playcanvas/scripts/posteffects/posteffect-verticaltiltshift.js

PlayCanvas WebGL game engine

// --------------- 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.
 */
function VerticalTiltShiftEffect(graphicsDevice) {
    pc.PostEffect.call(this, graphicsDevice);

    // Shader author: alteredq / http://alteredqualia.com/
    var fshader = [
        '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;',
        '}'
    ].join('\n');

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

    // uniforms
    this.focus = 0.35;
}

VerticalTiltShiftEffect.prototype = Object.create(pc.PostEffect.prototype);
VerticalTiltShiftEffect.prototype.constructor = VerticalTiltShiftEffect;

Object.assign(VerticalTiltShiftEffect.prototype, {
    render: function (inputTarget, outputTarget, rect) {
        var device = this.device;
        var 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);
    });
};