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:`Double Opcodes`.
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 type only the negate modifier is supported. This
36 includes instructions which are otherwise ignorant if the type is signed or
37 unsigned, such as TGSI_OPCODE_UADD.
39 For inputs with unsigned type no modifiers are allowed.
45 ^^^^^^^^^^^^^^^^^^^^^^^^^
47 These opcodes are guaranteed to be available regardless of the driver being
50 .. opcode:: ARL - Address Register Load
54 dst.x = \lfloor src.x\rfloor
56 dst.y = \lfloor src.y\rfloor
58 dst.z = \lfloor src.z\rfloor
60 dst.w = \lfloor src.w\rfloor
63 .. opcode:: MOV - Move
76 .. opcode:: LIT - Light Coefficients
84 dst.z = (src.x > 0) ? max(src.y, 0)^{clamp(src.w, -128, 128))} : 0
89 .. opcode:: RCP - Reciprocal
91 This instruction replicates its result.
98 .. opcode:: RSQ - Reciprocal Square Root
100 This instruction replicates its result.
104 dst = \frac{1}{\sqrt{|src.x|}}
107 .. opcode:: SQRT - Square Root
109 This instruction replicates its result.
116 .. opcode:: EXP - Approximate Exponential Base 2
120 dst.x = 2^{\lfloor src.x\rfloor}
122 dst.y = src.x - \lfloor src.x\rfloor
129 .. opcode:: LOG - Approximate Logarithm Base 2
133 dst.x = \lfloor\log_2{|src.x|}\rfloor
135 dst.y = \frac{|src.x|}{2^{\lfloor\log_2{|src.x|}\rfloor}}
137 dst.z = \log_2{|src.x|}
142 .. opcode:: MUL - Multiply
146 dst.x = src0.x \times src1.x
148 dst.y = src0.y \times src1.y
150 dst.z = src0.z \times src1.z
152 dst.w = src0.w \times src1.w
155 .. opcode:: ADD - Add
159 dst.x = src0.x + src1.x
161 dst.y = src0.y + src1.y
163 dst.z = src0.z + src1.z
165 dst.w = src0.w + src1.w
168 .. opcode:: DP3 - 3-component Dot Product
170 This instruction replicates its result.
174 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
177 .. opcode:: DP4 - 4-component Dot Product
179 This instruction replicates its result.
183 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w
186 .. opcode:: DST - Distance Vector
192 dst.y = src0.y \times src1.y
199 .. opcode:: MIN - Minimum
203 dst.x = min(src0.x, src1.x)
205 dst.y = min(src0.y, src1.y)
207 dst.z = min(src0.z, src1.z)
209 dst.w = min(src0.w, src1.w)
212 .. opcode:: MAX - Maximum
216 dst.x = max(src0.x, src1.x)
218 dst.y = max(src0.y, src1.y)
220 dst.z = max(src0.z, src1.z)
222 dst.w = max(src0.w, src1.w)
225 .. opcode:: SLT - Set On Less Than
229 dst.x = (src0.x < src1.x) ? 1 : 0
231 dst.y = (src0.y < src1.y) ? 1 : 0
233 dst.z = (src0.z < src1.z) ? 1 : 0
235 dst.w = (src0.w < src1.w) ? 1 : 0
238 .. opcode:: SGE - Set On Greater Equal Than
242 dst.x = (src0.x >= src1.x) ? 1 : 0
244 dst.y = (src0.y >= src1.y) ? 1 : 0
246 dst.z = (src0.z >= src1.z) ? 1 : 0
248 dst.w = (src0.w >= src1.w) ? 1 : 0
251 .. opcode:: MAD - Multiply And Add
255 dst.x = src0.x \times src1.x + src2.x
257 dst.y = src0.y \times src1.y + src2.y
259 dst.z = src0.z \times src1.z + src2.z
261 dst.w = src0.w \times src1.w + src2.w
264 .. opcode:: SUB - Subtract
268 dst.x = src0.x - src1.x
270 dst.y = src0.y - src1.y
272 dst.z = src0.z - src1.z
274 dst.w = src0.w - src1.w
277 .. opcode:: LRP - Linear Interpolate
281 dst.x = src0.x \times src1.x + (1 - src0.x) \times src2.x
283 dst.y = src0.y \times src1.y + (1 - src0.y) \times src2.y
285 dst.z = src0.z \times src1.z + (1 - src0.z) \times src2.z
287 dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
290 .. opcode:: CND - Condition
294 dst.x = (src2.x > 0.5) ? src0.x : src1.x
296 dst.y = (src2.y > 0.5) ? src0.y : src1.y
298 dst.z = (src2.z > 0.5) ? src0.z : src1.z
300 dst.w = (src2.w > 0.5) ? src0.w : src1.w
303 .. opcode:: DP2A - 2-component Dot Product And Add
307 dst.x = src0.x \times src1.x + src0.y \times src1.y + src2.x
309 dst.y = src0.x \times src1.x + src0.y \times src1.y + src2.x
311 dst.z = src0.x \times src1.x + src0.y \times src1.y + src2.x
313 dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x
316 .. opcode:: FRC - Fraction
320 dst.x = src.x - \lfloor src.x\rfloor
322 dst.y = src.y - \lfloor src.y\rfloor
324 dst.z = src.z - \lfloor src.z\rfloor
326 dst.w = src.w - \lfloor src.w\rfloor
329 .. opcode:: CLAMP - Clamp
333 dst.x = clamp(src0.x, src1.x, src2.x)
335 dst.y = clamp(src0.y, src1.y, src2.y)
337 dst.z = clamp(src0.z, src1.z, src2.z)
339 dst.w = clamp(src0.w, src1.w, src2.w)
