.. math::
- dst.x = \lfloor src.x\rfloor
+ dst.x = (int) \lfloor src.x\rfloor
- dst.y = \lfloor src.y\rfloor
+ dst.y = (int) \lfloor src.y\rfloor
- dst.z = \lfloor src.z\rfloor
+ dst.z = (int) \lfloor src.z\rfloor
- dst.w = \lfloor src.w\rfloor
+ dst.w = (int) \lfloor src.w\rfloor
.. opcode:: MOV - Move
dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
-.. opcode:: CND - Condition
+.. opcode:: FMA - Fused Multiply-Add
+
+Perform a * b + c with no intermediate rounding step.
.. math::
- dst.x = (src2.x > 0.5) ? src0.x : src1.x
+ dst.x = src0.x \times src1.x + src2.x
- dst.y = (src2.y > 0.5) ? src0.y : src1.y
+ dst.y = src0.y \times src1.y + src2.y
- dst.z = (src2.z > 0.5) ? src0.z : src1.z
+ dst.z = src0.z \times src1.z + src2.z
- dst.w = (src2.w > 0.5) ? src0.w : src1.w
+ dst.w = src0.w \times src1.w + src2.w
.. opcode:: DP2A - 2-component Dot Product And Add
.. opcode:: FLR - Floor
-This is identical to :opcode:`ARL`.
-
.. math::
dst.x = \lfloor src.x\rfloor
dst.w = |src.w|
-.. opcode:: RCC - Reciprocal Clamped
-
-This instruction replicates its result.
-
-XXX cleanup on aisle three
-
-.. math::
-
- 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)
-
-
.. opcode:: DPH - Homogeneous Dot Product
This instruction replicates its result.
dst = \cos{src.x}
-.. opcode:: DDX - Derivative Relative To X
+.. opcode:: DDX, DDX_FINE - Derivative Relative To X
+
+The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
+advertised. When it is, the fine version guarantees one derivative per row
+while DDX is allowed to be the same for the entire 2x2 quad.
.. math::
dst.w = partialx(src.w)
-.. opcode:: DDY - Derivative Relative To Y
+.. opcode:: DDY, DDY_FINE - Derivative Relative To Y
+
+The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
+advertised. When it is, the fine version guarantees one derivative per column
+while DDY is allowed to be the same for the entire 2x2 quad.
.. math::
TBD
-.. opcode:: 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
-
-.. note::
-
- Considered for removal.
-
-
.. opcode:: SEQ - Set On Equal
.. math::
dst.w = (src0.w == src1.w) ? 1.0F : 0.0F
-.. opcode:: SFL - Set On False
-
-This instruction replicates its result.
-
-.. math::
-
- dst = 0.0F
-
-.. note::
-
- Considered for removal.
-
-
.. opcode:: SGT - Set On Greater Than
.. math::
dst.w = (src0.w != src1.w) ? 1.0F : 0.0F
-.. opcode:: STR - Set On True
+.. opcode:: TEX - Texture Lookup
+
+ for array textures src0.y contains the slice for 1D,
+ and src0.z contain the slice for 2D.
-This instruction replicates its result.
+ 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 and cube maps.
+
+ for cube map array shadow textures, the reference value
+ cannot be passed in src0.w, and TEX2 must be used instead.
.. math::
- dst = 1.0F
+ coord = src0
+ shadow_ref = src0.z or src0.w (optional)
-.. opcode:: TEX - Texture Lookup
+ unit = src1
- for array textures src0.y contains the slice for 1D,
- and src0.z contain the slice for 2D.
+ dst = texture\_sample(unit, coord, shadow_ref)
- for shadow textures with no arrays, 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.
+.. opcode:: TEX2 - Texture Lookup (for shadow cube map arrays only)
- 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.
+ this is the same as TEX, but uses another reg to encode the
+ reference value.
.. math::
coord = src0
- bias = 0.0
+ 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
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
Considered for removal.
-.. opcode:: 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
-
-.. note::
-
- Considered for removal.
