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:: RCC - Reciprocal Clamped
409 This instruction replicates its result.
411 XXX cleanup on aisle three
415 dst = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.84467e+019) : clamp(1 / src.x, -1.84467e+019, -5.42101e-020)
418 .. opcode:: DPH - Homogeneous Dot Product
420 This instruction replicates its result.
424 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
427 .. opcode:: COS - Cosine
429 This instruction replicates its result.
436 .. opcode:: DDX - Derivative Relative To X
440 dst.x = partialx(src.x)
442 dst.y = partialx(src.y)
444 dst.z = partialx(src.z)
446 dst.w = partialx(src.w)
449 .. opcode:: DDY - Derivative Relative To Y
453 dst.x = partialy(src.x)
455 dst.y = partialy(src.y)
457 dst.z = partialy(src.z)
459 dst.w = partialy(src.w)
462 .. opcode:: PK2H - Pack Two 16-bit Floats
467 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
472 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
477 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
482 .. opcode:: RFL - Reflection Vector
486 dst.x = 2 \times (src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z) / (src0.x \times src0.x + src0.y \times src0.y + src0.z \times src0.z) \times src0.x - src1.x
488 dst.y = 2 \times (src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z) / (src0.x \times src0.x + src0.y \times src0.y + src0.z \times src0.z) \times src0.y - src1.y
490 dst.z = 2 \times (src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z) / (src0.x \times src0.x + src0.y \times src0.y + src0.z \times src0.z) \times src0.z - src1.z
496 Considered for removal.
499 .. opcode:: SEQ - Set On Equal
503 dst.x = (src0.x == src1.x) ? 1.0F : 0.0F
505 dst.y = (src0.y == src1.y) ? 1.0F : 0.0F
507 dst.z = (src0.z == src1.z) ? 1.0F : 0.0F
509 dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
512 .. opcode:: SFL - Set On False
514 This instruction replicates its result.
522 Considered for removal.
525 .. opcode:: SGT - Set On Greater Than
529 dst.x = (src0.x > src1.x) ? 1.0F : 0.0F
531 dst.y = (src0.y > src1.y) ? 1.0F : 0.0F
533 dst.z = (src0.z > src1.z) ? 1.0F : 0.0F
535 dst.w = (src0.w > src1.w) ? 1.0F : 0.0F
538 .. opcode:: SIN - Sine
540 This instruction replicates its result.
547 .. opcode:: SLE - Set On Less Equal Than
551 dst.x = (src0.x <= src1.x) ? 1.0F : 0.0F
553 dst.y = (src0.y <= src1.y) ? 1.0F : 0.0F
555 dst.z = (src0.z <= src1.z) ? 1.0F : 0.0F
557 dst.w = (src0.w <= src1.w) ? 1.0F : 0.0F
560 .. opcode:: SNE - Set On Not Equal
564 dst.x = (src0.x != src1.x) ? 1.0F : 0.0F
566 dst.y = (src0.y != src1.y) ? 1.0F : 0.0F
568 dst.z = (src0.z != src1.z) ? 1.0F : 0.0F
570 dst.w = (src0.w != src1.w) ? 1.0F : 0.0F
573 .. opcode:: STR - Set On True
575 This instruction replicates its result.
582 .. opcode:: TEX - Texture Lookup
584 for array textures src0.y contains the slice for 1D,
585 and src0.z contain the slice for 2D.
587 for shadow textures with no arrays, src0.z contains
590 for shadow textures with arrays, src0.z contains
591 the reference value for 1D arrays, and src0.w contains
592 the reference value for 2D arrays.
594 There is no way to pass a bias in the .w value for
595 shadow arrays, and GLSL doesn't allow this.
596 GLSL does allow cube shadows maps to take a bias value,
597 and we have to determine how this will look in TGSI.
605 dst = texture\_sample(unit, coord, bias)
607 .. opcode:: TXD - Texture Lookup with Derivatives
619 dst = texture\_sample\_deriv(unit, coord, bias, ddx, ddy)
622 .. opcode:: TXP - Projective Texture Lookup
626 coord.x = src0.x / src.w
628 coord.y = src0.y / src.w
630 coord.z = src0.z / src.w
636 dst = texture\_sample(unit, coord, bias)
639 .. opcode:: UP2H - Unpack Two 16-Bit Floats
645 Considered for removal.
647 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
653 Considered for removal.
655 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
661 Considered for removal.
663 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
669 Considered for removal.
671 .. opcode:: X2D - 2D Coordinate Transformation
675 dst.x = src0.x + src1.x \times src2.x + src1.y \times src2.y
677 dst.y = src0.y + src1.x \times src2.z + src1.y \times src2.w
679 dst.z = src0.x + src1.x \times src2.x + src1.y \times src2.y
681 dst.w = src0.y + src1.x \times src2.z + src1.y \times src2.w
685 Considered for removal.
688 .. opcode:: ARA - Address Register Add
694 Considered for removal.
696 .. opcode:: ARR - Address Register Load With Round
709 .. opcode:: SSG - Set Sign
713 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
715 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
717 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
719 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
722 .. opcode:: CMP - Compare
726 dst.x = (src0.x < 0) ? src1.x : src2.x
728 dst.y = (src0.y < 0) ? src1.y : src2.y
730 dst.z = (src0.z < 0) ? src1.z : src2.z
732 dst.w = (src0.w < 0) ? src1.w : src2.w
735 .. opcode:: KILL_IF - Conditional Discard
737 Conditional discard. Allowed in fragment shaders only.
741 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
746 .. opcode:: KILL - Discard
748 Unconditional discard. Allowed in fragment shaders only.
751 .. opcode:: SCS - Sine Cosine
764 .. opcode:: TXB - Texture Lookup With Bias
778 dst = texture\_sample(unit, coord, bias)
781 .. opcode:: NRM - 3-component Vector Normalise
785 dst.x = src.x / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
787 dst.y = src.y / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
789 dst.z = src.z / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
794 .. opcode:: DIV - Divide
798 dst.x = \frac{src0.x}{src1.x}
800 dst.y = \frac{src0.y}{src1.y}
802 dst.z = \frac{src0.z}{src1.z}
804 dst.w = \frac{src0.w}{src1.w}
807 .. opcode:: DP2 - 2-component Dot Product
809 This instruction replicates its result.
813 dst = src0.x \times src1.x + src0.y \times src1.y
816 .. opcode:: TXL - Texture Lookup With explicit LOD
830 dst = texture\_sample(unit, coord, lod)
833 .. opcode:: PUSHA - Push Address Register On Stack
842 Considered for cleanup.
846 Considered for removal.
848 .. opcode:: POPA - Pop Address Register From Stack
857 Considered for cleanup.
861 Considered for removal.
864 .. opcode:: BRA - Branch
870 Considered for removal.
873 .. opcode:: CALLNZ - Subroutine Call If Not Zero
879 Considered for cleanup.
883 Considered for removal.
887 ^^^^^^^^^^^^^^^^^^^^^^^^
889 These opcodes are primarily provided for special-use computational shaders.
890 Support for these opcodes indicated by a special pipe capability bit (TBD).
892 XXX doesn't look like most of the opcodes really belong here.
894 .. opcode:: CEIL - Ceiling
898 dst.x = \lceil src.x\rceil
900 dst.y = \lceil src.y\rceil
902 dst.z = \lceil src.z\rceil
904 dst.w = \lceil src.w\rceil
907 .. opcode:: TRUNC - Truncate
920 .. opcode:: MOD - Modulus
924 dst.x = src0.x \bmod src1.x
926 dst.y = src0.y \bmod src1.y
928 dst.z = src0.z \bmod src1.z
930 dst.w = src0.w \bmod src1.w
933 .. opcode:: UARL - Integer Address Register Load
935 Moves the contents of the source register, assumed to be an integer, into the
936 destination register, which is assumed to be an address (ADDR) register.