342 .. opcode:: FLR - Floor
344 This is identical to :opcode:`ARL`.
348 dst.x = \lfloor src.x\rfloor
350 dst.y = \lfloor src.y\rfloor
352 dst.z = \lfloor src.z\rfloor
354 dst.w = \lfloor src.w\rfloor
357 .. opcode:: ROUND - Round
370 .. opcode:: EX2 - Exponential Base 2
372 This instruction replicates its result.
379 .. opcode:: LG2 - Logarithm Base 2
381 This instruction replicates its result.
388 .. opcode:: POW - Power
390 This instruction replicates its result.
394 dst = src0.x^{src1.x}
396 .. opcode:: XPD - Cross Product
400 dst.x = src0.y \times src1.z - src1.y \times src0.z
402 dst.y = src0.z \times src1.x - src1.z \times src0.x
404 dst.z = src0.x \times src1.y - src1.x \times src0.y
409 .. opcode:: ABS - Absolute
422 .. opcode:: RCC - Reciprocal Clamped
424 This instruction replicates its result.
426 XXX cleanup on aisle three
430 dst = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020)
433 .. opcode:: DPH - Homogeneous Dot Product
435 This instruction replicates its result.
439 dst = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w
442 .. opcode:: COS - Cosine
444 This instruction replicates its result.
451 .. opcode:: DDX - Derivative Relative To X
455 dst.x = partialx(src.x)
457 dst.y = partialx(src.y)
459 dst.z = partialx(src.z)
461 dst.w = partialx(src.w)
464 .. opcode:: DDY - Derivative Relative To Y
468 dst.x = partialy(src.x)
470 dst.y = partialy(src.y)
472 dst.z = partialy(src.z)
474 dst.w = partialy(src.w)
477 .. opcode:: KILP - Predicated Discard
482 .. opcode:: PK2H - Pack Two 16-bit Floats
487 .. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
492 .. opcode:: PK4B - Pack Four Signed 8-bit Scalars
497 .. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
502 .. opcode:: RFL - Reflection Vector
506 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
508 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
510 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
516 Considered for removal.
519 .. opcode:: SEQ - Set On Equal
523 dst.x = (src0.x == src1.x) ? 1 : 0
525 dst.y = (src0.y == src1.y) ? 1 : 0
527 dst.z = (src0.z == src1.z) ? 1 : 0
529 dst.w = (src0.w == src1.w) ? 1 : 0
532 .. opcode:: SFL - Set On False
534 This instruction replicates its result.
542 Considered for removal.
545 .. opcode:: SGT - Set On Greater Than
549 dst.x = (src0.x > src1.x) ? 1 : 0
551 dst.y = (src0.y > src1.y) ? 1 : 0
553 dst.z = (src0.z > src1.z) ? 1 : 0
555 dst.w = (src0.w > src1.w) ? 1 : 0
558 .. opcode:: SIN - Sine
560 This instruction replicates its result.
567 .. opcode:: SLE - Set On Less Equal Than
571 dst.x = (src0.x <= src1.x) ? 1 : 0
573 dst.y = (src0.y <= src1.y) ? 1 : 0
575 dst.z = (src0.z <= src1.z) ? 1 : 0
577 dst.w = (src0.w <= src1.w) ? 1 : 0
580 .. opcode:: SNE - Set On Not Equal
584 dst.x = (src0.x != src1.x) ? 1 : 0
586 dst.y = (src0.y != src1.y) ? 1 : 0
588 dst.z = (src0.z != src1.z) ? 1 : 0
590 dst.w = (src0.w != src1.w) ? 1 : 0
593 .. opcode:: STR - Set On True
595 This instruction replicates its result.
602 .. opcode:: TEX - Texture Lookup
610 dst = texture_sample(unit, coord, bias)
612 for array textures src0.y contains the slice for 1D,
613 and src0.z contain the slice for 2D.
614 for shadow textures with no arrays, src0.z contains
616 for shadow textures with arrays, src0.z contains
617 the reference value for 1D arrays, and src0.w contains
618 the reference value for 2D arrays.
619 There is no way to pass a bias in the .w value for
620 shadow arrays, and GLSL doesn't allow this.
621 GLSL does allow cube shadows maps to take a bias value,
622 and we have to determine how this will look in TGSI.
624 .. opcode:: TXD - Texture Lookup with Derivatives
636 dst = texture_sample_deriv(unit, coord, bias, ddx, ddy)
639 .. opcode:: TXP - Projective Texture Lookup
643 coord.x = src0.x / src.w
645 coord.y = src0.y / src.w
647 coord.z = src0.z / src.w
653 dst = texture_sample(unit, coord, bias)
656 .. opcode:: UP2H - Unpack Two 16-Bit Floats
662 Considered for removal.
664 .. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
670 Considered for removal.
672 .. opcode:: UP4B - Unpack Four Signed 8-Bit Values
678 Considered for removal.
680 .. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
686 Considered for removal.
688 .. opcode:: X2D - 2D Coordinate Transformation
692 dst.x = src0.x + src1.x \times src2.x + src1.y \times src2.y
694 dst.y = src0.y + src1.x \times src2.z + src1.y \times src2.w
696 dst.z = src0.x + src1.x \times src2.x + src1.y \times src2.y
698 dst.w = src0.y + src1.x \times src2.z + src1.y \times src2.w
702 Considered for removal.
705 .. opcode:: ARA - Address Register Add
711 Considered for removal.
713 .. opcode:: ARR - Address Register Load With Round
726 .. opcode:: BRA - Branch
732 Considered for removal.
734 .. opcode:: CAL - Subroutine Call
740 .. opcode:: RET - Subroutine Call Return
745 .. opcode:: SSG - Set Sign
749 dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0
751 dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0
753 dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0
755 dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
758 .. opcode:: CMP - Compare
762 dst.x = (src0.x < 0) ? src1.x : src2.x
764 dst.y = (src0.y < 0) ? src1.y : src2.y
766 dst.z = (src0.z < 0) ? src1.z : src2.z
768 dst.w = (src0.w < 0) ? src1.w : src2.w
771 .. opcode:: KIL - Conditional Discard
775 if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0)
780 .. opcode:: SCS - Sine Cosine
793 .. opcode:: TXB - Texture Lookup With Bias
807 dst = texture_sample(unit, coord, bias)
810 .. opcode:: NRM - 3-component Vector Normalise
814 dst.x = src.x / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
816 dst.y = src.y / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
818 dst.z = src.z / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
823 .. opcode:: DIV - Divide
827 dst.x = \frac{src0.x}{src1.x}
829 dst.y = \frac{src0.y}{src1.y}
831 dst.z = \frac{src0.z}{src1.z}
833 dst.w = \frac{src0.w}{src1.w}
836 .. opcode:: DP2 - 2-component Dot Product
838 This instruction replicates its result.
842 dst = src0.x \times src1.x + src0.y \times src1.y
845 .. opcode:: TXL - Texture Lookup With explicit LOD
859 dst = texture_sample(unit, coord, lod)
862 .. opcode:: BRK - Break
864 Unconditionally moves the point of execution to the instruction after the
865 next endloop or endswitch. The instruction must appear within a loop/endloop
869 .. opcode:: BREAKC - Break Conditional
871 Conditionally moves the point of execution to the instruction after the
872 next endloop or endswitch. The instruction must appear within a loop/endloop
874 Condition evaluates to true if src0.x != 0 where src0.x is interpreted
875 as an integer register.
