Geometry Layout Commands

The geometry layout commands define how geometric shapes are drawn. Some geo layouts are contained after the Level data blocks and some are loaded with Level Command 0x17 The first byte of the geo layout command is the command type. Unlike the level commands, there is no length byte specified in the command. Most geo layout commands are constant length, however, some depend on the values set. Once geo layouts are loaded, they are processed into a graph node system. Graph nodes are a linked list that setup the rendering properties of display lists inside.

Every graph node has the same header. Depending on the geo layout cmd, the subsequent bytes will be different. Like geo layouts, graph nodes have no length byte.

Types of graph nodes. This value goes inside the first byte of the graph node header once the geo layout is loaded.

Branches to segmented address and stores 2 return addresses.

00 00 00 00 [SS SS SS SS]

/* Geo Layout 0x00 Rough translation. */
// 0x8038BD80 = Pointer to current Geo layout command
// 0x8038BCB8 = Pointer to array/table to where branch return pointers are stored.
// 0x8038BD7A = Branch depth value.
*(0x8038BCB8 + (0x8038BD7A * 4)) = *0x8038BD80 + 8; // Stores the pointer to the next geo command
*0x8038BD7A += 1; // Increment branch value
 
*(0x8038BCB8 + (0x8038BD7A * 4)) = (*0x8038BD78 << 16) + *0x8038BD7E; // Store another address
*0x8038BD7A += 1; // Increment branch value
*0x8038BD7E = *0x8038BD7A;
 
0x8038BD80 = SegmentedToVirtual(0x8038BD80 + 4); // Go to the segmented address.

Length: 8

The ending command to close.

01 00 00 00

Length: 4

Branches the current geo layout to another area within a RAM bank.

02 [AA] 00 00 [SS SS SS SS]

Length: 8

Ends the current geometry layout branch and returns to the area following the 0x02 command.

03 00 00 00

Length: 4

If you don't understand nodes, this is basically like a sub-folder.

04 00 00 00

Length: 4

Used at the end of the data within the opened node.

05 00 00 00

Length: 4

06 00 [XX XX]

Stores the pointer of the last node into the table at address (*0x8038BCAC). This table is usually empty except for the first entry (index 0), which holds the pointer to the node created by the geo layout 0x0F command. The size of the table is defined by the geo layout 0x08 command.

Example in a geometry layout:
0A 01 002D 0064 4E20 8029AA3C // Set camera frustum (FOV = 45, Near = 100, Far = 20000)
06 00 00 01 // Store pointer of the 0x0A command node to address ((*0x8038BCAC) + 4)

06 [OP] [VV VV]

Does an operation on the flags of the current node. (Flags are at offset 0x02 of the GraphNode structure)

Example in a geometry layout:
0A 01 002D 0064 4E20 8029AA3C // Set camera frustum (FOV = 45, Near = 100, Far = 20000)
07 00 00 01 // Set Node flags of 0x0A command to be 0x0001
07 01 01 00 // OR Node flags with 0x0100
07 02 00 01 // AND Node flags with 0x0001

Only used in geo layout of levels. Sets graph node type 0x0001

08 00 00 [AA] [XX XX] [YY YY] [WW WW] [HH HH]

struct GraphNodeRoot
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ u8 areaIndex;
    /*0x15*/ s8 unk15; // ?
    /*0x16*/ s16 x;
    /*0x18*/ s16 y;
    /*0x1A*/ s16 width; // half width, 160
    /*0x1C*/ s16 height; // half height
    /*0x1E*/ s16 numViews; // number of entries in mystery array
    /*0x20*/ struct GraphNode **views;
};

Length: C

Sets ortho matrix for level backgrounds.

It is unknown if this command is actually necessary or not. You can remove this command from a level's geometry layout and it won't affect the background, and changing the scale value has no visible effect either.