939 .. opcode:: SAD - Sum Of Absolute Differences
943 dst.x = |src0.x - src1.x| + src2.x
945 dst.y = |src0.y - src1.y| + src2.y
947 dst.z = |src0.z - src1.z| + src2.z
949 dst.w = |src0.w - src1.w| + src2.w
952 .. opcode:: TXF - Texel Fetch
954 As per NV_gpu_shader4, extract a single texel from a specified texture
955 image. The source sampler may not be a CUBE or SHADOW. src 0 is a
956 four-component signed integer vector used to identify the single texel
957 accessed. 3 components + level. src 1 is a 3 component constant signed
958 integer vector, with each component only have a range of -8..+8 (hw only
959 seems to deal with this range, interface allows for up to unsigned int).
960 TXF(uint_vec coord, int_vec offset).
963 .. opcode:: TXQ - Texture Size Query
965 As per NV_gpu_program4, retrieve the dimensions of the texture depending on
966 the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
967 depth), 1D array (width, layers), 2D array (width, height, layers).
968 Also return the number of accessible levels (last_level - first_level + 1)
971 For components which don't return a resource dimension, their value
979 dst.x = texture\_width(unit, lod)
981 dst.y = texture\_height(unit, lod)
983 dst.z = texture\_depth(unit, lod)
985 dst.w = texture\_levels(unit)
987 .. opcode:: TG4 - Texture Gather
989 As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
990 filtering operation and packs them into a single register. Only works with
991 2D, 2D array, cubemaps, and cubemaps arrays. For 2D textures, only the
992 addressing modes of the sampler and the top level of any mip pyramid are
993 used. Set W to zero. It behaves like the TEX instruction, but a filtered
994 sample is not generated. The four samples that contribute to filtering are
995 placed into xyzw in clockwise order, starting with the (u,v) texture
996 coordinate delta at the following locations (-, +), (+, +), (+, -), (-, -),
997 where the magnitude of the deltas are half a texel.
999 PIPE_CAP_TEXTURE_SM5 enhances this instruction to support shadow per-sample
1000 depth compares, single component selection, and a non-constant offset. It
1001 doesn't allow support for the GL independent offset to get i0,j0. This would
1002 require another CAP is hw can do it natively. For now we lower that before
1011 dst = texture\_gather4 (unit, coord, component)
1013 (with SM5 - cube array shadow)
1021 dst = texture\_gather (uint, coord, compare)
1023 .. opcode:: LODQ - level of detail query
1025 Compute the LOD information that the texture pipe would use to access the
1026 texture. The Y component contains the computed LOD lambda_prime. The X
1027 component contains the LOD that will be accessed, based on min/max lod's
1034 dst.xy = lodq(uint, coord);
1037 ^^^^^^^^^^^^^^^^^^^^^^^^
1038 These opcodes are used for integer operations.
1039 Support for these opcodes indicated by PIPE_SHADER_CAP_INTEGERS (all of them?)
1042 .. opcode:: I2F - Signed 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:: U2F - Unsigned Integer To Float
1059 Rounding is unspecified (round to nearest even suggested).
1063 dst.x = (float) src.x
1065 dst.y = (float) src.y
1067 dst.z = (float) src.z
1069 dst.w = (float) src.w
1072 .. opcode:: F2I - Float to Signed Integer
1074 Rounding is towards zero (truncate).
1075 Values outside signed range (including NaNs) produce undefined results.
1088 .. opcode:: F2U - Float to Unsigned Integer
1090 Rounding is towards zero (truncate).
1091 Values outside unsigned range (including NaNs) produce undefined results.
1095 dst.x = (unsigned) src.x
1097 dst.y = (unsigned) src.y
1099 dst.z = (unsigned) src.z
1101 dst.w = (unsigned) src.w
1104 .. opcode:: UADD - Integer Add
1106 This instruction works the same for signed and unsigned integers.
1107 The low 32bit of the result is returned.
1111 dst.x = src0.x + src1.x
1113 dst.y = src0.y + src1.y
1115 dst.z = src0.z + src1.z
1117 dst.w = src0.w + src1.w
1120 .. opcode:: UMAD - Integer Multiply And Add
1122 This instruction works the same for signed and unsigned integers.
1123 The multiplication returns the low 32bit (as does the result itself).
1127 dst.x = src0.x \times src1.x + src2.x
1129 dst.y = src0.y \times src1.y + src2.y
1131 dst.z = src0.z \times src1.z + src2.z
1133 dst.w = src0.w \times src1.w + src2.w
1136 .. opcode:: UMUL - Integer Multiply
1138 This instruction works the same for signed and unsigned integers.
1139 The low 32bit of the result is returned.
1143 dst.x = src0.x \times src1.x
1145 dst.y = src0.y \times src1.y
1147 dst.z = src0.z \times src1.z
1149 dst.w = src0.w \times src1.w
1152 .. opcode:: IMUL_HI - Signed Integer Multiply High Bits
1154 The high 32bits of the multiplication of 2 signed 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:: UMUL_HI - Unsigned Integer Multiply High Bits
1169 The high 32bits of the multiplication of 2 unsigned integers are returned.
1173 dst.x = (src0.x \times src1.x) >> 32
1175 dst.y = (src0.y \times src1.y) >> 32
1177 dst.z = (src0.z \times src1.z) >> 32
1179 dst.w = (src0.w \times src1.w) >> 32
1182 .. opcode:: IDIV - Signed Integer Division
1184 TBD: behavior for division by zero.
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:: UDIV - Unsigned Integer Division
