.z = src0.z / src0.w
609 dst = texture\_sample(unit, coord)
612 .. opcode:: UP2H - Unpack Two 16-Bit Floats
618 Considered for removal.
620 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
626 Considered for removal.
628 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
634 Considered for removal.
636 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
642 Considered for removal.
645 .. opcode:: ARR - Address Register Load With Round
658 .. opcode:: SSG - Set Sign
662 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
664 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
666 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
668 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
671 .. opcode:: CMP - Compare
675 dst.x = (src0.x < 0) ? src1.x : src2.x
677 dst.y = (src0.y < 0) ? src1.y : src2.y
679 dst.z = (src0.z < 0) ? src1.z : src2.z
681 dst.w = (src0.w < 0) ? src1.w : src2.w
684 .. opcode:: KILL_IF - Conditional Discard
686 Conditional discard. Allowed in fragment shaders only.
690 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
695 .. opcode:: KILL - Discard
697 Unconditional discard. Allowed in fragment shaders only.
700 .. opcode:: SCS - Sine Cosine
713 .. opcode:: TXB - Texture Lookup With Bias
715 for cube map array textures and shadow cube maps, the bias value
716 cannot be passed in src0.w, and TXB2 must be used instead.
718 if the target is a shadow texture, the reference value is always
719 in src.z (this prevents shadow 3d and shadow 2d arrays from
720 using this instruction, but this is not needed).
736 dst = texture\_sample(unit, coord, bias)
739 .. opcode:: TXB2 - Texture Lookup With Bias (some cube maps only)
741 this is the same as TXB, but uses another reg to encode the
742 lod bias value for cube map arrays and shadow cube maps.
743 Presumably shadow 2d arrays and shadow 3d targets could use
744 this encoding too, but this is not legal.
746 shadow cube map arrays are neither possible nor required.
756 dst = texture\_sample(unit, coord, bias)
759 .. opcode:: DIV - Divide
763 dst.x = \frac{src0.x}{src1.x}
765 dst.y = \frac{src0.y}{src1.y}
767 dst.z = \frac{src0.z}{src1.z}
769 dst.w = \frac{src0.w}{src1.w}
772 .. opcode:: DP2 - 2-component Dot Product
774 This instruction replicates its result.
778 dst = src0.x \times src1.x + src0.y \times src1.y
781 .. opcode:: TXL - Texture Lookup With explicit LOD
783 for cube map array textures, the explicit lod value
784 cannot be passed in src0.w, and TXL2 must be used instead.
786 if the target is a shadow texture, the reference value is always
787 in src.z (this prevents shadow 3d / 2d array / cube targets from
788 using this instruction, but this is not needed).
804 dst = texture\_sample(unit, coord, lod)
807 .. opcode:: TXL2 - Texture Lookup With explicit LOD (for cube map arrays only)
809 this is the same as TXL, but uses another reg to encode the
811 Presumably shadow 3d / 2d array / cube targets could use
812 this encoding too, but this is not legal.
814 shadow cube map arrays are neither possible nor required.
824 dst = texture\_sample(unit, coord, lod)
827 .. opcode:: PUSHA - Push Address Register On Stack
836 Considered for cleanup.
840 Considered for removal.
842 .. opcode:: POPA - Pop Address Register From Stack
851 Considered for cleanup.
855 Considered for removal.
858 .. opcode:: CALLNZ - Subroutine Call If Not Zero
864 Considered for cleanup.
868 Considered for removal.
872 ^^^^^^^^^^^^^^^^^^^^^^^^
874 These opcodes are primarily provided for special-use computational shaders.
875 Support for these opcodes indicated by a special pipe capability bit (TBD).
877 XXX doesn't look like most of the opcodes really belong here.
879 .. opcode:: CEIL - Ceiling
883 dst.x = \lceil src.x\rceil
885 dst.y = \lceil src.y\rceil
887 dst.z = \lceil src.z\rceil
889 dst.w = \lceil src.w\rceil
892 .. opcode:: TRUNC - Truncate
905 .. opcode:: MOD - Modulus
909 dst.x = src0.x \bmod src1.x
911 dst.y = src0.y \bmod src1.y
913 dst.z = src0.z \bmod src1.z
915 dst.w = src0.w \bmod src1.w
918 .. opcode:: UARL - Integer Address Register Load
920 Moves the contents of the source register, assumed to be an integer, into the
921 destination register, which is assumed to be an address (ADDR) register.
924 .. opcode:: SAD - Sum Of Absolute Differences
928 dst.x = |src0.x - src1.x| + src2.x
930 dst.y = |src0.y - src1.y| + src2.y
932 dst.z = |src0.z - src1.z| + src2.z
934 dst.w = |src0.w - src1.w| + src2.w
937 .. opcode:: TXF - Texel Fetch
939 As per NV_gpu_shader4, extract a single texel from a specified texture
940 image. The source sampler may not be a CUBE or SHADOW. src 0 is a
941 four-component signed integer vector used to identify the single texel
942 accessed. 3 components + level. Just like texture instructions, an optional
943 offset vector is provided, which is subject to various driver restrictions
944 (regarding range, source of offsets).
945 TXF(uint_vec coord, int_vec offset).
948 .. opcode:: TXQ - Texture Size Query
950 As per NV_gpu_program4, retrieve the dimensions of the texture depending on
951 the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
952 depth), 1D array (width, layers), 2D array (width, height, layers).
953 Also return the number of accessible levels (last_level - first_level + 1)
956 For components which don't return a resource dimension, their value
964 dst.x = texture\_width(unit, lod)
966 dst.y = texture\_height(unit, lod)
968 dst.z = texture\_depth(unit, lod)
970 dst.w = texture\_levels(unit)
972 .. opcode:: TG4 - Texture Gather
974 As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
975 filtering operation and packs them into a single register. Only works with
976 2D, 2D array, cubemaps, and cubemaps arrays. For 2D textures, only the
977 addressing modes of the sampler and the top level of any mip pyramid are
978 used. Set W to zero. It behaves like the TEX instruction, but a filtered
979 sample is not generated. The four samples that contribute to filtering are
980 placed into xyzw in clockwise order, starting with the (u,v) texture
981 coordinate delta at the following locations (-, +), (+, +), (+, -), (-, -),
982 where the magnitude of the deltas are half a texel.
