src/effects/GodRaysEffect.js
import {
Color,
LinearFilter,
MeshBasicMaterial,
RGBFormat,
Scene,
Uniform,
Vector2,
Vector3,
WebGLRenderTarget
} from "three";
import { KernelSize, GodRaysMaterial } from "../materials";
import { BlurPass, RenderPass, ShaderPass } from "../passes";
import { BlendFunction } from "./blending/BlendFunction.js";
import { Effect } from "./Effect.js";
import fragment from "./glsl/texture/shader.frag";
/**
* A vector.
*
* @type {Vector3}
* @private
*/
const v = new Vector3();
/**
* A god rays effect.
*/
export class GodRaysEffect extends Effect {
/**
* Constructs a new god rays effect.
*
* @param {Scene} scene - The main scene.
* @param {Camera} camera - The main camera.
* @param {Object3D} lightSource - The main light source.
* @param {Object} [options] - The options. See {@link GodRaysMaterial} for additional options.
* @param {BlendFunction} [options.blendFunction=BlendFunction.SCREEN] - The blend function of this effect.
* @param {Number} [options.resolutionScale=0.5] - The render texture resolution scale, relative to the screen render size.
* @param {Number} [options.samples=60.0] - The number of samples per pixel.
* @param {Number} [options.blur=true] - Whether the god rays should be blurred to reduce artifacts.
* @param {Number} [options.kernelSize=KernelSize.SMALL] - The blur kernel size. Has no effect if blur is disabled.
*/
constructor(scene, camera, lightSource, options = {}) {
const settings = Object.assign({
blendFunction: BlendFunction.SCREEN,
resolutionScale: 0.5,
samples: 60.0,
blur: true,
kernelSize: KernelSize.SMALL
}, options);
super("GodRaysEffect", fragment, {
blendFunction: settings.blendFunction,
uniforms: new Map([
["texture", new Uniform(null)]
])
});
/**
* The main scene.
*
* @type {Scene}
* @private
*/
this.scene = scene;
/**
* The main camera.
*
* @type {Camera}
* @private
*/
this.camera = camera;
/**
* The light source.
*
* @type {Object3D}
*/
this.lightSource = lightSource;
/**
* A scene that only contains the light source.
*
* @type {Scene}
* @private
*/
this.lightScene = new Scene();
/**
* The light position in screen space.
*
* @type {Vector3}
* @private
*/
this.screenPosition = new Vector2();
/**
* The original resolution.
*
* @type {Vector2}
* @private
*/
this.resolution = new Vector2();
/**
* A render target.
*
* @type {WebGLRenderTarget}
* @private
*/
this.renderTargetX = new WebGLRenderTarget(1, 1, {
minFilter: LinearFilter,
magFilter: LinearFilter,
stencilBuffer: false,
depthBuffer: false
});
this.renderTargetX.texture.name = "GodRays.TargetX";
this.renderTargetX.texture.generateMipmaps = false;
this.uniforms.get("texture").value = this.renderTargetX.texture;
/**
* A second render target.
*
* @type {WebGLRenderTarget}
* @private
*/
this.renderTargetY = this.renderTargetX.clone();
this.renderTargetY.texture.name = "GodRays.TargetY";
/**
* A render target for the masked light scene.
*
* @type {WebGLRenderTarget}
* @private
*/
this.renderTargetMask = new WebGLRenderTarget(1, 1, {
minFilter: LinearFilter,
magFilter: LinearFilter,
stencilBuffer: false
});
this.renderTargetMask.texture.name = "GodRays.Mask";
this.renderTargetMask.texture.generateMipmaps = false;
/**
* A pass that only renders the light source.
*
* @type {RenderPass}
* @private
*/
this.renderPassLight = new RenderPass(this.lightScene, camera, {
clearColor: new Color(0x000000)
});
/**
* A pass that renders the masked scene over the light source.
*
* @type {RenderPass}
* @private
*/
this.renderPassMask = new RenderPass(scene, camera, {
overrideMaterial: new MeshBasicMaterial({ color: 0x000000 })
});
this.renderPassMask.clear = false;
/**
* A blur pass.
*
* @type {BlurPass}
* @private
*/
this.blurPass = new BlurPass(settings);
/**
* A god rays pass.
*
* @type {ShaderPass}
* @private
*/
this.godRaysPass = new ShaderPass(new GodRaysMaterial(this.screenPosition, settings));
this.blur = settings.blur;
this.kernelSize = settings.kernelSize;
this.samples = settings.samples;
}
/**
* A texture that contains the intermediate result of this effect.
*
* This texture will be applied to the scene colors unless the blend function
* is set to `SKIP`.