1199 For division by 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:: UMOD - Unsigned Integer Remainder
1214 If second arg is zero, 0xffffffff is returned.
1218 dst.x = src0.x \ src1.x
1220 dst.y = src0.y \ src1.y
1222 dst.z = src0.z \ src1.z
1224 dst.w = src0.w \ src1.w
1227 .. opcode:: NOT - Bitwise Not
1240 .. opcode:: AND - Bitwise And
1244 dst.x = src0.x \& src1.x
1246 dst.y = src0.y \& src1.y
1248 dst.z = src0.z \& src1.z
1250 dst.w = src0.w \& src1.w
1253 .. opcode:: OR - Bitwise Or
1257 dst.x = src0.x | src1.x
1259 dst.y = src0.y | src1.y
1261 dst.z = src0.z | src1.z
1263 dst.w = src0.w | src1.w
1266 .. opcode:: XOR - Bitwise Xor
1270 dst.x = src0.x \oplus src1.x
1272 dst.y = src0.y \oplus src1.y
1274 dst.z = src0.z \oplus src1.z
1276 dst.w = src0.w \oplus src1.w
1279 .. opcode:: IMAX - Maximum of Signed Integers
1283 dst.x = max(src0.x, src1.x)
1285 dst.y = max(src0.y, src1.y)
1287 dst.z = max(src0.z, src1.z)
1289 dst.w = max(src0.w, src1.w)
1292 .. opcode:: UMAX - Maximum of Unsigned Integers
1296 dst.x = max(src0.x, src1.x)
1298 dst.y = max(src0.y, src1.y)
1300 dst.z = max(src0.z, src1.z)
1302 dst.w = max(src0.w, src1.w)
1305 .. opcode:: IMIN - Minimum of Signed Integers
1309 dst.x = min(src0.x, src1.x)
1311 dst.y = min(src0.y, src1.y)
1313 dst.z = min(src0.z, src1.z)
1315 dst.w = min(src0.w, src1.w)
1318 .. opcode:: UMIN - Minimum of Unsigned Integers
1322 dst.x = min(src0.x, src1.x)
1324 dst.y = min(src0.y, src1.y)
1326 dst.z = min(src0.z, src1.z)
1328 dst.w = min(src0.w, src1.w)
1331 .. opcode:: SHL - Shift Left
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:: ISHR - Arithmetic Shift Right (of Signed Integer)
1348 The shift count is masked with 0x1f before the shift is applied.
1352 dst.x = src0.x >> (0x1f \& src1.x)
1354 dst.y = src0.y >> (0x1f \& src1.y)
1356 dst.z = src0.z >> (0x1f \& src1.z)
1358 dst.w = src0.w >> (0x1f \& src1.w)
1361 .. opcode:: USHR - Logical Shift Right
1363 The shift count is masked with 0x1f before the shift is applied.
1367 dst.x = src0.x >> (unsigned) (0x1f \& src1.x)
1369 dst.y = src0.y >> (unsigned) (0x1f \& src1.y)
1371 dst.z = src0.z >> (unsigned) (0x1f \& src1.z)
1373 dst.w = src0.w >> (unsigned) (0x1f \& src1.w)
1376 .. opcode:: UCMP - Integer Conditional Move
1380 dst.x = src0.x ? src1.x : src2.x
1382 dst.y = src0.y ? src1.y : src2.y
1384 dst.z = src0.z ? src1.z : src2.z
1386 dst.w = src0.w ? src1.w : src2.w
1390 .. opcode:: ISSG - Integer Set Sign
1394 dst.x = (src0.x < 0) ? -1 : (src0.x > 0) ? 1 : 0
1396 dst.y = (src0.y < 0) ? -1 : (src0.y > 0) ? 1 : 0
1398 dst.z = (src0.z < 0) ? -1 : (src0.z > 0) ? 1 : 0
1400 dst.w = (src0.w < 0) ? -1 : (src0.w > 0) ? 1 : 0
1404 .. opcode:: FSLT - Float Set On Less Than (ordered)
1406 Same comparison as SLT but returns integer instead of 1.0/0.0 float
1410 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1412 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1414 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1416 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1419 .. opcode:: ISLT - Signed Integer Set On Less Than
1423 dst.x = (src0.x < src1.x) ? \sim 0 : 0
1425 dst.y = (src0.y < src1.y) ? \sim 0 : 0
1427 dst.z = (src0.z < src1.z) ? \sim 0 : 0
1429 dst.w = (src0.w < src1.w) ? \sim 0 : 0
1432 .. opcode:: USLT - Unsigned Integer Set On Less Than
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:: FSGE - Float Set On Greater Equal Than (ordered)
1447 Same comparison as SGE but returns integer instead of 1.0/0.0 float
1451 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1453 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1455 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1457 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1460 .. opcode:: ISGE - Signed Integer Set On Greater Equal Than
1464 dst.x = (src0.x >= src1.x) ? \sim 0 : 0
1466 dst.y = (src0.y >= src1.y) ? \sim 0 : 0
1468 dst.z = (src0.z >= src1.z) ? \sim 0 : 0
1470 dst.w = (src0.w >= src1.w) ? \sim 0 : 0
1473 .. opcode:: USGE - Unsigned Integer Set On Greater Equal Than
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:: FSEQ - Float Set On Equal (ordered)
1488 Same comparison as SEQ but returns integer instead of 1.0/0.0 float
1492 dst.x = (src0.x == src1.x) ? \sim 0 : 0
1494 dst.y = (src0.y == src1.y) ? \sim 0 : 0
1496 dst.z = (src0.z == src1.z) ? \sim 0 : 0
1498 dst.w = (src0.w == src1.w) ? \sim 0 : 0
1501 .. opcode:: USEQ - Integer Set On Equal
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:: FSNE - Float Set On Not Equal (unordered)
1516 Same comparison as SNE but returns integer instead of 1.0/0.0 float
1520 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1522 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1524 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1526 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1529 .. opcode:: USNE - Integer Set On Not Equal
1533 dst.x = (src0.x != src1.x) ? \sim 0 : 0
1535 dst.y = (src0.y != src1.y) ? \sim 0 : 0
1537 dst.z = (src0.z != src1.z) ? \sim 0 : 0
1539 dst.w = (src0.w != src1.w) ? \sim 0 : 0
1542 .. opcode:: INEG - Integer Negate
1557 .. opcode:: IABS - Integer Absolute Value
1571 These opcodes are used for bit-level manipulation of integers.
1573 .. opcode:: IBFE - Signed Bitfield Extract
1575 See SM5 instruction of the same name. Extracts a set of bits from the input,
1576 and sign-extends them if the high bit of the extracted window is set.
1580 def ibfe(value, offset, bits):
1581 offset = offset & 0x1f
1583 if bits == 0: return 0
1584 # Note: >> sign-extends
1585 if width + offset < 32:
1586 return (value << (32 - offset - bits)) >> (32 - bits)
1588 return value >> offset
1590 .. opcode:: UBFE - Unsigned Bitfield Extract
1592 See SM5 instruction of the same name. Extracts a set of bits from the input,
1593 without any sign-extension.
1597 def ubfe(value, offset, bits):
1598 offset = offset & 0x1f
1600 if bits == 0: return 0
1601 # Note: >> does not sign-extend
1602 if width + offset < 32:
1603 return (value << (32 - offset - bits)) >> (32 - bits)
1605 return value >> offset
1607 .. opcode:: BFI - Bitfield Insert
1609 See SM5 instruction of the same name. Replaces a bit region of 'base' with
1610 the low bits of 'insert'.
1614 def bfi(base, insert, offset, bits):
1615 offset = offset & 0x1f
1617 mask = ((1 << bits) - 1) << offset
1618 return ((insert << offset) & mask) | (base & ~mask)
1620 .. opcode:: BREV - Bitfield Reverse
1622 See SM5 instruction BFREV. Reverses the bits of the argument.
1624 .. opcode:: POPC - Population Count
1626 See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
1628 .. opcode:: LSB - Index of lowest set bit
1630 See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
1631 bit of the argument. Returns -1 if none are set.
1633 .. opcode:: IMSB - Index of highest non-sign bit
1635 See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
1636 non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
1637 highest 1 bit for positive numbers). Returns -1 if all bits are the same
1638 (i.e. for inputs 0 and -1).
1640 .. opcode:: UMSB - Index of highest set bit
1642 See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
1643 set bit of the argument. Returns -1 if none are set.