984 PIPE_CAP_TEXTURE_SM5 enhances this instruction to support shadow per-sample
985 depth compares, single component selection, and a non-constant offset. It
986 doesn't allow support for the GL independent offset to get i0,j0. This would
987 require another CAP is hw can do it natively. For now we lower that before
996 dst = texture\_gather4 (unit, coord, component)
998 (with SM5 - cube array shadow)
1006 dst = texture\_gather (uint, coord, compare)
1008 .. opcode:: LODQ - level of detail query
1010 Compute the LOD information that the texture pipe would use to access the
1011 texture. The Y component contains the computed LOD lambda_prime. The X
1012 component contains the LOD that will be accessed, based on min/max lod's
1019 dst.xy = lodq(uint, coord);
1022 ^^^^^^^^^^^^^^^^^^^^^^^^
1023 These opcodes are used for integer operations.
1024 Support for these opcodes indicated by PIPE_SHADER_CAP_INTEGERS (all of them?)
1027 .. opcode:: I2F - Signed Integer To Float
1029 Rounding is unspecified (round to nearest even suggested).
1033 dst.x = (float) src.x
1035 dst.y = (float) src.y
1037 dst.z = (float) src.z
1039 dst.w = (float) src.w
1042 .. opcode:: U2F - Unsigned Integer To Float
1044 Rounding is unspecified (round to nearest even suggested).
1048 dst.x = (float) src.x
1050 dst.y = (float) src.y
1052 dst.z = (float) src.z
1054 dst.w = (float) src.w
1057 .. opcode:: F2I - Float to Signed Integer
1059 Rounding is towards zero (truncate).
1060 Values outside signed range (including NaNs) produce undefined results.
1073 .. opcode:: F2U - Float to Unsigned Integer
1075 Rounding is towards zero (truncate).
1076 Values outside unsigned range (including NaNs) produce undefined results.
1080 dst.x = (unsigned) src.x
1082 dst.y = (unsigned) src.y
1084 dst.z = (unsigned) src.z
1086 dst.w = (unsigned) src.w
1089 .. opcode:: UADD - Integer Add
1091 This instruction works the same for signed and unsigned integers.
1092 The low 32bit of the result is returned.
1096 dst.x = src0.x + src1.x
1098 dst.y = src0.y + src1.y
1100 dst.z = src0.z + src1.z
1102 dst.w = src0.w + src1.w
1105 .. opcode:: UMAD - Integer Multiply And Add
1107 This instruction works the same for signed and unsigned integers.
1108 The multiplication returns the low 32bit (as does the result itself).
1112 dst.x = src0.x \times src1.x + src2.x
1114 dst.y = src0.y \times src1.y + src2.y
1116 dst.z = src0.z \times src1.z + src2.z
1118 dst.w = src0.w \times src1.w + src2.w
1121 .. opcode:: UMUL - Integer Multiply
1123 This instruction works the same for signed and unsigned integers.
1124 The low 32bit of the result is returned.
1128 dst.x = src0.x \times src1.x
1130 dst.y = src0.y \times src1.y
1132 dst.z = src0.z \times src1.z
1134 dst.w = src0.w \times src1.w
1137 .. opcode:: IMUL_HI - Signed Integer Multiply High Bits
1139 The high 32bits of the multiplication of 2 signed integers are returned.
1143 dst.x = (src0.x \times src1.x) >> 32
1145 dst.y = (src0.y \times src1.y) >> 32
1147 dst.z = (src0.z \times src1.z) >> 32
1149 dst.w = (src0.w \times src1.w) >> 32
1152 .. opcode:: UMUL_HI - Unsigned Integer Multiply High Bits
1154 The high 32bits of the multiplication of 2 unsigned integers are returned.
1158 dst.x = (src0.x \times src1.x) >> 32
1160 dst.y = (src0.y \times src1.y) >> 32
1162 dst.z = (src0.z \times src1.z) >> 32
1164 dst.w = (src0.w \times src1.w) >> 32
1167 .. opcode:: IDIV - Signed Integer Division
1169 TBD: behavior for division by zero.
1173 dst.x = src0.x \ src1.x
1175 dst.y = src0.y \ src1.y
1177 dst.z = src0.z \ src1.z
1179 dst.w = src0.w \ src1.w
1182 .. opcode:: UDIV - Unsigned Integer Division
1184 For division by zero, 0xffffffff is returned.
1188 dst.x = src0.x \ src1.x
1190 dst.y = src0.y \ src1.y
1192 dst.z = src0.z \ src1.z
1194 dst.w = src0.w \ src1.w
1197 .. opcode:: UMOD - Unsigned Integer Remainder
1199 If second arg is zero, 0xffffffff is returned.
1203 dst.x = src0.x \ src1.x
1205 dst.y = src0.y \ src1.y
1207 dst.z = src0.z \ src1.z
1209 dst.w = src0.w \ src1.w
1212 .. opcode:: NOT - Bitwise Not
1225 .. opcode:: AND - Bitwise And
1229 dst.x = src0.x \& src1.x
1231 dst.y = src0.y \& src1.y
1233 dst.z = src0.z \& src1.z
1235 dst.w = src0.w \& src1.w
1238 .. opcode:: OR - Bitwise Or
1242 dst.x = src0.x | src1.x
1244 dst.y = src0.y | src1.y
1246 dst.z = src0.z | src1.z
1248 dst.w = src0.w | src1.w
1251 .. opcode:: XOR - Bitwise Xor
1255 dst.x = src0.x \oplus src1.x
1257 dst.y = src0.y \oplus src1.y
1259 dst.z = src0.z \oplus src1.z
1261 dst.w = src0.w \oplus src1.w
1264 .. opcode:: IMAX - Maximum of Signed Integers
1268 dst.x = max(src0.x, src1.x)
1270 dst.y = max(src0.y, src1.y)
1272 dst.z = max(src0.z, src1.z)
1274 dst.w = max(src0.w, src1.w)
1277 .. opcode:: UMAX - Maximum of Unsigned Integers
1281 dst.x = max(src0.x, src1.x)
1283 dst.y = max(src0.y, src1.y)
1285 dst.z = max(src0.z, src1.z)
1287 dst.w = max(src0.w, src1.w)
1290 .. opcode:: IMIN - Minimum of Signed Integers
1294 dst.x = min(src0.x, src1.x)
1296 dst.y = min(src0.y, src1.y)
1298 dst.z = min(src0.z, src1.z)
1300 dst.w = min(src0.w, src1.w)
1303 .. opcode:: UMIN - Minimum of Unsigned Integers
1307 dst.x = min(src0.x, src1.x)
1309 dst.y = min(src0.y, src1.y)
1311 dst.z = min(src0.z, src1.z)
1313 dst.w = min(src0.w, src1.w)
1316 .. opcode:: SHL - Shift Left
1318 The shift count is masked with 0x1f before the shift is applied.
1322 dst.x = src0.x << (0x1f \& src1.x)
1324 dst.y = src0.y << (0x1f \& src1.y)
1326 dst.z = src0.z << (0x1f \& src1.z)
1328 dst.w = src0.w << (0x1f \& src1.w)
1331 .. opcode:: ISHR - Arithmetic Shift Right (of Signed Integer)
