TGSI
====
-TGSI, Tungsten Graphics Shader Instructions, is an intermediate language
+TGSI, Tungsten Graphics Shader Infrastructure, 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.
+Basics
+------
+
+All TGSI instructions, known as *opcodes*, operate on arbitrary-precision
+floating-point four-component vectors. An opcode may have up to one
+destination register, known as *dst*, and between zero and three source
+registers, called *src0* through *src2*, or simply *src* if there is only
+one.
+
+Some instructions, like :opcode:`I2F`, permit re-interpretation of vector
+components as integers. Other instructions permit using registers as
+two-component vectors with double precision; see :ref:`Double Opcodes`.
+
+When an instruction has a scalar result, the result is usually copied into
+each of the components of *dst*. When this happens, the result is said to be
+*replicated* to *dst*. :opcode:`RCP` is one such instruction.
+
Instruction Set
---------------
-From GL_NV_vertex_program
+Core ISA
^^^^^^^^^^^^^^^^^^^^^^^^^
+These opcodes are guaranteed to be available regardless of the driver being
+used.
-ARL - Address Register Load
+.. opcode:: ARL - Address Register Load
.. math::
dst.w = \lfloor src.w\rfloor
-MOV - Move
+.. opcode:: MOV - Move
.. math::
dst.w = src.w
-LIT - Light Coefficients
+.. opcode:: LIT - Light Coefficients
.. math::
dst.w = 1
-RCP - Reciprocal
-
-.. math::
+.. opcode:: RCP - Reciprocal
- dst.x = \frac{1}{src.x}
+This instruction replicates its result.
- dst.y = \frac{1}{src.x}
+.. math::
- dst.z = \frac{1}{src.x}
+ dst = \frac{1}{src.x}
- dst.w = \frac{1}{src.x}
+.. opcode:: RSQ - Reciprocal Square Root
-RSQ - Reciprocal Square Root
+This instruction replicates its result.
.. 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|}}
+ dst = \frac{1}{\sqrt{|src.x|}}
-EXP - Approximate Exponential Base 2
+.. opcode:: EXP - Approximate Exponential Base 2
.. math::
dst.w = 1
-LOG - Approximate Logarithm Base 2
+.. opcode:: LOG - Approximate Logarithm Base 2
.. math::
dst.w = 1
-MUL - Multiply
+.. opcode:: MUL - Multiply
.. math::
dst.w = src0.w \times src1.w
-ADD - Add
+.. opcode:: ADD - Add
.. math::
dst.w = src0.w + src1.w
-DP3 - 3-component Dot Product
+.. opcode:: DP3 - 3-component Dot Product
-.. math::
-
- dst.x = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+This instruction replicates its result.
- dst.y = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+.. math::
- dst.z = src0.x \times src1.x + src0.y \times src1.y + src0.z \times src1.z
+ dst = 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
+.. opcode:: DP4 - 4-component Dot Product
-DP4 - 4-component Dot Product
+This instruction replicates its result.
.. 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 = 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
+.. opcode:: DST - Distance Vector
.. math::
dst.w = src1.w
-MIN - Minimum
+.. opcode:: MIN - Minimum
.. math::
dst.w = min(src0.w, src1.w)
-MAX - Maximum
+.. opcode:: MAX - Maximum
.. math::
dst.w = max(src0.w, src1.w)
-SLT - Set On Less Than
+.. opcode:: SLT - Set On Less Than
.. math::
dst.w = (src0.w < src1.w) ? 1 : 0
-SGE - Set On Greater Equal Than
+.. opcode:: SGE - Set On Greater Equal Than
.. math::
dst.w = (src0.w >= src1.w) ? 1 : 0
-MAD - Multiply And Add
+.. opcode:: MAD - Multiply And Add
.. math::
dst.w = src0.w \times src1.w + src2.w
-SUB - Subtract
+.. opcode:: SUB - Subtract
.. math::
dst.w = src0.w - src1.w
-LRP - Linear Interpolate
+.. opcode:: LRP - Linear Interpolate
.. math::
- dst.x = src0.x \times (src1.x - src2.x) + src2.x
+ dst.x = src0.x \times src1.x + (1 - src0.x) \times src2.x
- dst.y = src0.y \times (src1.y - src2.y) + src2.y
+ dst.y = src0.y \times src1.y + (1 - src0.y) \times src2.y
- dst.z = src0.z \times (src1.z - src2.z) + src2.z
+ dst.z = src0.z \times src1.z + (1 - src0.z) \times src2.z
- dst.w = src0.w \times (src1.w - src2.w) + src2.w
+ dst.w = src0.w \times src1.w + (1 - src0.w) \times src2.w
-CND - Condition
+.. opcode:: CND - Condition
.. math::
dst.w = (src2.w > 0.5) ? src0.w : src1.w
-DP2A - 2-component Dot Product And Add
+.. opcode:: DP2A - 2-component Dot Product And Add
.. math::
dst.w = src0.x \times src1.x + src0.y \times src1.y + src2.x
-FRAC - Fraction
+.. opcode:: FRC - Fraction
.. math::
dst.w = src.w - \lfloor src.w\rfloor
-CLAMP - Clamp
+.. opcode:: CLAMP - Clamp
.. math::
dst.w = clamp(src0.w, src1.w, src2.w)
-FLR - Floor
+.. opcode:: FLR - Floor
-This is identical to ARL.
+This is identical to :opcode:`ARL`.
