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diff --git a/src/gallium/docs/build/html/_sources/tgsi.txt b/src/gallium/docs/build/html/_sources/tgsi.txt deleted file mode 100644 index 12687f29dc..0000000000 --- a/src/gallium/docs/build/html/_sources/tgsi.txt +++ /dev/null @@ -1,1271 +0,0 @@ -TGSI -==== - -TGSI, Tungsten Graphics Shader Instructions, is an intermediate language -for describing shaders. Since Gallium is inherently shaderful, shaders are -an important part of the API. TGSI is the only intermediate representation -used by all drivers. - -Instruction Set ---------------- - -From GL_NV_vertex_program -^^^^^^^^^^^^^^^^^^^^^^^^^ - - -ARL - Address Register Load - -.. math:: - - dst.x = \lfloor src.x\rfloor - - dst.y = \lfloor src.y\rfloor - - dst.z = \lfloor src.z\rfloor - - dst.w = \lfloor src.w\rfloor - - -MOV - Move - -.. math:: - - dst.x = src.x - - dst.y = src.y - - dst.z = src.z - - dst.w = src.w - - -LIT - Light Coefficients - -.. math:: - - dst.x = 1 - - dst.y = max(src.x, 0) - - dst.z = (src.x > 0) ? max(src.y, 0)^{clamp(src.w, -128, 128))} : 0 - - dst.w = 1 - - -RCP - Reciprocal - -.. math:: - - dst.x = \frac{1}{src.x} - - dst.y = \frac{1}{src.x} - - dst.z = \frac{1}{src.x} - - dst.w = \frac{1}{src.x} - - -RSQ - Reciprocal Square Root - -.. math:: - - dst.x = \frac{1}{\sqrt{|src.x|}} - - dst.y = \frac{1}{\sqrt{|src.x|}} - - dst.z = \frac{1}{\sqrt{|src.x|}} - - dst.w = \frac{1}{\sqrt{|src.x|}} - - -EXP - Approximate Exponential Base 2 - -.. math:: - - dst.x = 2^{\lfloor src.x\rfloor} - - dst.y = src.x - \lfloor src.x\rfloor - - dst.z = 2^{src.x} - - dst.w = 1 - - -LOG - Approximate Logarithm Base 2 - -.. math:: - - dst.x = \lfloor\log_2{|src.x|}\rfloor - - dst.y = \frac{|src.x|}{2^{\lfloor\log_2{|src.x|}\rfloor}} - - dst.z = \log_2{|src.x|} - - dst.w = 1 - - -MUL - Multiply - -.. math:: - - dst.x = src0.x \times src1.x - - dst.y = src0.y \times src1.y - - dst.z = src0.z \times src1.z - - dst.w = src0.w \times src1.w - - -ADD - Add - -.. math:: - - dst.x = src0.x + src1.x - - dst.y = src0.y + src1.y - - dst.z = src0.z + src1.z - - dst.w = src0.w + src1.w - - -DP3 - 3-component Dot Product - -.. math:: - - dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z - - dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z - - dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z - - dst.w = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z - - -DP4 - 4-component Dot Product - -.. math:: - - dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w - - dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w - - dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w - - dst.w = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src0.w \times src1.w - - -DST - Distance Vector - -.. math:: - - dst.x = 1 - - dst.y = src0.y \times src1.y - - dst.z = src0.z - - dst.w = src1.w - - -MIN - Minimum - -.. math:: - - dst.x = min(src0.x, src1.x) - - dst.y = min(src0.y, src1.y) - - dst.z = min(src0.z, src1.z) - - dst.w = min(src0.w, src1.w) - - -MAX - Maximum - -.. math:: - - dst.x = max(src0.x, src1.x) - - dst.y = max(src0.y, src1.y) - - dst.z = max(src0.z, src1.z) - - dst.w = max(src0.w, src1.w) - - -SLT - Set On Less Than - -.. math:: - - dst.x = (src0.x < src1.x) ? 1 : 0 - - dst.y = (src0.y < src1.y) ? 1 : 0 - - dst.z = (src0.z < src1.z) ? 1 : 0 - - dst.w = (src0.w < src1.w) ? 1 : 0 - - -SGE - Set On Greater Equal Than - -.. math:: - - dst.x = (src0.x >= src1.x) ? 