878 .. opcode:: IF - Float If
880 Start an IF ... ELSE .. ENDIF block. Condition evaluates to true if
884 where src0.x is interpreted as a floating point register.
887 .. opcode:: UIF - Bitwise If
889 Start an UIF ... ELSE .. ENDIF block. Condition evaluates to true if
893 where src0.x is interpreted as an integer register.
896 .. opcode:: ELSE - Else
898 Starts an else block, after an IF or UIF statement.
901 .. opcode:: ENDIF - End If
903 Ends an IF or UIF block.
906 .. opcode:: SWITCH - Switch
908 Starts a C-style switch expression. The switch consists of one or multiple
909 CASE statements, and at most one DEFAULT statement. Execution of a statement
910 ends when a BRK is hit, but just like in C falling through to other cases
911 without a break is allowed. Similarly, DEFAULT label is allowed anywhere not
912 just as last statement, and fallthrough is allowed into/from it.
913 CASE src arguments are evaluated at bit level against the SWITCH src argument.
918 (some instructions here)
921 (some instructions here)
924 (some instructions here)
929 .. opcode:: CASE - Switch case
931 This represents a switch case label. The src arg must be an integer immediate.
934 .. opcode:: DEFAULT - Switch default
936 This represents the default case in the switch, which is taken if no other
940 .. opcode:: ENDSWITCH - End of switch
942 Ends a switch expression.
945 .. opcode:: PUSHA - Push Address Register On Stack
954 Considered for cleanup.
958 Considered for removal.
960 .. opcode:: POPA - Pop Address Register From Stack
969 Considered for cleanup.
973 Considered for removal.
977 ^^^^^^^^^^^^^^^^^^^^^^^^
979 These opcodes are primarily provided for special-use computational shaders.
980 Support for these opcodes indicated by a special pipe capability bit (TBD).
982 XXX so let's discuss it, yeah?
984 .. opcode:: CEIL - Ceiling
988 dst.x = \lceil src.x\rceil
990 dst.y = \lceil src.y\rceil
992 dst.z = \lceil src.z\rceil
994 dst.w = \lceil src.w\rceil
997 .. opcode:: I2F - Integer To Float
1001 dst.x = (float) src.x
1003 dst.y = (float) src.y
1005 dst.z = (float) src.z
1007 dst.w = (float) src.w
1010 .. opcode:: NOT - Bitwise Not
1023 .. opcode:: TRUNC - Truncate
1027 dst.x = trunc(src.x)
1029 dst.y = trunc(src.y)
1031 dst.z = trunc(src.z)
1033 dst.w = trunc(src.w)
1036 .. opcode:: SHL - Shift Left
1040 dst.x = src0.x << src1.x
1042 dst.y = src0.y << src1.x
1044 dst.z = src0.z << src1.x
1046 dst.w = src0.w << src1.x
1049 .. opcode:: SHR - Shift Right
1053 dst.x = src0.x >> src1.x
1055 dst.y = src0.y >> src1.x
1057 dst.z = src0.z >> src1.x
1059 dst.w = src0.w >> src1.x
1062 .. opcode:: AND - Bitwise And
1066 dst.x = src0.x & src1.x
1068 dst.y = src0.y & src1.y
1070 dst.z = src0.z & src1.z
1072 dst.w = src0.w & src1.w
1075 .. opcode:: OR - Bitwise Or
1079 dst.x = src0.x | src1.x
1081 dst.y = src0.y | src1.y
1083 dst.z = src0.z | src1.z
1085 dst.w = src0.w | src1.w
1088 .. opcode:: MOD - Modulus
1092 dst.x = src0.x \bmod src1.x
1094 dst.y = src0.y \bmod src1.y
1096 dst.z = src0.z \bmod src1.z
1098 dst.w = src0.w \bmod src1.w
1101 .. opcode:: XOR - Bitwise Xor
1105 dst.x = src0.x \oplus src1.x
1107 dst.y = src0.y \oplus src1.y
1109 dst.z = src0.z \oplus src1.z
1111 dst.w = src0.w \oplus src1.w
1114 .. opcode:: UCMP - Integer Conditional Move
1118 dst.x = src0.x ? src1.x : src2.x
1120 dst.y = src0.y ? src1.y : src2.y
1122 dst.z = src0.z ? src1.z : src2.z
1124 dst.w = src0.w ? src1.w : src2.w
1127 .. opcode:: UARL - Integer Address Register Load
1129 Moves the contents of the source register, assumed to be an integer, into the
1130 destination register, which is assumed to be an address (ADDR) register.
1133 .. opcode:: IABS - Integer Absolute Value
1146 .. opcode:: SAD - Sum Of Absolute Differences
1150 dst.x = |src0.x - src1.x| + src2.x
1152 dst.y = |src0.y - src1.y| + src2.y
1154 dst.z = |src0.z - src1.z| + src2.z
1156 dst.w = |src0.w - src1.w| + src2.w
1159 .. opcode:: TXF - Texel Fetch (as per NV_gpu_shader4), extract a single texel
1160 from a specified texture image. The source sampler may
1161 not be a CUBE or SHADOW.
1162 src 0 is a four-component signed integer vector used to
1163 identify the single texel accessed. 3 components + level.
