Come ottenere un effetto shader "Glow" in OpenGL ES 2.0?

Question

Sto scrivendo un'app 3D per iOS. Sono nuovo di OpenGL ES 2.0, quindi sto ancora imparando a scrivere shader di base. Ho davvero bisogno di implementare un effetto "Glow" su alcuni dei miei modelli, basato sulla texturing.

Ecco un esempio:

.

Sto cercando esempi di codice per OpenGL ES 2.0. La maggior parte del codice che trovo su internet è o per desktop OpenGL o D3D.

Qualche idea?

Answer 1

Il sito Web GLSL Sandbox ha una raccolta di esempi di shader. This one has the glow and appears to be able to compile for ES.

Dovresti essere in grado di modificarli per estrarre gli uv dalla texture.

Ecco some code directly from this site:

#ifdef GL_ES 
precision mediump float; 
#endif 

#extension GL_OES_standard_derivatives : enable 

uniform float time; 
uniform vec2 mouse; 
uniform vec2 resolution; 

void main(void){ 

    vec2 p = (gl_FragCoord.xy * 2.0 - resolution)/min(resolution.x, resolution.y); 
    vec3 color1 = vec3(0.0, 0.3, 0.5); 
    vec3 color2 = vec3(0.5, 0.0, 0.3); 

    float f = 0.0; 
    float g = 0.0; 
    float h = 0.0; 
    float PI = 3.14159265; 
    for(float i = 0.0; i < 40.0; i++){ 
     if (floor(mouse.x * 41.0) < i) 
      break; 
     float s = sin(time + i * PI/20.0) * 0.8; 
     float c = cos(time + i * PI/20.0) * 0.8; 
     float d = abs(p.x + c); 
     float e = abs(p.y + s); 
     f += 0.001/d; 
     g += 0.001/e; 
     h += 0.00003/(d * e); 
    } 


    gl_FragColor = vec4(f * color1 + g * color2 + vec3(h), 1.0); 
} 

Answer 2

Prima di tutto ci sono tonnellate di algoritmi e tecniche per generare un effetto di bagliore. Voglio solo presentare una possibilità.

Per prima cosa è necessario creare un materiale auto-luminoso. Per questo uso un modello di luce blinn-phong modificato, in cui la direzione della sorgente di luce è sempre la direzione inversa del vettore normale del frammento.

varying vec3 vertPos; 
varying vec3 vertNV; 
varying vec3 vertCol; 

void main() 
{ 
    vec3 color = vertCol; 

    float shininess = 10.0; 
    vec3 normalV = normalize(vertNV); 
    vec3 eyeV = normalize(-vertPos); 
    vec3 halfV = normalize(eyeV + normalV); 
    float NdotH = max(0.0, dot(normalV, halfV)); 
    float glowFac = (shininess + 2.0) * pow(NdotH, shininess)/(2.0 * 3.14159265); 

    gl_FragColor = vec4(color.rgb * (0.5 + glowFac), 1.0); 
} 

In una seconda fase viene eseguito un algoritmo di sfocatura gaussiana sull'output. La scena viene scritta sul frame buffer con una texture associata al piano del colore. Un passaggio dello spazio sullo schermo utilizza la trama come input per rendere sfocato l'output.
Per motivi di prestazioni, l'algoritmo di sfocatura viene prima eseguito lungo l'asse X della finestra e in un ulteriore passaggio lungo l'asse Y della finestra.
Una descrizione dettagliata dell'algoritmo di sfocatura è disponibile alla risposta alla domanda OpenGL es 2.0 Gaussian blur on triangle.

varying vec2 vertPos; 
uniform sampler2D u_textureCol; 
uniform vec2 u_textureSize; 
uniform float u_sigma; 
uniform int u_width; 

float CalcGauss(float x, float sigma) 
{ 
    float coeff = 1.0/(2.0 * 3.14157 * sigma); 
    float expon = -(x*x)/(2.0 * sigma); 
    return (coeff*exp(expon)); 
} 

void main() 
{ 
    vec2 texC = vertPos.st * 0.5 + 0.5; 
    vec4 texCol = texture(u_textureCol, texC); 
    vec4 gaussCol = vec4(texCol.rgb, 1.0); 
    vec2 step = 1.0/u_textureSize; 
    for (int i = 1; i <= u_width; ++ i) 
    { 
     vec2 actStep = vec2(float(i) * step.x, 0.0); // this is for the X-axis 
     // vec2 actStep = vec2(0.0, float(i) * step.y); this would be for the Y-axis 

     float weight = CalcGauss(float(i)/float(u_width), u_sigma); 
     texCol = texture2D(u_textureCol, texC + actStep);  
     gaussCol += vec4(texCol.rgb * weight, weight); 
     texCol = texture2D(u_textureCol, texC - actStep); 
     gaussCol += vec4(texCol.rgb * weight, weight); 
    } 
    gaussCol.rgb /= gaussCol.w; 
    gl_FragColor = vec4(gaussCol.rgb, 1.0); 
} 

