PP1_FEATURE_ENABLE (GPU) Register Description
| Register Name | PP1_FEATURE_ENABLE |
|---|---|
| Offset Address | 0x000000A00C |
| Absolute Address | 0x00FD4BA00C (GPU) |
| Width | 32 |
| Type | rwNormal read/write |
| Reset Value | 0x00000000 |
| Description | Feature Enable Register |
PP1_FEATURE_ENABLE (GPU) Register Bit-Field Summary
| Field Name | Bits | Type | Reset Value | Description |
|---|---|---|---|---|
| Reserved | 31:7 | rwNormal read/write | 0x0 | Reserved, write as zero, read undefined. |
| SUMMATE_QUAD_COVER | 6 | rwNormal read/write | 0x0 | When set to 1, the coverage-to-alpha operates on a 2x2 fragment quad, and not individual fragments. This means that all 16 samples from a 2x2 quad are counted and converted to an alpha between 0.0 (0 samples) and 1.0 (16 samples), and that the alpha value is set for all the fragments in the 2x2 fragment quad. |
| ORIGIN_LOWER_LEFT | 5 | rwNormal read/write | 0x0 | This feature is still functional but deprecated, use Scaling Register on page 3-44 FLIP_FRAGOORD bit instead. The ORIGIN_LOWER_LEFT bit indicates whether the coordinate system for the screen XY position has its origin in the upper-left corner, y-axis increasing downwards or to lower-left corner, y-axis increasing upwards. The only hardware function that is currently affected by this bit is the Position Register function, and tile indices. The pixel processor considers the upper-left corner to be the origin. This bit must be set for use with OpenGL. |
| EARLYZ_DISABLE2 | 4 | rwNormal read/write | 0x0 | Setting this bit disables the second of two Early-Z mechanisms. Only use for debugging. For normal use, enable or disable Early-Z with the EARLYZ_ENABLE bit. |
| EARLYZ_DISABLE1 | 3 | rwNormal read/write | 0x0 | Setting this bit disables the first of two Early-Z mechanisms. Only use for debugging. For normal use, enable or disable Early-Z with the EARLYZ_ENABLE bit. |
| Reserved | 2 | rwNormal read/write | 0x0 | Reserved, write as zero, read undefined. |
| EARLYZ_ENABLE | 1 | rwNormal read/write | 0x0 | Setting this bit to 1 enables the Early Z-test mechanism in the rasterizer. EarlyZ is enabled by default. Enabling this test increases the performance in high-overdraw situations by performing multiple Z-tests per clock at the rasterizer level. The Early Z-test is not effective on Greater-Than depth test functions. |
| FP_TILEBUF_ENABLE | 0 | rwNormal read/write | 0x0 | Setting this bit to 1 sets the tile buffer to FP16 (1:5:10) component format instead of 8-bit component format. Enabling this feature has the following consequences: * multiple render targets cannot be used * internal multi-sampling or super-sampling anti-aliasing cannot be used * external write-back anti-aliasing technique cannot be used. |