Shader Built-in Variables
Built-in variables are frequently used in Shader code. There are two types: per-vertex attribute variables and per-shader uniform variables.
Below are the engine's built-in variables for reference when writing Shaders:
| Per-vertex Data | Attribute Name | Data Type |
|---|
| Vertex | POSITION | vec3 |
| Normal | NORMAL | vec3 |
| Tangent | TANGENT | vec4 |
| Vertex Color | COLOR_0 | vec4 |
| Bone Indices | JOINTS_0 | vec4 |
| Bone Weights | WEIGHTS_0 | vec4 |
| First UV Set | TEXCOORD_0 | vec2 |
| Second UV Set | TEXCOORD_1 | vec2 |
| Name | Type | Description |
|---|
| renderer_LocalMat | mat4 | Model local coordinate matrix |
| renderer_ModelMat | mat4 | Model world coordinate matrix |
| renderer_MVMat | mat4 | Model view matrix |
| renderer_MVPMat | mat4 | Model view projection matrix |
| renderer_NormalMat | mat4 | Normal matrix |
| Name | Type | Description |
|---|
| camera_ViewMat | mat4 | View matrix |
| camera_ProjMat | mat4 | Projection matrix |
| camera_VPMat | mat4 | View projection matrix |
| camera_ViewInvMat | mat4 | Inverse view matrix |
| camera_Position | vec3 | Camera position |
| camera_DepthTexture | sampler2D | Depth information texture |
| camera_OpaqueTexture | sampler2D | Opaque texture |
| camera_DepthBufferParams | Vec4 | Camera depth buffer parameters: (x: 1.0 - far / near, y: far / near, z: 0, w: 0) |
| camera_ProjectionParams | Vec4 | Projection matrix parameters: (x: flipProjection ? -1 : 1, y: near, z: far, w: 0) |
| Name | Type | Description |
|---|
| scene_ElapsedTime | vec4 | Total time since engine started: (x: t, y: sin(t), z: cos(t), w: 0) |
| scene_DeltaTime | vec4 | Time since last frame: (x: dt, y: 0, z: 0, w: 0) |
| Name | Type | Description |
|---|
| scene_FogColor | vec4 | Fog color |
| scene_FogParams | vec4 | Fog parameters: (x: -1/(end-start), y: end/(end-start), z: density / ln(2), w: density / sqr(ln(2)) |