1164 src 1 is a 3 component constant signed integer vector,
1165 with each component only have a range of
1166 -8..+8 (hw only seems to deal with this range, interface
1167 allows for up to unsigned int).
1168 TXF(uint_vec coord, int_vec offset).
1171 .. opcode:: TXQ - Texture Size Query (as per NV_gpu_program4)
1172 retrieve the dimensions of the texture
1173 depending on the target. For 1D (width), 2D/RECT/CUBE
1174 (width, height), 3D (width, height, depth),
1175 1D array (width, layers), 2D array (width, height, layers)
1181 dst.x = texture_width(unit, lod)
1183 dst.y = texture_height(unit, lod)
1185 dst.z = texture_depth(unit, lod)
1188 .. opcode:: CONT - Continue
1194 Support for CONT is determined by a special capability bit,
1195 ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
1199 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1201 These opcodes are only supported in geometry shaders; they have no meaning
1202 in any other type of shader.
1204 .. opcode:: EMIT - Emit
1209 .. opcode:: ENDPRIM - End Primitive
1217 These opcodes are part of :term:`GLSL`'s opcode set. Support for these
1218 opcodes is determined by a special capability bit, ``GLSL``.
1220 .. opcode:: BGNLOOP - Begin a Loop
1225 .. opcode:: BGNSUB - Begin Subroutine
1230 .. opcode:: ENDLOOP - End a Loop
1235 .. opcode:: ENDSUB - End Subroutine
1240 .. opcode:: NOP - No Operation
1245 .. opcode:: NRM4 - 4-component Vector Normalise
1247 This instruction replicates its result.
1251 dst = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
1259 .. opcode:: CALLNZ - Subroutine Call If Not Zero
1268 The double-precision opcodes reinterpret four-component vectors into
1269 two-component vectors with doubled precision in each component.
1271 Support for these opcodes is XXX undecided. :T
1273 .. opcode:: DADD - Add
1277 dst.xy = src0.xy + src1.xy
1279 dst.zw = src0.zw + src1.zw
1282 .. opcode:: DDIV - Divide
1286 dst.xy = src0.xy / src1.xy
1288 dst.zw = src0.zw / src1.zw
1290 .. opcode:: DSEQ - Set on Equal
1294 dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
1296 dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
1298 .. opcode:: DSLT - Set on Less than
1302 dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
1304 dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
1306 .. opcode:: DFRAC - Fraction
1310 dst.xy = src.xy - \lfloor src.xy\rfloor
1312 dst.zw = src.zw - \lfloor src.zw\rfloor
1315 .. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
1317 Like the ``frexp()`` routine in many math libraries, this opcode stores the
1318 exponent of its source to ``dst0``, and the significand to ``dst1``, such that
1319 :math:`dst1 \times 2^{dst0} = src` .
1323 dst0.xy = exp(src.xy)
1325 dst1.xy = frac(src.xy)
1327 dst0.zw = exp(src.zw)
1329 dst1.zw = frac(src.zw)
1331 .. opcode:: DLDEXP - Multiply Number by Integral Power of 2
1333 This opcode is the inverse of :opcode:`DFRACEXP`.
1337 dst.xy = src0.xy \times 2^{src1.xy}
1339 dst.zw = src0.zw \times 2^{src1.zw}
1341 .. opcode:: DMIN - Minimum
1345 dst.xy = min(src0.xy, src1.xy)
1347 dst.zw = min(src0.zw, src1.zw)
1349 .. opcode:: DMAX - Maximum
1353 dst.xy = max(src0.xy, src1.xy)
1355 dst.zw = max(src0.zw, src1.zw)
1357 .. opcode:: DMUL - Multiply
1361 dst.xy = src0.xy \times src1.xy
1363 dst.zw = src0.zw \times src1.zw
1366 .. opcode:: DMAD - Multiply And Add
1370 dst.xy = src0.xy \times src1.xy + src2.xy
1372 dst.zw = src0.zw \times src1.zw + src2.zw
1375 .. opcode:: DRCP - Reciprocal
1379 dst.xy = \frac{1}{src.xy}
1381 dst.zw = \frac{1}{src.zw}
1383 .. opcode:: DSQRT - Square Root
1387 dst.xy = \sqrt{src.xy}
1389 dst.zw = \sqrt{src.zw}
1392 .. _samplingopcodes:
1394 Resource Sampling Opcodes
1395 ^^^^^^^^^^^^^^^^^^^^^^^^^
1397 Those opcodes follow very closely semantics of the respective Direct3D
1398 instructions. If in doubt double check Direct3D documentation.
1400 .. opcode:: SAMPLE - Using provided address, sample data from the
1401 specified texture using the filtering mode identified
1402 by the gven sampler. The source data may come from
1403 any resource type other than buffers.
1404 SAMPLE dst, address, sampler_view, sampler
1406 SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]
1408 .. opcode:: SAMPLE_I - Simplified alternative to the SAMPLE instruction.
1409 Using the provided integer address, SAMPLE_I fetches data
1410 from the specified sampler view without any filtering.
1411 The source data may come from any resource type other
1413 SAMPLE_I dst, address, sampler_view
1415 SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]
1416 The 'address' is specified as unsigned integers. If the
1417 'address' is out of range [0...(# texels - 1)] the
1418 result of the fetch is always 0 in all components.
1419 As such the instruction doesn't honor address wrap
1420 modes, in cases where that behavior is desirable
1421 'SAMPLE' instruction should be used.
1422 address.w always provides an unsigned integer mipmap
1423 level. If the value is out of the range then the
1424 instruction always returns 0 in all components.
1425 address.yz are ignored for buffers and 1d textures.
1426 address.z is ignored for 1d texture arrays and 2d
1428 For 1D texture arrays address.y provides the array
1429 index (also as unsigned integer). If the value is
1430 out of the range of available array indices
1431 [0... (array size - 1)] then the opcode always returns
1432 0 in all components.
1433 For 2D texture arrays address.z provides the array
1434 index, otherwise it exhibits the same behavior as in
1435 the case for 1D texture arrays.