1646 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1648 These opcodes are only supported in geometry shaders; they have no meaning
1649 in any other type of shader.
1651 .. opcode:: EMIT - Emit
1653 Generate a new vertex for the current primitive into the specified vertex
1654 stream using the values in the output registers.
1657 .. opcode:: ENDPRIM - End Primitive
1659 Complete the current primitive in the specified vertex stream (consisting of
1660 the emitted vertices), and start a new one.
1666 These opcodes are part of :term:`GLSL`'s opcode set. Support for these
1667 opcodes is determined by a special capability bit, ``GLSL``.
1668 Some require glsl version 1.30 (UIF/BREAKC/SWITCH/CASE/DEFAULT/ENDSWITCH).
1670 .. opcode:: CAL - Subroutine Call
1676 .. opcode:: RET - Subroutine Call Return
1681 .. opcode:: CONT - Continue
1683 Unconditionally moves the point of execution to the instruction after the
1684 last bgnloop. The instruction must appear within a bgnloop/endloop.
1688 Support for CONT is determined by a special capability bit,
1689 ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
1692 .. opcode:: BGNLOOP - Begin a Loop
1694 Start a loop. Must have a matching endloop.
1697 .. opcode:: BGNSUB - Begin Subroutine
1699 Starts definition of a subroutine. Must have a matching endsub.
1702 .. opcode:: ENDLOOP - End a Loop
1704 End a loop started with bgnloop.
1707 .. opcode:: ENDSUB - End Subroutine
1709 Ends definition of a subroutine.
1712 .. opcode:: NOP - No Operation
1717 .. opcode:: BRK - Break
1719 Unconditionally moves the point of execution to the instruction after the
1720 next endloop or endswitch. The instruction must appear within a loop/endloop
1721 or switch/endswitch.
1724 .. opcode:: BREAKC - Break Conditional
1726 Conditionally 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.
1729 Condition evaluates to true if src0.x != 0 where src0.x is interpreted
1730 as an integer register.
1734 Considered for removal as it's quite inconsistent wrt other opcodes
1735 (could emulate with UIF/BRK/ENDIF).
1738 .. opcode:: IF - Float If
1740 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
1744 where src0.x is interpreted as a floating point register.
1747 .. opcode:: UIF - Bitwise If
1749 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
1753 where src0.x is interpreted as an integer register.
1756 .. opcode:: ELSE - Else
1758 Starts an else block, after an IF or UIF statement.
1761 .. opcode:: ENDIF - End If
1763 Ends an IF or UIF block.
1766 .. opcode:: SWITCH - Switch
1768 Starts a C-style switch expression. The switch consists of one or multiple
1769 CASE statements, and at most one DEFAULT statement. Execution of a statement
1770 ends when a BRK is hit, but just like in C falling through to other cases
1771 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
1772 just as last statement, and fallthrough is allowed into/from it.
1773 CASE src arguments are evaluated at bit level against the SWITCH src argument.
1779 (some instructions here)
1782 (some instructions here)
1785 (some instructions here)
1790 .. opcode:: CASE - Switch case
1792 This represents a switch case label. The src arg must be an integer immediate.
1795 .. opcode:: DEFAULT - Switch default
1797 This represents the default case in the switch, which is taken if no other
1801 .. opcode:: ENDSWITCH - End of switch
1803 Ends a switch expression.
1806 .. opcode:: NRM4 - 4-component Vector Normalise
1808 This instruction replicates its result.
1812 dst = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
1818 The interpolation instructions allow an input to be interpolated in a
1819 different way than its declaration. This corresponds to the GLSL 4.00
1820 interpolateAt* functions. The first argument of each of these must come from
1821 ``TGSI_FILE_INPUT``.
1823 .. opcode:: INTERP_CENTROID - Interpolate at the centroid
1825 Interpolates the varying specified by src0 at the centroid
1827 .. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
1829 Interpolates the varying specified by src0 at the sample id specified by
1830 src1.x (interpreted as an integer)
1832 .. opcode:: INTERP_OFFSET - Interpolate at the specified offset
1834 Interpolates the varying specified by src0 at the offset src1.xy from the
1835 pixel center (interpreted as floats)
1843 The double-precision opcodes reinterpret four-component vectors into
1844 two-component vectors with doubled precision in each component.
1846 Support for these opcodes is XXX undecided. :T
1848 .. opcode:: DADD - Add
1852 dst.xy = src0.xy + src1.xy
1854 dst.zw = src0.zw + src1.zw
1857 .. opcode:: DDIV - Divide
1861 dst.xy = src0.xy / src1.xy
1863 dst.zw = src0.zw / src1.zw
1865 .. opcode:: DSEQ - Set on Equal
1869 dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
1871 dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
1873 .. opcode:: DSLT - Set on Less than
1877 dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
1879 dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
1881 .. opcode:: DFRAC - Fraction
1885 dst.xy = src.xy - \lfloor src.xy\rfloor
1887 dst.zw = src.zw - \lfloor src.zw\rfloor
1890 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1892 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1893 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1894 :math:`dst1 \times 2^{dst0} = src` .
1898 dst0.xy = exp(src.xy)
1900 dst1.xy = frac(src.xy)
1902 dst0.zw = exp(src.zw)
1904 dst1.zw = frac(src.zw)
1906 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1908 This opcode is the inverse of :opcode:`DFRACEXP`.
1912 dst.xy = src0.xy \times 2^{src1.xy}
1914 dst.zw = src0.zw \times 2^{src1.zw}
1916 .. opcode:: DMIN - Minimum
1920 dst.xy = min(src0.xy, src1.xy)
1922 dst.zw = min(src0.zw, src1.zw)
1924 .. opcode:: DMAX - Maximum
1928 dst.xy = max(src0.xy, src1.xy)
1930 dst.zw = max(src0.zw, src1.zw)
1932 .. opcode:: DMUL - Multiply
1936 dst.xy = src0.xy \times src1.xy
1938 dst.zw = src0.zw \times src1.zw
1941 .. opcode:: DMAD - Multiply And Add
1945 dst.xy = src0.xy \times src1.xy + src2.xy
1947 dst.zw = src0.zw \times src1.zw + src2.zw
1950 .. opcode:: DRCP - Reciprocal
1954 dst.xy = \frac{1}{src.xy}
1956 dst.zw = \frac{1}{src.zw}
1958 .. opcode:: DSQRT - Square Root
1962 dst.xy = \sqrt{src.xy}
1964 dst.zw = \sqrt{src.zw}
1967 .. _samplingopcodes:
1969 Resource Sampling Opcodes
1970 ^^^^^^^^^^^^^^^^^^^^^^^^^
1972 Those opcodes follow very closely semantics of the respective Direct3D
1973 instructions. If in doubt double check Direct3D documentation.
1974 Note that the swizzle on SVIEW (src1) determines texel swizzling
1979 Using provided address, sample data from the specified texture using the
1980 filtering mode identified by the gven sampler. The source data may come from
1981 any resource type other than buffers.