1333 The shift count is masked with 0x1f before the shift is applied.
1337 dst.x = src0.x >> (0x1f \& src1.x)
1339 dst.y = src0.y >> (0x1f \& src1.y)
1341 dst.z = src0.z >> (0x1f \& src1.z)
1343 dst.w = src0.w >> (0x1f \& src1.w)
1346 .. opcode:: USHR - Logical Shift Right
1348 The shift count is masked with 0x1f before the shift is applied.
1352 dst.x = src0.x >> (unsigned) (0x1f \& src1.x)
1354 dst.y = src0.y >> (unsigned) (0x1f \& src1.y)
1356 dst.z = src0.z >> (unsigned) (0x1f \& src1.z)
1358 dst.w = src0.w >> (unsigned) (0x1f \& src1.w)
1361 .. opcode:: UCMP - Integer Conditional Move
1365 dst.x = src0.x ? src1.x : src2.x
1367 dst.y = src0.y ? src1.y : src2.y
1369 dst.z = src0.z ? src1.z : src2.z
1371 dst.w = src0.w ? src1.w : src2.w
1375 .. opcode:: ISSG - Integer Set Sign
1379 dst.x = (src0.x < 0) ? -1 : (src0.x > 0) ? 1 : 0
1381 dst.y = (src0.y < 0) ? -1 : (src0.y > 0) ? 1 : 0
1383 dst.z = (src0.z < 0) ? -1 : (src0.z > 0) ? 1 : 0
1385 dst.w = (src0.w < 0) ? -1 : (src0.w > 0) ? 1 : 0
1389 .. opcode:: FSLT - Float Set On Less Than (ordered)
1391 Same comparison as SLT but returns integer instead of 1.0/0.0 float
1395 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1397 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1399 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1401 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1404 .. opcode:: ISLT - Signed Integer Set On Less Than
1408 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1410 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1412 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1414 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1417 .. opcode:: USLT - Unsigned Integer Set On Less Than
1421 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1423 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1425 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1427 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1430 .. opcode:: FSGE - Float Set On Greater Equal Than (ordered)
1432 Same comparison as SGE but returns integer instead of 1.0/0.0 float
1436 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1438 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1440 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1442 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1445 .. opcode:: ISGE - Signed Integer Set On Greater Equal Than
1449 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1451 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1453 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1455 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1458 .. opcode:: USGE - Unsigned Integer Set On Greater Equal Than
1462 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1464 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1466 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1468 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1471 .. opcode:: FSEQ - Float Set On Equal (ordered)
1473 Same comparison as SEQ but returns integer instead of 1.0/0.0 float
1477 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1479 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1481 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1483 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1486 .. opcode:: USEQ - Integer Set On Equal
1490 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1492 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1494 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1496 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1499 .. opcode:: FSNE - Float Set On Not Equal (unordered)
1501 Same comparison as SNE but returns integer instead of 1.0/0.0 float
1505 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1507 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1509 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1511 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1514 .. opcode:: USNE - Integer Set On Not Equal
1518 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1520 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1522 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1524 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1527 .. opcode:: INEG - Integer Negate
1542 .. opcode:: IABS - Integer Absolute Value
1556 These opcodes are used for bit-level manipulation of integers.
1558 .. opcode:: IBFE - Signed Bitfield Extract
1560 See SM5 instruction of the same name. Extracts a set of bits from the input,
1561 and sign-extends them if the high bit of the extracted window is set.
1565 def ibfe(value, offset, bits):
1566 offset = offset & 0x1f
1568 if bits == 0: return 0
1569 # Note: >> sign-extends
1570 if width + offset < 32:
1571 return (value << (32 - offset - bits)) >> (32 - bits)
1573 return value >> offset
1575 .. opcode:: UBFE - Unsigned Bitfield Extract
1577 See SM5 instruction of the same name. Extracts a set of bits from the input,
1578 without any sign-extension.
1582 def ubfe(value, offset, bits):
1583 offset = offset & 0x1f
1585 if bits == 0: return 0
1586 # Note: >> does not sign-extend
1587 if width + offset < 32:
1588 return (value << (32 - offset - bits)) >> (32 - bits)
1590 return value >> offset
1592 .. opcode:: BFI - Bitfield Insert
1594 See SM5 instruction of the same name. Replaces a bit region of 'base' with
1595 the low bits of 'insert'.
1599 def bfi(base, insert, offset, bits):
1600 offset = offset & 0x1f
1602 mask = ((1 << bits) - 1) << offset
1603 return ((insert << offset) & mask) | (base & ~mask)
1605 .. opcode:: BREV - Bitfield Reverse
1607 See SM5 instruction BFREV. Reverses the bits of the argument.
1609 .. opcode:: POPC - Population Count
1611 See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
1613 .. opcode:: LSB - Index of lowest set bit
1615 See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
1616 bit of the argument. Returns -1 if none are set.
1618 .. opcode:: IMSB - Index of highest non-sign bit
1620 See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
1621 non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
1622 highest 1 bit for positive numbers). Returns -1 if all bits are the same
1623 (i.e. for inputs 0 and -1).
1625 .. opcode:: UMSB - Index of highest set bit
1627 See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
1628 set bit of the argument. Returns -1 if none are set.
1631 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1633 These opcodes are only supported in geometry shaders; they have no meaning
1634 in any other type of shader.
1636 .. opcode:: EMIT - Emit
1638 Generate a new vertex for the current primitive into the specified vertex
1639 stream using the values in the output registers.
1642 .. opcode:: ENDPRIM - End Primitive
1644 Complete the current primitive in the specified vertex stream (consisting of
1645 the emitted vertices), and start a new one.
1651 These opcodes are part of :term:`GLSL`'s opcode set. Support for these
1652 opcodes is determined by a special capability bit, ``GLSL``.
1653 Some require glsl version 1.30 (UIF/BREAKC/SWITCH/CASE/DEFAULT/ENDSWITCH).
1655 .. opcode:: CAL - Subroutine Call
1661 .. opcode:: RET - Subroutine Call Return
1666 .. opcode:: CONT - Continue
1668 Unconditionally moves the point of execution to the instruction after the
1669 last bgnloop. The instruction must appear within a bgnloop/endloop.
1673 Support for CONT is determined by a special capability bit,
1674 ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
1677 .. opcode:: BGNLOOP - Begin a Loop
1679 Start a loop. Must have a matching endloop.
1682 .. opcode:: BGNSUB - Begin Subroutine
1684 Starts definition of a subroutine. Must have a matching endsub.
1687 .. opcode:: ENDLOOP - End a Loop
1689 End a loop started with bgnloop.
1692 .. opcode:: ENDSUB - End Subroutine
1694 Ends definition of a subroutine.
1697 .. opcode:: NOP - No Operation
1702 .. opcode:: BRK - Break
1704 Unconditionally moves the point of execution to the instruction after the
1705 next endloop or endswitch. The instruction must appear within a loop/endloop
1706 or switch/endswitch.
