NV2A/Pixel Combiner

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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 D3D name GL Name Stage 1 Stage 2 Stage 3 Stage 4 Notes
0x00 PS_TEXTUREMODES_NONE NONE
0x01 PS_TEXTUREMODES_PROJECT2D tex TEXTURE_2D
0x02 PS_TEXTUREMODES_PROJECT3D tex TEXTURE_3D
0x03 PS_TEXTUREMODES_CUBEMAP tex TEXTURE_CUBE_MAP_ARB
0x04 PS_TEXTUREMODES_PASSTHRU texcoord 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 texbrdf
0x09 PS_TEXTUREMODES_DOT_ST texm3x2tex?[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 texm3x3diff DOT_PRODUCT_DIFFUSE_CUBE_MAP_NV[citation needed]
0x0C PS_TEXTUREMODES_DOT_RFLCT_SPEC texm3x3spec DOT_PRODUCT_CONST_EYE_REFLECT_CUBE_MAP_NV[citation needed]
0x0D PS_TEXTUREMODES_DOT_STR_3D texm3x3tex DOT_PRODUCT_TEXTURE_3D_NV
0x0E PS_TEXTUREMODES_DOT_STR_CUBE texm3x3vspec 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 texm3x3pad
texm3x2pad
DOT_PRODUCT_NV
0x12 PS_TEXTUREMODES_DOT_RFLCT_SPEC_CONST texm3x3spec DOT_PRODUCT_CONST_EYE_REFLECT_CUBE_MAP_NV

Debugging

PIX from the Microsoft XDK provides great debugging capabilities.

References and links