Function addCustomShader

addCustomShader(
    extra: PhiraExtra,
    shaderPath: string,
    startBeat: number,
    endBeat: number,
    vars?: Record<string, Variable>,
    options?: Omit<CreateEffectOptions, "vars">,
): number
Create a custom shader effect from a file path.

Custom shader paths must start with /. The shader file should be a GLSL 1.00 fragment shader placed in the chart package.
Parameters
- extra: PhiraExtra
  PhiraExtra to modify.
- shaderPath: string
  Path to the shader file (e.g., "/shaders/myeffect.glsl").
- startBeat: number
  Start beat.
- endBeat: number
  End beat.
- vars: Record<string, Variable> = {}
  Uniform variable overrides.
- options: Omit<CreateEffectOptions, "vars"> = {}
  Additional effect options.
Returns number
Index of the new effect.
Example
```
addCustomShader(extra, '/red_overlay', 2, 4, {
  factor: animateValue(2, 4, 0, 1),
});
```
- Defined in extra.ts:942