09 00 [AA AA]

Length: 4

struct GraphNodeOrthoProjection
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ f32 scale;
};

Set camera frustum properties. Only used in geo layout of levels. GraphNode type 0x03

0A [AA] [BB BB] [NN NN] [FF FF] {EE EE EE EE}

struct GraphNodePerspective
{
    /*0x00*/ struct FnGraphNode fnNode;
    /*0x14*/ void *Function
    /*0x18*/ s32 unused;
    /*0x1C*/ f32 fov;   // horizontal field of view in degrees
    /*0x20*/ s16 near;  // near clipping plane
    /*0x22*/ s16 far;   // far clipping plane
};

Length: 8-C (variable)

Starts geometry layout with no parameters whatsoever. Seems to use a pre-set render area.

0B 00 00 00

struct GraphNodeStart
{
    /*0x00*/ struct GraphNode node;
};

Length: 4

This command is used in level geometry layouts. Z-Buffering is disabled when rendering the skybox, and re-enabled when rendering level geometry. GraphNode type 0x04

0C [AA] 00 00

[ 0C 01 00 00 ] will add the following Fast3D data to the following node:

E7 00 00 00 00 00 00 00
B7 00 00 00 00 00 00 01
// Node's Fast3D commands
E7 00 00 00 00 00 00 00
B6 00 00 00 00 00 00 01

Length: 4

Used in WF, CCM, TTM, SSL levels and some geo layouts. This command will make the following node only render in a certain distance range away from the camera. GraphNode type 0x0B

0D 00 00 00 [AA AA] [BB BB]

Example from “Grassy Level Part” in Whomp's fortress:

0049E3A8 / 0E000958 [ 20 00 07 D0 ]
0049E3AC / 0E00095C [ 04 00 00 00 ]
0049E3B0 / 0E000960    [ 0D 00 00 00 F8 30 1F 40 ]
0049E3B8 / 0E000968    [ 04 00 00 00 ]
0049E3BC / 0E00096C       [ 15 01 00 00 07 00 AB A0 ] // Real geometry (Camera is nearby)
0049E3C4 / 0E000974       [ 15 06 00 00 07 00 AF B8 ]
0049E3CC / 0E00097C    [ 05 00 00 00 ]
0049E3D0 / 0E000980    [ 0D 00 00 00 1F 40 4E 20 ]
0049E3D8 / 0E000988    [ 04 00 00 00 ]
0049E3DC / 0E00098C       [ 15 01 00 00 07 00 AE C8 ] // Fake geometry (Camera is far away)
0049E3E4 / 0E000994    [ 05 00 00 00 ]
0049E3E8 / 0E000998 [ 05 00 00 00 ]
0049E3EC / 0E00099C [ 01 00 00 00 ]

struct GraphNodeLevelOfDetail
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ s16 minDistance;
    /*0x16*/ s16 maxDistance;
};

Length: 8

Loads ASM in RAM that switches between the receding display lists within the node. GraphNode type 0x0C

0E 00 00 [NN] [AA AA AA AA]

struct GraphNodeSwitchCase
{
    /*0x00*/ struct FnGraphNode fnNode;
    /*0x14*/ void *Function
    /*0x18*/ s32 unused;
    /*0x1C*/ s16 numCases;
    /*0x1E*/ s16 selectedCase;
};

Length: 8

GraphNode type 0x14.

0F 00 [TT TT] [XX XX] [YY YY] [ZZ ZZ] [UU UU] [VV VV] [WW WW] [AA AA AA AA]

struct GraphNodeCamera
{
    /*0x00*/ struct FnGraphNode fnNode;
    /*0x18*/ union {
        s32 preset;
        struct LevelCamera *levelCamera;
    } config;
    /*0x1C*/ Vec3f from;
    /*0x28*/ Vec3f to;
    /*0x34*/ void *matrixPtr; // pointer to look-at matrix of this camera as a Mat4
    /*0x38*/ s16 roll; // roll in look at matrix. Doesn't account for light direction unlike rollScreen.
    /*0x3A*/ s16 rollScreen; // rolls screen while keeping the light direction consistent
};