1436 The exact semantics of the source address are presented
1438 resource type X Y Z W
1439 ------------- ------------------------
1440 PIPE_BUFFER x ignored
1441 PIPE_TEXTURE_1D x mpl
1442 PIPE_TEXTURE_2D x y mpl
1443 PIPE_TEXTURE_3D x y z mpl
1444 PIPE_TEXTURE_RECT x y mpl
1445 PIPE_TEXTURE_CUBE not allowed as source
1446 PIPE_TEXTURE_1D_ARRAY x idx mpl
1447 PIPE_TEXTURE_2D_ARRAY x y idx mpl
1449 Where 'mpl' is a mipmap level and 'idx' is the
1452 .. opcode:: SAMPLE_I_MS - Just like SAMPLE_I but allows fetch data from
1453 multi-sampled surfaces.
1454 SAMPLE_I_MS dst, address, sampler_view, sample
1456 .. opcode:: SAMPLE_B - Just like the SAMPLE instruction with the
1457 exception that an additional bias is applied to the
1458 level of detail computed as part of the instruction
1460 SAMPLE_B dst, address, sampler_view, sampler, lod_bias
1462 SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x
1464 .. opcode:: SAMPLE_C - Similar to the SAMPLE instruction but it
1465 performs a comparison filter. The operands to SAMPLE_C
1466 are identical to SAMPLE, except that there is an additional
1467 float32 operand, reference value, which must be a register
1468 with single-component, or a scalar literal.
1469 SAMPLE_C makes the hardware use the current samplers
1470 compare_func (in pipe_sampler_state) to compare
1471 reference value against the red component value for the
1472 surce resource at each texel that the currently configured
1473 texture filter covers based on the provided coordinates.
1474 SAMPLE_C dst, address, sampler_view.r, sampler, ref_value
1476 SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x
1478 .. opcode:: SAMPLE_C_LZ - Same as SAMPLE_C, but LOD is 0 and derivatives
1479 are ignored. The LZ stands for level-zero.
1480 SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value
1482 SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x
1485 .. opcode:: SAMPLE_D - SAMPLE_D is identical to the SAMPLE opcode except
1486 that the derivatives for the source address in the x
1487 direction and the y direction are provided by extra
1489 SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y
1491 SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]
1493 .. opcode:: SAMPLE_L - SAMPLE_L is identical to the SAMPLE opcode except
1494 that the LOD is provided directly as a scalar value,
1495 representing no anisotropy.
1496 SAMPLE_L dst, address, sampler_view, sampler, explicit_lod
1498 SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x
1500 .. opcode:: GATHER4 - Gathers the four texels to be used in a bi-linear
1501 filtering operation and packs them into a single register.
1502 Only works with 2D, 2D array, cubemaps, and cubemaps arrays.
1503 For 2D textures, only the addressing modes of the sampler and
1504 the top level of any mip pyramid are used. Set W to zero.
1505 It behaves like the SAMPLE instruction, but a filtered
1506 sample is not generated. The four samples that contribute
1507 to filtering are placed into xyzw in counter-clockwise order,
1508 starting with the (u,v) texture coordinate delta at the
1509 following locations (-, +), (+, +), (+, -), (-, -), where
1510 the magnitude of the deltas are half a texel.
1513 .. opcode:: SVIEWINFO - query the dimensions of a given sampler view.
1514 dst receives width, height, depth or array size and
1515 number of mipmap levels as int4. The dst can have a writemask
1516 which will specify what info is the caller interested
1518 SVIEWINFO dst, src_mip_level, sampler_view
1520 SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]
1521 src_mip_level is an unsigned integer scalar. If it's
1522 out of range then returns 0 for width, height and
1523 depth/array size but the total number of mipmap is
1524 still returned correctly for the given sampler view.
1525 The returned width, height and depth values are for
1526 the mipmap level selected by the src_mip_level and
1527 are in the number of texels.
1528 For 1d texture array width is in dst.x, array size
1529 is in dst.y and dst.zw are always 0.
1531 .. opcode:: SAMPLE_POS - query the position of a given sample.
1532 dst receives float4 (x, y, 0, 0) indicated where the
1533 sample is located. If the resource is not a multi-sample
1534 resource and not a render target, the result is 0.
1536 .. opcode:: SAMPLE_INFO - dst receives number of samples in x.
1537 If the resource is not a multi-sample resource and
1538 not a render target, the result is 0.
1541 .. _resourceopcodes:
1543 Resource Access Opcodes
1544 ^^^^^^^^^^^^^^^^^^^^^^^
1546 .. opcode:: LOAD - Fetch data from a shader resource
1548 Syntax: ``LOAD dst, resource, address``
1550 Example: ``LOAD TEMP[0], RES[0], TEMP[1]``
1552 Using the provided integer address, LOAD fetches data
1553 from the specified buffer or texture without any
1556 The 'address' is specified as a vector of unsigned
1557 integers. If the 'address' is out of range the result
1560 Only the first mipmap level of a resource can be read
1561 from using this instruction.
1563 For 1D or 2D texture arrays, the array index is
1564 provided as an unsigned integer in address.y or
1565 address.z, respectively. address.yz are ignored for
1566 buffers and 1D textures. address.z is ignored for 1D
1567 texture arrays and 2D textures. address.w is always
1570 .. opcode:: STORE - Write data to a shader resource
1572 Syntax: ``STORE resource, address, src``
1574 Example: ``STORE RES[0], TEMP[0], TEMP[1]``
1576 Using the provided integer address, STORE writes data
1577 to the specified buffer or texture.
1579 The 'address' is specified as a vector of unsigned
1580 integers. If the 'address' is out of range the result
1583 Only the first mipmap level of a resource can be
1584 written to using this instruction.
1586 For 1D or 2D texture arrays, the array index is
1587 provided as an unsigned integer in address.y or
1588 address.z, respectively. address.yz are ignored for
1589 buffers and 1D textures. address.z is ignored for 1D
1590 texture arrays and 2D textures. address.w is always
1594 .. _threadsyncopcodes:
1596 Inter-thread synchronization opcodes
1597 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1599 These opcodes are intended for communication between threads running
1600 within the same compute grid. For now they're only valid in compute
1603 .. opcode:: MFENCE - Memory fence
1605 Syntax: ``MFENCE resource``
1607 Example: ``MFENCE RES[0]``
1609 This opcode forces strong ordering between any memory access
1610 operations that affect the specified resource. This means that
1611 previous loads and stores (and only those) will be performed and
1612 visible to other threads before the program execution continues.
