playcanvas/scripts/posteffects/posteffect-verticaltiltshift.js

Open-source WebGL/WebGPU 3D engine for the web

// --------------- POST EFFECT DEFINITION --------------- //
/**
 * @class
 * @name VerticalTiltShiftEffect
 * @classdesc Simple fake tilt-shift effect, modulating two pass Gaussian blur by vertical position.
 * @description Creates new instance of the post effect.
 * @augments PostEffect
 * @param {GraphicsDevice} graphicsDevice - The graphics device of the application.
 * @property {number} focus Controls where the "focused" horizontal line lies.
 */
class VerticalTiltShiftEffect extends pc.PostEffect {
    constructor(graphicsDevice) {
        super(graphicsDevice);

        // Shader author: alteredq / http://alteredqualia.com/
        const fshader = /* glsl */`
            uniform sampler2D uColorBuffer;
            uniform float uV;
            uniform float uR;

            varying vec2 vUv0;

            void main() {
                vec4 sum = vec4( 0.0 );
                float vv = uV * abs( uR - vUv0.y );

                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y - 4.0 * vv ) ) * 0.051;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y - 3.0 * vv ) ) * 0.0918;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y - 2.0 * vv ) ) * 0.12245;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y - 1.0 * vv ) ) * 0.1531;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y ) ) * 0.1633;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y + 1.0 * vv ) ) * 0.1531;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y + 2.0 * vv ) ) * 0.12245;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y + 3.0 * vv ) ) * 0.0918;
                sum += texture2D( uColorBuffer, vec2( vUv0.x, vUv0.y + 4.0 * vv ) ) * 0.051;

                gl_FragColor = sum;
            }
        `;

        this.shader = pc.ShaderUtils.createShader(graphicsDevice, {
            uniqueName: 'VerticalTiltShiftShader',
            attributes: { aPosition: pc.SEMANTIC_POSITION },
            vertexGLSL: pc.PostEffect.quadVertexShader,
            fragmentGLSL: fshader
        });

        // uniforms
        this.focus = 0.35;
    }

    render(inputTarget, outputTarget, rect) {
        const device = this.device;
        const scope = device.scope;

        scope.resolve('uV').setValue(1 / inputTarget.height);
        scope.resolve('uR').setValue(this.focus);
        scope.resolve('uColorBuffer').setValue(inputTarget.colorBuffer);
        this.drawQuad(outputTarget, this.shader, rect);
    }
}

// ----------------- SCRIPT DEFINITION ------------------ //
var VerticalTiltShift = pc.createScript('verticalTiltShift');

VerticalTiltShift.attributes.add('focus', {
    type: 'number',
    default: 0.35,
    min: 0,
    max: 1,
    title: 'Focus'
});

// initialize code called once per entity
VerticalTiltShift.prototype.initialize = function () {
    this.effect = new VerticalTiltShiftEffect(this.app.graphicsDevice);
    this.effect.focus = this.focus;

    this.on('attr:focus', function (value) {
        this.effect.focus = value;
    }, this);

    var queue = this.entity.camera.postEffects;
    queue.addEffect(this.effect);

    this.on('state', function (enabled) {
        if (enabled) {
            queue.addEffect(this.effect);
        } else {
            queue.removeEffect(this.effect);
        }
    });

    this.on('destroy', function () {
        queue.removeEffect(this.effect);
    });
};