PostEffect class

A custom, user-authored post-processing effect: a fragment shader that reads the current color and writes a new one.

This is the post-processing counterpart of ShaderMaterial. Author a fragment shader, compile it through the flutter_gpu_shaders build hook into a .shaderbundle, load it, wrap it in a PostEffect, and add it to Scene.postProcess.customEffects.

Engine-bound resources

The engine binds the current color to a sampler2D input_color, which the shader samples at the v_uv varying:

uniform sampler2D input_color;
in vec2 v_uv;
out vec4 frag_color;
void main() { frag_color = texture(input_color, v_uv); }

Set useFrameInfo to also receive a PostFrameInfo block with the target resolution, texel size, and a seconds time value:

uniform PostFrameInfo {
  vec2 resolution;
  vec2 texel_size;
  float time;
  float _pad;
} frame;

Declare your own uniform blocks and textures and set them by name with setUniformBlock / setTexture, exactly like ShaderMaterial; the std140 packing rules are the same (see MATERIALS.md).

A PostInsertion.beforeTonemap effect should output linear HDR premultiplied by alpha; a PostInsertion.afterTonemap effect works on the display-referred image.

Constructors

PostEffect({Shader? fragmentShader, PostInsertion insertion = PostInsertion.beforeTonemap, bool enabled = true, bool useFrameInfo = false})

Properties

enabled ↔ bool: Whether this effect runs. Disabled effects are skipped.
getter/setter pair
fragmentShader → Shader: The fragment shader run for this effect. Set it via the constructor or setFragmentShader; reading it throws until one is set.
no setter
hashCode → int: The hash code for this object.
no setterinherited
insertion ↔ PostInsertion: Where in the chain this effect runs.
getter/setter pair
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
textureNames → Iterable<String>: All currently-bound sampler names.
no setter
uniformBlockNames → Iterable<String>: All currently-bound uniform block names.
no setter
useFrameInfo ↔ bool: Whether the engine binds the PostFrameInfo block. Set this when the shader declares and uses it.
getter/setter pair

Methods

bindUniforms(RenderPass pass, HostBuffer transientsBuffer) → void: Binds this effect's own uniform blocks and textures. Engine-internal.
getTexture(String name) → Texture?: Reads back a previously-set texture binding, or null.
getUniformBlock(String name) → ByteData?: Reads back a previously-set uniform block, or null.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
setFragmentShader(Shader shader) → void: Assigns the fragment shader run for this effect.
setTexture(String name, Texture? texture, {SamplerOptions? sampler}) → void: Assigns a texture to a sampler uniform by name.
setUniformBlock(String name, ByteData? bytes) → void: Assigns the byte contents of a uniform block by name (std140 layout).
setUniformBlockFromFloats(String name, List<double> floats) → void: Convenience wrapper around setUniformBlock that packs floats.
toString() → String: A string representation of this object.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
inherited