.. math::
dst.w = \lfloor src.w\rfloor
-ROUND - Round
+.. opcode:: ROUND - Round
.. math::
dst.w = round(src.w)
-EX2 - Exponential Base 2
-
-.. math::
+.. opcode:: EX2 - Exponential Base 2
- dst.x = 2^{src.x}
+This instruction replicates its result.
- dst.y = 2^{src.x}
+.. math::
- dst.z = 2^{src.x}
+ dst = 2^{src.x}
- dst.w = 2^{src.x}
+.. opcode:: LG2 - Logarithm Base 2
-LG2 - Logarithm Base 2
+This instruction replicates its result.
.. math::
- dst.x = \log_2{src.x}
+ dst = \log_2{src.x}
- dst.y = \log_2{src.x}
- dst.z = \log_2{src.x}
+.. opcode:: POW - Power
- dst.w = \log_2{src.x}
-
-
-POW - Power
+This instruction replicates its result.
.. 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}
+ dst = src0.x^{src1.x}
-XPD - Cross Product
+.. opcode:: XPD - Cross Product
.. math::
dst.w = 1
-ABS - Absolute
+.. opcode:: ABS - Absolute
.. math::
dst.w = |src.w|
-RCC - Reciprocal Clamped
+.. opcode:: RCC - Reciprocal Clamped
+
+This instruction replicates its result.
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 = (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)
+.. opcode:: DPH - Homogeneous Dot Product
-DPH - Homogeneous Dot Product
+This instruction replicates its result.
.. 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 = 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
+.. opcode:: COS - Cosine
-COS - Cosine
+This instruction replicates its result.
.. math::
- dst.x = \cos{src.x}
-
- dst.y = \cos{src.x}
-
- dst.z = \cos{src.x}
+ dst = \cos{src.x}
- dst.w = \cos{src.w}
-
-DDX - Derivative Relative To X
+.. opcode:: DDX - Derivative Relative To X
.. math::
dst.w = partialx(src.w)
-DDY - Derivative Relative To Y
+.. opcode:: DDY - Derivative Relative To Y
.. math::
dst.w = partialy(src.w)
-KILP - Predicated Discard
+.. opcode:: KILP - Predicated Discard
discard
-PK2H - Pack Two 16-bit Floats
+.. opcode:: PK2H - Pack Two 16-bit Floats
TBD
-PK2US - Pack Two Unsigned 16-bit Scalars
+.. opcode:: PK2US - Pack Two Unsigned 16-bit Scalars
TBD
-PK4B - Pack Four Signed 8-bit Scalars
+.. opcode:: PK4B - Pack Four Signed 8-bit Scalars
TBD
-PK4UB - Pack Four Unsigned 8-bit Scalars
+.. opcode:: PK4UB - Pack Four Unsigned 8-bit Scalars
TBD
-RFL - Reflection Vector
+.. opcode:: RFL - Reflection Vector
.. math::
dst.w = 1
-Considered for removal.
+.. note::
+
+ Considered for removal.
-SEQ - Set On Equal
+.. opcode:: 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
+.. opcode:: SFL - Set On False
+
+This instruction replicates its result.
.. math::
- dst.x = 0
- dst.y = 0
- dst.z = 0
- dst.w = 0
+ dst = 0
-Considered for removal.
+.. note::
-SGT - Set On Greater Than
+ Considered for removal.
+
+
+.. opcode:: 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
+ dst.z = (src0.z > src1.z) ? 1 : 0
-SIN - Sine
+ dst.w = (src0.w > src1.w) ? 1 : 0
-.. math::
- dst.x = \sin{src.x}
+.. opcode:: SIN - Sine
- dst.y = \sin{src.x}
+This instruction replicates its result.
- dst.z = \sin{src.x}
+.. math::
- dst.w = \sin{src.w}
+ dst = \sin{src.x}
-SLE - Set On Less Equal Than
+.. opcode:: 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
+.. opcode:: 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
+.. opcode:: STR - Set On True
+
+This instruction replicates its result.
.. math::
- dst.x = 1
- dst.y = 1
- dst.z = 1
- dst.w = 1
+ dst = 1
-TEX - Texture Lookup
+.. opcode:: TEX - Texture Lookup
- TBD
+.. math::
+ coord = src0
-TXD - Texture Lookup with Derivatives
+ bias = 0.0
- TBD
+ dst = texture_sample(unit, coord, bias)
+ 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 arrays, src0.z contains
+ the reference value for 1D arrays, and src0.w contains
+ the reference value for 2D arrays.
+ 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.
-TXP - Projective Texture Lookup
+.. opcode:: TXD - Texture Lookup with Derivatives
- TBD
+.. math::
+
+ coord = src0
+
+ ddx = src1
+
+ ddy = src2
+
+ bias = 0.0
+
+ dst = texture_sample_deriv(unit, coord, bias, ddx, ddy)
+
+
+.. opcode:: TXP - Projective Texture Lookup
+
+.. math::
+
+ coord.x = src0.x / src.w
+
+ coord.y = src0.y / src.w
+
+ coord.z = src0.z / src.w
+
+ coord.w = src0.w
+
+ bias = 0.0
+
+ dst = texture_sample(unit, coord, bias)
-UP2H - Unpack Two 16-Bit Floats
+.. opcode:: UP2H - Unpack Two 16-Bit Floats
TBD
- Considered for removal.
+.. note::
-UP2US - Unpack Two Unsigned 16-Bit Scalars
+ Considered for removal.