Vedi anche le risposte alla seguente domanda:

• OpenGL es 2.0 Gaussian blur on triangle
• What kind of blurs can be implemented in pixel shaders?

Vedere il seguente esempio WebGL simile che mette tutto insieme:

var readInput = true; 
 
function changeEventHandler(event){ 
 
    readInput = true; 
 
} 
 
    
 
(function loadscene() { 
 
    
 
    var resize, gl, progDraw, progBlurX, progPost, vp_size, blurFB; 
 
    var bufCube = {}; 
 
    var bufQuad = {}; 
 
    var shininess = 10.0; 
 
    var glow = 10.0; 
 
    var sigma = 0.8; 
 
    
 
    function render(delteMS){ 
 

 
     if (readInput) { 
 
      readInput = false; 
 
      var sliderScale = 100; 
 
      shininess = document.getElementById("shine").value; 
 
      glow  = document.getElementById("glow").value/sliderScale; 
 
      sigma  = document.getElementById("sigma").value/sliderScale; 
 
     } 
 

 
     Camera.create(); 
 
     Camera.vp = vp_size; 
 
      
 
     gl.enable(gl.DEPTH_TEST); 
 
     gl.clearColor(0.0, 0.0, 0.0, 1.0); 
 
     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); 
 

 
     // set up framebuffer 
 
     gl.bindFramebuffer(gl.FRAMEBUFFER, blurFB[0]); 
 
     gl.viewport(0, 0, blurFB[0].width, blurFB[0].height); 
 
     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); 
 
    
 
     // set up draw shader 
 
     ShaderProgram.Use(progDraw.prog); 
 
     ShaderProgram.SetUniformM44(progDraw.prog, "u_projectionMat44", Camera.Perspective()); 
 
     ShaderProgram.SetUniformM44(progDraw.prog, "u_viewMat44", Camera.LookAt()); 
 
     var modelMat = IdentityMat44() 
 
     modelMat = RotateAxis(modelMat, CalcAng(delteMS, 13.0), 0); 
 
     modelMat = RotateAxis(modelMat, CalcAng(delteMS, 17.0), 1); 
 
     ShaderProgram.SetUniformM44(progDraw.prog, "u_modelMat44", modelMat); 
 
     ShaderProgram.SetUniformF1(progDraw.prog, "u_shininess", shininess); 
 
     ShaderProgram.SetUniformF1(progDraw.prog, "u_glow", glow); 
 
     
 
     // draw scene 
 
     VertexBuffer.Draw(bufCube); 
 

 
     // set blur-X framebuffer and bind frambuffer texture 
 
     gl.bindFramebuffer(gl.FRAMEBUFFER, blurFB[1]); 
 
     gl.viewport(0, 0, blurFB[1].width, blurFB[1].height); 
 
     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); 
 
     var texUnit = 1; 
 
     gl.activeTexture(gl.TEXTURE0 + texUnit); 
 
     gl.bindTexture(gl.TEXTURE_2D, blurFB[0].color0_texture); 
 

 
     // set up blur-X shader 
 
     ShaderProgram.Use(progBlurX.prog); 
 
     ShaderProgram.SetUniformI1(progBlurX.prog , "u_texture", texUnit) 
 
     ShaderProgram.SetUniformF2(progBlurX.prog , "u_textureSize", vp_size); 
 
     ShaderProgram.SetUniformF1(progBlurX.prog , "u_sigma", sigma) 
 

 
     // draw full screen space 
 
     gl.enableVertexAttribArray(progBlurX.inPos); 
 
     gl.bindBuffer(gl.ARRAY_BUFFER, bufQuad.pos); 
 
     gl.vertexAttribPointer(progBlurX.inPos, 2, gl.FLOAT, false, 0, 0); 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx); 
 
     gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0); 
 
     gl.disableVertexAttribArray(progBlurX.inPos); 
 