-
-
-.. opcode:: ARA - Address Register Add
-
- TBD
-
-.. note::
-
- Considered for removal.
.. opcode:: ARR - Address Register Load With Round
.. math::
- dst.x = round(src.x)
+ dst.x = (int) round(src.x)
- dst.y = round(src.y)
+ dst.y = (int) round(src.y)
- dst.z = round(src.z)
+ dst.z = (int) round(src.z)
- dst.w = round(src.w)
+ dst.w = (int) round(src.w)
.. opcode:: SSG - Set Sign
.. 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 = src.y
+ coord.y = src0.y
- coord.z = src.z
+ coord.z = src0.z
- coord.w = 1.0
+ coord.w = none
- bias = src.z
+ bias = src0.w
+
+ unit = src1
dst = texture\_sample(unit, coord, bias)
-.. opcode:: NRM - 3-component Vector Normalise
+.. 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::
- dst.x = src.x / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
+ coord = src0
- dst.y = src.y / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
+ bias = src1.x
- dst.z = src.z / (src.x \times src.x + src.y \times src.y + src.z \times src.z)
+ unit = src2
- dst.w = 1
+ dst = texture\_sample(unit, coord, bias)
.. opcode:: DIV - Divide
.. 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
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)
Considered for removal.
-.. opcode:: BRA - Branch
-
- pc = target
-
-.. note::
-
- Considered for removal.
-
-
.. opcode:: CALLNZ - Subroutine Call If Not Zero
TBD
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).
As per NV_gpu_program4, retrieve the dimensions of the texture depending on
the target. For 1D (width), 2D/RECT/CUBE (width, height), 3D (width, height,
- depth), 1D array (width, layers), 2D array (width, height, layers)
+ depth), 1D array (width, layers), 2D array (width, height, layers).
+ Also return the number of accessible levels (last_level - first_level + 1)
+ in W.
+
+ For components which don't return a resource dimension, their value
+ is undefined.
+
.. math::
dst.z = texture\_depth(unit, lod)
+ dst.w = texture\_levels(unit)
+
.. opcode:: TG4 - Texture Gather
As per ARB_texture_gather, gathers the four texels to be used in a bi-linear
dst.w = |src.w|
+Bitwise ISA
+^^^^^^^^^^^
+These opcodes are used for bit-level manipulation of integers.
+
+.. opcode:: IBFE - Signed Bitfield Extract
+
+ See SM5 instruction of the same name. Extracts a set of bits from the input,
+ and sign-extends them if the high bit of the extracted window is set.
+
+ Pseudocode::
+
+ def ibfe(value, offset, bits):
+ offset = offset & 0x1f
+ bits = bits & 0x1f
+ if bits == 0: return 0
+ # Note: >> sign-extends
+ if width + offset < 32:
+ return (value << (32 - offset - bits)) >> (32 - bits)
+ else:
+ return value >> offset
+
+.. opcode:: UBFE - Unsigned Bitfield Extract
+
+ See SM5 instruction of the same name. Extracts a set of bits from the input,
+ without any sign-extension.
+
+ Pseudocode::
+
+ def ubfe(value, offset, bits):
+ offset = offset & 0x1f
+ bits = bits & 0x1f
+ if bits == 0: return 0
+ # Note: >> does not sign-extend
+ if width + offset < 32:
+ return (value << (32 - offset - bits)) >> (32 - bits)
+ else:
+ return value >> offset
+
+.. opcode:: BFI - Bitfield Insert
+
+ See SM5 instruction of the same name. Replaces a bit region of 'base' with
+ the low bits of 'insert'.
+
+ Pseudocode::
+
+ def bfi(base, insert, offset, bits):
+ offset = offset & 0x1f
+ bits = bits & 0x1f
+ mask = ((1 << bits) - 1) << offset
+ return ((insert << offset) & mask) | (base & ~mask)
+
+.. opcode:: BREV - Bitfield Reverse
+
+ See SM5 instruction BFREV. Reverses the bits of the argument.