+
+.. opcode:: UP2US - Unpack Two Unsigned 16-Bit Scalars
TBD
- Considered for removal.
+.. note::
+
+ Considered for removal.
-UP4B - Unpack Four Signed 8-Bit Values
+.. opcode:: UP4B - Unpack Four Signed 8-Bit Values
TBD
- Considered for removal.
+.. note::
+
+ Considered for removal.
-UP4UB - Unpack Four Unsigned 8-Bit Scalars
+.. opcode:: UP4UB - Unpack Four Unsigned 8-Bit Scalars
TBD
- Considered for removal.
+.. note::
-X2D - 2D Coordinate Transformation
+ 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
-Considered for removal.
+ dst.w = src0.y + src1.x \times src2.z + src1.y \times src2.w
+.. note::
-From GL_NV_vertex_program2
-^^^^^^^^^^^^^^^^^^^^^^^^^^
+ Considered for removal.
-ARA - Address Register Add
+.. opcode:: ARA - Address Register Add
TBD
- Considered for removal.
+.. note::
-ARR - Address Register Load With Round
+ Considered for removal.
+
+.. opcode:: ARR - Address Register Load With Round
.. math::
dst.w = round(src.w)
-BRA - Branch
+.. opcode:: BRA - Branch
pc = target
- Considered for removal.
+.. note::
+
+ Considered for removal.
-CAL - Subroutine Call
+.. opcode:: CAL - Subroutine Call
push(pc)
pc = target
-RET - Subroutine Call Return
+.. opcode:: RET - Subroutine Call Return
pc = pop()
- Potential restrictions:
- \times Only occurs at end of function.
-SSG - Set Sign
+.. opcode:: SSG - Set Sign
.. math::
dst.w = (src.w > 0) ? 1 : (src.w < 0) ? -1 : 0
-CMP - Compare
+.. opcode:: CMP - Compare
.. math::
dst.w = (src0.w < 0) ? src1.w : src2.w
-KIL - Conditional Discard
+.. opcode:: KIL - Conditional Discard
.. math::
endif
-SCS - Sine Cosine
+.. opcode:: SCS - Sine Cosine
.. math::
dst.z = 0
- dst.y = 1
+ dst.w = 1
-TXB - Texture Lookup With Bias
+.. opcode:: TXB - Texture Lookup With Bias
- TBD
+.. math::
+
+ coord.x = src.x
+
+ coord.y = src.y
+ coord.z = src.z
-NRM - 3-component Vector Normalise
+ coord.w = 1.0
+
+ bias = src.z
+
+ dst = texture_sample(unit, coord, bias)
+
+
+.. opcode:: NRM - 3-component Vector Normalise
.. math::
dst.w = 1
-DIV - Divide
+.. opcode:: DIV - Divide
.. math::
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
+.. opcode:: DP2 - 2-component Dot Product
+This instruction replicates its result.
-TXL - Texture Lookup With LOD
-
- TBD
-
-
-BRK - Break
+.. math::
- TBD
+ dst = src0.x \times src1.x + src0.y \times src1.y
-IF - If
+.. opcode:: TXL - Texture Lookup With explicit LOD
- TBD
+.. math::
+ coord.x = src0.x
-BGNFOR - Begin a For-Loop
+ coord.y = src0.y
- dst.x = floor(src.x)
- dst.y = floor(src.y)
- dst.z = floor(src.z)
+ coord.z = src0.z
- if (dst.y <= 0)
- pc = [matching ENDFOR] + 1
- endif
+ coord.w = 1.0
- Note: The destination must be a loop register.
- The source must be a constant register.
+ lod = src0.w
- Considered for cleanup / removal.
+ dst = texture_sample(unit, coord, lod)
-REP - Repeat
+.. opcode:: BRK - Break
TBD
-ELSE - Else
+.. opcode:: IF - If
TBD
-ENDIF - End If
+.. opcode:: ELSE - Else
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
+.. opcode:: ENDIF - End If
TBD
-PUSHA - Push Address Register On Stack
+.. opcode:: PUSHA - Push Address Register On Stack
push(src.x)
push(src.y)
push(src.z)
push(src.w)
- Considered for cleanup / removal.
+.. note::
-POPA - Pop Address Register From Stack
+ Considered for cleanup.
+
+.. note::
+
+ Considered for removal.
+
+.. opcode:: POPA - Pop Address Register From Stack
dst.w = pop()
dst.z = pop()
dst.y = pop()
dst.x = pop()
- Considered for cleanup / removal.
+.. note::
+
+ Considered for cleanup.
+
+.. note::
+ Considered for removal.
-From GL_NV_gpu_program4
+
+Compute ISA
^^^^^^^^^^^^^^^^^^^^^^^^
+These opcodes are primarily provided for special-use computational shaders.
Support for these opcodes indicated by a special pipe capability bit (TBD).
-CEIL - Ceiling
+XXX so let's discuss it, yeah?
+
+.. opcode:: CEIL - Ceiling
.. math::
dst.w = \lceil src.w\rceil
-I2F - Integer To Float
+.. opcode:: I2F - Integer To Float
.. math::
dst.w = (float) src.w
-NOT - Bitwise Not
+.. opcode:: NOT - Bitwise Not
.. math::
dst.w = ~src.w
-TRUNC - Truncate
-
-XXX how is this different from floor?