1983 Syntax: ``SAMPLE dst, address, sampler_view, sampler``
1985 Example: ``SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]``
1987 .. opcode:: SAMPLE_I
1989 Simplified alternative to the SAMPLE instruction. Using the provided
1990 integer address, SAMPLE_I fetches data from the specified sampler view
1991 without any filtering. The source data may come from any resource type
1994 Syntax: ``SAMPLE_I dst, address, sampler_view``
1996 Example: ``SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]``
1998 The 'address' is specified as unsigned integers. If the 'address' is out of
1999 range [0...(# texels - 1)] the result of the fetch is always 0 in all
2000 components. As such the instruction doesn't honor address wrap modes, in
2001 cases where that behavior is desirable 'SAMPLE' instruction should be used.
2002 address.w always provides an unsigned integer mipmap level. If the value is
2003 out of the range then the instruction always returns 0 in all components.
2004 address.yz are ignored for buffers and 1d textures. address.z is ignored
2005 for 1d texture arrays and 2d textures.
2007 For 1D texture arrays address.y provides the array index (also as unsigned
2008 integer). If the value is out of the range of available array indices
2009 [0... (array size - 1)] then the opcode always returns 0 in all components.
2010 For 2D texture arrays address.z provides the array index, otherwise it
2011 exhibits the same behavior as in the case for 1D texture arrays. The exact
2012 semantics of the source address are presented in the table below:
2014 +---------------------------+----+-----+-----+---------+
2015 | resource type | X | Y | Z | W |
2016 +===========================+====+=====+=====+=========+
2017 | ``PIPE_BUFFER`` | x | | | ignored |
2018 +---------------------------+----+-----+-----+---------+
2019 | ``PIPE_TEXTURE_1D`` | x | | | mpl |
2020 +---------------------------+----+-----+-----+---------+
2021 | ``PIPE_TEXTURE_2D`` | x | y | | mpl |
2022 +---------------------------+----+-----+-----+---------+
2023 | ``PIPE_TEXTURE_3D`` | x | y | z | mpl |
2024 +---------------------------+----+-----+-----+---------+
2025 | ``PIPE_TEXTURE_RECT`` | x | y | | mpl |
2026 +---------------------------+----+-----+-----+---------+
2027 | ``PIPE_TEXTURE_CUBE`` | not allowed as source |
2028 +---------------------------+----+-----+-----+---------+
2029 | ``PIPE_TEXTURE_1D_ARRAY`` | x | idx | | mpl |
2030 +---------------------------+----+-----+-----+---------+
2031 | ``PIPE_TEXTURE_2D_ARRAY`` | x | y | idx | mpl |
2032 +---------------------------+----+-----+-----+---------+
2034 Where 'mpl' is a mipmap level and 'idx' is the array index.
2036 .. opcode:: SAMPLE_I_MS
2038 Just like SAMPLE_I but allows fetch data from multi-sampled surfaces.
2040 Syntax: ``SAMPLE_I_MS dst, address, sampler_view, sample``
2042 .. opcode:: SAMPLE_B
2044 Just like the SAMPLE instruction with the exception that an additional bias
2045 is applied to the level of detail computed as part of the instruction
2048 Syntax: ``SAMPLE_B dst, address, sampler_view, sampler, lod_bias``
2050 Example: ``SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2052 .. opcode:: SAMPLE_C
2054 Similar to the SAMPLE instruction but it performs a comparison filter. The
2055 operands to SAMPLE_C are identical to SAMPLE, except that there is an
2056 additional float32 operand, reference value, which must be a register with
2057 single-component, or a scalar literal. SAMPLE_C makes the hardware use the
2058 current samplers compare_func (in pipe_sampler_state) to compare reference
2059 value against the red component value for the surce resource at each texel
2060 that the currently configured texture filter covers based on the provided
2063 Syntax: ``SAMPLE_C dst, address, sampler_view.r, sampler, ref_value``
2065 Example: ``SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2067 .. opcode:: SAMPLE_C_LZ
2069 Same as SAMPLE_C, but LOD is 0 and derivatives are ignored. The LZ stands
2072 Syntax: ``SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value``
2074 Example: ``SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x``
2077 .. opcode:: SAMPLE_D
2079 SAMPLE_D is identical to the SAMPLE opcode except that the derivatives for
2080 the source address in the x direction and the y direction are provided by
2083 Syntax: ``SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y``
2085 Example: ``SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]``
2087 .. opcode:: SAMPLE_L
2089 SAMPLE_L is identical to the SAMPLE opcode except that the LOD is provided
2090 directly as a scalar value, representing no anisotropy.
2092 Syntax: ``SAMPLE_L dst, address, sampler_view, sampler, explicit_lod``
2094 Example: ``SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x``
2098 Gathers the four texels to be used in a bi-linear filtering operation and
2099 packs them into a single register. Only works with 2D, 2D array, cubemaps,
2100 and cubemaps arrays. For 2D textures, only the addressing modes of the
2101 sampler and the top level of any mip pyramid are used. Set W to zero. It
2102 behaves like the SAMPLE instruction, but a filtered sample is not
2103 generated. The four samples that contribute to filtering are placed into
2104 xyzw in counter-clockwise order, starting with the (u,v) texture coordinate
2105 delta at the following locations (-, +), (+, +), (+, -), (-, -), where the
2106 magnitude of the deltas are half a texel.
2109 .. opcode:: SVIEWINFO
2111 Query the dimensions of a given sampler view. dst receives width, height,
2112 depth or array size and number of mipmap levels as int4. The dst can have a
2113 writemask which will specify what info is the caller interested in.
2115 Syntax: ``SVIEWINFO dst, src_mip_level, sampler_view``
2117 Example: ``SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]``
2119 src_mip_level is an unsigned integer scalar. If it's out of range then
2120 returns 0 for width, height and depth/array size but the total number of
2121 mipmap is still returned correctly for the given sampler view. The returned
2122 width, height and depth values are for the mipmap level selected by the
2123 src_mip_level and are in the number of texels. For 1d texture array width
2124 is in dst.x, array size is in dst.y and dst.z is 0. The number of mipmaps is
2125 still in dst.w. In contrast to d3d10 resinfo, there's no way in the tgsi
2126 instruction encoding to specify the return type (float/rcpfloat/uint), hence
2127 always using uint. Also, unlike the SAMPLE instructions, the swizzle on src1
2128 resinfo allowing swizzling dst values is ignored (due to the interaction
2129 with rcpfloat modifier which requires some swizzle handling in the state
2132 .. opcode:: SAMPLE_POS
2134 Query the position of a given sample. dst receives float4 (x, y, 0, 0)
2135 indicated where the sample is located. If the resource is not a multi-sample
2136 resource and not a render target, the result is 0.
2138 .. opcode:: SAMPLE_INFO
2140 dst receives number of samples in x. If the resource is not a multi-sample
2141 resource and not a render target, the result is 0.
2144 .. _resourceopcodes:
2146 Resource Access Opcodes
2147 ^^^^^^^^^^^^^^^^^^^^^^^
2149 .. opcode:: LOAD - Fetch data from a shader resource
2151 Syntax: ``LOAD dst, resource, address``
2153 Example: ``LOAD TEMP[0], RES[0], TEMP[1]``
2155 Using the provided integer address, LOAD fetches data
2156 from the specified buffer or texture without any
2159 The 'address' is specified as a vector of unsigned
2160 integers. If the 'address' is out of range the result
2163 Only the first mipmap level of a resource can be read
2164 from using this instruction.