+
+.. opcode:: POPC - Population Count
+
+ See SM5 instruction COUNTBITS. Counts the number of set bits in the argument.
+
+.. opcode:: LSB - Index of lowest set bit
+
+ See SM5 instruction FIRSTBIT_LO. Computes the 0-based index of the first set
+ bit of the argument. Returns -1 if none are set.
+
+.. opcode:: IMSB - Index of highest non-sign bit
+
+ See SM5 instruction FIRSTBIT_SHI. Computes the 0-based index of the highest
+ non-sign bit of the argument (i.e. highest 0 bit for negative numbers,
+ highest 1 bit for positive numbers). Returns -1 if all bits are the same
+ (i.e. for inputs 0 and -1).
+
+.. opcode:: UMSB - Index of highest set bit
+
+ See SM5 instruction FIRSTBIT_HI. Computes the 0-based index of the highest
+ set bit of the argument. Returns -1 if none are set.
Geometry ISA
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. opcode:: EMIT - Emit
- Generate a new vertex for the current primitive using the values in the
- output registers.
+ Generate a new vertex for the current primitive into the specified vertex
+ stream using the values in the output registers.
.. opcode:: ENDPRIM - End Primitive
- Complete the current primitive (consisting of the emitted vertices),
- and start a new one.
+ Complete the current primitive in the specified vertex stream (consisting of
+ the emitted vertices), and start a new one.
GLSL ISA
Ends a switch expression.
-.. opcode:: NRM4 - 4-component Vector Normalise
+Interpolation ISA
+^^^^^^^^^^^^^^^^^
-This instruction replicates its result.
+The interpolation instructions allow an input to be interpolated in a
+different way than its declaration. This corresponds to the GLSL 4.00
+interpolateAt* functions. The first argument of each of these must come from
+``TGSI_FILE_INPUT``.
-.. math::
+.. opcode:: INTERP_CENTROID - Interpolate at the centroid
+
+ Interpolates the varying specified by src0 at the centroid
- dst = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
+.. opcode:: INTERP_SAMPLE - Interpolate at the specified sample
+
+ Interpolates the varying specified by src0 at the sample id specified by
+ src1.x (interpreted as an integer)
+
+.. opcode:: INTERP_OFFSET - Interpolate at the specified offset
+
+ Interpolates the varying specified by src0 at the offset src1.xy from the
+ pixel center (interpreted as floats)
.. _doubleopcodes:
The double-precision opcodes reinterpret four-component vectors into
two-component vectors with doubled precision in each component.
-Support for these opcodes is XXX undecided. :T
+.. opcode:: DABS - Absolute
+
+ dst.xy = |src0.xy|
+ dst.zw = |src0.zw|
.. opcode:: DADD - Add
dst.zw = src0.zw + src1.zw
-
-.. opcode:: DDIV - Divide
+.. opcode:: DSEQ - Set on Equal
.. math::
- dst.xy = src0.xy / src1.xy
+ dst.x = src0.xy == src1.xy ? \sim 0 : 0
- dst.zw = src0.zw / src1.zw
+ dst.z = src0.zw == src1.zw ? \sim 0 : 0
-.. opcode:: DSEQ - Set on Equal
+.. opcode:: DSNE - Set on Equal
.. math::
- dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
+ dst.x = src0.xy != src1.xy ? \sim 0 : 0
- dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
+ dst.z = src0.zw != src1.zw ? \sim 0 : 0
.. opcode:: DSLT - Set on Less than