Length: 0x14

Applies translation & rotation to the following node. GraphNode type 0x15

10 [AA] [BB BB] [XX XX] [YY YY] [ZZ ZZ] [RX RX] [RY RY] [RZ RZ]

struct GraphNodeTranslationRotation
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
    /*0x18*/ Vec3s translation;
    /*0x1E*/ Vec3s rotation;
};

Length: 0x10

Applies translation to the child nodes, and a display list if one is specified. You can start a geometry layout with this command to set the offset for the entire model. You cannot start a geometry layout and load a display list at the same time, as it will cause the game to freeze (white-screen). GraphNode type 0x16

11 [B][L] [XX XX] [YY YY] [ZZ ZZ] {AA AA AA AA}

struct GraphNodeTranslation
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
    /*0x18*/ Vec3s translation;
    u8 pad1E[2];
};

Length: 8-C (variable)

Note: You can't just use the 8-byte version of 0x11 command just anywhere. It seems like the command needs a joint in it's parent node(s) for it to work properly (created from geo layout commands 0x11, 0x12, and 0x13).

0B000000
04000000
  11 00 0000 0100 0000 // This will cause a crash
  04000000
    15 01 00 00 0700A290
  05000000
05000000
01000000

0B000000
04000000
  11 80 0000 0100 0000 00000000 // This will work, since it creates a joint.
  04000000
    15 01 00 00 0700A290
  05000000
05000000
01000000

11 00 0000 0100 0000 // This will also work, since it is starting the geo layout.
04000000
    15 01 00 00 0700A290
05000000
01000000

0B000000
04000000
  13 01 0000 0000 0000 00000000
  04000000
    11 00 0000 0100 0000 // This will also work, since there is a joint above it.
    04000000
      15 01 00 00 0700A290
    05000000
  05000000
05000000
01000000

Applies rotation to the child nodes, and a display list if one is specified. You can start a geometry layout with this command to set the rotation for the entire model. You cannot start a geometry layout and load a display list at the same time, as it will cause the game to freeze (white-screen). GraphNode type 0x17

12 [B][L] [RX RX] [RY RY] [RZ RZ] {AA AA AA AA}

struct GraphNodeRotation
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
    /*0x18*/ Vec3s rotation;
    u8 pad1E[2];
};

Length: 8-C (variable)

Note: You can't just use the 8-byte version of 0x12 command just anywhere. It seems like the command needs a joint in it's parent node(s) for it to work properly (created from geo layout commands 0x11, 0x12, and 0x13).

(see geo layout command 0x11 for examples)

Loads display list with drawing layer and offsets the model and the node's children on X/Y/Z axis. GraphNode type 0x19

13 [LL] [XX XX] [YY YY] [ZZ ZZ] [AA AA AA AA]

struct GraphNodeAnimatedPart
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
    /*0x18*/ Vec3s translation;
};

* GraphNode part that transforms itself and its children based on animation data. This animation data is not stored in the node itself but in global variables that are set when object nodes are processed if the object has animation. Used for Mario, enemies and anything else with animation data. The display list can be null, in which case it won't draw anything itself.

Length: C

Almost identical with the geometry layout 0x11 command, except that it will billboard the node and it's children without needing the use of 0x21 in the behavior script. You can start a geometry layout with this command to billboard and set the offset for the entire model. You cannot start a geometry layout and load a display list at the same time, as it will cause the game to freeze (white-screen). GraphNode type 0x1A

14 [B][L] [XX XX] [YY YY] [ZZ ZZ] {AA AA AA AA}

struct GraphNodeBillboard
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
    /*0x18*/ Vec3s translation;
};

Length: 8-C (variable)

Loads display list with drawing layer and no other properties. GraphNode type 0x1B

15 [LL] 00 00 [AA AA AA AA]

struct GraphNodeDisplayList
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
};

Length: 8

Used at start of the geo layout, with shadow type, solidity, and size. GraphNode type 0x28