+.. opcode:: TRUNC - Truncate
.. math::
dst.w = trunc(src.w)
-SHL - Shift Left
+.. opcode:: SHL - Shift Left
.. math::
dst.w = src0.w << src1.x
-SHR - Shift Right
+.. opcode:: SHR - Shift Right
.. math::
dst.w = src0.w >> src1.x
-AND - Bitwise And
+.. opcode:: AND - Bitwise And
.. math::
dst.w = src0.w & src1.w
-OR - Bitwise Or
+.. opcode:: OR - Bitwise Or
.. math::
dst.w = src0.w | src1.w
-MOD - Modulus
+.. opcode:: MOD - Modulus
.. math::
dst.w = src0.w \bmod src1.w
-XOR - Bitwise Xor
+.. opcode:: XOR - Bitwise Xor
+
+.. math::
+
+ dst.x = src0.x \oplus src1.x
+
+ dst.y = src0.y \oplus src1.y
+
+ dst.z = src0.z \oplus src1.z
+
+ dst.w = src0.w \oplus src1.w
+
+
+.. opcode:: UCMP - Integer Conditional Move
.. math::
- dst.x = src0.x ^ src1.x
+ 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.y = src0.y ^ src1.y
+ dst.w = src0.w ? src1.w : src2.w
- dst.z = src0.z ^ src1.z
- dst.w = src0.w ^ src1.w
+.. opcode:: UARL - Integer Address Register Load
+ Moves the contents of the source register, assumed to be an integer, into the
+ destination register, which is assumed to be an address (ADDR) register.
-SAD - Sum Of Absolute Differences
+
+.. opcode:: IABS - Integer Absolute Value
+
+.. math::
+
+ dst.x = |src.x|
+
+ dst.y = |src.y|
+
+ dst.z = |src.z|
+
+ dst.w = |src.w|
+
+
+.. opcode:: SAD - Sum Of Absolute Differences
.. math::
dst.w = |src0.w - src1.w| + src2.w
-TXF - Texel Fetch
+.. opcode:: TXF - Texel Fetch (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).
+ TXF(uint_vec coord, int_vec offset).
- TBD
+.. opcode:: TXQ - Texture Size Query (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)
-TXQ - Texture Size Query
+.. math::
- TBD
+ lod = src0
+
+ dst.x = texture_width(unit, lod)
+ dst.y = texture_height(unit, lod)
-CONT - Continue
+ dst.z = texture_depth(unit, lod)
+
+
+.. opcode:: CONT - Continue
TBD
+.. note::
+
+ Support for CONT is determined by a special capability bit,
+ ``TGSI_CONT_SUPPORTED``. See :ref:`Screen` for more information.
+
-From GL_NV_geometry_program4
+Geometry ISA
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+These opcodes are only supported in geometry shaders; they have no meaning
+in any other type of shader.
-EMIT - Emit
+.. opcode:: EMIT - Emit
TBD
-ENDPRIM - End Primitive
+.. opcode:: ENDPRIM - End Primitive
TBD
-From GLSL
+GLSL ISA
^^^^^^^^^^
+These opcodes are part of :term:`GLSL`'s opcode set. Support for these
+opcodes is determined by a special capability bit, ``GLSL``.
-BGNLOOP - Begin a Loop
+.. opcode:: BGNLOOP - Begin a Loop
TBD
-BGNSUB - Begin Subroutine
+.. opcode:: BGNSUB - Begin Subroutine
TBD
-ENDLOOP - End a Loop
+.. opcode:: ENDLOOP - End a Loop
TBD
-ENDSUB - End Subroutine
+.. opcode:: ENDSUB - End Subroutine
TBD
+.. opcode:: NOP - No Operation
-NOP - No Operation
+ Do nothing.
- Do nothing.
-NRM4 - 4-component Vector Normalise
+.. opcode:: 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}
+This instruction replicates its result.
- 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}
+.. math::
- 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}
+ dst = \frac{src.x}{src.x \times src.x + src.y \times src.y + src.z \times src.z + src.w \times src.w}
ps_2_x
^^^^^^^^^^^^
+XXX wait what
-CALLNZ - Subroutine Call If Not Zero
+.. opcode:: CALLNZ - Subroutine Call If Not Zero
TBD
-IFC - If
+.. opcode:: IFC - If
TBD
-BREAKC - Break Conditional
+.. opcode:: BREAKC - Break Conditional
TBD
+.. _doubleopcodes:
+
+Double ISA
+^^^^^^^^^^^^^^^
+
+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:: DADD - Add
+
+.. math::
+
+ dst.xy = src0.xy + src1.xy
+
+ dst.zw = src0.zw + src1.zw
+
+
+.. opcode:: DDIV - Divide
+
+.. math::
+
+ dst.xy = src0.xy / src1.xy
+
+ dst.zw = src0.zw / src1.zw
+
+.. opcode:: DSEQ - Set on Equal
+
+.. math::
+
+ dst.xy = src0.xy == src1.xy ? 1.0F : 0.0F
+
+ dst.zw = src0.zw == src1.zw ? 1.0F : 0.0F
+
+.. opcode:: DSLT - Set on Less than
+
+.. math::
+
+ dst.xy = src0.xy < src1.xy ? 1.0F : 0.0F
+
+ dst.zw = src0.zw < src1.zw ? 1.0F : 0.0F
+
+.. opcode:: DFRAC - Fraction
+
+.. math::
+
+ dst.xy = src.xy - \lfloor src.xy\rfloor
+
+ dst.zw = src.zw - \lfloor src.zw\rfloor
+
+
+.. opcode:: DFRACEXP - Convert Number to Fractional and Integral Components
+
+Like the ``frexp()`` routine in many math libraries, this opcode stores the
+exponent of its source to ``dst0``, and the significand to ``dst1``, such that
+:math:`dst1 \times 2^{dst0} = src` .