.. math::
- dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
+ dst.x = src0.xy < src1.xy ? \sim 0 : 0
- dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
+ dst.z = src0.zw < src1.zw ? \sim 0 : 0
+
+.. opcode:: DSGE - Set on Greater equal
+
+.. math::
+
+ dst.x = src0.xy >= src1.xy ? \sim 0 : 0
+
+ dst.z = src0.zw >= src1.zw ? \sim 0 : 0
.. opcode:: DFRAC - Fraction
dst.zw = src.zw - \lfloor src.zw\rfloor
+.. opcode:: DTRUNC - Truncate
+
+.. math::
+
+ dst.xy = trunc(src.xy)
+
+ dst.zw = trunc(src.zw)
+
+.. opcode:: DCEIL - Ceiling
+
+.. math::
+
+ dst.xy = \lceil src.xy\rceil
+
+ dst.zw = \lceil src.zw\rceil
+
+.. opcode:: DFLR - Floor
+
+.. math::
+
+ dst.xy = \lfloor src.xy\rfloor
+
+ dst.zw = \lfloor src.zw\rfloor
+
+.. opcode:: DROUND - Fraction
+
+.. math::
+
+ dst.xy = round(src.xy)
+
+ dst.zw = round(src.zw)
+
+.. opcode:: DSSG - Set Sign
+
+.. math::
+
+ dst.xy = (src.xy > 0) ? 1.0 : (src.xy < 0) ? -1.0 : 0.0
+
+ dst.zw = (src.zw > 0) ? 1.0 : (src.zw < 0) ? -1.0 : 0.0
.. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
.. opcode:: DLDEXP - Multiply Number by Integral Power of 2
-This opcode is the inverse of :opcode:`DFRACEXP`.
+This opcode is the inverse of :opcode:`DFRACEXP`. The second
+source is an integer.
.. math::
- dst.xy = src0.xy \times 2^{src1.xy}
+ dst.xy = src0.xy \times 2^{src1.x}
- dst.zw = src0.zw \times 2^{src1.zw}
+ dst.zw = src0.zw \times 2^{src1.y}
.. opcode:: DMIN - Minimum
dst.zw = src0.zw \times src1.zw + src2.zw
+.. opcode:: DFMA - Fused Multiply-Add
+
+Perform a * b + c with no intermediate rounding step.
+
+.. math::
+
+ dst.xy = src0.xy \times src1.xy + src2.xy
+
+ dst.zw = src0.zw \times src1.zw + src2.zw
+
+
.. opcode:: DRCP - Reciprocal
.. math::
dst.zw = \sqrt{src.zw}
+.. opcode:: DRSQ - Reciprocal Square Root
+
+.. math::
+
+ dst.xy = \frac{1}{\sqrt{src.xy}}
+
+ dst.zw = \frac{1}{\sqrt{src.zw}}
+
+.. opcode:: F2D - Float to Double
+
+.. math::
+
+ dst.xy = double(src0.x)
+
+ dst.zw = double(src0.y)
+
+.. opcode:: D2F - Double to Float
+
+.. math::
+
+ dst.x = float(src0.xy)
+
+ dst.y = float(src0.zw)
+
+.. opcode:: I2D - Int to Double
+
+.. math::
+
+ dst.xy = double(src0.x)
+
+ dst.zw = double(src0.y)
+
+.. opcode:: D2I - Double to Int
+
+.. math::
+
+ dst.x = int(src0.xy)
+
+ dst.y = int(src0.zw)
+
+.. opcode:: U2D - Unsigned Int to Double
+
+.. math::
+
+ dst.xy = double(src0.x)
+
+ dst.zw = double(src0.y)
+
+.. opcode:: D2U - Double to Unsigned Int
+
+.. math::
+
+ dst.x = unsigned(src0.xy)
+
+ dst.y = unsigned(src0.zw)
.. _samplingopcodes:
^^^^^^^^^^^^^^^^^^^^^^^^
Declarations can optional have an ArrayID attribute which can be referred by
-indirect addressing operands. An ArrayID of zero is reserved and treaded as
+indirect addressing operands. An ArrayID of zero is reserved and treated as
if no ArrayID is specified.
If an indirect addressing operand refers to a specific declaration by using
If no ArrayID is specified with an indirect addressing operand the whole
register file might be accessed by this operand. This is strongly discouraged
and will prevent packing of scalar/vec2 arrays and effective alias analysis.
