SCG file format

This file contains geometric data of the model.

struct SCG {
  SCGHeader header;
  SCGBody body;
}

Header

There are two node counts with the same value. Our implementation uses the first node count however the reason behind why there's two is unknown.

• Magic: should always be "SCPG".
• Version: should always be 1

struct SCGHeader {
  char magic[4];
  uint32 version;
  uint32 nodeCount;
  uint32 nodeCount2;
}

Body

The rest of the file is just keyed archives.

struct SCGBody {
  KA polygonGroups[header.nodeCount];
}

Polygon group

• Name: always "PolygonGroup"
• Id: an 8 byte buffer and can be interpreted as a uint64.
• Cube texture coordinates count: how many coordinates for a cube texture is in this group.
• Index count: the number of entries in indices.
• Index format: the format of indices; 0 means indices is an array of uint16 and 1 means an array of uint32.
• Indices: the indices of the mesh as an array of integers.
• Packing: it is unknown what this does; doesn't seem to affect the mesh.
• Primitive count: the number of primitives in vertices.
• Render hardware interface primitive type: what type of vertices is in vertices.
• Texture coordinates count: the number of texture coordinates in vertices.
• Vertex count: the number of vertices.
• Vertex format: a uint32 that represents the format of the attributes of vertices in vertices.
  • To check if a vertex attribute is present, mask a bit shifted one with the format integer and see if it isn't 0.
    • Example: vertexFormat & (1 << VertexAttribute.TANGENT) != 0 will be true if the tangent property is present for all vertices.
  • To get the full format of a single vertex, map through all members of VertexAttribute (incrementing order) and generate a list of all present attributes.
  • The aquired format is repeated vertexCount number of times.
    • Example: if the resulting format is [VertexAttribute.VERTEX, VertexAttribute.TEXCOORD0, VertexAttribute.NORMAL], the entirety of vertices will be Vector3 normal, Vector2 texcoord0, and Vector3 normal over and over again.
    • The vector sizes of each vertex attribute type is documented below as vertexAttributeVectorSizes
  • Note that all vertices have the VertexAttribute.VERTEX attribute.
• Assembling the indices and vertices appropriately will result in a 3d mesh.

interface PolygonGroup {
  "##name": "PolygonGroup";
  "#id": Buffer;
  cubeTextureCoordCount: number;
  indexCount: number;
  indexFormat: 0 | 1;
  indices: Buffer;
  packing: 0 | 1;
  primitiveCount: number;
  rhi_primitiveType: RHIPrimitiveType;
  textureCoordCount: number;
  vertexCount: number;
  vertexFormat: number;
  vertices: Buffer;
}

Primitives

enum RHIPrimitiveType {
  TRIANGLELIST = 1,
  TRIANGLESTRIP = 2,
  LINELIST = 10,
}

This documentation will only discuss information native to SCPG.

• Vertex: always present in all vertices.
• Texture & cube texture coordinates: use the first available entry when trying to access highest lod textures.
• Hard joint index: serves as a discriminator for vertices; can be used to split up the mesh; is used to split up the armor plates on the armor models.
• Pivot deprecated: you should never encounter this.

enum VertexAttribute {
  VERTEX = 0,
  NORMAL = 1,
  COLOR = 2,
  TEXCOORD0 = 3,
  TEXCOORD1 = 4,
  TEXCOORD2 = 5,
  TEXCOORD3 = 6,
  TANGENT = 7,
  BINORMAL = 8,
  HARD_JOINTINDEX = 9,
  PIVOT4 = 10,
  PIVOT_DEPRECATED = 11,
  FLEXIBILITY = 12,
  ANGLE_SIN_COS = 13,
  JOINTINDEX = 14,
  JOINTWEIGHT = 15,
  CUBETEXCOORD0 = 16,
  CUBETEXCOORD1 = 17,
  CUBETEXCOORD2 = 18,
  CUBETEXCOORD3 = 19,
}

const vertexAttributeVectorSizes = {
  [VertexAttribute.VERTEX]: 3,
  [VertexAttribute.NORMAL]: 3,
  [VertexAttribute.COLOR]: 1,
  [VertexAttribute.TEXCOORD0]: 2,
  [VertexAttribute.TEXCOORD1]: 2,
  [VertexAttribute.TEXCOORD2]: 2,
  [VertexAttribute.TEXCOORD3]: 2,
  [VertexAttribute.TANGENT]: 3,
  [VertexAttribute.BINORMAL]: 3,
  [VertexAttribute.HARD_JOINTINDEX]: 1,
  [VertexAttribute.CUBETEXCOORD0]: 3,
  [VertexAttribute.CUBETEXCOORD1]: 3,
  [VertexAttribute.CUBETEXCOORD2]: 3,
  [VertexAttribute.CUBETEXCOORD3]: 3,
  [VertexAttribute.PIVOT4]: 4,
  [VertexAttribute.PIVOT_DEPRECATED]: 3,
  [VertexAttribute.FLEXIBILITY]: 1,
  [VertexAttribute.ANGLE_SIN_COS]: 2,
  [VertexAttribute.JOINTINDEX]: 4,
  [VertexAttribute.JOINTWEIGHT]: 4,
};