Image Format Validation Rules

Not every combination of ImageFormat parameters is considered valid. Some are functionally meaningless or inconsistent, while others are simply not allowed.

• The ImageFormat::LineAlign field must be 1, 2, 4, or 8. This value is ignored if the glimg::PixelDataType is a compressed format; they do not use the line alignment.

• If the glimg::PixelDataType is not a compressed format, then:

  • The glimg::ComponentOrder cannot be ORDER_COMPRESSED.
  • The glimg::Bitdepth cannot be BD_COMPRESSED.

• If the glimg::PixelDataType is compressed format, then:

  • The glimg::ComponentOrder must be ORDER_COMPRESSED.
  • The glimg::Bitdepth must be BD_COMPRESSED.
  • If the glimg::PixelDataType uses BC1, then the glimg::PixelComponents must be one of the RGB or RGBA formats (not RGBX or others).
  • If the glimg::PixelDataType uses BC2, BC3, or BC7, then the glimg::PixelComponents must include an alpha channel.
  • If the glimg::PixelDataType uses BC4, signed or unsigned, then the glimg::PixelComponents must be FMT_COLOR_RED.
  • If the glimg::PixelDataType uses BC5, signed or unsigned, then the glimg::PixelComponents must be FMT_COLOR_RG.
  • If the glimg::PixelDataType uses BC5, signed or unsigned, then the glimg::PixelComponents must be FMT_COLOR_RGB.

• The glimg::PixelDataType DT_SHARED_EXP_FLOAT can only be used with The glimg::ComponentOrder of ORDER_RGBE, glimg::Bitdepth of BD_PACKED_32_BIT_5999_REV, and a glimg::PixelComponents of FMT_COLOR_RGB.

  • The glimg::ComponentOrder of ORDER_RGBE can only be used with the glimg::PixelDataType DT_SHARED_EXP_FLOAT, as above.
  • The glimg::Bitdepth of BD_PACKED_32_BIT_5999_REV can only be used as above.

• If the glimg::PixelComponents includes depth:

  • The glimg::ComponentOrder must be ORDER_DEPTH_STENCIL.
  • The glimg::PixelDataType is must be either DT_NORM_UNSIGNED_INTEGER or DT_FLOAT.
  • If glimg::PixelDataType is DT_FLOAT, then the glimg::Bitdepth must be BD_PER_COMP_32 and glimg::PixelComponents must be FMT_DEPTH.
  • If glimg::PixelDataType is DT_NORM_UNSIGNED_INTEGER, then either of the following must be true:
    • The glimg::Bitdepth must be BD_PER_COMP_16 and glimg::PixelComponents must be FMT_DEPTH.
    • the glimg::Bitdepth must be BD_PACKED_32_BIT_248 and glimg::PixelComponents must be FMT_DEPTH_X.

• The glimg::Bitdepth BD_PACKED_32_BIT_248 may only be used with a glimg::PixelComponents of FMT_DEPTH_X.

• Non depth glimg::PixelComponents that use a glimg::PixelDataType of DT_FLOAT must have a glimg::Bitdepth of 16-bit per component or greater, or must use BD_PACKED_32_BIT_101111_REV.

• glimg::PixelComponents that use the sRGB colorspace may only be used with a glimg::PixelDataType of DT_NORM_UNSIGNED_INTEGER.

• The glimg::Bitdepth BD_PACKED_32_BIT_101111_REV can only be used with a glimg::PixelDataType of DT_FLOAT, a glimg::ComponentOrder of ORDER_RGBA, and a glimg::PixelComponents of FMT_COLOR_RGB.

• If the glimg::Bitdepth is packed, and the glimg::PixelComponents does not include depth, and the glimg::PixelDataType is not DT_SHARED_EXP_FLOAT:

  • The glimg::PixelDataType must be either signed normalized, unsigned normalized, or floating point.
  • glimg::PixelComponents with 3 live components (the Xs don't count) can only be used with glimg::Bitdepth's of BD_PACKED_16_BIT_565, BD_PACKED_16_BIT_565_REV or BD_PACKED_32_BIT_101111_REV.
  • glimg::PixelComponents with 4 live components can only be used with glimg::Bitdepth's that have 4 components.

• If the glimg::Bitdepth is BD_PER_COMP_32, then the glimg::PixelDataType must not be a normalized integer.

• The glimg::ComponentOrder ORDER_BGRA may only be used on glimg::PixelComponents with 3 or more components.