2166 For 1D or 2D texture arrays, the array index is
2167 provided as an unsigned integer in address.y or
2168 address.z, respectively. address.yz are ignored for
2169 buffers and 1D textures. address.z is ignored for 1D
2170 texture arrays and 2D textures. address.w is always
2173 .. opcode:: STORE - Write data to a shader resource
2175 Syntax: ``STORE resource, address, src``
2177 Example: ``STORE RES[0], TEMP[0], TEMP[1]``
2179 Using the provided integer address, STORE writes data
2180 to the specified buffer or texture.
2182 The 'address' is specified as a vector of unsigned
2183 integers. If the 'address' is out of range the result
2186 Only the first mipmap level of a resource can be
2187 written to using this instruction.
2189 For 1D or 2D texture arrays, the array index is
2190 provided as an unsigned integer in address.y or
2191 address.z, respectively. address.yz are ignored for
2192 buffers and 1D textures. address.z is ignored for 1D
2193 texture arrays and 2D textures. address.w is always
2197 .. _threadsyncopcodes:
2199 Inter-thread synchronization opcodes
2200 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2202 These opcodes are intended for communication between threads running
2203 within the same compute grid. For now they're only valid in compute
2206 .. opcode:: MFENCE - Memory fence
2208 Syntax: ``MFENCE resource``
2210 Example: ``MFENCE RES[0]``
2212 This opcode forces strong ordering between any memory access
2213 operations that affect the specified resource. This means that
2214 previous loads and stores (and only those) will be performed and
2215 visible to other threads before the program execution continues.
2218 .. opcode:: LFENCE - Load memory fence
2220 Syntax: ``LFENCE resource``
2222 Example: ``LFENCE RES[0]``
2224 Similar to MFENCE, but it only affects the ordering of memory loads.
2227 .. opcode:: SFENCE - Store memory fence
2229 Syntax: ``SFENCE resource``
2231 Example: ``SFENCE RES[0]``
2233 Similar to MFENCE, but it only affects the ordering of memory stores.
2236 .. opcode:: BARRIER - Thread group barrier
2240 This opcode suspends the execution of the current thread until all
2241 the remaining threads in the working group reach the same point of
2242 the program. Results are unspecified if any of the remaining
2243 threads terminates or never reaches an executed BARRIER instruction.
2251 These opcodes provide atomic variants of some common arithmetic and
2252 logical operations. In this context atomicity means that another
2253 concurrent memory access operation that affects the same memory
2254 location is guaranteed to be performed strictly before or after the
2255 entire execution of the atomic operation.
2257 For the moment they're only valid in compute programs.
2259 .. opcode:: ATOMUADD - Atomic integer addition
2261 Syntax: ``ATOMUADD dst, resource, offset, src``
2263 Example: ``ATOMUADD TEMP[0], RES[0], TEMP[1], TEMP[2]``
2265 The following operation is performed atomically on each component:
2269 dst_i = resource[offset]_i
2271 resource[offset]_i = dst_i + src_i
2274 .. opcode:: ATOMXCHG - Atomic exchange
2276 Syntax: ``ATOMXCHG dst, resource, offset, src``
2278 Example: ``ATOMXCHG TEMP[0], RES[0], TEMP[1], TEMP[2]``
2280 The following operation is performed atomically on each component:
2284 dst_i = resource[offset]_i
2286 resource[offset]_i = src_i
2289 .. opcode:: ATOMCAS - Atomic compare-and-exchange
2291 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
2293 Example: ``ATOMCAS TEMP[0], RES[0], TEMP[1], TEMP[2], TEMP[3]``
2295 The following operation is performed atomically on each component:
2299 dst_i = resource[offset]_i
2301 resource[offset]_i = (dst_i == cmp_i ? src_i : dst_i)
2304 .. opcode:: ATOMAND - Atomic bitwise And
2306 Syntax: ``ATOMAND dst, resource, offset, src``
2308 Example: ``ATOMAND TEMP[0], RES[0], TEMP[1], TEMP[2]``
2310 The following operation is performed atomically on each component:
2314 dst_i = resource[offset]_i
2316 resource[offset]_i = dst_i \& src_i
2319 .. opcode:: ATOMOR - Atomic bitwise Or
2321 Syntax: ``ATOMOR dst, resource, offset, src``
2323 Example: ``ATOMOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2325 The following operation is performed atomically on each component:
2329 dst_i = resource[offset]_i
2331 resource[offset]_i = dst_i | src_i
2334 .. opcode:: ATOMXOR - Atomic bitwise Xor
2336 Syntax: ``ATOMXOR dst, resource, offset, src``
2338 Example: ``ATOMXOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
2340 The following operation is performed atomically on each component:
2344 dst_i = resource[offset]_i
2346 resource[offset]_i = dst_i \oplus src_i
2349 .. opcode:: ATOMUMIN - Atomic unsigned minimum
2351 Syntax: ``ATOMUMIN dst, resource, offset, src``
2353 Example: ``ATOMUMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
2355 The following operation is performed atomically on each component:
2359 dst_i = resource[offset]_i
2361 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
2364 .. opcode:: ATOMUMAX - Atomic unsigned maximum
2366 Syntax: ``ATOMUMAX dst, resource, offset, src``
2368 Example: ``ATOMUMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
2370 The following operation is performed atomically on each component:
2374 dst_i = resource[offset]_i
2376 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
2379 .. opcode:: ATOMIMIN - Atomic signed minimum
2381 Syntax: ``ATOMIMIN dst, resource, offset, src``
2383 Example: ``ATOMIMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
2385 The following operation is performed atomically on each component:
2389 dst_i = resource[offset]_i
2391 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
2394 .. opcode:: ATOMIMAX - Atomic signed maximum
2396 Syntax: ``ATOMIMAX dst, resource, offset, src``
2398 Example: ``ATOMIMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
2400 The following operation is performed atomically on each component:
2404 dst_i = resource[offset]_i
2406 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
2410 Explanation of symbols used
2411 ------------------------------
2418 :math:`|x|` Absolute value of `x`.
2420 :math:`\lceil x \rceil` Ceiling of `x`.
2422 clamp(x,y,z) Clamp x between y and z.
2423 (x < y) ? y : (x > z) ? z : x
2425 :math:`\lfloor x\rfloor` Floor of `x`.
2427 :math:`\log_2{x}` Logarithm of `x`, base 2.
2429 max(x,y) Maximum of x and y.
2432 min(x,y) Minimum of x and y.
2435 partialx(x) Derivative of x relative to fragment's X.
2437 partialy(x) Derivative of x relative to fragment's Y.
2439 pop() Pop from stack.
2441 :math:`x^y` `x` to the power `y`.
2443 push(x) Push x on stack.
2447 trunc(x) Truncate x, i.e. drop the fraction bits.
2454 discard Discard fragment.
2458 target Label of target instruction.
2469 Declares a register that is will be referenced as an operand in Instruction
2472 File field contains register file that is being declared and is one
2475 UsageMask field specifies which of the register components can be accessed
2476 and is one of TGSI_WRITEMASK.
2478 The Local flag specifies that a given value isn't intended for
2479 subroutine parameter passing and, as a result, the implementation
2480 isn't required to give any guarantees of it being preserved across
2481 subroutine boundaries. As it's merely a compiler hint, the
2482 implementation is free to ignore it.