1615 .. opcode:: LFENCE - Load memory fence
1617 Syntax: ``LFENCE resource``
1619 Example: ``LFENCE RES[0]``
1621 Similar to MFENCE, but it only affects the ordering of memory loads.
1624 .. opcode:: SFENCE - Store memory fence
1626 Syntax: ``SFENCE resource``
1628 Example: ``SFENCE RES[0]``
1630 Similar to MFENCE, but it only affects the ordering of memory stores.
1633 .. opcode:: BARRIER - Thread group barrier
1637 This opcode suspends the execution of the current thread until all
1638 the remaining threads in the working group reach the same point of
1639 the program. Results are unspecified if any of the remaining
1640 threads terminates or never reaches an executed BARRIER instruction.
1648 These opcodes provide atomic variants of some common arithmetic and
1649 logical operations. In this context atomicity means that another
1650 concurrent memory access operation that affects the same memory
1651 location is guaranteed to be performed strictly before or after the
1652 entire execution of the atomic operation.
1654 For the moment they're only valid in compute programs.
1656 .. opcode:: ATOMUADD - Atomic integer addition
1658 Syntax: ``ATOMUADD dst, resource, offset, src``
1660 Example: ``ATOMUADD TEMP[0], RES[0], TEMP[1], TEMP[2]``
1662 The following operation is performed atomically on each component:
1666 dst_i = resource[offset]_i
1668 resource[offset]_i = dst_i + src_i
1671 .. opcode:: ATOMXCHG - Atomic exchange
1673 Syntax: ``ATOMXCHG dst, resource, offset, src``
1675 Example: ``ATOMXCHG TEMP[0], RES[0], TEMP[1], TEMP[2]``
1677 The following operation is performed atomically on each component:
1681 dst_i = resource[offset]_i
1683 resource[offset]_i = src_i
1686 .. opcode:: ATOMCAS - Atomic compare-and-exchange
1688 Syntax: ``ATOMCAS dst, resource, offset, cmp, src``
1690 Example: ``ATOMCAS TEMP[0], RES[0], TEMP[1], TEMP[2], TEMP[3]``
1692 The following operation is performed atomically on each component:
1696 dst_i = resource[offset]_i
1698 resource[offset]_i = (dst_i == cmp_i ? src_i : dst_i)
1701 .. opcode:: ATOMAND - Atomic bitwise And
1703 Syntax: ``ATOMAND dst, resource, offset, src``
1705 Example: ``ATOMAND TEMP[0], RES[0], TEMP[1], TEMP[2]``
1707 The following operation is performed atomically on each component:
1711 dst_i = resource[offset]_i
1713 resource[offset]_i = dst_i \& src_i
1716 .. opcode:: ATOMOR - Atomic bitwise Or
1718 Syntax: ``ATOMOR dst, resource, offset, src``
1720 Example: ``ATOMOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
1722 The following operation is performed atomically on each component:
1726 dst_i = resource[offset]_i
1728 resource[offset]_i = dst_i | src_i
1731 .. opcode:: ATOMXOR - Atomic bitwise Xor
1733 Syntax: ``ATOMXOR dst, resource, offset, src``
1735 Example: ``ATOMXOR TEMP[0], RES[0], TEMP[1], TEMP[2]``
1737 The following operation is performed atomically on each component:
1741 dst_i = resource[offset]_i
1743 resource[offset]_i = dst_i \oplus src_i
1746 .. opcode:: ATOMUMIN - Atomic unsigned minimum
1748 Syntax: ``ATOMUMIN dst, resource, offset, src``
1750 Example: ``ATOMUMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
1752 The following operation is performed atomically on each component:
1756 dst_i = resource[offset]_i
1758 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
1761 .. opcode:: ATOMUMAX - Atomic unsigned maximum
1763 Syntax: ``ATOMUMAX dst, resource, offset, src``
1765 Example: ``ATOMUMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
1767 The following operation is performed atomically on each component:
1771 dst_i = resource[offset]_i
1773 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
1776 .. opcode:: ATOMIMIN - Atomic signed minimum
1778 Syntax: ``ATOMIMIN dst, resource, offset, src``
1780 Example: ``ATOMIMIN TEMP[0], RES[0], TEMP[1], TEMP[2]``
1782 The following operation is performed atomically on each component:
1786 dst_i = resource[offset]_i
1788 resource[offset]_i = (dst_i < src_i ? dst_i : src_i)
1791 .. opcode:: ATOMIMAX - Atomic signed maximum
1793 Syntax: ``ATOMIMAX dst, resource, offset, src``
1795 Example: ``ATOMIMAX TEMP[0], RES[0], TEMP[1], TEMP[2]``
1797 The following operation is performed atomically on each component:
1801 dst_i = resource[offset]_i
1803 resource[offset]_i = (dst_i > src_i ? dst_i : src_i)
1807 Explanation of symbols used
1808 ------------------------------
1815 :math:`|x|` Absolute value of `x`.
1817 :math:`\lceil x \rceil` Ceiling of `x`.
1819 clamp(x,y,z) Clamp x between y and z.
1820 (x < y) ? y : (x > z) ? z : x
1822 :math:`\lfloor x\rfloor` Floor of `x`.
1824 :math:`\log_2{x}` Logarithm of `x`, base 2.
1826 max(x,y) Maximum of x and y.
1829 min(x,y) Minimum of x and y.
1832 partialx(x) Derivative of x relative to fragment's X.
1834 partialy(x) Derivative of x relative to fragment's Y.
1836 pop() Pop from stack.
1838 :math:`x^y` `x` to the power `y`.
1840 push(x) Push x on stack.
1844 trunc(x) Truncate x, i.e. drop the fraction bits.
1851 discard Discard fragment.
1855 target Label of target instruction.
1866 Declares a register that is will be referenced as an operand in Instruction
1869 File field contains register file that is being declared and is one
1872 UsageMask field specifies which of the register components can be accessed
1873 and is one of TGSI_WRITEMASK.