+
+.. math::
+
+ dst0.xy = exp(src.xy)
+
+ dst1.xy = frac(src.xy)
+
+ dst0.zw = exp(src.zw)
+
+ dst1.zw = frac(src.zw)
+
+.. opcode:: DLDEXP - Multiply Number by Integral Power of 2
+
+This opcode is the inverse of :opcode:`DFRACEXP`.
+
+.. math::
+
+ dst.xy = src0.xy \times 2^{src1.xy}
+
+ dst.zw = src0.zw \times 2^{src1.zw}
+
+.. opcode:: DMIN - Minimum
+
+.. math::
+
+ dst.xy = min(src0.xy, src1.xy)
+
+ dst.zw = min(src0.zw, src1.zw)
+
+.. opcode:: DMAX - Maximum
+
+.. math::
+
+ dst.xy = max(src0.xy, src1.xy)
+
+ dst.zw = max(src0.zw, src1.zw)
+
+.. opcode:: DMUL - Multiply
+
+.. math::
+
+ dst.xy = src0.xy \times src1.xy
+
+ dst.zw = src0.zw \times src1.zw
+
+
+.. opcode:: DMAD - Multiply And Add
+
+.. math::
+
+ dst.xy = src0.xy \times src1.xy + src2.xy
+
+ dst.zw = src0.zw \times src1.zw + src2.zw
+
+
+.. opcode:: DRCP - Reciprocal
+
+.. math::
+
+ dst.xy = \frac{1}{src.xy}
+
+ dst.zw = \frac{1}{src.zw}
+
+.. opcode:: DSQRT - Square Root
+
+.. math::
+
+ dst.xy = \sqrt{src.xy}
+
+ dst.zw = \sqrt{src.zw}
+
+
+.. _samplingopcodes:
+
+Resource Sampling Opcodes
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Those opcodes follow very closely semantics of the respective Direct3D
+instructions. If in doubt double check Direct3D documentation.
+
+.. opcode:: SAMPLE - Using provided address, sample data from the
+ specified texture using the filtering mode identified
+ by the gven sampler. The source data may come from
+ any resource type other than buffers.
+ SAMPLE dst, address, sampler_view, sampler
+ e.g.
+ SAMPLE TEMP[0], TEMP[1], SVIEW[0], SAMP[0]
+
+.. opcode:: SAMPLE_I - Simplified alternative to the SAMPLE instruction.
+ Using the provided integer address, SAMPLE_I fetches data
+ from the specified sampler view without any filtering.
+ The source data may come from any resource type other
+ than CUBE.
+ SAMPLE_I dst, address, sampler_view
+ e.g.
+ SAMPLE_I TEMP[0], TEMP[1], SVIEW[0]
+ The 'address' is specified as unsigned integers. If the
+ 'address' is out of range [0...(# texels - 1)] the
+ result of the fetch is always 0 in all components.
+ As such the instruction doesn't honor address wrap
+ modes, in cases where that behavior is desirable
+ 'SAMPLE' instruction should be used.
+ address.w always provides an unsigned integer mipmap
+ level. If the value is out of the range then the
+ instruction always returns 0 in all components.
+ address.yz are ignored for buffers and 1d textures.
+ address.z is ignored for 1d texture arrays and 2d
+ textures.
+ For 1D texture arrays address.y provides the array
+ index (also as unsigned integer). If the value is
+ out of the range of available array indices
+ [0... (array size - 1)] then the opcode always returns
+ 0 in all components.
+ For 2D texture arrays address.z provides the array
+ index, otherwise it exhibits the same behavior as in
+ the case for 1D texture arrays.
+ The exact semantics of the source address are presented
+ in the table below:
+ resource type X Y Z W
+ ------------- ------------------------
+ PIPE_BUFFER x ignored
+ PIPE_TEXTURE_1D x mpl
+ PIPE_TEXTURE_2D x y mpl
+ PIPE_TEXTURE_3D x y z mpl
+ PIPE_TEXTURE_RECT x y mpl
+ PIPE_TEXTURE_CUBE not allowed as source
+ PIPE_TEXTURE_1D_ARRAY x idx mpl
+ PIPE_TEXTURE_2D_ARRAY x y idx mpl
+
+ Where 'mpl' is a mipmap level and 'idx' is the
+ array index.
+
+.. opcode:: SAMPLE_I_MS - Just like SAMPLE_I but allows fetch data from
+ multi-sampled surfaces.
+
+.. opcode:: SAMPLE_B - Just like the SAMPLE instruction with the
+ exception that an additiona bias is applied to the
+ level of detail computed as part of the instruction
+ execution.
+ SAMPLE_B dst, address, sampler_view, sampler, lod_bias
+ e.g.
+ SAMPLE_B TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2].x
+
+.. opcode:: SAMPLE_C - Similar to the SAMPLE instruction but it
+ performs a comparison filter. The operands to SAMPLE_C
+ are identical to SAMPLE, except that tere is an additional
+ float32 operand, reference value, which must be a register
+ with single-component, or a scalar literal.