1709 .. opcode:: BREAKC - Break Conditional
1711 Conditionally moves the point of execution to the instruction after the
1712 next endloop or endswitch. The instruction must appear within a loop/endloop
1713 or switch/endswitch.
1714 Condition evaluates to true if src0.x != 0 where src0.x is interpreted
1715 as an integer register.
1719 Considered for removal as it's quite inconsistent wrt other opcodes
1720 (could emulate with UIF/BRK/ENDIF).
1723 .. opcode:: IF - Float If
1725 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
1729 where src0.x is interpreted as a floating point register.
1732 .. opcode:: UIF - Bitwise If
1734 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
1738 where src0.x is interpreted as an integer register.
1741 .. opcode:: ELSE - Else
1743 Starts an else block, after an IF or UIF statement.
1746 .. opcode:: ENDIF - End If
1748 Ends an IF or UIF block.
1751 .. opcode:: SWITCH - Switch
1753 Starts a C-style switch expression. The switch consists of one or multiple
1754 CASE statements, and at most one DEFAULT statement. Execution of a statement
1755 ends when a BRK is hit, but just like in C falling through to other cases
1756 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
1757 just as last statement, and fallthrough is allowed into/from it.
1758 CASE src arguments are evaluated at bit level against the SWITCH src argument.
1764 (some instructions here)
1767 (some instructions here)
1770 (some instructions here)
1775 .. opcode:: CASE - Switch case
1777 This represents a switch case label. The src arg must be an integer immediate.
1780 .. opcode:: DEFAULT - Switch default
1782 This represents the default case in the switch, which is taken if no other
1786 .. opcode:: ENDSWITCH - End of switch
1788 Ends a switch expression.
1794 The interpolation instructions allow an input to be interpolated in a
1795 different way than its declaration. This corresponds to the GLSL 4.00
1796 interpolateAt* functions. The first argument of each of these must come from
1797 ``TGSI_FILE_INPUT``.
1799 .. opcode:: INTERP_CENTROID - Interpolate at the centroid
1801 Interpolates the varying specified by src0 at the centroid
1803 .. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
1805 Interpolates the varying specified by src0 at the sample id specified by
1806 src1.x (interpreted as an integer)
1808 .. opcode:: INTERP_OFFSET - Interpolate at the specified offset
1810 Interpolates the varying specified by src0 at the offset src1.xy from the
1811 pixel center (interpreted as floats)
1819 The double-precision opcodes reinterpret four-component vectors into
1820 two-component vectors with doubled precision in each component.
1822 Support for these opcodes is XXX undecided. :T
1824 .. opcode:: DADD - Add
1828 dst.xy = src0.xy + src1.xy
1830 dst.zw = src0.zw + src1.zw
1833 .. opcode:: DDIV - Divide
1837 dst.xy = src0.xy / src1.xy
1839 dst.zw = src0.zw / src1.zw
1841 .. opcode:: DSEQ - Set on Equal
1845 dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
1847 dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
1849 .. opcode:: DSLT - Set on Less than
1853 dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
1855 dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
1857 .. opcode:: DFRAC - Fraction
1861 dst.xy = src.xy - \lfloor src.xy\rfloor
1863 dst.zw = src.zw - \lfloor src.zw\rfloor
1866 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1868 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1869 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1870 :math:`dst1 \times 2^{dst0} = src` .
1874 dst0.xy = exp(src.xy)
1876 dst1.xy = frac(src.xy)
1878 dst0.zw = exp(src.zw)
1880 dst1.zw = frac(src.zw)
1882 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1884 This opcode is the inverse of :opcode:`DFRACEXP`.
1888 dst.xy = src0.xy \times 2^{src1.xy}
1890 dst.zw = src0.zw \times 2^{src1.zw}
1892 .. opcode:: DMIN - Minimum
1896 dst.xy = min(src0.xy, src1.xy)
1898 dst.zw = min(src0.zw, src1.zw)
1900 .. opcode:: DMAX - Maximum
1904 dst.xy = max(src0.xy, src1.xy)
1906 dst.zw = max(src0.zw, src1.zw)
1908 .. opcode:: DMUL - Multiply
1912 dst.xy = src0.xy \times src1.xy
1914 dst.zw = src0.zw \times src1.zw
1917 .. opcode:: DMAD - Multiply And Add
1921 dst.xy = src0.xy \times src1.xy + src2.xy
1923 dst.zw = src0.zw \times src1.zw + src2.zw
1926 .. opcode:: DRCP - Reciprocal
1930 dst.xy = \frac{1}{src.xy}
1932 dst.zw = \frac{1}{src.zw}
1934 .. opcode:: DSQRT - Square Root
1938 dst.xy = \sqrt{src.xy}
1940 dst.zw = \sqrt{src.zw}
1943 .. _samplingopcodes:
1945 Resource Sampling Opcodes
1946 ^^^^^^^^^^^^^^^^^^^^^^^^^
1948 Those opcodes follow very closely semantics of the respective Direct3D
1949 instructions. If in doubt double check Direct3D documentation.
1950 Note that the swizzle on SVIEW (src1) determines texel swizzling
1955 Using provided address, sample data from the specified texture using the
1956 filtering mode identified by the gven sampler. The source data may come from
1957 any resource type other than buffers.
1959 Syntax: ``SAMPLE dst, address, sampler_view, sampler``
1961 Example: ``SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]``
1963 .. opcode:: SAMPLE_I
1965 Simplified alternative to the SAMPLE instruction. Using the provided
1966 integer address, SAMPLE_I fetches data from the specified sampler view
1967 without any filtering. The source data may come from any resource type
1970 Syntax: ``SAMPLE_I dst, address, sampler_view``
1972 Example: ``SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]``
1974 The 'address' is specified as unsigned integers. If the 'address' is out of
1975 range [0...(# texels - 1)] the result of the fetch is always 0 in all
1976 components. As such the instruction doesn't honor address wrap modes, in
1977 cases where that behavior is desirable 'SAMPLE' instruction should be used.
1978 address.w always provides an unsigned integer mipmap level. If the value is
1979 out of the range then the instruction always returns 0 in all components.
1980 address.yz are ignored for buffers and 1d textures. address.z is ignored
1981 for 1d texture arrays and 2d textures.
1983 For 1D texture arrays address.y provides the array index (also as unsigned
1984 integer). If the value is out of the range of available array indices
1985 [0... (array size - 1)] then the opcode always returns 0 in all components.
