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GPU/Commands

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< GPU
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This page describes the structure of the buffer for GX command 1 with the registers at 0x1EF018E0. This buffer is used for GPU commands including OpenGL commands, each 8-byte entry in the buffer is a command. Cmd+0 is the command parameter, and cmd+4 is the command header.

Invalid GPU command parameters including NaN floats can cause the GPU to hang, this then causes the GSP module to hang as well.

Command Header

Bit Description
19-0 Command ID
30-20 Total words following the command, if any.
31 ?

The first word in the parameter data structure is the command parameter value, the rest of the data structure is from the data following the command. The word after the last data structure word is padding when needed for 8-byte alignment, for the following command.

Commands

CommandID Parameter Description
0x000F0010 Value is 0x12345678 This command is always the last command in the buffer.
0x000F0110 Value 0x1 This command is immediately before CmdID 0x000F0010, this is also used elsewhere for beginning rendering of mesh(es) as well.
0x000F0111 Value 0x1 This command is immediately before CmdID 0x000F0110, however CmdID 0x000F0110 doesn't always follow this command.
0x000F0040 u32, valid values are 0x1 and 0x2, values 0x0 and 0x3 have the same effect as value 0x2. Only bits 1-0 are used. Value 2 = GL_FRONT/GL_CW or GL_BACK/GL_CCW. Value 1 = GL_FRONT/GL_CCW or GL_BACK/GL_CW.
0x000F0041 float See command set 0x000F0041.
0x000F0042 float See command set 0x000F0041.
0x000F0043 float See command set 0x000F0041.
0x000F0044 float See command set 0x000F0041.
0x801F004D First word in parameter structure ?
0x0002025E u32, val<<8. This sets the GL rendering mode.
0x000F0068 u32 See command set 0x000F0041.
0x000F006E u32 See command set 0x000F0111.
0x809F0081 This is used to set the current texture info used for rendering, see command set 0x809F0081.
0x000F008E u32 color type This command sets the texture color type, see command set 0x809F0081.
0x805F0091 This sets current texture info, see command 0x805F0091.
0x805F0099 This sets current texture info, see command 0x805F0099.
0x80XF00C0 See command set 0x80XF00C0.
0x800F00C4 See command set 0x80XF00C0.
0x80XF00C8 See command set 0x80XF00C0.
0x800F00CC See command set 0x80XF00C0.
0x80XF00D0 See command set 0x80XF00C0.
0x800F00D4 See command set 0x80XF00C0.
0x80XF00D8 See command set 0x80XF00C0.
0x800F00DC See command set 0x80XF00C0.
0x80XF00F0 See command set 0x80XF00C0.
0x800F00F4 See command set 0x80XF00C0.
0x80XF00F8 See command set 0x80XF00C0.
0x800F00FC See command set 0x80XF00C0.
0x00020100 u32, value is 0x00E40100 This command is used immediately before CmdID 0x000F0101.
0x000F00E6 Value zero See command set 0x000F00E6.
0x000F00E8 See command set 0x000F00E6.
0x000F0101 u32 Color related?
0x000F0104 u32 glAlphaFunc()?
0x00010107 See command set CmdID 0x00010107.
0x00020107 See command set CmdID 0x00010107.
0x00030107 See command set CmdID 0x00030107.
0x000F0116 u32 See command set 0x000F0111.
0x000F0117 u32 See command set 0x000F0111.
0x000F011C Physical address>>3 See command set 0x000F0111.
0x000F011D Physical address>>3 See command set 0x000F0111.
0x000F011E u32 See command set 0x000F0111.
0x826F0200 See command set 0x826F0200.
0x00080126 See command set CmdID 0x00030107.
0x000F0227 u32 This specifies the address of an array containing vertex array indices, and the data-type of the indices, used for rendering primitives. See command set glDrawElements().
0x000F0228 u32 total elements in the array to use for rendering. See command set glDrawElements().
0x803F0232 See command set 0x826F0200.
0x000F02B0 u32, value is 0x7FFF0000 | val. Texture related?
0x801F02BB See command set 0x826F0200.
0x000F02C0 0x80000000 | Type This is used immediately before CmdID 0xXXXF02C1. This type field controls the command parameter buffer type.
0xXXXF02C1 First word in the first entry A list of entries follow this command.

Command Sets

glDrawElements()

See GPU GL Arrays.

glClear() / glClearColor()

The GPU does not have dedicated commands for clearing the color buffer, therefore applications implement color buffer clearing by rendering a quad. Applications normally store this vertex and color array in the GSP application heap.

CmdID 0x809F0081

This sets current texture info, see GPU textures.

CmdID 0x80XF00C0
Command Index CommandID Parameter Description
0 0x802F00C0 + slotindex*8
1 0x800F00C4 + slotindex*8

This is used to set various rendering parameters for the slot indicated by the CmdID. There's a total of 6 slots.

Parameter structure for CmdID 0x804F00C0

Index Word Description
0 Value 0xFFF0FFF / 0x0
1 Value 0x0
2 Value 0x0
3 Value 0xFFFFFFFF
4 Value 0x0

This CmdID is 0x804F00C0 + slotindex*8. This individual command is used instead of the 0x80XF00C0 command set when none of the associated rendering parameters for this slot are set.

Parameter structure for CmdID 0x802F00C0

Index Word Description
0 ?
1 ?
2 ?

This CmdID is 0x802F00C0 + slotindex*8.