+ SAMPLE_C makes the hardware use the current samplers
+ compare_func (in pipe_sampler_state) to compare
+ reference value against the red component value for the
+ surce resource at each texel that the currently configured
+ texture filter covers based on the provided coordinates.
+ SAMPLE_C dst, address, sampler_view.r, sampler, ref_value
+ e.g.
+ SAMPLE_C TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x
+
+.. opcode:: SAMPLE_C_LZ - Same as SAMPLE_C, but LOD is 0 and derivatives
+ are ignored. The LZ stands for level-zero.
+ SAMPLE_C_LZ dst, address, sampler_view.r, sampler, ref_value
+ e.g.
+ SAMPLE_C_LZ TEMP[0], TEMP[1], SVIEW[0].r, SAMP[0], TEMP[2].x
+
+
+.. opcode:: SAMPLE_D - SAMPLE_D is identical to the SAMPLE opcode except
+ that the derivatives for the source address in the x
+ direction and the y direction are provided by extra
+ parameters.
+ SAMPLE_D dst, address, sampler_view, sampler, der_x, der_y
+ e.g.
+ SAMPLE_D TEMP[0], TEMP[1], SVIEW[0], SAMP[0], TEMP[2], TEMP[3]
+
+.. opcode:: SAMPLE_L - SAMPLE_L is identical to the SAMPLE opcode except
+ that the LOD is provided directly as a scalar value,
+ representing no anisotropy. Source addresses A channel
+ is used as the LOD.
+ SAMPLE_L dst, address, sampler_view, sampler
+ e.g.
+ SAMPLE_L TEMP[0], TEMP[1], SVIEW[0], SAMP[0]
+
+.. opcode:: GATHER4 - Gathers the four texels to be used in a bi-linear
+ filtering operation and packs them into a single register.
+ Only works with 2D, 2D array, cubemaps, and cubemaps arrays.
+ For 2D textures, only the addressing modes of the sampler and
+ the top level of any mip pyramid are used. Set W to zero.
+ It behaves like the SAMPLE instruction, but a filtered
+ sample is not generated. The four samples that contribute
+ to filtering are placed into xyzw in counter-clockwise order,
+ starting with the (u,v) texture coordinate delta at the
+ following locations (-, +), (+, +), (+, -), (-, -), where
+ the magnitude of the deltas are half a texel.
+
+
+.. opcode:: SVIEWINFO - query the dimensions of a given sampler view.
+ dst receives width, height, depth or array size and
+ number of mipmap levels. The dst can have a writemask
+ which will specify what info is the caller interested
+ in.
+ SVIEWINFO dst, src_mip_level, sampler_view
+ e.g.
+ SVIEWINFO TEMP[0], TEMP[1].x, SVIEW[0]
+ src_mip_level is an unsigned integer scalar. If it's
+ out of range then returns 0 for width, height and
+ depth/array size but the total number of mipmap is
+ still returned correctly for the given sampler view.
+ The returned width, height and depth values are for
+ the mipmap level selected by the src_mip_level and
+ are in the number of texels.
+ For 1d texture array width is in dst.x, array size
+ is in dst.y and dst.zw are always 0.
+
+.. opcode:: SAMPLE_POS - query the position of a given sample.
+ dst receives float4 (x, y, 0, 0) indicated where the
+ sample is located. If the resource is not a multi-sample
+ resource and not a render target, the result is 0.
+
+.. opcode:: SAMPLE_INFO - dst receives number of samples in x.
+ If the resource is not a multi-sample resource and
+ not a render target, the result is 0.
+
+
+.. _resourceopcodes:
+
+Resource Access Opcodes
+^^^^^^^^^^^^^^^^^^^^^^^
+
+.. opcode:: LOAD - Fetch data from a shader resource
+
+ Syntax: ``LOAD dst, resource, address``
+
+ Example: ``LOAD TEMP[0], RES[0], TEMP[1]``
+
+ Using the provided integer address, LOAD fetches data
+ from the specified buffer or texture without any
+ filtering.
+
+ The 'address' is specified as a vector of unsigned
+ integers. If the 'address' is out of range the result
+ is unspecified.
+
+ Only the first mipmap level of a resource can be read
+ from using this instruction.
+
+ For 1D or 2D texture arrays, the array index is
+ provided as an unsigned integer in address.y or
+ address.z, respectively. address.yz are ignored for
+ buffers and 1D textures. address.z is ignored for 1D
+ texture arrays and 2D textures. address.w is always
+ ignored.
+
Explanation of symbols used
------------------------------
round(x) Round x.
- trunc(x) Truncate x.
+ trunc(x) Truncate x, i.e. drop the fraction bits.
Keywords
discard Discard fragment.
- dst First destination register.
+ pc Program counter.
- dst0 First destination register.
+ target Label of target instruction.
- pc Program counter.
- src First source register.
+Other tokens
+---------------
- src0 First source register.
- src1 Second source register.
+Declaration
+^^^^^^^^^^^
- src2 Third source register.
- target Label of target instruction.
+Declares a register that is will be referenced as an operand in Instruction
+tokens.
+File field contains register file that is being declared and is one
+of TGSI_FILE.
-Other tokens
----------------
+UsageMask field specifies which of the register components can be accessed
+and is one of TGSI_WRITEMASK.
+
+If Dimension flag is set to 1, a Declaration Dimension token follows.
+
+If Semantic flag is set to 1, a Declaration Semantic token follows.
+
+If Interpolate flag is set to 1, a Declaration Interpolate token follows.
