From 71cf0b1efad73c9e2a55b781c6765040da17728d Mon Sep 17 00:00:00 2001
From: Stanislav Fifik <standa.fifik@gmail.com>
Date: Fri, 12 Apr 2024 14:21:22 +0000
Subject: [PATCH] :sparkles: softedge

---
 src/nodes/WebGL/SoftEdge.ts | 152 ++++++++++++++++++++++++++++++++++++
 src/nodes/index.ts          |   1 +
 2 files changed, 153 insertions(+)
 create mode 100644 src/nodes/WebGL/SoftEdge.ts

diff --git a/src/nodes/WebGL/SoftEdge.ts b/src/nodes/WebGL/SoftEdge.ts
new file mode 100644
index 0000000..9b5eba4
--- /dev/null
+++ b/src/nodes/WebGL/SoftEdge.ts
@@ -0,0 +1,152 @@
+import WebGL from './WebGl';
+import {
+    ImageVar,
+    NumberVar
+} from '../io/AbstractIOSet';
+
+const inputs = {
+    image: {
+        type: 'Image',
+    } as ImageVar,
+    radius: {
+        type: 'Number',
+        default: 8,
+        min: 0,
+    } as NumberVar,
+    sigma: {
+        type: 'Number',
+        default: 1,
+        step: 0.1,
+        min: 0,
+    } as NumberVar,
+    passes: {
+        type: 'Number',
+        default: 1,
+    } as NumberVar,
+}
+
+
+const outputs = {
+    image: {
+        type: 'Image',
+    } as ImageVar,
+    width: {
+        type: 'Number',
+    } as NumberVar,
+    height: {
+        type: 'Number',
+    } as NumberVar
+}
+
+export default class SoftEdge extends WebGL<typeof inputs> {
+
+    _lastRadiusValue?: number;
+
+    constructor() {
+        super('SoftEdge', inputs)
+    }
+
+    _passes() {
+
+        const passes = Array(Math.max(this.in.passes.value, 0))
+            .fill(null)
+            .flatMap((x, i) => {
+                return [
+                    (gl, program) => {
+                        if (i === 0) {
+                            this._setParams(gl, program)
+                        }
+                        this._setDirection(gl, program, [1, 0]) // Horizontal SoftEdge
+                    },
+                    (gl, program) => {
+                        this._setDirection(gl, program, [0, 1]) // Vertical SoftEdge
+                    }
+                ]
+            });
+        return passes;
+    }
+
+    setup() {
+        if (this.in.radius.value !== this._lastRadiusValue) {
+            this.program = undefined;
+        }
+        super.setup();
+        this._lastRadiusValue = this.in.radius.value;
+    }
+
+    get frag() {
+        const RADIUS = Math.ceil(this.in.radius.value);
+        const KERNEL_SIZE = RADIUS + 1;
+        return `
+        precision mediump float;
+
+        const int RADIUS = ${RADIUS};
+        // Our texture
+        uniform sampler2D u_image;
+
+        uniform vec2 u_resolution;
+        uniform vec2 u_direction;
+        uniform vec2 u_textureSize;
+
+        uniform float u_kernel[${KERNEL_SIZE}];
+
+        // The texCoords passed in from the vertex shader.
+        varying vec2 v_texCoord;
+
+        void main() {
+            vec2 onePixel = vec2(1.0, 1.0) / u_textureSize;
+
+            float totalWeight = u_kernel[0]; // Center weight
+            vec4 colorSum = texture2D(u_image, v_texCoord) * totalWeight; // center pixel
+
+            for (int i = 1; i < ${KERNEL_SIZE}; i++) {
+                float weight = u_kernel[i];
+                totalWeight += weight * 2.0; // Consider both sides of the kernel
+                vec4 color1 = texture2D(u_image, v_texCoord + onePixel * (u_direction * float(i)));
+                vec4 color2 = texture2D(u_image, v_texCoord - onePixel * (u_direction * float(i)));
+                colorSum += vec4((color1 + color2).rgb, 2.0 * min(color1.a, color2.a)) * weight;
+            }
+
+            vec4 color = colorSum / totalWeight;
+            vec4 originalColor = texture2D(u_image, v_texCoord);
+            float alpha = min(color.a, texture2D(u_image, v_texCoord).a);
+            gl_FragColor = vec4(originalColor.rgb * alpha, alpha);
+        }
+        `
+    }
+
+    gaussian(x, sigma) {
+        const coeff = 1.0 / (2.0 * Math.PI * sigma * sigma);
+        const expon = -(x * x) / (2.0 * sigma * sigma);
+        return coeff * Math.exp(expon);
+    }
+
+    createGaussianKernel(radius, sigma) {
+        const kernelSize = radius + 1;
+        const kernel = new Float32Array(kernelSize);
+
+        for (let i = 0; i < kernelSize; i++) {
+            kernel[i] = this.gaussian(i, sigma);
+        }
+
+        return kernel;
+    }
+
+
+    _setDirection(gl: WebGLRenderingContext, program: WebGLProgram, direction: [number, number]) {
+        gl.uniform2f(gl.getUniformLocation(program, 'u_direction'), direction[0], direction[1]);
+    }
+
+    /**
+     *
+     * @param {WebGLRenderingContext} gl
+     * @param {*} program
+     */
+    _setParams(gl, program) {
+        const kernel = this.createGaussianKernel(
+            this.in.radius.value,
+            this.in.sigma.value,
+        )
+        gl.uniform1fv(gl.getUniformLocation(program, 'u_kernel'), kernel);
+    }
+}
\ No newline at end of file
diff --git a/src/nodes/index.ts b/src/nodes/index.ts
index 98ec11e..3fac825 100644
--- a/src/nodes/index.ts
+++ b/src/nodes/index.ts
@@ -17,6 +17,7 @@ export {default as GradientMap} from './WebGL/GradientMap';
 export {default as ColorLookupTable} from './WebGL/ColorLookupTable';
 export {default as Vignette} from './WebGL/Vignette';
 export {default as Blur} from './WebGL/Blur';
+export {default as SoftEdge} from './WebGL/SoftEdge';
 export {default as Edge} from './WebGL/Edge';
 export {default as KernelPreset} from './WebGL/KernelPreset';
 // Math