src/passes/Pass.js
import {
BufferAttribute,
BufferGeometry,
Camera,
Mesh,
Scene
} from "three";
/**
* A dummy camera
*
* @type {Camera}
* @private
*/
const dummyCamera = new Camera();
/**
* Shared fullscreen geometry.
*
* @type {BufferGeometry}
* @private
*/
let geometry = null;
/**
* Returns a shared fullscreen triangle.
*
* The size of the screen is 2x2 units (NDC). A triangle that fills the screen
* needs to be 4 units wide and 4 units tall.
*
* @private
* @return {BufferGeometry} The fullscreen geometry.
*/
function getFullscreenTriangle() {
if(geometry === null) {
const vertices = new Float32Array([-1, -1, 0, 3, -1, 0, -1, 3, 0]);
const uvs = new Float32Array([0, 0, 2, 0, 0, 2]);
geometry = new BufferGeometry();
// Added for backward compatibility (setAttribute was added in three r110).
if(geometry.setAttribute !== undefined) {
geometry.setAttribute("position", new BufferAttribute(vertices, 3));
geometry.setAttribute("uv", new BufferAttribute(uvs, 2));
} else {
geometry.addAttribute("position", new BufferAttribute(vertices, 3));
geometry.addAttribute("uv", new BufferAttribute(uvs, 2));
}
}
return geometry;
}
/**
* An abstract pass.
*
* Passes that do not rely on the depth buffer should explicitly disable the
* depth test and depth write flags of their fullscreen shader material.
*
* Fullscreen passes use a shared fullscreen triangle:
* https://michaldrobot.com/2014/04/01/gcn-execution-patterns-in-full-screen-passes/
*
* @implements {Initializable}
* @implements {Resizable}
* @implements {Disposable}
*/
export class Pass {
/**
* Constructs a new pass.
*
* @param {String} [name] - The name of this pass. Does not have to be unique.
* @param {Scene} [scene] - The scene to render. The default scene contains a single mesh that fills the screen.
* @param {Camera} [camera] - A camera. Fullscreen effect passes don't require a camera.
*/
constructor(name = "Pass", scene = new Scene(), camera = dummyCamera) {
/**
* The name of this pass.
*
* @type {String}
*/
this.name = name;
/**
* The scene to render.
*
* @type {Scene}
* @protected
*/
this.scene = scene;
/**
* The camera.
*
* @type {Camera}
* @protected
*/
this.camera = camera;
/**
* A mesh that fills the screen.
*
* @type {Mesh}
* @private
*/
this.screen = null;
/**
* Indicates whether this pass should render to texture.
*
* @type {Boolean}
* @private
*/
this.rtt = true;
/**
* Only relevant for subclassing.
*
* Indicates whether the {@link EffectComposer} should swap the frame
* buffers after this pass has finished rendering.
*
* Set this to `false` if this pass doesn't render to the output buffer or
* the screen. Otherwise, the contents of the input buffer will be lost.
*
* @type {Boolean}
*/
this.needsSwap = true;
/**
* Only relevant for subclassing.
*
* Indicates whether the {@link EffectComposer} should prepare a depth
* texture for this pass.
*
* Set this to `true` if this pass relies on depth information from a
* preceding {@link RenderPass}.
*
* @type {Boolean}
*/
this.needsDepthTexture = false;
/**
* Indicates whether this pass should be executed.
*
* @type {Boolean}
*/
this.enabled = true;
}
/**
* Indicates whether this pass should render to screen.
*
* @type {Boolean}
*/
get renderToScreen() {
return !this.rtt;
}
/**
* Sets the render to screen flag.
*
* If the flag is changed to a different value, the fullscreen material will
* be updated as well.
*
* @type {Boolean}
*/
set renderToScreen(value) {
if(this.rtt === value) {
const material = this.getFullscreenMaterial();
if(material !== null) {
material.needsUpdate = true;
}
this.rtt = !value;
}
}
/**
* Returns the current fullscreen material.
*
* @return {Material} The current fullscreen material, or null if there is none.
*/
getFullscreenMaterial() {
return (this.screen !== null) ? this.screen.material : null;
}
/**
* Sets the fullscreen material.
*
* The material will be assigned to a mesh that fills the screen. The mesh
* will be created once a material is assigned via this method.
*
* @protected
* @param {Material} material - A fullscreen material.
*/
setFullscreenMaterial(material) {
let screen = this.screen;
if(screen !== null) {
screen.material = material;
} else {
screen = new Mesh(getFullscreenTriangle(), material);
screen.frustumCulled = false;
if(this.scene === null) {
this.scene = new Scene();
}
this.scene.add(screen);
this.screen = screen;
}
}
/**
* Returns the current depth texture.
*
* @return {Texture} The current depth texture, or null if there is none.
*/
getDepthTexture() {
return null;
}
/**
* Sets the depth texture.
*
* This method will be called automatically by the {@link EffectComposer}.
*
* You may override this method if your pass relies on the depth information
* of a preceding {@link RenderPass}.
*
* @param {Texture} depthTexture - A depth texture.
* @param {Number} [depthPacking=0] - The depth packing.
*/
setDepthTexture(depthTexture, depthPacking = 0) {}
/**
* Renders the effect.
*
* This is an abstract method that must be overridden.
*
* @abstract
* @throws {Error} An error is thrown if the method is not overridden.
* @param {WebGLRenderer} renderer - The renderer.
* @param {WebGLRenderTarget} inputBuffer - A frame buffer that contains the result of the previous pass.
* @param {WebGLRenderTarget} outputBuffer - A frame buffer that serves as the output render target unless this pass renders to screen.
* @param {Number} [deltaTime] - The time between the last frame and the current one in seconds.
* @param {Boolean} [stencilTest] - Indicates whether a stencil mask is active.
*/
render(renderer, inputBuffer, outputBuffer, deltaTime, stencilTest) {
throw new Error("Render method not implemented!");
}
/**
* Updates this pass with the renderer's size.
*
* You may override this method in case you want to be informed about the size
* of the main frame buffer.
*
* The {@link EffectComposer} calls this method before this pass is
* initialized and every time its own size is updated.
*
* @param {Number} width - The renderer's width.
* @param {Number} height - The renderer's height.
* @example this.myRenderTarget.setSize(width, height);
*/
setSize(width, height) {}
/**
* Performs initialization tasks.
*
* By overriding this method you gain access to the renderer. You'll also be
* able to configure your custom render targets to use the appropriate format
* (RGB or RGBA).
*
* The provided renderer can be used to warm up special off-screen render
* targets by performing a preliminary render operation.
*
* The {@link EffectComposer} calls this method when this pass is added to its
* queue, but not before its size has been set.
*
* @param {WebGLRenderer} renderer - The renderer.
* @param {Boolean} alpha - Whether the renderer uses the alpha channel or not.
* @param {Number} frameBufferType - The type of the main frame buffers.
* @example if(!alpha && frameBufferType === UnsignedByteType) { this.myRenderTarget.texture.format = RGBFormat; }
*/
initialize(renderer, alpha, frameBufferType) {}
/**
* Performs a shallow search for disposable properties and deletes them. The
* pass will be inoperative after this method was called!
*
* The {@link EffectComposer} calls this method when it is being destroyed.
* You may, however, use it independently to free memory when you are certain
* that you don't need this pass anymore.
*/
dispose() {
const material = this.getFullscreenMaterial();
if(material !== null) {
material.dispose();
}
for(const key of Object.keys(this)) {
const property = this[key];
if(property !== null && typeof property.dispose === "function") {
if(property instanceof Scene) {
continue;
}
/** @ignore */
this[key].dispose();
}
}
}
}