1986 For 2D texture arrays address.z provides the array index, otherwise it
1987 exhibits the same behavior as in the case for 1D texture arrays. The exact
1988 semantics of the source address are presented in the table below:
1990 +---------------------------+----+-----+-----+---------+
1991 | resource type | X | Y | Z | W |
1992 +===========================+====+=====+=====+=========+
1993 | ``PIPE_BUFFER`` | x | | | ignored |
1994 +---------------------------+----+-----+-----+---------+
1995 | ``PIPE_TEXTURE_1D`` | x | | | mpl |
1996 +---------------------------+----+-----+-----+---------+
1997 | ``PIPE_TEXTURE_2D`` | x | y | | mpl |
1998 +---------------------------+----+-----+-----+---------+
1999 | ``PIPE_TEXTURE_3D`` | x | y | z | mpl |
2000 +---------------------------+----+-----+-----+---------+
2001 | ``PIPE_TEXTURE_RECT`` | x | y | | mpl |
2002 +---------------------------+----+-----+-----+---------+
2003 | ``PIPE_TEXTURE_CUBE`` | not allowed as source |
2004 +---------------------------+----+-----+-----+---------+
2005 | ``PIPE_TEXTURE_1D_ARRAY`` | x | idx | | mpl |
2006 +---------------------------+----+-----+-----+---------+
2007 | ``PIPE_TEXTURE_2D_ARRAY`` | x | y | idx | mpl |
2008 +---------------------------+----+-----+-----+---------+
2010 Where 'mpl' is a mipmap level and 'idx' is the array index.
2012 .. opcode:: SAMPLE_I_MS
2014 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2016 Syntax: ``SAMPLE_I_MS dst, address, sampler_view, sample``
2018 .. opcode:: SAMPLE_B
2020 Just like the SAMPLE instruction with the exception that an additional bias
2021 is applied to the level of detail computed as part of the instruction
2024 Syntax: ``SAMPLE_B dst, address, sampler_view, sampler, lod_bias``
2026 Example: ``SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2028 .. opcode:: SAMPLE_C
2030 Similar to the SAMPLE instruction but it performs a comparison filter. The
2031 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2032 additional float32 operand, reference value, which must be a register with
2033 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2034 current samplers compare_func (in pipe_sampler_state) to compare reference
2035 value against the red component value for the surce resource at each texel
2036 that the currently configured texture filter covers based on the provided
2039 Syntax: ``SAMPLE_C dst, address, sampler_view.r, sampler, ref_value``
2041 Example: ``SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2043 .. opcode:: SAMPLE_C_LZ
2045 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2048 Syntax: ``SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value``
2050 Example: ``SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2053 .. opcode:: SAMPLE_D
2055 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2056 the source address in the x direction and the y direction are provided by
2059 Syntax: ``SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y``
2061 Example: ``SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]``
2063 .. opcode:: SAMPLE_L
2065 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2066 directly as a scalar value, representing no anisotropy.
2068 Syntax: ``SAMPLE_L dst, address, sampler_view, sampler, explicit_lod``
2070 Example: ``SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2074 Gathers the four texels to be used in a bi-linear filtering operation and
2075 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2076 and cubemaps arrays. For 2D textures, only the addressing modes of the
2077 sampler and the top level of any mip pyramid are used. Set W to zero. It
2078 behaves like the SAMPLE instruction, but a filtered sample is not
2079 generated. The four samples that contribute to filtering are placed into
2080 xyzw in counter-clockwise order, starting with the (u,v) texture coordinate
2081 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2082 magnitude of the deltas are half a texel.
2085 .. opcode:: SVIEWINFO
2087 Query the dimensions of a given sampler view. dst receives width, height,
2088 depth or array size and number of mipmap levels as int4. The dst can have a
2089 writemask which will specify what info is the caller interested in.
2091 Syntax: ``SVIEWINFO dst, src_mip_level, sampler_view``
2093 Example: ``SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]``
2095 src_mip_level is an unsigned integer scalar. If it's out of range then
2096 returns 0 for width, height and depth/array size but the total number of
2097 mipmap is still returned correctly for the given sampler view. The returned
2098 width, height and depth values are for the mipmap level selected by the
2099 src_mip_level and are in the number of texels. For 1d texture array width
2100 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2101 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2102 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2103 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2104 resinfo allowing swizzling dst values is ignored (due to the interaction
2105 with rcpfloat modifier which requires some swizzle handling in the state
2108 .. opcode:: SAMPLE_POS
2110 Query the position of a given sample. dst receives float4 (x, y, 0, 0)
2111 indicated where the sample is located. If the resource is not a multi-sample
2112 resource and not a render target, the result is 0.
2114 .. opcode:: SAMPLE_INFO
2116 dst receives number of samples in x. If the resource is not a multi-sample
2117 resource and not a render target, the result is 0.
2120 .. _resourceopcodes:
2122 Resource Access Opcodes
2123 ^^^^^^^^^^^^^^^^^^^^^^^
2125 .. opcode:: LOAD - Fetch data from a shader resource
2127 Syntax: ``LOAD dst, resource, address``
2129 Example: ``LOAD TEMP[0], RES[0], TEMP[1]``
2131 Using the provided integer address, LOAD fetches data
2132 from the specified buffer or texture without any
2135 The 'address' is specified as a vector of unsigned
2136 integers. If the 'address' is out of range the result
2139 Only the first mipmap level of a resource can be read
2140 from using this instruction.
2142 For 1D or 2D texture arrays, the array index is
2143 provided as an unsigned integer in address.y or
2144 address.z, respectively. address.yz are ignored for
2145 buffers and 1D textures. address.z is ignored for 1D
2146 texture arrays and 2D textures. address.w is always
2149 .. opcode:: STORE - Write data to a shader resource
2151 Syntax: ``STORE resource, address, src``
2153 Example: ``STORE RES[0], TEMP[0], TEMP[1]``
2155 Using the provided integer address, STORE writes data
2156 to the specified buffer or texture.
2158 The 'address' is specified as a vector of unsigned
2159 integers. If the 'address' is out of range the result
2162 Only the first mipmap level of a resource can be
2163 written to using this instruction.
2165 For 1D or 2D texture arrays, the array index is
2166 provided as an unsigned integer in address.y or
2167 address.z, respectively. address.yz are ignored for
2168 buffers and 1D textures. address.z is ignored for 1D
2169 texture arrays and 2D textures. address.w is always
2173 .. _threadsyncopcodes:
2175 Inter-thread synchronization opcodes
2176 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2178 These opcodes are intended for communication between threads running
2179 within the same compute grid. For now they're only valid in compute
2182 .. opcode:: MFENCE - Memory fence
2184 Syntax: ``MFENCE resource``
2186 Example: ``MFENCE RES[0]``
2188 This opcode forces strong ordering between any memory access
2189 operations that affect the specified resource. This means that
2190 previous loads and stores (and only those) will be performed and
2191 visible to other threads before the program execution continues.