*
* @type {Texture}
*/
get texture() {
return this.renderTargetX.texture;
}
/**
* The internal god rays material.
*
* @type {GodRaysMaterial}
*/
get godRaysMaterial() {
return this.godRaysPass.getFullscreenMaterial();
}
/**
* Indicates whether dithering is enabled.
*
* @type {Boolean}
*/
get dithering() {
return this.godRaysMaterial.dithering;
}
/**
* Enables or disables dithering.
*
* @type {Boolean}
*/
set dithering(value) {
const material = this.godRaysMaterial;
material.dithering = value;
material.needsUpdate = true;
}
/**
* Indicates whether the god rays should be blurred to reduce artifacts.
*
* @type {Boolean}
*/
get blur() {
return this.blurPass.enabled;
}
/**
* @type {Boolean}
*/
set blur(value) {
this.blurPass.enabled = value;
}
/**
* The blur kernel size.
*
* @type {KernelSize}
*/
get kernelSize() {
return this.blurPass.kernelSize;
}
/**
* @type {KernelSize}
*/
set kernelSize(value) {
this.blurPass.kernelSize = value;
}
/**
* Returns the current resolution scale.
*
* @return {Number} The resolution scale.
*/
getResolutionScale() {
return this.blurPass.getResolutionScale();
}
/**
* Sets the resolution scale.
*
* @param {Number} scale - The new resolution scale.
*/
setResolutionScale(scale) {
this.blurPass.setResolutionScale(scale);
this.setSize(this.resolution.x, this.resolution.y);
}
/**
* The number of samples per pixel.
*
* @type {Number}
*/
get samples() {
return this.godRaysMaterial.samples;
}
/**
* This value must be carefully chosen. A higher value improves quality but
* also increases the GPU load.
*
* @type {Number}
*/
set samples(value) {
this.godRaysMaterial.samples = value;
}
/**
* Updates this effect.
*
* @param {WebGLRenderer} renderer - The renderer.
* @param {WebGLRenderTarget} inputBuffer - A frame buffer that contains the result of the previous pass.
* @param {Number} [delta] - The time between the last frame and the current one in seconds.
*/
update(renderer, inputBuffer, delta) {
const scene = this.scene;
const lightSource = this.lightSource;
const renderTargetMask = this.renderTargetMask;
const renderTargetY = this.renderTargetY;
let background, parent;
// Compute the screen light position and translate it to [0.0, 1.0].
v.copy(lightSource.position).project(this.camera);
this.screenPosition.set(
Math.max(0.0, Math.min(1.0, (v.x + 1.0) * 0.5)),
Math.max(0.0, Math.min(1.0, (v.y + 1.0) * 0.5)),
);
parent = lightSource.parent;
background = scene.background;
scene.background = null;
this.lightScene.add(lightSource);
/* First, render the light source. Then render the scene into the same
buffer using a mask override material with depth test enabled. */
this.renderPassLight.render(renderer, renderTargetMask);
this.renderPassMask.render(renderer, renderTargetMask);
if(parent !== null) {
parent.add(lightSource);
}
scene.background = background;
inputBuffer = renderTargetMask;
if(this.blur) {
// Blur the masked scene to reduce artifacts.
this.blurPass.render(renderer, inputBuffer, renderTargetY);
inputBuffer = renderTargetY;
}
// Blur the masked scene along radial lines towards the light source.
this.godRaysPass.render(renderer, inputBuffer, this.renderTargetX);
}
/**
* Updates the size of internal render targets.
*
* @param {Number} width - The width.
* @param {Number} height - The height.
*/
setSize(width, height) {
this.resolution.set(width, height);
this.renderPassLight.setSize(width, height);
this.renderPassMask.setSize(width, height);
this.blurPass.setSize(width, height);
this.godRaysPass.setSize(width, height);
width = this.blurPass.width;
height = this.blurPass.height;
this.renderTargetMask.setSize(width, height);
this.renderTargetX.setSize(width, height);
this.renderTargetY.setSize(width, height);
}
/**
* Performs initialization tasks.
*
* @param {WebGLRenderer} renderer - The renderer.
* @param {Boolean} alpha - Whether the renderer uses the alpha channel or not.
*/
initialize(renderer, alpha) {
this.renderPassLight.initialize(renderer, alpha);
this.renderPassMask.initialize(renderer, alpha);
this.blurPass.initialize(renderer, alpha);
this.godRaysPass.initialize(renderer, alpha);
if(!alpha) {
this.renderTargetMask.texture.format = RGBFormat;
this.renderTargetX.texture.format = RGBFormat;
this.renderTargetY.texture.format = RGBFormat;
}
}
}