Engine API Reference - v2.24.0-beta.28
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    Class CameraFrameEffect

    Base class of an effect registered with a CameraFrame. An effect is constructed with the graphics device, its id and its declarations - the compose slot it applies at and its shader chunk - and exposes its parameters as fields. Declarations are fixed for the life of the effect; anything that depends on a parameter is a getter instead, like CameraFrameEffect#active.

    An effect contributes to the composition: you supply its shader chunk (GLSL and WGSL) and write its entry function under a conventional name, apply<Id>. The camera frame generates the call to that function at the effect's slot, and rebuilds the compose shader when an effect becomes active or inactive, or changes one of its defines. The chunk is only included while the effect is active, so it needs no #ifdef guard of its own - defines are for an effect's own variants, set with CameraFrameEffect#setDefine. The chunk can be overridden by name like the built-in chunks: a chunk set in ShaderChunks under compose<Id>PS replaces the effect's own source. <ID> (the id in upper snake case) is defined while the effect is active, should another chunk need to know. Each debug view name the effect lists is backed the same way as the entry function, by a debug<Name>() function in the chunk.

    All effects registered to a compose slot are called in registration order from within the single compose pass, so contributing to the composition never costs an additional full-screen pass.

    An effect can also own passes, for work the composition cannot do in a single sample per pixel, such as a blur at a lower resolution or rendering into the scene. It creates them in CameraFrameEffect#createPasses, from the frame resources it CameraFrameEffect#requires, adding each to the stage of the frame it runs at, and its chunk reads what they render through the uniforms it sets with CameraFrameEffect#setUniform. An effect whose passes resolve the scene, such as an anti-aliasing, replaces the scene color the rest of the frame reads in CameraFrameEffect#resolveScene. An effect owning passes does not need a compose slot.

    Every chunk can read what the composition provides: the scene color, sceneTexture, and sceneTextureSize - the width, height, 1 / width and 1 / height of the scene texture. Use the size for anything which depends on the resolution, such as texel offsets, pixel sizes or the aspect ratio, as it is always current for the camera being drawn. An effect requiring the scene depth, see CameraFrameEffect#requires, can also read it with getLinearScreenDepth(uv).

    Like the rest of the camera frame, an effect is configured when CameraFrame#update is called: changes to its parameters, and adding or removing it, take effect at the next update, and every frame rendered after it uses exactly what the update applied.

    Lifetime:

    // A tint applied in display space, after tone mapping. The chunk declares its uniform and the
    // entry function applyTint, which the composition calls as `result = applyTint(result, uv)`.
    class TintEffect extends CameraFrameEffect {
    color = new Color(1, 0.9, 0.8);

    tintColor = new Float32Array(3);

    constructor(device) {
    super(device, 'tint', {
    slot: COMPOSESLOT_LDR,
    glsl: `
    uniform vec3 tintColor;
    vec3 applyTint(vec3 color, vec2 uv) {
    return color * tintColor;
    }
    `,
    wgsl: `
    uniform tintColor: vec3f;
    fn applyTint(color: vec3f, uv: vec2f) -> vec3f {
    return color * uniform.tintColor;
    }
    `
    });
    }

    update() {
    this.tintColor[0] = this.color.r;
    this.tintColor[1] = this.color.g;
    this.tintColor[2] = this.color.b;
    this.setUniform('tintColor', this.tintColor);
    }
    }

    cameraFrame.addEffect(new TintEffect(app.graphicsDevice));
    cameraFrame.update();