+
+If file is TGSI_FILE_RESOURCE, a Declaration Resource token follows.
Declaration Semantic
^^^^^^^^^^^^^^^^^^^^^^^^
+ Vertex and fragment shader input and output registers may be labeled
+ with semantic information consisting of a name and index.
Follows Declaration token if Semantic bit is set.
The meanings of the individual semantic names are explained in the following
sections.
+TGSI_SEMANTIC_POSITION
+""""""""""""""""""""""
+
+For vertex shaders, TGSI_SEMANTIC_POSITION indicates the vertex shader
+output register which contains the homogeneous vertex position in the clip
+space coordinate system. After clipping, the X, Y and Z components of the
+vertex will be divided by the W value to get normalized device coordinates.
+
+For fragment shaders, TGSI_SEMANTIC_POSITION is used to indicate that
+fragment shader input contains the fragment's window position. The X
+component starts at zero and always increases from left to right.
+The Y component starts at zero and always increases but Y=0 may either
+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.
+
+Fragment shaders may also declare an output register with
+TGSI_SEMANTIC_POSITION. Only the Z component is writable. This allows
+the fragment shader to change the fragment's Z position.
+
+
+
+TGSI_SEMANTIC_COLOR
+"""""""""""""""""""
+
+For vertex shader outputs or fragment shader inputs/outputs, this
+label indicates that the resister contains an R,G,B,A color.
+
+Several shader inputs/outputs may contain colors so the semantic index
+is used to distinguish them. For example, color[0] may be the diffuse
+color while color[1] may be the specular color.
+
+This label is needed so that the flat/smooth shading can be applied
+to the right interpolants during rasterization.
+
+
+
+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 shader,
+so all BCOLORs effectively become regular COLORs in the fragment shader.
+
+
+TGSI_SEMANTIC_FOG
+"""""""""""""""""
+
+Vertex shader inputs and outputs and fragment shader inputs may be
+labeled with TGSI_SEMANTIC_FOG to indicate that the register contains
+a fog coordinate in the form (F, 0, 0, 1). Typically, the fragment
+shader will use the fog coordinate to compute a fog blend factor which
+is used to blend the normal fragment color with a constant fog color.
+
+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
+"""""""""""""""""""
+
+Vertex shader input and output registers may be labeled with
+TGIS_SEMANTIC_PSIZE to indicate that the register contains a point size
+in the form (S, 0, 0, 1). The point size controls the width or diameter
+of points for rasterization. This label cannot be used in fragment
+shaders.
-FACE
-""""
+When using this semantic, be sure to set the appropriate state in the
+:ref:`rasterizer` first.
+
+
+TGSI_SEMANTIC_GENERIC
+"""""""""""""""""""""
+
+All vertex/fragment shader inputs/outputs not labeled with any other
+semantic label can be considered to be generic attributes. Typical
+uses of generic inputs/outputs are texcoords and user-defined values.
+
+
+TGSI_SEMANTIC_NORMAL
+""""""""""""""""""""
+
+Indicates that a vertex shader input is a normal vector. This is
+typically only used for legacy graphics APIs.
+
+
+TGSI_SEMANTIC_FACE
+""""""""""""""""""
+
+This label applies to fragment shader inputs only and indicates that
+the register contains front/back-face information of the form (F, 0,
+0, 1). The first component will be positive when the fragment belongs
+to a front-facing polygon, and negative when the fragment belongs to a
+back-facing polygon.
+
+
+TGSI_SEMANTIC_EDGEFLAG
+""""""""""""""""""""""
+
+For vertex shaders, this sematic label indicates that an input or
+output is a boolean edge flag. The register layout is [F, x, x, x]
+where F is 0.0 or 1.0 and x = don't care. Normally, the vertex shader
+simply copies the edge flag input to the edgeflag output.
+
+Edge flags are used to control which lines or points are actually
+drawn when the polygon mode converts triangles/quads/polygons into
+points or lines.
+
+TGSI_SEMANTIC_STENCIL
+""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates than an output
+is a writable stencil reference value. Only the Y component is writable.
+This allows the fragment shader to change the fragments stencilref value.
+
+
+Declaration Interpolate
+^^^^^^^^^^^^^^^^^^^^^^^
+
+This token is only valid for fragment shader INPUT declarations.
+
+The Interpolate field specifes the way input is being interpolated by
+the rasteriser and is one of TGSI_INTERPOLATE_*.
+
+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
+should be interpolated according to cylindrical wrapping rules.
+
+
+Declaration Sampler View
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+ Follows Declaration token if file is TGSI_FILE_SAMPLER_VIEW.
+
+ DCL SVIEW[#], resource, type(s)
+
+ Declares a shader input sampler view and assigns it to a SVIEW[#]
+ register.
+
+ resource can be one of BUFFER, 1D, 2D, 3D, 1DArray and 2DArray.
+
+ type must be 1 or 4 entries (if specifying on a per-component
+ level) out of UNORM, SNORM, SINT, UINT and FLOAT.
+
+
+Declaration Resource
+^^^^^^^^^^^^^^^^^^^^
+
+ Follows Declaration token if file is TGSI_FILE_RESOURCE.
+
+ DCL RES[#], resource [, RAW]
+
+ Declares a shader input resource and assigns it to a RES[#]
+ register.
+
+ resource can be one of BUFFER, 1D, 2D, 3D, CUBE, 1DArray and
+ 2DArray.