+This is only legal for TEMP and CONST register files.
Declaration Semantic
^^^^^^^^^^^^^^^^^^^^^^^^
indicate the top of the window or the bottom depending on the fragment
coordinate origin convention (see TGSI_PROPERTY_FS_COORD_ORIGIN).
The Z coordinate ranges from 0 to 1 to represent depth from the front
-to the back of the Z buffer. The W component contains the reciprocol
-of the interpolated vertex position W component.
+to the back of the Z buffer. The W component contains the interpolated
+reciprocal of the vertex position W component (corresponding to gl_Fragcoord,
+but unlike d3d10 which interpolates the same 1/w but then gives back
+the reciprocal of the interpolated value).
Fragment shaders may also declare an output register with
TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
For geometry shaders, this semantic label indicates that an output
contains the index of the viewport (and scissor) to use.
-Only the X value is used.
+This is an integer value, and only the X component is used.
TGSI_SEMANTIC_LAYER
For geometry shaders, this semantic label indicates that an output
contains the layer value to use for the color and depth/stencil surfaces.
-Only the X value is used. (Also known as rendertarget array index.)
+This is an integer value, and only the X component is used.
+(Also known as rendertarget array index.)
TGSI_SEMANTIC_CULLDIST
which specifies the maximum number of registers which can be
annotated with those semantics.
+TGSI_SEMANTIC_SAMPLEID
+""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates that a system value
+contains the current sample id (i.e. gl_SampleID).
+This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_SAMPLEPOS
+"""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates that a system value
+contains the current sample's position (i.e. gl_SamplePosition). Only the X
+and Y values are used.
+
+TGSI_SEMANTIC_SAMPLEMASK
+""""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates that an output contains
+the sample mask used to disable further sample processing
+(i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
+
+TGSI_SEMANTIC_INVOCATIONID
+""""""""""""""""""""""""""
+
+For geometry shaders, this semantic label indicates that a system value
+contains the current invocation id (i.e. gl_InvocationID).
+This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_INSTANCEID
+""""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the current instance id (i.e. gl_InstanceID). It does not include the base
+instance. This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_VERTEXID
+""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the current vertex id (i.e. gl_VertexID). It does (unlike in d3d10) include the
+base vertex. This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_VERTEXID_NOBASE
+"""""""""""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the current vertex id without including the base vertex (this corresponds to
+d3d10 vertex id, so TGSI_SEMANTIC_VERTEXID_NOBASE + TGSI_SEMANTIC_BASEVERTEX
+== TGSI_SEMANTIC_VERTEXID). This is an integer value, and only the X component
+is used.
+
+TGSI_SEMANTIC_BASEVERTEX
+""""""""""""""""""""""""
+
+For vertex shaders, this semantic label indicates that a system value contains
+the base vertex (i.e. gl_BaseVertex). Note that for non-indexed draw calls,
+this contains the first (or start) value instead.
+This is an integer value, and only the X component is used.
+
+TGSI_SEMANTIC_PRIMID
+""""""""""""""""""""
+
+For geometry and fragment shaders, this semantic label indicates the value
+contains the primitive id (i.e. gl_PrimitiveID). This is an integer value,
+and only the X component is used.
+FIXME: This right now can be either a ordinary input or a system value...
+
+
+TGSI_SEMANTIC_PATCH
+"""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates a
+generic per-patch attribute. Such semantics will not implicitly be per-vertex
+arrays.
+
+TGSI_SEMANTIC_TESSCOORD
+"""""""""""""""""""""""
+
+For tessellation evaluation shaders, this semantic label indicates the
+coordinates of the vertex being processed. This is available in XYZ; W is
+undefined.
+
+TGSI_SEMANTIC_TESSOUTER
+"""""""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates the
+outer tessellation levels of the patch. Isoline tessellation will only have XY
+defined, triangle will have XYZ and quads will have XYZW defined. This
+corresponds to gl_TessLevelOuter.