2194 .. opcode:: LFENCE - Load memory fence
2196 Syntax: ``LFENCE resource``
2198 Example: ``LFENCE RES[0]``
2200 Similar to MFENCE, but it only affects the ordering of memory loads.
2203 .. opcode:: SFENCE - Store memory fence
2205 Syntax: ``SFENCE resource``
2207 Example: ``SFENCE RES[0]``
2209 Similar to MFENCE, but it only affects the ordering of memory stores.
2212 .. opcode:: BARRIER - Thread group barrier
2216 This opcode suspends the execution of the current thread until all
2217 the remaining threads in the working group reach the same point of
2218 the program. Results are unspecified if any of the remaining
2219 threads terminates or never reaches an executed BARRIER instruction.
2227 These opcodes provide atomic variants of some common arithmetic and
2228 logical operations. In this context atomicity means that another
2229 concurrent memory access operation that affects the same memory
2230 location is guaranteed to be performed strictly before or after the
2231 entire execution of the atomic operation.
2233 For the moment they're only valid in compute programs.
2235 .. opcode:: ATOMUADD - Atomic integer addition
2237 Syntax: ``ATOMUADD dst, resource, offset, src``
2239 Example: ``ATOMUADD TEMP[0], RES[0], TEMP[1], TEMP[2]``
2241 The following operation is performed atomically on each component:
2245 dst_i = resource[offset]_i
2247 resource[offset]_i = dst_i + src_i
2250 .. opcode:: ATOMXCHG - Atomic exchange
2252 Syntax: ``ATOMXCHG dst, resource, offset, src``
2254 Example: ``ATOMXCHG TEMP[0], RES[0], TEMP[1], TEMP[2]``
2256 The following operation is performed atomically on each component:
2260 dst_i = resource[offset]_i
2262 resource[offset]_i = src_i
2265 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2267 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
2269 Example: ``ATOMCAS TEMP[0], RES[0], TEMP[1], TEMP[2], TEMP[3]``
2271 The following operation is performed atomically on each component:
2275 dst_i = resource[offset]_i
2277 resource[offset]_i = (dst_i == cmp_i ? src_i : dst_i)
2280 .. opcode:: ATOMAND - Atomic bitwise And
2282 Syntax: ``ATOMAND dst, resource, offset, src``
2284 Example: ``ATOMAND TEMP[0], RES[0], TEMP[1], TEMP[2]``
2286 The following operation is performed atomically on each component:
2290 dst_i = resource[offset]_i
2292 resource[offset]_i = dst_i \& src_i
2295 .. opcode:: ATOMOR - Atomic bitwise Or
2297 Syntax: ``ATOMOR dst, resource, offset, src``
2299 Example: ``ATOMOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2301 The following operation is performed atomically on each component:
2305 dst_i = resource[offset]_i
2307 resource[offset]_i = dst_i | src_i
2310 .. opcode:: ATOMXOR - Atomic bitwise Xor
2312 Syntax: ``ATOMXOR dst, resource, offset, src``
2314 Example: ``ATOMXOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2316 The following operation is performed atomically on each component:
2320 dst_i = resource[offset]_i
2322 resource[offset]_i = dst_i \oplus src_i
2325 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2327 Syntax: ``ATOMUMIN dst, resource, offset, src``
2329 Example: ``ATOMUMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
2331 The following operation is performed atomically on each component:
2335 dst_i = resource[offset]_i
2337 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
2340 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2342 Syntax: ``ATOMUMAX dst, resource, offset, src``
2344 Example: ``ATOMUMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
2346 The following operation is performed atomically on each component:
2350 dst_i = resource[offset]_i
2352 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
2355 .. opcode:: ATOMIMIN - Atomic signed minimum
2357 Syntax: ``ATOMIMIN dst, resource, offset, src``
2359 Example: ``ATOMIMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
2361 The following operation is performed atomically on each component:
2365 dst_i = resource[offset]_i
2367 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
2370 .. opcode:: ATOMIMAX - Atomic signed maximum
2372 Syntax: ``ATOMIMAX dst, resource, offset, src``
2374 Example: ``ATOMIMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
2376 The following operation is performed atomically on each component:
2380 dst_i = resource[offset]_i
2382 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
2386 Explanation of symbols used
2387 ------------------------------
2394 :math:`|x|` Absolute value of `x`.
2396 :math:`\lceil x \rceil` Ceiling of `x`.
2398 clamp(x,y,z) Clamp x between y and z.
2399 (x < y) ? y : (x > z) ? z : x
2401 :math:`\lfloor x\rfloor` Floor of `x`.
2403 :math:`\log_2{x}` Logarithm of `x`, base 2.
2405 max(x,y) Maximum of x and y.
2408 min(x,y) Minimum of x and y.
2411 partialx(x) Derivative of x relative to fragment's X.
2413 partialy(x) Derivative of x relative to fragment's Y.
2415 pop() Pop from stack.
2417 :math:`x^y` `x` to the power `y`.
2419 push(x) Push x on stack.
2423 trunc(x) Truncate x, i.e. drop the fraction bits.
2430 discard Discard fragment.
2434 target Label of target instruction.
2445 Declares a register that is will be referenced as an operand in Instruction
2448 File field contains register file that is being declared and is one
2451 UsageMask field specifies which of the register components can be accessed
2452 and is one of TGSI_WRITEMASK.
2454 The Local flag specifies that a given value isn't intended for
2455 subroutine parameter passing and, as a result, the implementation
2456 isn't required to give any guarantees of it being preserved across
2457 subroutine boundaries. As it's merely a compiler hint, the
2458 implementation is free to ignore it.
2460 If Dimension flag is set to 1, a Declaration Dimension token follows.
2462 If Semantic flag is set to 1, a Declaration Semantic token follows.
2464 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
2466 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
2468 If Array flag is set to 1, a Declaration Array token follows.
2471 ^^^^^^^^^^^^^^^^^^^^^^^^
2473 Declarations can optional have an ArrayID attribute which can be referred by
2474 indirect addressing operands. An ArrayID of zero is reserved and treaded as
2475 if no ArrayID is specified.
2477 If an indirect addressing operand refers to a specific declaration by using
2478 an ArrayID only the registers in this declaration are guaranteed to be
2479 accessed, accessing any register outside this declaration results in undefined
2480 behavior. Note that for compatibility the effective index is zero-based and
2481 not relative to the specified declaration
2483 If no ArrayID is specified with an indirect addressing operand the whole
2484 register file might be accessed by this operand. This is strongly discouraged
2485 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
2487 Declaration Semantic
2488 ^^^^^^^^^^^^^^^^^^^^^^^^
2490 Vertex and fragment shader input and output registers may be labeled
2491 with semantic information consisting of a name and index.