1 : 0 - - dst.y = (src0.y >= src1.y) ? 1 : 0 - - dst.z = (src0.z >= src1.z) ? 1 : 0 - - dst.w = (src0.w >= src1.w) ? 1 : 0 - - -MAD - Multiply And Add - -.. math:: - - dst.x = src0.x \times src1.x + src2.x - - dst.y = src0.y \times src1.y + src2.y - - dst.z = src0.z \times src1.z + src2.z - - dst.w = src0.w \times src1.w + src2.w - - -SUB - Subtract - -.. math:: - - dst.x = src0.x - src1.x - - dst.y = src0.y - src1.y - - dst.z = src0.z - src1.z - - dst.w = src0.w - src1.w - - -LRP - Linear Interpolate - -.. math:: - - dst.x = src0.x \times (src1.x - src2.x) + src2.x - - dst.y = src0.y \times (src1.y - src2.y) + src2.y - - dst.z = src0.z \times (src1.z - src2.z) + src2.z - - dst.w = src0.w \times (src1.w - src2.w) + src2.w - - -CND - Condition - -.. math:: - - dst.x = (src2.x > 0.5) ? src0.x : src1.x - - dst.y = (src2.y > 0.5) ? src0.y : src1.y - - dst.z = (src2.z > 0.5) ? src0.z : src1.z - - dst.w = (src2.w > 0.5) ? src0.w : src1.w - - -DP2A - 2-component Dot Product And Add - -.. math:: - - dst.x = src0.x \times src1.x + src0.y \times src1.y + src2.x - - dst.y = src0.x \times src1.x + src0.y \times src1.y + src2.x - - dst.z = src0.x \times src1.x + src0.y \times src1.y + src2.x - - dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x - - -FRAC - Fraction - -.. math:: - - dst.x = src.x - \lfloor src.x\rfloor - - dst.y = src.y - \lfloor src.y\rfloor - - dst.z = src.z - \lfloor src.z\rfloor - - dst.w = src.w - \lfloor src.w\rfloor - - -CLAMP - Clamp - -.. math:: - - dst.x = clamp(src0.x, src1.x, src2.x) - - dst.y = clamp(src0.y, src1.y, src2.y) - - dst.z = clamp(src0.z, src1.z, src2.z) - - dst.w = clamp(src0.w, src1.w, src2.w) - - -FLR - Floor - -This is identical to ARL. - -.. math:: - - dst.x = \lfloor src.x\rfloor - - dst.y = \lfloor src.y\rfloor - - dst.z = \lfloor src.z\rfloor - - dst.w = \lfloor src.w\rfloor - - -ROUND - Round - -.. math:: - - dst.x = round(src.x) - - dst.y = round(src.y) - - dst.z = round(src.z) - - dst.w = round(src.w) - - -EX2 - Exponential Base 2 - -.. math:: - - dst.x = 2^{src.x} - - dst.y = 2^{src.x} - - dst.z = 2^{src.x} - - dst.w = 2^{src.x} - - -LG2 - Logarithm Base 2 - -.. math:: - - dst.x = \log_2{src.x} - - dst.y = \log_2{src.x} - - dst.z = \log_2{src.x} - - dst.w = \log_2{src.x} - - -POW - Power - -.. math:: - - dst.x = src0.x^{src1.x} - - dst.y = src0.x^{src1.x} - - dst.z = src0.x^{src1.x} - - dst.w = src0.x^{src1.x} - -XPD - Cross Product - -.. math:: - - dst.x = src0.y \times src1.z - src1.y \times src0.z - - dst.y = src0.z \times src1.x - src1.z \times src0.x - - dst.z = src0.x \times src1.y - src1.x \times src0.y - - dst.w = 1 - - -ABS - Absolute - -.. math:: - - dst.x = |src.x| - - dst.y = |src.y| - - dst.z = |src.z| - - dst.w = |src.w| - - -RCC - Reciprocal Clamped - -XXX cleanup on aisle three - -.. math:: - - dst.x = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020) - - dst.y = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020) - - dst.z = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020) - - dst.w = (1 / src.x) > 0 ? clamp(1 / src.x, 5.42101e-020, 1.884467e+019) : clamp(1 / src.x, -1.884467e+019, -5.42101e-020) - - -DPH - Homogeneous Dot Product - -.. math:: - - dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w - - dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w - - dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w - - dst.w = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z + src1.w - - -COS - Cosine - -.. math:: - - dst.x = \cos{src.x} - - dst.y = \cos{src.x} - - dst.z = \cos{src.x} - - dst.w = \cos{src.w} - - -DDX - Derivative Relative To X - -.. math:: - - dst.x = partialx(src.x) - - dst.y = partialx(src.y) - - dst.z = partialx(src.z) - - dst.w = partialx(src.w) - - -DDY - Derivative Relative To Y - -.. math:: - - dst.x = partialy(src.x) - - dst.y = partialy(src.y) - - dst.z = partialy(src.z) - - dst.w = partialy(src.w) - - -KILP - Predicated Discard - - discard - - -PK2H - Pack Two 16-bit Floats - - TBD - - -PK2US - Pack Two Unsigned 16-bit Scalars - - TBD - - -PK4B - Pack Four Signed 8-bit Scalars - - TBD - - -PK4UB - Pack Four Unsigned 8-bit Scalars - - TBD - - -RFL - Reflection Vector - -.. math:: - - 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 - - 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 - - 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 - - dst.w = 1 - -Considered for removal. - - -SEQ - Set On Equal - -.. math:: - - dst.x = (src0.x == src1.x) ? 1 : 0 - dst.y = (src0.y == src1.y) ? 1 : 0 - dst.z = (src0.z == src1.z) ? 1 : 0 - dst.w = (src0.w == src1.w) ? 1 : 0 - - -SFL - Set On False - -.. math:: - - dst.x = 0 - dst.y = 0 - dst.z = 0 - dst.w = 0 - -Considered for removal. - -SGT - Set On Greater Than - -.. math:: - - dst.x = (src0.x > src1.x) ? 1 : 0 - dst.y = (src0.y > src1.y) ? 1 : 0 - dst.z = (src0.z > src1.z) ? 1 : 0 - dst.w = (src0.w > src1.w) ? 1 : 0 - - -SIN - Sine - -.. math:: - - dst.x = \sin{src.x} - - dst.y = \sin{src.x} - - dst.z = \sin{src.x} - - dst.w = \sin{src.w} - - -SLE - Set On Less Equal Than - -.. math:: - - dst.x = (src0.x <= src1.x) ? 1 : 0 - dst.y = (src0.y <= src1.y) ? 1 : 0 - dst.z = (src0.z <= src1.z) ? 1 : 0 - dst.w = (src0.w <= src1.w) ? 1 : 0 - - -SNE - Set On Not Equal - -.. math:: - - dst.x = (src0.x != src1.x) ? 1 : 0 - dst.y = (src0.y != src1.y) ? 1 : 0 - dst.z = (src0.z != src1.z) ? 1 : 0 - dst.w = (src0.w != src1.w) ? 1 : 0 - - -STR - Set On True - -.. math:: - - dst.x = 1 - dst.y = 1 - dst.z = 1 - dst.w = 1 - - -TEX - Texture Lookup - - TBD - - -TXD - Texture Lookup with Derivatives - - TBD - - -TXP - Projective Texture Lookup - - TBD - - -UP2H - Unpack Two 16-Bit Floats - - TBD - - Considered for removal. - -UP2US - Unpack Two Unsigned 16-Bit Scalars - - TBD - - Considered for removal. - -UP4B - Unpack Four Signed 8-Bit Values - - TBD - - Considered for removal. - -UP4UB - Unpack Four Unsigned 8-Bit Scalars - - TBD - - Considered for removal. - -X2D - 2D Coordinate Transformation - -.. math:: - - dst.x = src0.x + src1.x \times src2.x + src1.y \times src2.y - dst.y = src0.y + src1.x \times src2.z + src1.y \times src2.w - dst.z = src0.x + src1.x \times src2.x + src1.y \times src2.y - dst.w = src0.y + src1.x \times src2.z + src1.y \times src2.w - -Considered for removal. - - -From GL_NV_vertex_program2 -^^^^^^^^^^^^^^^^^^^^^^^^^^ - - -ARA - Address Register Add - - TBD - - Considered for removal. - -ARR - Address Register Load With Round - -.. math:: - - dst.x = round(src.x) - - dst.y = round(src.y) - - dst.z = round(src.z) - - dst.w = round(src.w) - - -BRA - Branch - - pc = target - - Considered for removal. - -CAL - Subroutine Call - - push(pc) - pc = target - - -RET - Subroutine Call Return - - pc = pop() - - Potential restrictions: - \times Only occurs at end of function. - -SSG - Set Sign - -.. math:: - - dst.x = (src.x > 0) ? 