1875 The Local flag specifies that a given value isn't intended for
1876 subroutine parameter passing and, as a result, the implementation
1877 isn't required to give any guarantees of it being preserved across
1878 subroutine boundaries. As it's merely a compiler hint, the
1879 implementation is free to ignore it.
1881 If Dimension flag is set to 1, a Declaration Dimension token follows.
1883 If Semantic flag is set to 1, a Declaration Semantic token follows.
1885 If Interpolate flag is set to 1, a Declaration Interpolate token follows.
1887 If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
1889 If Array flag is set to 1, a Declaration Array token follows.
1892 ^^^^^^^^^^^^^^^^^^^^^^^^
1894 Declarations can optional have an ArrayID attribute which can be referred by
1895 indirect addressing operands. An ArrayID of zero is reserved and treaded as
1896 if no ArrayID is specified.
1898 If an indirect addressing operand refers to a specific declaration by using
1899 an ArrayID only the registers in this declaration are guaranteed to be
1900 accessed, accessing any register outside this declaration results in undefined
1901 behavior. Note that for compatibility the effective index is zero-based and
1902 not relative to the specified declaration
1904 If no ArrayID is specified with an indirect addressing operand the whole
1905 register file might be accessed by this operand. This is strongly discouraged
1906 and will prevent packing of scalar/vec2 arrays and effective alias analysis.
1908 Declaration Semantic
1909 ^^^^^^^^^^^^^^^^^^^^^^^^
1911 Vertex and fragment shader input and output registers may be labeled
1912 with semantic information consisting of a name and index.
1914 Follows Declaration token if Semantic bit is set.
1916 Since its purpose is to link a shader with other stages of the pipeline,
1917 it is valid to follow only those Declaration tokens that declare a register
1918 either in INPUT or OUTPUT file.
1920 SemanticName field contains the semantic name of the register being declared.
1921 There is no default value.
1923 SemanticIndex is an optional subscript that can be used to distinguish
1924 different register declarations with the same semantic name. The default value
1927 The meanings of the individual semantic names are explained in the following
1930 TGSI_SEMANTIC_POSITION
1931 """"""""""""""""""""""
1933 For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
1934 output register which contains the homogeneous vertex position in the clip
1935 space coordinate system. After clipping, the X, Y and Z components of the
1936 vertex will be divided by the W value to get normalized device coordinates.
1938 For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
1939 fragment shader input contains the fragment's window position. The X
1940 component starts at zero and always increases from left to right.
1941 The Y component starts at zero and always increases but Y=0 may either
1942 indicate the top of the window or the bottom depending on the fragment
1943 coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
1944 The Z coordinate ranges from 0 to 1 to represent depth from the front
1945 to the back of the Z buffer. The W component contains the reciprocol
1946 of the interpolated vertex position W component.
1948 Fragment shaders may also declare an output register with
1949 TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
1950 the fragment shader to change the fragment's Z position.
1957 For vertex shader outputs or fragment shader inputs/outputs, this
1958 label indicates that the resister contains an R,G,B,A color.
1960 Several shader inputs/outputs may contain colors so the semantic index
1961 is used to distinguish them. For example, color[0] may be the diffuse
1962 color while color[1] may be the specular color.
1964 This label is needed so that the flat/smooth shading can be applied
1965 to the right interpolants during rasterization.
1969 TGSI_SEMANTIC_BCOLOR
1970 """"""""""""""""""""
1972 Back-facing colors are only used for back-facing polygons, and are only valid
1973 in vertex shader outputs. After rasterization, all polygons are front-facing
1974 and COLOR and BCOLOR end up occupying the same slots in the fragment shader,
1975 so all BCOLORs effectively become regular COLORs in the fragment shader.
1981 Vertex shader inputs and outputs and fragment shader inputs may be
1982 labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
1983 a fog coordinate in the form (F, 0, 0, 1). Typically, the fragment
1984 shader will use the fog coordinate to compute a fog blend factor which
1985 is used to blend the normal fragment color with a constant fog color.
1987 Only the first component matters when writing from the vertex shader;
1988 the driver will ensure that the coordinate is in this format when used
1989 as a fragment shader input.
1995 Vertex shader input and output registers may be labeled with
1996 TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
1997 in the form (S, 0, 0, 1). The point size controls the width or diameter
1998 of points for rasterization. This label cannot be used in fragment
2001 When using this semantic, be sure to set the appropriate state in the
2002 :ref:`rasterizer` first.
2005 TGSI_SEMANTIC_TEXCOORD
2006 """"""""""""""""""""""
2008 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2010 Vertex shader outputs and fragment shader inputs may be labeled with
2011 this semantic to make them replaceable by sprite coordinates via the
2012 sprite_coord_enable state in the :ref:`rasterizer`.
2013 The semantic index permitted with this semantic is limited to <= 7.
2015 If the driver does not support TEXCOORD, sprite coordinate replacement
2016 applies to inputs with the GENERIC semantic instead.
2018 The intended use case for this semantic is gl_TexCoord.
2021 TGSI_SEMANTIC_PCOORD
2022 """"""""""""""""""""
2024 Only available if PIPE_CAP_TGSI_TEXCOORD is exposed !
2026 Fragment shader inputs may be labeled with TGSI_SEMANTIC_PCOORD to indicate
2027 that the register contains sprite coordinates in the form (x, y, 0, 1), if
2028 the current primitive is a point and point sprites are enabled. Otherwise,
2029 the contents of the register are undefined.
2031 The intended use case for this semantic is gl_PointCoord.
2034 TGSI_SEMANTIC_GENERIC
2035 """""""""""""""""""""
2037 All vertex/fragment shader inputs/outputs not labeled with any other
2038 semantic label can be considered to be generic attributes. Typical
2039 uses of generic inputs/outputs are texcoords and user-defined values.
2042 TGSI_SEMANTIC_NORMAL
2043 """"""""""""""""""""
2045 Indicates that a vertex shader input is a normal vector. This is
2046 typically only used for legacy graphics APIs.