16 00 00 [AA] 00 [BB] [CC CC]

struct GraphNodeShadow
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ s16 shadowScale; // diameter (when a circle) or side (when a square) of shadow
    /*0x16*/ u8 shadowSolidity; // opacity of shadow, 255 = opaque
    /*0x17*/ u8 shadowType; // see ShadowType enum in shadow.h
};
enum ShadowType
{
    SHADOW_CIRCLE_9_VERTS = 0,
    SHADOW_CIRCLE_4_VERTS = 1,
    SHADOW_CIRCLE_4_VERTS_FLAT_UNUSED = 2,
    SHADOW_SQUARE_PERMANENT = 10,
    SHADOW_SQUARE_SCALABLE = 11,
    SHADOW_SQUARE_TOGGLABLE = 12,
    /**
     * This defines an offset after which rectangular shadows with custom
     * widths and heights can be defined.
     */
    SHADOW_RECTANGLE_HARDCODED_OFFSET = 50,
    SHADOW_CIRCLE_PLAYER = 99
};

Length: 8

Sets up rendering for 3D Objects. Without it, 0x24 objects placed in level do not render. GraphNode type 0x29

17 00 00 00

Length: 4

Used in some original objects to point to ASM in RAM, for misc. effects such as vertex rippling. GraphNode type 0x2A

The 3rd and 4th bytes are parameters passed into the asm function. Argument register a1 is a pointer to the node data, and the parameters are stored as a word at offset 0x18.

18 00 [XX XX] [AA AA AA AA]

struct GraphNodeGenerated
{
    /*0x00*/ struct FnGraphNode fnNode;
    /*0x18*/ u32 parameter; // extra context for the function
};

Length: 8

Set background image or color. GraphNode type 0x2C

19 00 [TT TT] [AA AA AA AA]

struct GraphNodeBackground
{
    /*0x00*/ struct FnGraphNode fnNode;
    /*0x18*/ s32 unused;
    /*0x1C*/ s32 background; // background ID, or rgba5551 color if fnNode.func is null
};

Length: 8

Examples:

[ 19 00 00 00 80 27 63 D4 ] # Bob-Omb's Battlefield
[ 19 00 00 01 80 27 63 D4 ] # Lethal Lava Land
[ 19 00 00 02 80 27 63 D4 ] # Wet Dry World
[ 19 00 00 03 80 27 63 D4 ] # Rainbow Ride
[ 19 00 00 04 80 27 63 D4 ] # Cool Cool Mountain
[ 19 00 00 05 80 27 63 D4 ] # Shifting Sand Land
[ 19 00 00 06 80 27 63 D4 ] # Big Boo's Haunt
[ 19 00 00 07 80 27 63 D4 ] # Bowser 1 Course
[ 19 00 00 08 80 27 63 D4 ] # Jolly Roger Bay
[ 19 00 00 09 80 27 63 D4 ] # Bowser 3 Course
[ 19 00 00 01 00 00 00 00 ] # Secret Slide, pure black background

Doesn't do anything, nop. This command is never used in any of the scripts.

Length: 8

Scales the receding data uniformly. GraphNode type 0x1c

1D [A][B] 00 00 [SS SS SS SS] {DD DD DD DD}

struct GraphNodeScale
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ void *displayList;
    /*0x18*/ f32 scale;
};

Length: 8-C (variable)

Doesn't do anything, nop. This command is never used in any of the scripts.

Length: 8

Doesn't do anything, nop. This command is never used in any of the scripts.

Length: 0x10

Starts the geometry layout with no shadow and a render area. GraphNode type 0x2F. If not set, a default of 300 is used.

20 00 [AA AA]

struct GraphNodeCullingRadius
{
    /*0x00*/ struct GraphNode node;
    /*0x14*/ s16 cullingRadius; // specifies the 'sphere radius' for purposes of frustrum culling
    u8 pad1E[2];
};

Length: 4

Level Commands

• https://github.com/n64decomp/sm64/blob/master/
• http://origami64.net/showthread.php?tid=9
• http://www.smwcentral.net/?p=viewthread&t=74776
• https://sites.google.com/site/kazemario64/geo-layout-polygon-commands
• http://qubedstudios.rustedlogic.net/Mario64_HackingDoc1.5.txt