✨ multipass filter

src/nodes/WebGL/Blur.js

@@ -0,0 +1,82 @@
+import WebGL from './WebGl';
+
+
+export default class Blur extends WebGL {
+
+    constructor() {
+        super('Blur', {
+            amount: {
+                type: 'Number',
+                default: 0,
+            },
+        })
+    }
+
+    _passes() {
+        const passes = Array(this.in.amount.value)
+            .fill(null)
+            .map((x, i) => (gl, program) => this._setParams(gl, program));
+        return passes;
+    }
+
+    get frag() {
+        return `
+        precision mediump float;
+
+        // our texture
+        uniform sampler2D u_image;
+
+        uniform vec2 u_resolution;
+        uniform vec2 u_textureSize;
+
+        // the texCoords passed in from the vertex shader.
+        varying vec2 v_texCoord;
+
+        uniform float kernel[9];
+
+        void main() {
+            vec2 onePixel = vec2(1.0, 1.0) / u_textureSize;
+
+            float weight = kernel[0] +
+                kernel[1] +
+                kernel[2] +
+                kernel[3] +
+                kernel[4] +
+                kernel[5] +
+                kernel[6] +
+                kernel[7] +
+                kernel[8];
+
+            vec4 colorSum =
+                texture2D(u_image, v_texCoord + onePixel * vec2(-1, -1)) * kernel[0] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(0, -1)) * kernel[1] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(1, -1)) * kernel[2] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(-1, 0)) * kernel[3] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(0, 0)) * kernel[4] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(1, 0)) * kernel[5] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(-1, 1)) * kernel[6] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(0, 1)) * kernel[7] +
+                texture2D(u_image, v_texCoord + onePixel * vec2(1, 1)) * kernel[8];
+
+            gl_FragColor = colorSum / weight;
+        }
+        `
+    }
+
+    get amount() {
+        return this.in.amount.value;
+    }
+
+    /**
+     *
+     * @param {WebGLRenderingContext} gl
+     * @param {*} program
+     */
+    _setParams(gl, program) {
+        gl.uniform1fv(gl.getUniformLocation(program, 'kernel'), [
+            0.045, 0.122, 0.045,
+            0.122, 0.332, 0.122,
+            0.045, 0.122, 0.045
+        ]);
+    }
+}

src/nodes/WebGL/WebGl.js

@@ -30,10 +30,13 @@ export default class WebGL extends Node {
 
     get vert() {
         return `
+        precision mediump float;
         attribute vec2 a_position;
         attribute vec2 a_texCoord;
 
         uniform vec2 u_resolution;
+        uniform vec2 u_textureSize;
+        uniform float u_flip_y;
 
         varying vec2 v_texCoord;
 
@@ -47,7 +50,7 @@ export default class WebGL extends Node {
            // convert from 0->2 to -1->+1 (clipspace)
            vec2 clipSpace = zeroToTwo - 1.0;
 
-           gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);
+           gl_Position = vec4(clipSpace * vec2(1, u_flip_y), 0, 1);
 
            // pass the texCoord to the fragment shader
            // The GPU will interpolate this value between points.
@@ -133,6 +136,37 @@ export default class WebGL extends Node {
         return texture;
     }
 
+    _createFrameBuffer(gl, {width, height}) {
+        const texture = this.createTexture(gl);
+
+        const frameBuffer = gl.createFramebuffer();
+        gl.texImage2D(
+            gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0,
+            gl.RGBA, gl.UNSIGNED_BYTE, null);
+
+        gl.bindFramebuffer(gl.FRAMEBUFFER, frameBuffer);
+        gl.framebufferTexture2D(
+            gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
+        return {frameBuffer, texture};
+    }
+
+    _passes() {
+        return [
+            (gl, program, image) => {
+                console.log('pass1')
+                this._setParams(gl, program);
+            },
+            (gl, program, image) => {
+                console.log('pass2')
+                this._setParams(gl, program);
+            },
+            (gl, program, image) => {
+                console.log('pass3')
+                this._setParams(gl, program);
+            }
+        ]
+    }
+
     _setParams(gl, program) {
 
     }
@@ -146,7 +180,6 @@ export default class WebGL extends Node {
         if (!this.program) {
             this.program = this.compileProgram(gl);
             gl.useProgram(this.program);
-            this.createTexture(gl);
         }
     }
 
@@ -161,6 +194,7 @@ export default class WebGL extends Node {
         if (width === 0 || height === 0) {
             return;
         }
+
         this.setup();
         const canvas = this.canvas;
         canvas.width = width;
@@ -169,6 +203,14 @@ export default class WebGL extends Node {
         const gl = canvas.getContext('webgl');
         const program = this.program;
 
+        const frameBuffers = [
+            this._createFrameBuffer(gl, {width, height}),
+            this._createFrameBuffer(gl, {width, height}),
+        ];
+        gl.bindFramebuffer(gl.FRAMEBUFFER, null);
+
+        this.createTexture(gl);
+
         gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
         gl.clearColor(0, 0, 0, 0);
         gl.clear(gl.COLOR_BUFFER_BIT);
@@ -177,13 +219,13 @@ export default class WebGL extends Node {
         const positionLocation = gl.getAttribLocation(program, "a_position");
         const texcoordLocation = gl.getAttribLocation(program, "a_texCoord");
         const resolutionLocation = gl.getUniformLocation(program, "u_resolution");
+        const flipLocation = gl.getUniformLocation(program, "u_flip_y");
 
         if (this.image) {
             // Upload the image into the texture.
             gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, await createImageBitmap(this.image));
         }
 
-
         const texcoordBuffer = gl.createBuffer();
         gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
         gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
@@ -226,14 +268,28 @@ export default class WebGL extends Node {
         gl.vertexAttribPointer(
             texcoordLocation, size, type, normalize, stride, offset);
 
+        const passes = this._passes();
+        for (let iter = 0; iter < passes.length; iter++) {
+            const frameBuffer = frameBuffers[iter%2];
+            if (iter === passes.length -1) { // last
+                gl.bindFramebuffer(gl.FRAMEBUFFER, null);
+                gl.uniform1f(flipLocation, -1);
+            } else {
+                gl.uniform1f(flipLocation, 1);
+                gl.bindFramebuffer(gl.FRAMEBUFFER, frameBuffer.frameBuffer);
+            }
+
+            passes[iter](gl, program);
             // set the resolution
             gl.uniform2f(resolutionLocation, gl.canvas.width, gl.canvas.height);
-
-        this._setParams(gl, program);
+            gl.uniform2f(gl.getUniformLocation(program, "u_textureSize"), width, height);
 
             // Draw the rectangle.
             gl.drawArrays(gl.TRIANGLES, 0, 6);
 
+            gl.bindTexture(gl.TEXTURE_2D, frameBuffer.texture);
+        }
+
         const resultCanvas = canvasPool2D.createCanvas();
         resultCanvas.width = 1;
         resultCanvas.height = 1;

src/nodes/index.js

@@ -11,7 +11,8 @@ export {default as BrightnessContrast} from './WebGL/BrightnessContrast';
 export {default as HSV} from './WebGL/HSV';
 export {default as Sepia} from './WebGL/Sepia';
 export {default as GreenScreen} from './WebGL/Greenscreen';
-export {default as Channels} from './WebGL/Channels'
+export {default as Channels} from './WebGL/Channels';
+export {default as Blur} from './WebGL/Blur';
 // Math
 export {default as Numbers} from './Math/Numbers';
 export {default as NumberBinaryOperation} from './Math/NumberBinaryOperation';