2052 This label applies to fragment shader inputs only and indicates that
2053 the register contains front/back-face information of the form (F, 0,
2054 0, 1). The first component will be positive when the fragment belongs
2055 to a front-facing polygon, and negative when the fragment belongs to a
2056 back-facing polygon.
2059 TGSI_SEMANTIC_EDGEFLAG
2060 """"""""""""""""""""""
2062 For vertex shaders, this sematic label indicates that an input or
2063 output is a boolean edge flag. The register layout is [F, x, x, x]
2064 where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
2065 simply copies the edge flag input to the edgeflag output.
2067 Edge flags are used to control which lines or points are actually
2068 drawn when the polygon mode converts triangles/quads/polygons into
2071 TGSI_SEMANTIC_STENCIL
2072 """"""""""""""""""""""
2074 For fragment shaders, this semantic label indicates than an output
2075 is a writable stencil reference value. Only the Y component is writable.
2076 This allows the fragment shader to change the fragments stencilref value.
2079 Declaration Interpolate
2080 ^^^^^^^^^^^^^^^^^^^^^^^
2082 This token is only valid for fragment shader INPUT declarations.
2084 The Interpolate field specifes the way input is being interpolated by
2085 the rasteriser and is one of TGSI_INTERPOLATE_*.
2087 The CylindricalWrap bitfield specifies which register components
2088 should be subject to cylindrical wrapping when interpolating by the
2089 rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
2090 should be interpolated according to cylindrical wrapping rules.
2093 Declaration Sampler View
2094 ^^^^^^^^^^^^^^^^^^^^^^^^
2096 Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
2098 DCL SVIEW[#], resource, type(s)
2100 Declares a shader input sampler view and assigns it to a SVIEW[#]
2103 resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
2105 type must be 1 or 4 entries (if specifying on a per-component
2106 level) out of UNORM, SNORM, SINT, UINT and FLOAT.
2109 Declaration Resource
2110 ^^^^^^^^^^^^^^^^^^^^
2112 Follows Declaration token if file is TGSI_FILE_RESOURCE.
2114 DCL RES[#], resource [, WR] [, RAW]
2116 Declares a shader input resource and assigns it to a RES[#]
2119 resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
2122 If the RAW keyword is not specified, the texture data will be
2123 subject to conversion, swizzling and scaling as required to yield
2124 the specified data type from the physical data format of the bound
2127 If the RAW keyword is specified, no channel conversion will be
2128 performed: the values read for each of the channels (X,Y,Z,W) will
2129 correspond to consecutive words in the same order and format
2130 they're found in memory. No element-to-address conversion will be
2131 performed either: the value of the provided X coordinate will be
2132 interpreted in byte units instead of texel units. The result of
2133 accessing a misaligned address is undefined.
2135 Usage of the STORE opcode is only allowed if the WR (writable) flag
2140 ^^^^^^^^^^^^^^^^^^^^^^^^
2143 Properties are general directives that apply to the whole TGSI program.
2148 Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
2149 The default value is UPPER_LEFT.
2151 If UPPER_LEFT, the position will be (0,0) at the upper left corner and
2152 increase downward and rightward.
2153 If LOWER_LEFT, the position will be (0,0) at the lower left corner and
2154 increase upward and rightward.
2156 OpenGL defaults to LOWER_LEFT, and is configurable with the
2157 GL_ARB_fragment_coord_conventions extension.
2159 DirectX 9/10 use UPPER_LEFT.
2161 FS_COORD_PIXEL_CENTER
2162 """""""""""""""""""""
2164 Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
2165 The default value is HALF_INTEGER.
2167 If HALF_INTEGER, the fractionary part of the position will be 0.5
2168 If INTEGER, the fractionary part of the position will be 0.0
2170 Note that this does not affect the set of fragments generated by
2171 rasterization, which is instead controlled by gl_rasterization_rules in the
2174 OpenGL defaults to HALF_INTEGER, and is configurable with the
2175 GL_ARB_fragment_coord_conventions extension.
2177 DirectX 9 uses INTEGER.
2178 DirectX 10 uses HALF_INTEGER.
2180 FS_COLOR0_WRITES_ALL_CBUFS
2181 """"""""""""""""""""""""""
2182 Specifies that writes to the fragment shader color 0 are replicated to all
2183 bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
2184 fragData is directed to a single color buffer, but fragColor is broadcast.
2187 """"""""""""""""""""""""""
2188 If this property is set on the program bound to the shader stage before the
2189 fragment shader, user clip planes should have no effect (be disabled) even if
2190 that shader does not write to any clip distance outputs and the rasterizer's
2191 clip_plane_enable is non-zero.
2192 This property is only supported by drivers that also support shader clip
2194 This is useful for APIs that don't have UCPs and where clip distances written
2195 by a shader cannot be disabled.
2198 Texture Sampling and Texture Formats
2199 ------------------------------------
2201 This table shows how texture image components are returned as (x,y,z,w) tuples
2202 by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
2203 :opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
2206 +--------------------+--------------+--------------------+--------------+
2207 | Texture Components | Gallium | OpenGL | Direct3D 9 |
2208 +====================+==============+====================+==============+
2209 | R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
2210 +--------------------+--------------+--------------------+--------------+
2211 | RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
2212 +--------------------+--------------+--------------------+--------------+
2213 | RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
2214 +--------------------+--------------+--------------------+--------------+
2215 | RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
2216 +--------------------+--------------+--------------------+--------------+
2217 | A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
2218 +--------------------+--------------+--------------------+--------------+
2219 | L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
2220 +--------------------+--------------+--------------------+--------------+
2221 | LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
2222 +--------------------+--------------+--------------------+--------------+
2223 | I | (i, i, i, i) | (i, i, i, i) | N/A |
2224 +--------------------+--------------+--------------------+--------------+
2225 | UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
2226 | | | [#envmap-bumpmap]_ | |
2227 +--------------------+--------------+--------------------+--------------+
2228 | Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
2229 | | | [#depth-tex-mode]_ | |
2230 +--------------------+--------------+--------------------+--------------+
2231 | S | (s, s, s, s) | unknown | unknown |
2232 +--------------------+--------------+--------------------+--------------+
2234 .. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
2235 .. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
2236 or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.