CmdID 0x000F00E6
Command Index CommandID Parameter Description
0 0x000F00E6 Value 0 ?
1 0x000F00E8

This is the last command set used for rendering a mesh.

CmdID 0x000F0041
Command Index CommandID Parameter Description
0 0x000F0041 float This corresponds to the framebuffer width.
1 0x000F0043 float This parameter value is calculated the same way as the CmdID 0x000F0041 parameter, except the framebuffer height is used instead.
2 0x000F0042 float This corresponds to the framebuffer width.
3 0x000F0044 float This parameter value value is calculated the same way as the CmdID 0x000F0042 parameter, except the framebuffer height is used instead.
4 0x000F0068 u32 This sets the X/Y coordinates used for glViewport().

This command set initializes the projection matrix. This command set is used twice when beginning rendering for each screen. The framebuffer width used here for the main screen is 240, however this is 480 with stereoscopy enabled for the second time this command set is used.

CmdID 0x000F0111
Command Index CommandID Parameter Description
0 0x000F0111 Value 1
1 0x000F0110 Value 1
2 0x000F0117 Bits15-0 = unk, 31-16 = unk. Unknown, normally the input parameter is value 0x2.
3 0x000F011D Physical address>>3 This initializes the framebuffer address used for rendering, this framebuffer is used for the input framebuffer with GX command 3 and 4. This command is used immediately after CmdID 0x000F0117.
4 0x000F0116 ?
5 0x000F011C Physical address>>3 Unknown, normally this address is located in VRAM.
6 0x000F011E u32 This sets the width and height for the framebuffer used for rendering. Therefore this is glViewport(), x/y are specified by CmdID 0x000F0068.
7 0x000F006E Same input parameter value as CmdID 0x000F011E.

This command set is normally used after the two 0x000F0041 command sets.

CmdID 0x00030107
Command Index CommandID Parameter Description
0 0x00030107
1 0x00080126 type<<24

This command set is used for disabling the alpha-testing info set by command set 0x00010107? The GL AlphaFunction used here is normally GL_ALWAYS.

CmdID 0x00010107
Command Index CommandID Parameter Description
0 0x00010107 Same format as CmdID 0x00030107.
1 0x00080126 type<<24
0 0x00020107 Same value as CmdID 0x00030107.

Parameter format for CmdIDs 0x00030107, 0x00020107, and 0x00010107

Bit Description
0 0 = disable GL_ALPHA_TEST, 1 = enable GL_ALPHA_TEST?
3-1 Unused?
7-4 Alpha function
11-8 Color to blend with?
12 ?
31-13 Unused

Alpha function values

Value GL AlphaFunction
0 GL_NEVER
1 GL_ALWAYS
2 GL_EQUAL
3 GL_NOTEQUAL
4 GL_LESS
5 GL_LEQUAL
6 GL_GREATER
7 GL_GEQUAL

Alpha types for CmdID 0x00080126

Type GL AlphaFunction
0 GL_NEVER
1 GL_ALWAYS
2 GL_GREATER/GL_GEQUAL
3 The remaining GL alpha functions.

Parameter value format for CmdID 0x000F0104

Bit Description
0 0 = disable GL_ALPHA_TEST, 1 = enable GL_ALPHA_TEST?
3-1 Unused?
7-4 Alpha function
15-8 u8 ref, range is 0-255?
31-16 Unused?

This is glAlphaFunc()?

Parameter value format for CmdID 0x000F011E

Bit Description
11-0 Framebuffer/viewport width
23-12 Framebuffer/viewport height - 1
24 Must be set
31-25 Unused?

This specifies the width/height for glViewport(). Normally the framebuffer width and height is set to the same dimensions used with GX command 3 and 4.

Parameter value format for CmdID 0x000F0068

Bit Description
15-0 X
31-16 Y

This specifies the X/Y coordinates for glViewport().

Parameter structure for CmdID 0x000F00E8

Index Word Description
0x7f-0x00 ?

Entries for CmdID 0xXXXF02C1

Index Word Description
0 float
1 float
2 float
3 float

Color Entry

Index Word Description
0 float Red component
1 float Blue component
2 float Green component
3 float Alpha
4 float
5 float
6 float
7 float

Types for CmdID 0x000F02C0

Value Entries per chunk Description
0x00 4 This specifies 16-floats for a 4x4 matrix, used for glLoadMatrix() for the projection matrix.
0x04 4 This specifies a 4x4 matrix, used for glLoadMatrix() for the model-view matrix. This is usually an identity matrix.
0x08 One color entry via two CmdID 0xXXXF02C1 entries. Sets the color.
0x0A 4 Specifies a 4x4 matrix, used for glLoadMatrix() for the texture matrix.(Index0)
0x0E 3 Specifies a 4x3 texture matrix.(Index1)
0x11 3 Specifies a 4x3 texture matrix.(Index2)
0x14 <=30 Used to specify a 4xN matrix, where N is the total CmdID 0xXXXF02C1 entries. This is glMultMatrix() for the model-view matrix, except the input matrix is 4xN instead of 4x4.
0x4C 4 This specifies a 4x4 float matrix.
0x50, 0x53, and 0x56 1 ?
0x51, 0x54, and 0x57 1 ?
0x52, 0x55, and 0x58 1 ?
0x59 1 Unknown, the entry data is floats converted from s32s.
0x5A 2 Color related?
0x5C 1 ?

For matrices, the rows are flipped: the GPU handles the 4th row as the 1st row, 3rd row as the 2nd row, etc.

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