diff options
| -rw-r--r-- | src/gallium/docs/source/tgsi.rst | 127 |
1 files changed, 102 insertions, 25 deletions
diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst index 093bf7dd19d..ac0ea5413b3 100644 --- a/src/gallium/docs/source/tgsi.rst +++ b/src/gallium/docs/source/tgsi.rst @@ -584,25 +584,44 @@ This instruction replicates its result. for array textures src0.y contains the slice for 1D, and src0.z contain the slice for 2D. - for shadow textures with no arrays, src0.z contains - the reference value. + for shadow textures with no arrays (and not cube map), + src0.z contains the reference value. for shadow textures with arrays, src0.z contains the reference value for 1D arrays, and src0.w contains - the reference value for 2D arrays. + the reference value for 2D arrays and cube maps. - There is no way to pass a bias in the .w value for - shadow arrays, and GLSL doesn't allow this. - GLSL does allow cube shadows maps to take a bias value, - and we have to determine how this will look in TGSI. + for cube map array shadow textures, the reference value + cannot be passed in src0.w, and TEX2 must be used instead. .. math:: coord = src0 - bias = 0.0 + shadow_ref = src0.z or src0.w (optional) + + unit = src1 + + dst = texture\_sample(unit, coord, shadow_ref) + + +.. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only) + + this is the same as TEX, but uses another reg to encode the + reference value. + +.. math:: + + coord = src0 + + shadow_ref = src1.x + + unit = src2 + + dst = texture\_sample(unit, coord, shadow_ref) + + - dst = texture\_sample(unit, coord, bias) .. opcode:: TXD - Texture Lookup with Derivatives @@ -614,26 +633,26 @@ This instruction replicates its result. ddy = src2 - bias = 0.0 + unit = src3 - dst = texture\_sample\_deriv(unit, coord, bias, ddx, ddy) + dst = texture\_sample\_deriv(unit, coord, ddx, ddy) .. opcode:: TXP - Projective Texture Lookup .. math:: - coord.x = src0.x / src.w + coord.x = src0.x / src0.w - coord.y = src0.y / src.w + coord.y = src0.y / src0.w - coord.z = src0.z / src.w + coord.z = src0.z / src0.w coord.w = src0.w - bias = 0.0 + unit = src1 - dst = texture\_sample(unit, coord, bias) + dst = texture\_sample(unit, coord) .. opcode:: UP2H - Unpack Two 16-Bit Floats @@ -763,17 +782,46 @@ This instruction replicates its result. .. opcode:: TXB - Texture Lookup With Bias + for cube map array textures and shadow cube maps, the bias value + cannot be passed in src0.w, and TXB2 must be used instead. + + if the target is a shadow texture, the reference value is always + in src.z (this prevents shadow 3d and shadow 2d arrays from + using this instruction, but this is not needed). + .. math:: - coord.x = src.x + coord.x = src0.x + + coord.y = src0.y - coord.y = src.y + coord.z = src0.z - coord.z = src.z + coord.w = none - coord.w = 1.0 + bias = src0.w - bias = src.z + unit = src1 + + dst = texture\_sample(unit, coord, bias) + + +.. opcode:: TXB2 - Texture Lookup With Bias (some cube maps only) + + this is the same as TXB, but uses another reg to encode the + lod bias value for cube map arrays and shadow cube maps. + Presumably shadow 2d arrays and shadow 3d targets could use + this encoding too, but this is not legal. + + shadow cube map arrays are neither possible nor required. + +.. math:: + + coord = src0 + + bias = src1.x + + unit = src2 dst = texture\_sample(unit, coord, bias) @@ -815,6 +863,13 @@ This instruction replicates its result. .. opcode:: TXL - Texture Lookup With explicit LOD + for cube map array textures, the explicit lod value + cannot be passed in src0.w, and TXL2 must be used instead. + + if the target is a shadow texture, the reference value is always + in src.z (this prevents shadow 3d / 2d array / cube targets from + using this instruction, but this is not needed). + .. math:: coord.x = src0.x @@ -823,10 +878,32 @@ This instruction replicates its result. coord.z = src0.z - coord.w = 1.0 + coord.w = none lod = src0.w + unit = src1 + + dst = texture\_sample(unit, coord, lod) + + +.. opcode:: TXL2 - Texture Lookup With explicit LOD (for cube map arrays only) + + this is the same as TXL, but uses another reg to encode the + explicit lod value. + Presumably shadow 3d / 2d array / cube targets could use + this encoding too, but this is not legal. + + shadow cube map arrays are neither possible nor required. + +.. math:: + + coord = src0 + + lod = src1.x + + unit = src2 + dst = texture\_sample(unit, coord, lod) @@ -954,9 +1031,9 @@ XXX doesn't look like most of the opcodes really belong here. As per NV_gpu_shader4, extract a single texel from a specified texture image. The source sampler may not be a CUBE or SHADOW. src 0 is a four-component signed integer vector used to identify the single texel - accessed. 3 components + level. src 1 is a 3 component constant signed - integer vector, with each component only have a range of -8..+8 (hw only - seems to deal with this range, interface allows for up to unsigned int). + accessed. 3 components + level. Just like texture instructions, an optional + offset vector is provided, which is subject to various driver restrictions + (regarding range, source of offsets). TXF(uint_vec coord, int_vec offset). |