2493 Follows Declaration token if Semantic bit is set.
2495 Since its purpose is to link a shader with other stages of the pipeline,
2496 it is valid to follow only those Declaration tokens that declare a register
2497 either in INPUT or OUTPUT file.
2499 SemanticName field contains the semantic name of the register being declared.
2500 There is no default value.
2502 SemanticIndex is an optional subscript that can be used to distinguish
2503 different register declarations with the same semantic name. The default value
2506 The meanings of the individual semantic names are explained in the following
2509 TGSI_SEMANTIC_POSITION
2510 """"""""""""""""""""""
2512 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
2513 output register which contains the homogeneous vertex position in the clip
2514 space coordinate system. After clipping, the X, Y and Z components of the
2515 vertex will be divided by the W value to get normalized device coordinates.
2517 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
2518 fragment shader input contains the fragment's window position. The X
2519 component starts at zero and always increases from left to right.
2520 The Y component starts at zero and always increases but Y=0 may either
2521 indicate the top of the window or the bottom depending on the fragment
2522 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
2523 The Z coordinate ranges from 0 to 1 to represent depth from the front
2524 to the back of the Z buffer. The W component contains the reciprocol
2525 of the interpolated vertex position W component.
2527 Fragment shaders may also declare an output register with
2528 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
2529 the fragment shader to change the fragment's Z position.
2536 For vertex shader outputs or fragment shader inputs/outputs, this
2537 label indicates that the resister contains an R,G,B,A color.
2539 Several shader inputs/outputs may contain colors so the semantic index
2540 is used to distinguish them. For example, color[0] may be the diffuse
2541 color while color[1] may be the specular color.
2543 This label is needed so that the flat/smooth shading can be applied
2544 to the right interpolants during rasterization.
2548 TGSI_SEMANTIC_BCOLOR
2549 """"""""""""""""""""
2551 Back-facing colors are only used for back-facing polygons, and are only valid
2552 in vertex shader outputs. After rasterization, all polygons are front-facing
2553 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
2554 so all BCOLORs effectively become regular COLORs in the fragment shader.
2560 Vertex shader inputs and outputs and fragment shader inputs may be
2561 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
2562 a fog coordinate. Typically, the fragment shader will use the fog coordinate
2563 to compute a fog blend factor which is used to blend the normal fragment color
2564 with a constant fog color. But fog coord really is just an ordinary vec4
2565 register like regular semantics.
2571 Vertex shader input and output registers may be labeled with
2572 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
2573 in the form (S, 0, 0, 1). The point size controls the width or diameter
2574 of points for rasterization. This label cannot be used in fragment
2577 When using this semantic, be sure to set the appropriate state in the
2578 :ref:`rasterizer` first.
2581 TGSI_SEMANTIC_TEXCOORD
2582 """"""""""""""""""""""
2584 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2586 Vertex shader outputs and fragment shader inputs may be labeled with
2587 this semantic to make them replaceable by sprite coordinates via the
2588 sprite_coord_enable state in the :ref:`rasterizer`.
2589 The semantic index permitted with this semantic is limited to <= 7.
2591 If the driver does not support TEXCOORD, sprite coordinate replacement
2592 applies to inputs with the GENERIC semantic instead.
2594 The intended use case for this semantic is gl_TexCoord.
2597 TGSI_SEMANTIC_PCOORD
2598 """"""""""""""""""""
2600 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2602 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
2603 that the register contains sprite coordinates in the form (x, y, 0, 1), if
2604 the current primitive is a point and point sprites are enabled. Otherwise,
2605 the contents of the register are undefined.
2607 The intended use case for this semantic is gl_PointCoord.
2610 TGSI_SEMANTIC_GENERIC
2611 """""""""""""""""""""
2613 All vertex/fragment shader inputs/outputs not labeled with any other
2614 semantic label can be considered to be generic attributes. Typical
2615 uses of generic inputs/outputs are texcoords and user-defined values.
2618 TGSI_SEMANTIC_NORMAL
2619 """"""""""""""""""""
2621 Indicates that a vertex shader input is a normal vector. This is
2622 typically only used for legacy graphics APIs.
2628 This label applies to fragment shader inputs only and indicates that
2629 the register contains front/back-face information of the form (F, 0,
2630 0, 1). The first component will be positive when the fragment belongs
2631 to a front-facing polygon, and negative when the fragment belongs to a
2632 back-facing polygon.
2635 TGSI_SEMANTIC_EDGEFLAG
2636 """"""""""""""""""""""
2638 For vertex shaders, this sematic label indicates that an input or
2639 output is a boolean edge flag. The register layout is [F, x, x, x]
2640 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
2641 simply copies the edge flag input to the edgeflag output.
2643 Edge flags are used to control which lines or points are actually
2644 drawn when the polygon mode converts triangles/quads/polygons into
2648 TGSI_SEMANTIC_STENCIL
2649 """""""""""""""""""""
2651 For fragment shaders, this semantic label indicates that an output
2652 is a writable stencil reference value. Only the Y component is writable.
2653 This allows the fragment shader to change the fragments stencilref value.
2656 TGSI_SEMANTIC_VIEWPORT_INDEX
2657 """"""""""""""""""""""""""""
2659 For geometry shaders, this semantic label indicates that an output
2660 contains the index of the viewport (and scissor) to use.
2661 Only the X value is used.
2667 For geometry shaders, this semantic label indicates that an output
2668 contains the layer value to use for the color and depth/stencil surfaces.
2669 Only the X value is used. (Also known as rendertarget array index.)
2672 TGSI_SEMANTIC_CULLDIST
2673 """"""""""""""""""""""
2675 Used as distance to plane for performing application-defined culling
2676 of individual primitives against a plane. When components of vertex
2677 elements are given this label, these values are assumed to be a
2678 float32 signed distance to a plane. Primitives will be completely
2679 discarded if the plane distance for all of the vertices in the
2680 primitive are < 0. If a vertex has a cull distance of NaN, that
2681 vertex counts as "out" (as if its < 0);
2682 The limits on both clip and cull distances are bound
2683 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2684 the maximum number of components that can be used to hold the
2685 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2686 which specifies the maximum number of registers which can be
2687 annotated with those semantics.
2690 TGSI_SEMANTIC_CLIPDIST
2691 """"""""""""""""""""""
2693 When components of vertex elements are identified this way, these
2694 values are each assumed to be a float32 signed distance to a plane.
2695 Primitive setup only invokes rasterization on pixels for which
2696 the interpolated plane distances are >= 0. Multiple clip planes
2697 can be implemented simultaneously, by annotating multiple
2698 components of one or more vertex elements with the above specified
2699 semantic. The limits on both clip and cull distances are bound
2700 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2701 the maximum number of components that can be used to hold the
2702 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2703 which specifies the maximum number of registers which can be
2704 annotated with those semantics.
