SKSL Script

Defines a custom filter effect using a SkiaSharp Shading Language (SKSL) shader. Runs as a per-pixel program through Skia.

Library location

Library → Filter Effect → Script → SKSL Script

Properties

Script

The SKSL shader source.

• Type: string
• Default:

  uniform shader src;
  uniform float progress;  // 0.0 - 1.0
  uniform float duration;  // seconds
  uniform float time;      // seconds
  uniform float width;     // render target width (device px)
  uniform float height;    // render target height (device px)
  // Also available:
  // uniform float2 iResolution;  // (width, height) in device px
  // uniform float  iScale;       // working density (device px per logical px)
  // uniform float  iTime;
  
  half4 main(float2 fragCoord) {
      half4 c = src.eval(fragCoord);
      return c;
  }

• Animatable: No

Usage

Provide a main(float2 coord) → half4 shader. The source layer is provided through src and animatable parameters are passed as uniforms.

Resolution scaling

Beutl can render at a working density that differs from the project resolution — for example a downscaled preview or a supersampled export. width / height / iResolution report the device-pixel size of the render target at that density, and iScale is the working density in device pixels per logical pixel (1.0 when unscaled).

A shader that works in normalized coordinates (for example fragCoord / iResolution) is automatically resolution-independent and needs no changes. If your shader uses absolute pixel literals — a fixed radius, offset, or border width measured in pixels — multiply them by iScale so they keep the same on-screen size at any density. A shader that never reads iScale renders exactly as before at scale 1.0.

Source

src/Beutl.Engine/Graphics/FilterEffects/SKSLScriptEffect.cs