+
+ If the RAW keyword is not specified, the texture data will be
+ subject to conversion, swizzling and scaling as required to yield
+ the specified data type from the physical data format of the bound
+ resource.
+
+ If the RAW keyword is specified, no channel conversion will be
+ performed: the values read for each of the channels (X,Y,Z,W) will
+ correspond to consecutive words in the same order and format
+ they're found in memory. No element-to-address conversion will be
+ performed either: the value of the provided X coordinate will be
+ interpreted in byte units instead of texel units. The result of
+ accessing a misaligned address is undefined.
+
+
+Properties
+^^^^^^^^^^^^^^^^^^^^^^^^
- Valid only in a fragment shader INPUT declaration.
- FACE.x is negative when the primitive is back facing. FACE.x is positive
- when the primitive is front facing.
+ Properties are general directives that apply to the whole TGSI program.
+
+FS_COORD_ORIGIN
+"""""""""""""""
+
+Specifies the fragment shader TGSI_SEMANTIC_POSITION coordinate origin.
+The default value is UPPER_LEFT.
+
+If UPPER_LEFT, the position will be (0,0) at the upper left corner and
+increase downward and rightward.
+If LOWER_LEFT, the position will be (0,0) at the lower left corner and
+increase upward and rightward.
+
+OpenGL defaults to LOWER_LEFT, and is configurable with the
+GL_ARB_fragment_coord_conventions extension.
+
+DirectX 9/10 use UPPER_LEFT.
+
+FS_COORD_PIXEL_CENTER
+"""""""""""""""""""""
+
+Specifies the fragment shader TGSI_SEMANTIC_POSITION pixel center convention.
+The default value is HALF_INTEGER.
+
+If HALF_INTEGER, the fractionary part of the position will be 0.5
+If INTEGER, the fractionary part of the position will be 0.0
+
+Note that this does not affect the set of fragments generated by
+rasterization, which is instead controlled by gl_rasterization_rules in the
+rasterizer.
+
+OpenGL defaults to HALF_INTEGER, and is configurable with the
+GL_ARB_fragment_coord_conventions extension.
+
+DirectX 9 uses INTEGER.
+DirectX 10 uses HALF_INTEGER.
+
+FS_COLOR0_WRITES_ALL_CBUFS
+""""""""""""""""""""""""""
+Specifies that writes to the fragment shader color 0 are replicated to all
+bound cbufs. This facilitates OpenGL's fragColor output vs fragData[0] where
+fragData is directed to a single color buffer, but fragColor is broadcast.
+
+VS_PROHIBIT_UCPS
+""""""""""""""""""""""""""
+If this property is set on the program bound to the shader stage before the
+fragment shader, user clip planes should have no effect (be disabled) even if
+that shader does not write to any clip distance outputs and the rasterizer's
+clip_plane_enable is non-zero.
+This property is only supported by drivers that also support shader clip
+distance outputs.
+This is useful for APIs that don't have UCPs and where clip distances written
+by a shader cannot be disabled.
+
+
+Texture Sampling and Texture Formats
+------------------------------------
+
+This table shows how texture image components are returned as (x,y,z,w) tuples
+by TGSI texture instructions, such as :opcode:`TEX`, :opcode:`TXD`, and
+:opcode:`TXP`. For reference, OpenGL and Direct3D conventions are shown as
+well.
+
++--------------------+--------------+--------------------+--------------+
+| Texture Components | Gallium | OpenGL | Direct3D 9 |
++====================+==============+====================+==============+
+| R | (r, 0, 0, 1) | (r, 0, 0, 1) | (r, 1, 1, 1) |
++--------------------+--------------+--------------------+--------------+
+| RG | (r, g, 0, 1) | (r, g, 0, 1) | (r, g, 1, 1) |
++--------------------+--------------+--------------------+--------------+
+| RGB | (r, g, b, 1) | (r, g, b, 1) | (r, g, b, 1) |
++--------------------+--------------+--------------------+--------------+
+| RGBA | (r, g, b, a) | (r, g, b, a) | (r, g, b, a) |
++--------------------+--------------+--------------------+--------------+
+| A | (0, 0, 0, a) | (0, 0, 0, a) | (0, 0, 0, a) |
++--------------------+--------------+--------------------+--------------+
+| L | (l, l, l, 1) | (l, l, l, 1) | (l, l, l, 1) |
++--------------------+--------------+--------------------+--------------+
+| LA | (l, l, l, a) | (l, l, l, a) | (l, l, l, a) |
++--------------------+--------------+--------------------+--------------+
+| I | (i, i, i, i) | (i, i, i, i) | N/A |
++--------------------+--------------+--------------------+--------------+
+| UV | XXX TBD | (0, 0, 0, 1) | (u, v, 1, 1) |
+| | | [#envmap-bumpmap]_ | |
++--------------------+--------------+--------------------+--------------+
+| Z | XXX TBD | (z, z, z, 1) | (0, z, 0, 1) |
+| | | [#depth-tex-mode]_ | |
++--------------------+--------------+--------------------+--------------+
+| S | (s, s, s, s) | unknown | unknown |
++--------------------+--------------+--------------------+--------------+
+
+.. [#envmap-bumpmap] http://www.opengl.org/registry/specs/ATI/envmap_bumpmap.txt
+.. [#depth-tex-mode] the default is (z, z, z, 1) but may also be (0, 0, 0, z)
+ or (z, z, z, z) depending on the value of GL_DEPTH_TEXTURE_MODE.
projects / mesa.git / blobdiff