GLSL Script

Defines a custom filter effect using a GLSL fragment shader. Runs through the GPU rendering backend.

Library location

Library → Filter Effect → Script → GLSL Script

Properties

Script (FragmentShader)

The GLSL fragment shader source.

• Type: string
• Default:

  #version 450
  
  layout(location = 0) in vec2 fragCoord; // 0.0 - 1.0
  layout(location = 0) out vec4 outColor;
  
  layout(set = 0, binding = 0) uniform sampler2D srcTexture;
  
  layout(push_constant) uniform PushConstants {
      float progress;   // 0.0 - 1.0
      float duration;   // seconds
      float time;       // seconds
      float width;      // render target width (device px)
      float height;     // render target height (device px)
      float scale;      // working scale w (1.0 = unscaled); multiply absolute-px literals by this
  } pc;
  
  void main() {
      vec4 c = texture(srcTexture, fragCoord);
      outColor = c;
  }

• Animatable: No

Usage

Provide a fragment shader that writes the output color from the input source texture and any animatable 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 report the device-pixel size of the render target at that density, and scale is the working density in device pixels per logical pixel (1.0 when unscaled).

The default fragCoord input is already normalized to 0.0 – 1.0, so a shader that samples with it 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 scale so they keep the same on-screen size at any density. A shader that never reads scale renders exactly as before at scale 1.0.

Source

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