    // The same effect without a class, for effects driven by data
    const tint = new CameraFrameEffect(app.graphicsDevice, 'tint', { slot: COMPOSESLOT_LDR, glsl, wgsl });
    tint.setUniform('tintColor', new Float32Array([1, 0.9, 0.8]));
    cameraFrame.addEffect(tint);
    cameraFrame.update();
    // A glow owning a pass: the pass blurs the half resolution scene into a render target of the
    // effect, which the chunk adds to the scene. GlowPass is a RenderPassShaderQuad blurring the
    // texture it is given, see RenderPassShaderQuad.
    class GlowEffect extends CameraFrameEffect {
    constructor(device) {
    super(device, 'glow', {
    slot: COMPOSESLOT_HDR,
    requires: [FRAMERESOURCE_SCENECOLORHALF],
    glsl: `
    uniform sampler2D glowTexture;
    vec3 applyGlow(vec3 color, vec2 uv) {
    return color + texture2DLod(glowTexture, uv, 0.0).rgb;
    }
    `,
    wgsl: `
    var glowTexture: texture_2d<f32>;
    var glowTextureSampler: sampler;
    fn applyGlow(color: vec3f, uv: vec2f) -> vec3f {
    return color + textureSampleLevel(glowTexture, glowTextureSampler, uv, 0.0).rgb;
    }
    `
    });
    }

    createPasses(resources, passes) {
    // the render target of the pass is resized to the half resolution scene every frame
    const { sceneColorHalf } = resources;
    this._target = new RenderTarget({
    colorBuffer: new Texture(this.device, {
    name: 'GlowTexture',
    width: 1,
    height: 1,
    format: this.cameraFrame.hdrFormat,
    mipmaps: false
    }),
    depth: false
    });

    this._pass = new GlowPass(this.device, sceneColorHalf);
    this._pass.init(this._target, { resizeSource: sceneColorHalf });
    passes.postResolve.push(this._pass);

    this.setUniform('glowTexture', this._target.colorBuffer);
    }

    destroyPasses() {
    this._pass?.destroy();
    this._pass = null;
    this._target?.destroyTextureBuffers();
    this._target?.destroy();
    this._target = null;
    }
    }

    Hierarchy (View Summary)

    Index
    • Creates a new effect.

      Parameters

      • device: GraphicsDevice

        The graphics device.

      • id: string

        The identifier of the effect, unique among the effects of a camera frame. The names of the chunk, its entry function and its define are derived from it.

      • Optionaloptions: {
            chunkName?: string;
            debugViews?: string[];
            entryPoint?: string;
            glsl?: string;
            requires?: string[];
            slot?: string;
            wgsl?: string;
        } = {}

        The declarations of the effect. All are optional.

        • OptionalchunkName?: string

          The name the compose chunk can be overridden under, when it should differ from the derived compose<Id>PS.

        • OptionaldebugViews?: string[]

          The names of the debug views the chunk provides. Each view name requires the chunk to declare a vec3 debug<Name>() function, and is available while the effect is active.

        • OptionalentryPoint?: string

          The name of the function the composition calls, when it should differ from the derived apply<Id>.

        • Optionalglsl?: string

          The GLSL source of the compose chunk.

        • Optionalrequires?: string[]

          The frame resources the effect needs, the FRAMERESOURCE_* constants, see CameraFrameEffect#requires.

        • Optionalslot?: string

          The compose slot the entry function is called at, one of the COMPOSESLOT_* constants. Omit for an effect that does not take part in the composition, for example one that only owns passes.

        • Optionalwgsl?: string

          The WGSL source of the compose chunk.

      Returns CameraFrameEffect

    cameraFrame: CameraFrame | null = null

    The camera frame the effect is registered with, or null.

    The graphics device.

    enabled: boolean = true

    Whether the effect is enabled. An effect can additionally disable itself from its own parameters, see CameraFrameEffect#active.

    • get cameraExposureScale(): number

      Gets the scale the effect applies to the exposure of the camera this frame, multiplying the exposure of the scene, or of the physical camera with physical units - for effects adapting the exposure to what the camera sees. Read every frame while the effect takes part, after CameraFrameEffect#frameUpdate; the camera frame applies the product of the scales of the effects taking part, and the camera renders with its own exposure again once none does. Defaults to 1.