2706 TGSI_SEMANTIC_SAMPLEID
2707 """"""""""""""""""""""
2709 For fragment shaders, this semantic label indicates that a system value
2710 contains the current sample id (i.e. gl_SampleID). Only the X value is used.
2712 TGSI_SEMANTIC_SAMPLEPOS
2713 """""""""""""""""""""""
2715 For fragment shaders, this semantic label indicates that a system value
2716 contains the current sample's position (i.e. gl_SamplePosition). Only the X
2717 and Y values are used.
2719 TGSI_SEMANTIC_SAMPLEMASK
2720 """"""""""""""""""""""""
2722 For fragment shaders, this semantic label indicates that an output contains
2723 the sample mask used to disable further sample processing
2724 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
2726 TGSI_SEMANTIC_INVOCATIONID
2727 """"""""""""""""""""""""""
2729 For geometry shaders, this semantic label indicates that a system value
2730 contains the current invocation id (i.e. gl_InvocationID). Only the X value is
2733 Declaration Interpolate
2734 ^^^^^^^^^^^^^^^^^^^^^^^
2736 This token is only valid for fragment shader INPUT declarations.
2738 The Interpolate field specifes the way input is being interpolated by
2739 the rasteriser and is one of TGSI_INTERPOLATE_*.
2741 The Location field specifies the location inside the pixel that the
2742 interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
2743 when per-sample shading is enabled, the implementation may choose to
2744 interpolate at the sample irrespective of the Location field.
2746 The CylindricalWrap bitfield specifies which register components
2747 should be subject to cylindrical wrapping when interpolating by the
2748 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
2749 should be interpolated according to cylindrical wrapping rules.
2752 Declaration Sampler View
2753 ^^^^^^^^^^^^^^^^^^^^^^^^
2755 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
2757 DCL SVIEW[#], resource, type(s)
2759 Declares a shader input sampler view and assigns it to a SVIEW[#]
2762 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
2764 type must be 1 or 4 entries (if specifying on a per-component
2765 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
2768 Declaration Resource
2769 ^^^^^^^^^^^^^^^^^^^^
2771 Follows Declaration token if file is TGSI_FILE_RESOURCE.
2773 DCL RES[#], resource [, WR] [, RAW]
2775 Declares a shader input resource and assigns it to a RES[#]
2778 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
2781 If the RAW keyword is not specified, the texture data will be
2782 subject to conversion, swizzling and scaling as required to yield
2783 the specified data type from the physical data format of the bound
2786 If the RAW keyword is specified, no channel conversion will be
2787 performed: the values read for each of the channels (X,Y,Z,W) will
2788 correspond to consecutive words in the same order and format
2789 they're found in memory. No element-to-address conversion will be
2790 performed either: the value of the provided X coordinate will be
2791 interpreted in byte units instead of texel units. The result of
2792 accessing a misaligned address is undefined.
2794 Usage of the STORE opcode is only allowed if the WR (writable) flag
2799 ^^^^^^^^^^^^^^^^^^^^^^^^
2801 Properties are general directives that apply to the whole TGSI program.
2806 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
2807 The default value is UPPER_LEFT.
2809 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
2810 increase downward and rightward.
2811 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
2812 increase upward and rightward.
2814 OpenGL defaults to LOWER_LEFT, and is configurable with the
2815 GL_ARB_fragment_coord_conventions extension.
2817 DirectX 9/10 use UPPER_LEFT.
2819 FS_COORD_PIXEL_CENTER
2820 """""""""""""""""""""
2822 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
2823 The default value is HALF_INTEGER.
2825 If HALF_INTEGER, the fractionary part of the position will be 0.5
2826 If INTEGER, the fractionary part of the position will be 0.0
2828 Note that this does not affect the set of fragments generated by
2829 rasterization, which is instead controlled by half_pixel_center in the
2832 OpenGL defaults to HALF_INTEGER, and is configurable with the
2833 GL_ARB_fragment_coord_conventions extension.
2835 DirectX 9 uses INTEGER.
2836 DirectX 10 uses HALF_INTEGER.
2838 FS_COLOR0_WRITES_ALL_CBUFS
2839 """"""""""""""""""""""""""
2840 Specifies that writes to the fragment shader color 0 are replicated to all
2841 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
2842 fragData is directed to a single color buffer, but fragColor is broadcast.
2845 """"""""""""""""""""""""""
2846 If this property is set on the program bound to the shader stage before the
2847 fragment shader, user clip planes should have no effect (be disabled) even if
2848 that shader does not write to any clip distance outputs and the rasterizer's
2849 clip_plane_enable is non-zero.
2850 This property is only supported by drivers that also support shader clip
2852 This is useful for APIs that don't have UCPs and where clip distances written
2853 by a shader cannot be disabled.
2858 Specifies the number of times a geometry shader should be executed for each
2859 input primitive. Each invocation will have a different
2860 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
2863 VS_WINDOW_SPACE_POSITION
2864 """"""""""""""""""""""""""
2865 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
2866 is assumed to contain window space coordinates.
2867 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
2868 directly taken from the 4-th component of the shader output.
2869 Naturally, clipping is not performed on window coordinates either.
2870 The effect of this property is undefined if a geometry or tessellation shader
2873 Texture Sampling and Texture Formats
2874 ------------------------------------
2876 This table shows how texture image components are returned as (x,y,z,w) tuples
2877 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
2878 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
2881 +--------------------+--------------+--------------------+--------------+
2882 | Texture Components | Gallium | OpenGL | Direct3D 9 |
2883 +====================+==============+====================+==============+
2884 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
2885 +--------------------+--------------+--------------------+--------------+
2886 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
2887 +--------------------+--------------+--------------------+--------------+
2888 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
2889 +--------------------+--------------+--------------------+--------------+
2890 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
2891 +--------------------+--------------+--------------------+--------------+
2892 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
2893 +--------------------+--------------+--------------------+--------------+
2894 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
2895 +--------------------+--------------+--------------------+--------------+
2896 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
2897 +--------------------+--------------+--------------------+--------------+
2898 | I | (i, i, i, i) | (i, i, i, i) | N/A |
2899 +--------------------+--------------+--------------------+--------------+
2900 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
2901 | | | [#envmap-bumpmap]_ | |
2902 +--------------------+--------------+--------------------+--------------+
2903 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
2904 | | | [#depth-tex-mode]_ | |
2905 +--------------------+--------------+--------------------+--------------+
2906 | S | (s, s, s, s) | unknown | unknown |
2907 +--------------------+--------------+--------------------+--------------+
2909 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
2910 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
2911 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.