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GPU/Commands: Difference between revisions

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| 0x0100
| 0x0100
| <nowiki>0x00E40000 | val</nowiki>.
| <nowiki>0x00E40000 | val</nowiki>.
| Val0 = unknown, val1 = unknown, val3 = unknown. The default val used here is 0.
| See command set 0x0100.
|-
|-
| 0x0101
| 0x0101
| u32
| See command set 0x0100.
|-
| 0x0102
| u32
| u32
| See command set 0x0100.
| See command set 0x0100.
Line 415: Line 419:
| 0x0100
| 0x0100
| Value 0x00E40100
| Value 0x00E40100
| ?
| Controls color compositing
|-
|-
| 1
| 1
| 0x0101
| 0x0101
| 0x01010000 when disabled?
| 0x01010000 when disabled
| ?
| Alphablending equations and factors
|-
|-
| 2
| 2
| 0x0103
| 0x0103
| This is set to zero when the command 0x0101 parameter is value 0x01010000.
| This is set to zero when the command 0x0101 parameter is value 0x01010000.
| ?
| Constant color for alphablending
|}
|}


Line 1,015: Line 1,019:
| Unused
| Unused
|}
|}
=== Parameter value format for command 0x0100 ===
This command controls color compositing. It is typically used right after commands 0x0101 or 0x0102 to select the appropriate blending mode.
Alphablending and color logic op can't be used together. Attempting to issue commands 0x0101 and 0x0102 at the same time can freeze the GPU.
For blending to work correctly, color buffer reading needs to be enabled (see command set 0x0112). Otherwise zero values will be used as destination color/alpha.
{| class="wikitable" border="1"
!  Bit
!  Description
|-
| 0
| Weird mode (see below)
|-
| 1
| When set, nothing is drawn to the color buffer. It is unknown if this also affects the depth and stencil buffers. This bit can cause a noisy picture when used with bit 0.
|-
| 8
| Selects blending mode. 0 = color logic op, 1 = alphablending
|-
| 23-20
| Unknown, typically set to 0xE4. No observed effect when changing this.
|-
| 25-24
| 0 = normal, 1-3 = apply dithering (3 = 0% source)
|}
When "weird mode" is enabled, the source color/alpha values are ignored. Instead, each 16-bit value in the destination color buffer is converted according to its bits 14-8, as follows:
* if bits 14-8 are between 0x00 and 0x03, the value is replaced with 0x0000
* if bits 14-8 are between 0x7D and 0x7F, the value is replaced with 0x7FFF
* in all other cases, the value is left unchanged


=== Parameter value format for command 0x0101 ===
=== Parameter value format for command 0x0101 ===
Line 1,111: Line 1,147:
| 14
| 14
| GL_SRC_ALPHA_SATURATE
| GL_SRC_ALPHA_SATURATE
|}
=== Parameter value format for command 0x0102 ===
This command controls color logic op.
{| class="wikitable" border="1"
!  Bit
!  Description
|-
| 3-0
| Logic operation
|}
Source/destination factor values:
{| class="wikitable" border="1"
!  Value
!  Description
|-
| 0
| GL_CLEAR
|-
| 1
| GL_AND
|-
| 2
| GL_AND_REVERSE
|-
| 3
| GL_COPY
|-
| 4
| GL_SET
|-
| 5
| GL_COPY_INVERTED
|-
| 6
| GL_NOOP
|-
| 7
| GL_INVERT
|-
| 8
| GL_NAND
|-
| 9
| GL_OR
|-
| 10
| GL_NOR
|-
| 11
| GL_XOR
|-
| 12
| GL_EQUIV
|-
| 13
| GL_AND_INVERTED
|-
| 14
| GL_OR_REVERSE
|-
| 15
| GL_OR_INVERTED
|}
|}


Line 1,148: Line 1,248:
|-
|-
| 0
| 0
| 0x0 = unknown, 0xF = unknown. Only bits 3-0 are used.(Values 0x1-0xF all have the same effect)
| Setting bits 3-0 to a nonzero value allows the GPU to read from the color buffer.
|-
|-
| 1
| 1
Retrieved from "https://www.3dbrew.org/wiki/GPU/Commands"