lit
Returns a lighting coefficient vector.
| ret lit(n_dot_l, n_dot_h, m) |
|---|
This function returns a lighting coefficient vector (ambient, diffuse, specular, 1) where:
- ambient = 1
- diffuse = n · l < 0 ? 0 : n · l
- specular = n · l < 0 || n · h < 0 ? 0 : (n · h) ^ m
Where the vector n is the normal vector, l is the direction to light and h is the half vector.
Parameters
| Item | Description |
|---|---|
| n_dot_l |
[in] The dot product of the normalized surface normal and the light vector. |
| n_dot_h |
[in] The dot product of the half-angle vector and the surface normal. |
| m |
[in] A specular exponent. |
Return Value
The lighting coefficient vector.
Type Description
| Name | Template Type | Component Type | Size |
|---|---|---|---|
| n_dot_l | scalar | float | 1 |
| n_dot_h | scalar | float | 1 |
| m | scalar | float | 1 |
| ret | vector | float | 4 |
Minimum Shader Model
This function is supported in the following shader models.
| Shader Model | Supported |
|---|---|
| Shader Model 2 (DirectX HLSL) and higher shader models | yes |
| Shader Model 1 (DirectX HLSL) | yes (vs_1_1 only) |