2484 If Dimension flag is set to 1, a Declaration Dimension token follows.
2486 If Semantic flag is set to 1, a Declaration Semantic token follows.
2488 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
2490 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
2492 If Array flag is set to 1, a Declaration Array token follows.
2495 ^^^^^^^^^^^^^^^^^^^^^^^^
2497 Declarations can optional have an ArrayID attribute which can be referred by
2498 indirect addressing operands. An ArrayID of zero is reserved and treaded as
2499 if no ArrayID is specified.
2501 If an indirect addressing operand refers to a specific declaration by using
2502 an ArrayID only the registers in this declaration are guaranteed to be
2503 accessed, accessing any register outside this declaration results in undefined
2504 behavior. Note that for compatibility the effective index is zero-based and
2505 not relative to the specified declaration
2507 If no ArrayID is specified with an indirect addressing operand the whole
2508 register file might be accessed by this operand. This is strongly discouraged
2509 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
2511 Declaration Semantic
2512 ^^^^^^^^^^^^^^^^^^^^^^^^
2514 Vertex and fragment shader input and output registers may be labeled
2515 with semantic information consisting of a name and index.
2517 Follows Declaration token if Semantic bit is set.
2519 Since its purpose is to link a shader with other stages of the pipeline,
2520 it is valid to follow only those Declaration tokens that declare a register
2521 either in INPUT or OUTPUT file.
2523 SemanticName field contains the semantic name of the register being declared.
2524 There is no default value.
2526 SemanticIndex is an optional subscript that can be used to distinguish
2527 different register declarations with the same semantic name. The default value
2530 The meanings of the individual semantic names are explained in the following
2533 TGSI_SEMANTIC_POSITION
2534 """"""""""""""""""""""
2536 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
2537 output register which contains the homogeneous vertex position in the clip
2538 space coordinate system. After clipping, the X, Y and Z components of the
2539 vertex will be divided by the W value to get normalized device coordinates.
2541 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
2542 fragment shader input contains the fragment's window position. The X
2543 component starts at zero and always increases from left to right.
2544 The Y component starts at zero and always increases but Y=0 may either
2545 indicate the top of the window or the bottom depending on the fragment
2546 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
2547 The Z coordinate ranges from 0 to 1 to represent depth from the front
2548 to the back of the Z buffer. The W component contains the reciprocol
2549 of the interpolated vertex position W component.
2551 Fragment shaders may also declare an output register with
2552 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
2553 the fragment shader to change the fragment's Z position.
2560 For vertex shader outputs or fragment shader inputs/outputs, this
2561 label indicates that the resister contains an R,G,B,A color.
2563 Several shader inputs/outputs may contain colors so the semantic index
2564 is used to distinguish them. For example, color[0] may be the diffuse
2565 color while color[1] may be the specular color.
2567 This label is needed so that the flat/smooth shading can be applied
2568 to the right interpolants during rasterization.
2572 TGSI_SEMANTIC_BCOLOR
2573 """"""""""""""""""""
2575 Back-facing colors are only used for back-facing polygons, and are only valid
2576 in vertex shader outputs. After rasterization, all polygons are front-facing
2577 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
2578 so all BCOLORs effectively become regular COLORs in the fragment shader.
2584 Vertex shader inputs and outputs and fragment shader inputs may be
2585 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
2586 a fog coordinate. Typically, the fragment shader will use the fog coordinate
2587 to compute a fog blend factor which is used to blend the normal fragment color
2588 with a constant fog color. But fog coord really is just an ordinary vec4
2589 register like regular semantics.
2595 Vertex shader input and output registers may be labeled with
2596 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
2597 in the form (S, 0, 0, 1). The point size controls the width or diameter
2598 of points for rasterization. This label cannot be used in fragment
2601 When using this semantic, be sure to set the appropriate state in the
2602 :ref:`rasterizer` first.
2605 TGSI_SEMANTIC_TEXCOORD
2606 """"""""""""""""""""""
2608 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2610 Vertex shader outputs and fragment shader inputs may be labeled with
2611 this semantic to make them replaceable by sprite coordinates via the
2612 sprite_coord_enable state in the :ref:`rasterizer`.
2613 The semantic index permitted with this semantic is limited to <= 7.
2615 If the driver does not support TEXCOORD, sprite coordinate replacement
2616 applies to inputs with the GENERIC semantic instead.
2618 The intended use case for this semantic is gl_TexCoord.
2621 TGSI_SEMANTIC_PCOORD
2622 """"""""""""""""""""
2624 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2626 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
2627 that the register contains sprite coordinates in the form (x, y, 0, 1), if
2628 the current primitive is a point and point sprites are enabled. Otherwise,
2629 the contents of the register are undefined.
2631 The intended use case for this semantic is gl_PointCoord.
2634 TGSI_SEMANTIC_GENERIC
2635 """""""""""""""""""""
2637 All vertex/fragment shader inputs/outputs not labeled with any other
2638 semantic label can be considered to be generic attributes. Typical
2639 uses of generic inputs/outputs are texcoords and user-defined values.
2642 TGSI_SEMANTIC_NORMAL
2643 """"""""""""""""""""
2645 Indicates that a vertex shader input is a normal vector. This is
2646 typically only used for legacy graphics APIs.
2652 This label applies to fragment shader inputs only and indicates that
2653 the register contains front/back-face information of the form (F, 0,
2654 0, 1). The first component will be positive when the fragment belongs
2655 to a front-facing polygon, and negative when the fragment belongs to a
2656 back-facing polygon.
2659 TGSI_SEMANTIC_EDGEFLAG
2660 """"""""""""""""""""""
2662 For vertex shaders, this sematic label indicates that an input or
2663 output is a boolean edge flag. The register layout is [F, x, x, x]
2664 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
2665 simply copies the edge flag input to the edgeflag output.
2667 Edge flags are used to control which lines or points are actually
2668 drawn when the polygon mode converts triangles/quads/polygons into
2672 TGSI_SEMANTIC_STENCIL
2673 """""""""""""""""""""
2675 For fragment shaders, this semantic label indicates that an output
2676 is a writable stencil reference value. Only the Y component is writable.
2677 This allows the fragment shader to change the fragments stencilref value.
2680 TGSI_SEMANTIC_VIEWPORT_INDEX
2681 """"""""""""""""""""""""""""
2683 For geometry shaders, this semantic label indicates that an output
2684 contains the index of the viewport (and scissor) to use.
2685 Only the X value is used.
2691 For geometry shaders, this semantic label indicates that an output
2692 contains the layer value to use for the color and depth/stencil surfaces.
2693 Only the X value is used. (Also known as rendertarget array index.)
2696 TGSI_SEMANTIC_CULLDIST
2697 """"""""""""""""""""""
2699 Used as distance to plane for performing application-defined culling
2700 of individual primitives against a plane. When components of vertex
2701 elements are given this label, these values are assumed to be a
2702 float32 signed distance to a plane. Primitives will be completely
2703 discarded if the plane distance for all of the vertices in the
2704 primitive are < 0. If a vertex has a cull distance of NaN, that
2705 vertex counts as "out" (as if its < 0);
2706 The limits on both clip and cull distances are bound
2707 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2708 the maximum number of components that can be used to hold the
2709 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2710 which specifies the maximum number of registers which can be
2711 annotated with those semantics.