1 : (src.x < 0) ? -1 : 0 - - dst.y = (src.y > 0) ? 1 : (src.y < 0) ? -1 : 0 - - dst.z = (src.z > 0) ? 1 : (src.z < 0) ? -1 : 0 - - dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0 - - -CMP - Compare - -.. math:: - - dst.x = (src0.x < 0) ? src1.x : src2.x - - dst.y = (src0.y < 0) ? src1.y : src2.y - - dst.z = (src0.z < 0) ? src1.z : src2.z - - dst.w = (src0.w < 0) ? src1.w : src2.w - - -KIL - Conditional Discard - -.. math:: - - if (src.x < 0 || src.y < 0 || src.z < 0 || src.w < 0) - discard - endif - - -SCS - Sine Cosine - -.. math:: - - dst.x = \cos{src.x} - - dst.y = \sin{src.x} - - dst.z = 0 - - dst.y = 1 - - -TXB - Texture Lookup With Bias - - TBD - - -NRM - 3-component Vector Normalise - -.. math:: - - dst.x = src.x / (src.x \times src.x + src.y \times src.y + src.z \times src.z) - - dst.y = src.y / (src.x \times src.x + src.y \times src.y + src.z \times src.z) - - dst.z = src.z / (src.x \times src.x + src.y \times src.y + src.z \times src.z) - - dst.w = 1 - - -DIV - Divide - -.. math:: - - dst.x = \frac{src0.x}{src1.x} - - dst.y = \frac{src0.y}{src1.y} - - dst.z = \frac{src0.z}{src1.z} - - dst.w = \frac{src0.w}{src1.w} - - -DP2 - 2-component Dot Product - -.. math:: - - dst.x = src0.x \times src1.x + src0.y \times src1.y - - dst.y = src0.x \times src1.x + src0.y \times src1.y - - dst.z = src0.x \times src1.x + src0.y \times src1.y - - dst.w = src0.x \times src1.x + src0.y \times src1.y - - -TXL - Texture Lookup With LOD - - TBD - - -BRK - Break - - TBD - - -IF - If - - TBD - - -BGNFOR - Begin a For-Loop - - dst.x = floor(src.x) - dst.y = floor(src.y) - dst.z = floor(src.z) - - if (dst.y <= 0) - pc = [matching ENDFOR] + 1 - endif - - Note: The destination must be a loop register. - The source must be a constant register. - - Considered for cleanup / removal. - - -REP - Repeat - - TBD - - -ELSE - Else - - TBD - - -ENDIF - End If - - TBD - - -ENDFOR - End a For-Loop - - dst.x = dst.x + dst.z - dst.y = dst.y - 1.0 - - if (dst.y > 0) - pc = [matching BGNFOR instruction] + 1 - endif - - Note: The destination must be a loop register. - - Considered for cleanup / removal. - -ENDREP - End Repeat - - TBD - - -PUSHA - Push Address Register On Stack - - push(src.x) - push(src.y) - push(src.z) - push(src.w) - - Considered for cleanup / removal. - -POPA - Pop Address Register From Stack - - dst.w = pop() - dst.z = pop() - dst.y = pop() - dst.x = pop() - - Considered for cleanup / removal. - - -From GL_NV_gpu_program4 -^^^^^^^^^^^^^^^^^^^^^^^^ - -Support for these opcodes indicated by a special pipe capability bit (TBD). - -CEIL - Ceiling - -.. math:: - - dst.x = \lceil src.x\rceil - - dst.y = \lceil src.y\rceil - - dst.z = \lceil src.z\rceil - - dst.w = \lceil src.w\rceil - - -I2F - Integer To Float - -.. math:: - - dst.x = (float) src.x - - dst.y = (float) src.y - - dst.z = (float) src.z - - dst.w = (float) src.w - - -NOT - Bitwise Not - -.. math:: - - dst.x = ~src.x - - dst.y = ~src.y - - dst.z = ~src.z - - dst.w = ~src.w - - -TRUNC - Truncate - -XXX how is this different from floor? - -.. math:: - - dst.x = trunc(src.x) - - dst.y = trunc(src.y) - - dst.z = trunc(src.z) - - dst.w = trunc(src.w) - - -SHL - Shift Left - -.. math:: - - dst.x = src0.x << src1.x - - dst.y = src0.y << src1.x - - dst.z = src0.z << src1.x - - dst.w = src0.w << src1.x - - -SHR - Shift Right - -.. math:: - - dst.x = src0.x >> src1.x - - dst.y = src0.y >> src1.x - - dst.z = src0.z >> src1.x - - dst.w = src0.w >> src1.x - - -AND - Bitwise And - -.. math:: - - dst.x = src0.x & src1.x - - dst.y = src0.y & src1.y - - dst.z = src0.z & src1.z - - dst.w = src0.w & src1.w - - -OR - Bitwise Or - -.. math:: - - dst.x = src0.x | src1.x - - dst.y = src0.y | src1.y - - dst.z = src0.z | src1.z - - dst.w = src0.w | src1.w - - -MOD - Modulus - -.. math:: - - dst.x = src0.x \bmod src1.x - - dst.y = src0.y \bmod src1.y - - dst.z = src0.z \bmod src1.z - - dst.w = src0.w \bmod src1.w - - -XOR - Bitwise Xor - -.. math:: - - dst.x = src0.x ^ src1.x - - dst.y = src0.y ^ src1.y - - dst.z = src0.z ^ src1.z - - dst.w = src0.w ^ src1.w - - -SAD - Sum Of Absolute Differences - -.. math:: - - dst.x = |src0.x - src1.x| + src2.x - - dst.y = |src0.y - src1.y| + src2.y - - dst.z = |src0.z - src1.z| + src2.z - - dst.w = |src0.w - src1.w| + src2.w - - -TXF - Texel Fetch - - TBD - - -TXQ - Texture Size Query - - TBD - - -CONT - Continue - - TBD - - -From GL_NV_geometry_program4 -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - - -EMIT - Emit - - TBD - - -ENDPRIM - End Primitive - - TBD - - -From GLSL -^^^^^^^^^^ - - -BGNLOOP - Begin a Loop - - TBD - - -BGNSUB - Begin Subroutine - - TBD - - -ENDLOOP - End a Loop - - TBD - - -ENDSUB - End Subroutine - - TBD - - - -NOP - No Operation - - Do nothing. - -NRM4 - 4-component Vector Normalise - -.. math:: - - dst.x = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w} - - dst.y = \frac{src.y}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w} - - dst.z = \frac{src.z}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w} - - dst.w = \frac{src.w}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w} - - -ps_2_x -^^^^^^^^^^^^ - - -CALLNZ - Subroutine Call If Not Zero - - TBD - - -IFC - If - - TBD - - -BREAKC - Break Conditional - - TBD - - -Explanation of symbols used ------------------------------- - - -Functions -^^^^^^^^^^^^^^ - - - :math:`|x|` Absolute value of `x`. - - :math:`\lceil x \rceil` Ceiling of `x`. - - clamp(x,y,z) Clamp x between y and z. - (x < y) ? y : (x > z) ? z : x - - :math:`\lfloor x\rfloor` Floor of `x`. - - :math:`\log_2{x}` Logarithm of `x`, base 2. - - max(x,y) Maximum of x and y. - (x > y) ? x : y - - min(x,y) Minimum of x and y. - (x < y) ? x : y - - partialx(x) Derivative of x relative to fragment's X. - - partialy(x) Derivative of x relative to fragment's Y. - - pop() Pop from stack. - - :math:`x^y` `x` to the power `y`. - - push(x) Push x on stack. - - round(x) Round x. - - trunc(x) Truncate x. - - -Keywords -^^^^^^^^^^^^^ - - - discard Discard fragment. - - dst First destination register. - - dst0 First destination register. - - pc Program counter. - - src First source register. - - src0 First source register. - - src1 Second source register. - - src2 Third source register. - - target Label of target instruction. - - -Other tokens ---------------- - - -Declaration Semantic -^^^^^^^^^^^^^^^^^^^^^^^^ - - - Follows Declaration token if Semantic bit is set. - - Since its purpose is to link a shader with other stages of the pipeline, - it is valid to follow only those Declaration tokens that declare a register - either in INPUT or OUTPUT file. - - SemanticName field contains the semantic name of the register being declared. - There is no default value. - - SemanticIndex is an optional subscript that can be used to