      // an effect brightening the image by one stop
      get cameraExposureScale() {
      return 2;
      }

      Returns number

    • get entryPoint(): string

      Gets the name of the function the composition calls at the effect's slot. Derived from the id as apply<Id> unless given. The signature depends on the slot: colour slots take (vec3 color, vec2 uv) and return the colour, COMPOSESLOT_SCENE takes and returns a vec4.

      Returns string

    • get requires(): string[]

      Gets the frame resources the effect needs, the FRAMERESOURCE_* constants - for its passes, or for its compose chunk, such as the scene depth. The camera frame provides them while the effect is active. Requirements which depend on the device are computed when constructing the effect; override this as a getter when they depend on a parameter, and the camera frame provides what it returns from the next CameraFrame#update.

      Returns string[]

    • Creates the passes the effect owns, when it has any. Called by CameraFrame#update when it builds the frame graph, for an active effect registered with the camera frame. Implementing it is what makes an effect own passes. The effect adds each pass to the array of the stage it runs at, in execution order - one effect can run passes at several stages:

      createPasses(resources, passes) {
      this._pass = new MyPass(this.device, resources.sceneColorHalf);
      passes.postResolve.push(this._pass);
      }

      The effect owns the passes it creates: it releases them in CameraFrameEffect#destroyPasses.

      The resources are stable: each texture stays the same object until the passes are destroyed, so it can be handed to the passes once, here. Its size can change, as render targets resize with the canvas, so its dimensions must not be cached. Values which change from frame to frame, the resolved scene color among them, are never resources - they are handed to CameraFrameEffect#frameUpdate instead.

      Parameters

      Returns void

    • Destroys the effect, removing it from its camera frame if it is still registered and releasing everything it owns, the passes it created included. Subclasses which create resources in their constructor release them in an override, calling super.destroy(). The removal takes effect for the frames rendered after the next CameraFrame#update, which is due before the next frame renders.

      Returns void

    • Called every frame while the effect takes part in the frame, while the frame is being prepared and before any pass renders, with the values of that frame. Most effects do not need it: their configuration belongs in CameraFrameEffect#update, which runs only when the camera frame is updated. Values derived from the resolution, which can change without an update, are computed here from the sizes in the frame, or in the shader from sceneTextureSize. Anything which changes over time advances here by the time of the frame, its dt.

      Parameters

      Returns void

    • Returns the compose chunk source for a shader language.

      Parameters

      • shaderLanguage: string

        SHADERLANGUAGE_GLSL or SHADERLANGUAGE_WGSL.

      Returns string | null

      The source, or null when the effect has no chunk.

    • Resolves the scene, for an effect whose passes run at the resolve stage - see CameraFrameEffectPasses. Called every frame while the effect's passes take part in the frame, before any pass renders and before CameraFrameEffect#frameUpdate is called on any effect, in the order the effects are registered. The effect hands its passes the scene color the effects before it resolved, and replaces it with the texture they render to this frame, which the effects after it, the half resolution copy of the scene and the composition then read:

      resolveScene(scene) {
      this._pass.setSourceTexture(scene.texture);
      scene.texture = this._pass.outputTexture;
      }

      An effect resolving the scene to another resolution also sets the width and the height. The default implementation leaves the scene unchanged.

      Parameters

      Returns void

    • Sets a define on the compose shader. The define persists until changed, so fixed defines can be set once in the constructor and those depending on the parameters from CameraFrameEffect#update. A value of false, null or undefined removes it. Changing a define rebuilds the compose shader.

      Parameters

      • name: string

        The define name.

      • value: any

        The value.

      Returns void

    • Sets the value of a uniform the effect's shader chunk reads. Like a material parameter, the value is stored by reference, so an array or a texture can be updated in place. Set the values in CameraFrameEffect#update, or in CameraFrameEffect#frameUpdate for a value which changes every frame.

      Parameters

      • name: string

        The name of the uniform, as declared in the chunk.

      • value: number | number[] | ArrayBufferView<ArrayBufferLike> | Texture

        The value.

      Returns void