2714 TGSI_SEMANTIC_CLIPDIST
2715 """"""""""""""""""""""
2717 When components of vertex elements are identified this way, these
2718 values are each assumed to be a float32 signed distance to a plane.
2719 Primitive setup only invokes rasterization on pixels for which
2720 the interpolated plane distances are >= 0. Multiple clip planes
2721 can be implemented simultaneously, by annotating multiple
2722 components of one or more vertex elements with the above specified
2723 semantic. The limits on both clip and cull distances are bound
2724 by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT define which defines
2725 the maximum number of components that can be used to hold the
2726 distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
2727 which specifies the maximum number of registers which can be
2728 annotated with those semantics.
2730 TGSI_SEMANTIC_SAMPLEID
2731 """"""""""""""""""""""
2733 For fragment shaders, this semantic label indicates that a system value
2734 contains the current sample id (i.e. gl_SampleID). Only the X value is used.
2736 TGSI_SEMANTIC_SAMPLEPOS
2737 """""""""""""""""""""""
2739 For fragment shaders, this semantic label indicates that a system value
2740 contains the current sample's position (i.e. gl_SamplePosition). Only the X
2741 and Y values are used.
2743 TGSI_SEMANTIC_SAMPLEMASK
2744 """"""""""""""""""""""""
2746 For fragment shaders, this semantic label indicates that an output contains
2747 the sample mask used to disable further sample processing
2748 (i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
2750 TGSI_SEMANTIC_INVOCATIONID
2751 """"""""""""""""""""""""""
2753 For geometry shaders, this semantic label indicates that a system value
2754 contains the current invocation id (i.e. gl_InvocationID). Only the X value is
2757 Declaration Interpolate
2758 ^^^^^^^^^^^^^^^^^^^^^^^
2760 This token is only valid for fragment shader INPUT declarations.
2762 The Interpolate field specifes the way input is being interpolated by
2763 the rasteriser and is one of TGSI_INTERPOLATE_*.
2765 The Location field specifies the location inside the pixel that the
2766 interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
2767 when per-sample shading is enabled, the implementation may choose to
2768 interpolate at the sample irrespective of the Location field.
2770 The CylindricalWrap bitfield specifies which register components
2771 should be subject to cylindrical wrapping when interpolating by the
2772 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
2773 should be interpolated according to cylindrical wrapping rules.
2776 Declaration Sampler View
2777 ^^^^^^^^^^^^^^^^^^^^^^^^
2779 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
2781 DCL SVIEW[#], resource, type(s)
2783 Declares a shader input sampler view and assigns it to a SVIEW[#]
2786 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
2788 type must be 1 or 4 entries (if specifying on a per-component
2789 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
2792 Declaration Resource
2793 ^^^^^^^^^^^^^^^^^^^^
2795 Follows Declaration token if file is TGSI_FILE_RESOURCE.
2797 DCL RES[#], resource [, WR] [, RAW]
2799 Declares a shader input resource and assigns it to a RES[#]
2802 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
2805 If the RAW keyword is not specified, the texture data will be
2806 subject to conversion, swizzling and scaling as required to yield
2807 the specified data type from the physical data format of the bound
2810 If the RAW keyword is specified, no channel conversion will be
2811 performed: the values read for each of the channels (X,Y,Z,W) will
2812 correspond to consecutive words in the same order and format
2813 they're found in memory. No element-to-address conversion will be
2814 performed either: the value of the provided X coordinate will be
2815 interpreted in byte units instead of texel units. The result of
2816 accessing a misaligned address is undefined.
2818 Usage of the STORE opcode is only allowed if the WR (writable) flag
2823 ^^^^^^^^^^^^^^^^^^^^^^^^
2825 Properties are general directives that apply to the whole TGSI program.
2830 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
2831 The default value is UPPER_LEFT.
2833 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
2834 increase downward and rightward.
2835 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
2836 increase upward and rightward.
2838 OpenGL defaults to LOWER_LEFT, and is configurable with the
2839 GL_ARB_fragment_coord_conventions extension.
2841 DirectX 9/10 use UPPER_LEFT.
2843 FS_COORD_PIXEL_CENTER
2844 """""""""""""""""""""
2846 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
2847 The default value is HALF_INTEGER.
2849 If HALF_INTEGER, the fractionary part of the position will be 0.5
2850 If INTEGER, the fractionary part of the position will be 0.0
2852 Note that this does not affect the set of fragments generated by
2853 rasterization, which is instead controlled by half_pixel_center in the
2856 OpenGL defaults to HALF_INTEGER, and is configurable with the
2857 GL_ARB_fragment_coord_conventions extension.
2859 DirectX 9 uses INTEGER.
2860 DirectX 10 uses HALF_INTEGER.
2862 FS_COLOR0_WRITES_ALL_CBUFS
2863 """"""""""""""""""""""""""
2864 Specifies that writes to the fragment shader color 0 are replicated to all
2865 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
2866 fragData is directed to a single color buffer, but fragColor is broadcast.
2869 """"""""""""""""""""""""""
2870 If this property is set on the program bound to the shader stage before the
2871 fragment shader, user clip planes should have no effect (be disabled) even if
2872 that shader does not write to any clip distance outputs and the rasterizer's
2873 clip_plane_enable is non-zero.
2874 This property is only supported by drivers that also support shader clip
2876 This is useful for APIs that don't have UCPs and where clip distances written
2877 by a shader cannot be disabled.
2882 Specifies the number of times a geometry shader should be executed for each
2883 input primitive. Each invocation will have a different
2884 TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
2887 VS_WINDOW_SPACE_POSITION
2888 """"""""""""""""""""""""""
2889 If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
2890 is assumed to contain window space coordinates.
2891 Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
2892 directly taken from the 4-th component of the shader output.
2893 Naturally, clipping is not performed on window coordinates either.
2894 The effect of this property is undefined if a geometry or tessellation shader
2897 Texture Sampling and Texture Formats
2898 ------------------------------------
2900 This table shows how texture image components are returned as (x,y,z,w) tuples
2901 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
2902 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
2905 +--------------------+--------------+--------------------+--------------+
2906 | Texture Components | Gallium | OpenGL | Direct3D 9 |
2907 +====================+==============+====================+==============+
2908 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
2909 +--------------------+--------------+--------------------+--------------+
2910 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
2911 +--------------------+--------------+--------------------+--------------+
2912 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
2913 +--------------------+--------------+--------------------+--------------+
2914 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
2915 +--------------------+--------------+--------------------+--------------+
2916 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
2917 +--------------------+--------------+--------------------+--------------+
2918 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
2919 +--------------------+--------------+--------------------+--------------+
2920 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
2921 +--------------------+--------------+--------------------+--------------+
2922 | I | (i, i, i, i) | (i, i, i, i) | N/A |
2923 +--------------------+--------------+--------------------+--------------+
2924 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
2925 | | | [#envmap-bumpmap]_ | |
2926 +--------------------+--------------+--------------------+--------------+
2927 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
2928 | | | [#depth-tex-mode]_ | |
2929 +--------------------+--------------+--------------------+--------------+
2930 | S | (s, s, s, s) | unknown | unknown |
2931 +--------------------+--------------+--------------------+--------------+
2933 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
2934 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
2935 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.