+
+TGSI_SEMANTIC_TESSINNER
+"""""""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates the
+inner tessellation levels of the patch. The X value is only defined for
+triangle tessellation, while quads will have XY defined. This is entirely
+undefined for isoline tessellation.
+
+TGSI_SEMANTIC_VERTICESIN
+""""""""""""""""""""""""
+
+For tessellation evaluation/control shaders, this semantic label indicates the
+number of vertices provided in the input patch. Only the X value is defined.
+
Declaration Interpolate
^^^^^^^^^^^^^^^^^^^^^^^
The Interpolate field specifes the way input is being interpolated by
the rasteriser and is one of TGSI_INTERPOLATE_*.
+The Location field specifies the location inside the pixel that the
+interpolation should be done at, one of ``TGSI_INTERPOLATE_LOC_*``. Note that
+when per-sample shading is enabled, the implementation may choose to
+interpolate at the sample irrespective of the Location field.
+
The CylindricalWrap bitfield specifies which register components
should be subject to cylindrical wrapping when interpolating by the
rasteriser. If TGSI_CYLINDRICAL_WRAP_X is set to 1, the X component
type must be 1 or 4 entries (if specifying on a per-component
level) out of UNORM, SNORM, SINT, UINT and FLOAT.
+For TEX\* style texture sample opcodes (as opposed to SAMPLE\* opcodes
+which take an explicit SVIEW[#] source register), there may be optionally
+SVIEW[#] declarations. In this case, the SVIEW index is implied by the
+SAMP index, and there must be a corresponding SVIEW[#] declaration for
+each SAMP[#] declaration. Drivers are free to ignore this if they wish.
+But note in particular that some drivers need to know the sampler type
+(float/int/unsigned) in order to generate the correct code, so cases
+where integer textures are sampled, SVIEW[#] declarations should be
+used.
+
+NOTE: It is NOT legal to mix SAMPLE\* style opcodes and TEX\* opcodes
+in the same shader.
Declaration Resource
^^^^^^^^^^^^^^^^^^^^
This is useful for APIs that don't have UCPs and where clip distances written
by a shader cannot be disabled.
+GS_INVOCATIONS
+""""""""""""""
+
+Specifies the number of times a geometry shader should be executed for each
+input primitive. Each invocation will have a different
+TGSI_SEMANTIC_INVOCATIONID system value set. If not specified, assumed to
+be 1.
+
+VS_WINDOW_SPACE_POSITION
+""""""""""""""""""""""""""
+If this property is set on the vertex shader, the TGSI_SEMANTIC_POSITION output
+is assumed to contain window space coordinates.
+Division of X,Y,Z by W and the viewport transformation are disabled, and 1/W is
+directly taken from the 4-th component of the shader output.
+Naturally, clipping is not performed on window coordinates either.
+The effect of this property is undefined if a geometry or tessellation shader
+are in use.
+
+TCS_VERTICES_OUT
+""""""""""""""""
+
+The number of vertices written by the tessellation control shader. This
+effectively defines the patch input size of the tessellation evaluation shader
+as well.
+
+TES_PRIM_MODE
+"""""""""""""
+
+This sets the tessellation primitive mode, one of ``PIPE_PRIM_TRIANGLES``,
+``PIPE_PRIM_QUADS``, or ``PIPE_PRIM_LINES``. (Unlike in GL, there is no
+separate isolines settings, the regular lines is assumed to mean isolines.)
+
+TES_SPACING
+"""""""""""
+
+This sets the spacing mode of the tessellation generator, one of
+``PIPE_TESS_SPACING_*``.
+
+TES_VERTEX_ORDER_CW
+"""""""""""""""""""
+
+This sets the vertex order to be clockwise if the value is 1, or
+counter-clockwise if set to 0.
+
+TES_POINT_MODE
+""""""""""""""
+
+If set to a non-zero value, this turns on point mode for the tessellator,
+which means that points will be generated instead of primitives.
+
Texture Sampling and Texture Formats
------------------------------------
projects / mesa.git / blobdiff