Difference between revisions of "NV2A/Pixel Combiner"

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(→‎Data types)
Line 14: Line 14:
  
 
{| class="wikitable"
 
{| class="wikitable"
−
! floating-point !! 8-bit fixed-point !! 9-bit fixed-point !! 16 bit fixed-point
+
! floating-point !! 8-bit fixed-point !! 9-bit fixed-point !! 16-bit fixed-point
 
|-
 
|-
 
|    1.0        ||    n/a          ||      255          ||      n/a   
 
|    1.0        ||    n/a          ||      255          ||      n/a   
Line 28: Line 28:
 
|  -1.00392...  ||    n/a          ||    -256          ||      n/a
 
|  -1.00392...  ||    n/a          ||    -256          ||      n/a
 
|}
 
|}
 +
 +
This means:
 +
 +
* 8-bit fixed-point: [-128, 127] → [-128/128, 127/128] → [-1.0, 0.99218...]
 +
* 9-bit fixed-point: [-256, 255] → [-256/255, 255/255] → [-1.00392..., 1.0]
 +
* 16-bit fixed-point: [-32768, 32767] → [-32768/32768, 32767/32768] → [-1.0, 0.99996...]
 +
 +
It is not known if the NV2A really implements these 3 datatypes.
 +
It is also not yet known how exactly conversion or negation of these types would work.
  
 
== Texturing modes ==
 
== Texturing modes ==

Revision as of 17:11, 25 May 2017

The NV2A implements at least parts of the following OpenGL extensions:


Data types

NV_texture_shader suggests that: "The 8-bit and 16-bit signed fixed-point types are used for signed internal texture formats, while the 9-bit signed fixed-point type is used for register combiners computations." Here is a table from the GL extension:

floating-point 8-bit fixed-point 9-bit fixed-point 16-bit fixed-point
1.0 n/a 255 n/a
0.99996... n/a n/a 32767
0.99218... 127 n/a n/a
0.0 0 0 0
-1.0 -128 -255 -32768
-1.00392... n/a -256 n/a

This means:

  • 8-bit fixed-point: [-128, 127] → [-128/128, 127/128] → [-1.0, 0.99218...]
  • 9-bit fixed-point: [-256, 255] → [-256/255, 255/255] → [-1.00392..., 1.0]
  • 16-bit fixed-point: [-32768, 32767] → [-32768/32768, 32767/32768] → [-1.0, 0.99996...]

It is not known if the NV2A really implements these 3 datatypes. It is also not yet known how exactly conversion or negation of these types would work.

Texturing modes

ID Name GL Name Stage 1 Stage 2 Stage 3 Stage 4 Notes
0x00 PS_TEXTUREMODES_NONE
texcoord?[citation needed] 		NONE ✔ ✔ ✔ ✔
0x01 PS_TEXTUREMODES_PROJECT2D
tex 		TEXTURE_2D ✔ ✔ ✔ ✔
0x02 PS_TEXTUREMODES_PROJECT3D TEXTURE_3D ✔ ✔ ✔ ✔
0x03 PS_TEXTUREMODES_CUBEMAP TEXTURE_CUBE_MAP_ARB ✔ ✔ ✔ ✔
0x04 PS_TEXTUREMODES_PASSTHRU
texcoord?[citation needed] 		PASS_THROUGH_NV ✔ ✔ ✔ ✔
0x05 PS_TEXTUREMODES_CLIPPLANE
texkill 		CULL_FRAGMENT_NV ✔ ✔ ✔ ✔
0x06 PS_TEXTUREMODES_BUMPENVMAP
texbem 		OFFSET_TEXTURE_2D_NV ✗ ✔ ✔ ✔
0x07 PS_TEXTUREMODES_BUMPENVMAP_LUM
texbeml 		OFFSET_TEXTURE_2D_SCALE_NV ✗ ✔ ✔ ✔
0x08 PS_TEXTUREMODES_BRDF
texm3x2tex 		✗ ✗ ✔ ✔
0x09 PS_TEXTUREMODES_DOT_ST
texm3x2pad?[citation needed] 		DOT_PRODUCT_NV[citation needed] ✗ ✗ ✔ ✔
0x0A PS_TEXTUREMODES_DOT_ZW
texm3x2tex?[citation needed] 		DOT_PRODUCT_NV[citation needed] ✗ ✗ ✔ ✔
0x0B PS_TEXTUREMODES_DOT_RFLCT_DIFF DOT_PRODUCT_DIFFUSE_CUBE_MAP_NV[citation needed] ✗ ✗ ✔ ✗
0x0C PS_TEXTUREMODES_DOT_RFLCT_SPEC DOT_PRODUCT_CONST_EYE_REFLECT_CUBE_MAP_NV[citation needed] ✗ ✗ ✗ ✔
0x0D PS_TEXTUREMODES_DOT_STR_3D DOT_PRODUCT_TEXTURE_3D_NV ✗ ✗ ✗ ✔
0x0E PS_TEXTUREMODES_DOT_STR_CUBE DOT_PRODUCT_REFLECT_CUBE_MAP_NV ✗ ✗ ✗ ✔
0x0F PS_TEXTUREMODES_DPNDNT_AR
texreg2ar 		DEPENDENT_AR_TEXTURE_2D_NV ✗ ✔ ✔ ✔
0x10 PS_TEXTUREMODES_DPNDNT_GB
texreg2gb 		DEPENDENT_GB_TEXTURE_2D_NV ✗ ✔ ✔ ✔
0x11 PS_TEXTUREMODES_DOTPRODUCT DOT_PRODUCT_NV ✗ ✔ ✔ ✗
0x12 PS_TEXTUREMODES_DOT_RFLCT_SPEC_CONST DOT_PRODUCT_CONST_EYE_REFLECT_CUBE_MAP_NV ✗ ✗ ✗ ✔

Also known from nvidia docs:

  • texm3x3pad [stage 1, stage 2]
  • texm3x3spec [stage 3]
  • texm3x3vspec [stage 3]
  • texm3x3tex [stage 3]

Debugging

PIX from the Microsoft XDK provides great debugging capabilities.

References and links

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