distinguish - different register declarations with the same semantic name. The default value - is 0. - - The meanings of the individual semantic names are explained in the following - sections. - -TGSI_SEMANTIC_POSITION -"""""""""""""""""""""" - -Position, sometimes known as HPOS or WPOS for historical reasons, is the -location of the vertex in space, in ``(x, y, z, w)`` format. ``x``, ``y``, and ``z`` -are the Cartesian coordinates, and ``w`` is the homogenous coordinate and used -for the perspective divide, if enabled. - -As a vertex shader output, position should be scaled to the viewport. When -used in fragment shaders, position will --- - -XXX --- wait a minute. Should position be in [0,1] for x and y? - -XXX additionally, is there a way to configure the perspective divide? it's -accelerated on most chipsets AFAIK... - -Position, if not specified, usually defaults to ``(0, 0, 0, 1)``, and can -be partially specified as ``(x, y, 0, 1)`` or ``(x, y, z, 1)``. - -XXX usually? can we solidify that? - -TGSI_SEMANTIC_COLOR -""""""""""""""""""" - -Colors are used to, well, color the primitives. Colors are always in -``(r, g, b, a)`` format. - -If alpha is not specified, it defaults to 1. - -TGSI_SEMANTIC_BCOLOR -"""""""""""""""""""" - -Back-facing colors are only used for back-facing polygons, and are only valid -in vertex shader outputs. After rasterization, all polygons are front-facing -and COLOR and BCOLOR end up occupying the same slots in the fragment, so -all BCOLORs effectively become regular COLORs in the fragment shader. - -TGSI_SEMANTIC_FOG -""""""""""""""""" - -The fog coordinate historically has been used to replace the depth coordinate -for generation of fog in dedicated fog blocks. Gallium, however, does not use -dedicated fog acceleration, placing it entirely in the fragment shader -instead. - -The fog coordinate should be written in ``(f, 0, 0, 1)`` format. Only the first -component matters when writing from the vertex shader; the driver will ensure -that the coordinate is in this format when used as a fragment shader input. - -TGSI_SEMANTIC_PSIZE -""""""""""""""""""" - -PSIZE, or point size, is used to specify point sizes per-vertex. It should -be in ``(p, n, x, f)`` format, where ``p`` is the point size, ``n`` is the minimum -size, ``x`` is the maximum size, and ``f`` is the fade threshold. - -XXX this is arb_vp. is this what we actually do? should double-check... - -When using this semantic, be sure to set the appropriate state in the -:ref:`rasterizer` first. - -TGSI_SEMANTIC_GENERIC -""""""""""""""""""""" - -Generic semantics are nearly always used for texture coordinate attributes, -in ``(s, t, r, q)`` format. ``t`` and ``r`` may be unused for certain kinds -of lookups, and ``q`` is the level-of-detail bias for biased sampling. - -These attributes are called "generic" because they may be used for anything -else, including parameters, texture generation information, or anything that -can be stored inside a four-component vector. - -TGSI_SEMANTIC_NORMAL -"""""""""""""""""""" - -XXX no clue. - -TGSI_SEMANTIC_FACE -"""""""""""""""""" - -FACE is the facing bit, to store the facing information for the fragment -shader. ``(f, 0, 0, 1)`` is the format. The first component will be positive -when the fragment is front-facing, and negative when the component is -back-facing. - -TGSI_SEMANTIC_EDGEFLAG -"""""""""""""""""""""" - -XXX no clue |