 
     // reset framebuffer and bind frambuffer texture 
 
     gl.bindFramebuffer(gl.FRAMEBUFFER, null); 
 
     gl.viewport(0, 0, vp_size[0], vp_size[1]); 
 
     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); 
 
     texUnit = 2; 
 
     gl.activeTexture(gl.TEXTURE0 + texUnit); 
 
     gl.bindTexture(gl.TEXTURE_2D, blurFB[1].color0_texture); 
 

 
     // set up pst process shader 
 
     ShaderProgram.Use(progPost.prog); 
 
     ShaderProgram.SetUniformI1(progPost.prog, "u_texture", texUnit) 
 
     ShaderProgram.SetUniformF2(progPost.prog, "u_textureSize", vp_size); 
 
     ShaderProgram.SetUniformF1(progPost.prog, "u_sigma", sigma); 
 

 
     // draw full screen space 
 
     gl.enableVertexAttribArray(progPost.inPos); 
 
     gl.bindBuffer(gl.ARRAY_BUFFER, bufQuad.pos); 
 
     gl.vertexAttribPointer(progPost.inPos, 2, gl.FLOAT, false, 0, 0); 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx); 
 
     gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0); 
 
     gl.disableVertexAttribArray(progPost.inPos); 
 

 
     requestAnimationFrame(render); 
 
    } 
 
    
 
    function resize() { 
 
     //vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight]; 
 
     vp_size = [window.innerWidth, window.innerHeight] 
 
     canvas.width = vp_size[0]; 
 
     canvas.height = vp_size[1]; 
 

 
     var fbsize = Math.max(vp_size[0], vp_size[1])-1; 
 
     fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2 
 
     fbsize = fbsize * 2 
 

 
     blurFB = []; 
 
     for (var i = 0; i < 2; ++ i) { 
 
      fb = gl.createFramebuffer(); 
 
      fb.width = fbsize; 
 
      fb.height = fbsize; 
 
      gl.bindFramebuffer(gl.FRAMEBUFFER, fb); 
 
      fb.color0_texture = gl.createTexture(); 
 
      gl.bindTexture(gl.TEXTURE_2D, fb.color0_texture); 
 
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST); 
 
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST); 
 
      gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, fb.width, fb.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null); 
 
      fb.renderbuffer = gl.createRenderbuffer(); 
 
      gl.bindRenderbuffer(gl.RENDERBUFFER, fb.renderbuffer); 
 
      gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, fb.width, fb.height); 
 
      gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, fb.color0_texture, 0); 
 
      gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, fb.renderbuffer); 
 
      gl.bindTexture(gl.TEXTURE_2D, null); 
 
      gl.bindRenderbuffer(gl.RENDERBUFFER, null); 
 
      gl.bindFramebuffer(gl.FRAMEBUFFER, null); 
 
      blurFB.push(fb); 
 
     } 
 
    } 
 
    
 
    function initScene() { 
 
    
 
     canvas = document.getElementById("canvas"); 
 
     gl = canvas.getContext("experimental-webgl"); 
 
     if (!gl) 
 
     return null; 
 
    
 
     progDraw = {} 
 
     progDraw.prog = ShaderProgram.Create( 
 
     [ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER }, 
 
      { source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER } 
 
     ]); 
 
     if (!progDraw.prog) 
 
      return null; 
 
     progDraw.inPos = gl.getAttribLocation(progDraw.prog, "inPos"); 
 
     progDraw.inNV = gl.getAttribLocation(progDraw.prog, "inNV"); 
 
     progDraw.inCol = gl.getAttribLocation(progDraw.prog, "inCol"); 
 

 
     progBlurX = {} 
 
     progBlurX.prog = ShaderProgram.Create( 
 
     [ { source : "post-shader-vs", stage : gl.VERTEX_SHADER }, 
 
      { source : "blurX-shader-fs", stage : gl.FRAGMENT_SHADER } 
 
     ]); 
 
     progBlurX.inPos = gl.getAttribLocation(progBlurX.prog, "inPos"); 
 
     if (!progBlurX.prog) 
 
      return;  
 

 
     progPost = {} 
 
     progPost.prog = ShaderProgram.Create( 
 
     [ { source : "post-shader-vs", stage : gl.VERTEX_SHADER }, 
 
      { source : "blurY-shader-fs", stage : gl.FRAGMENT_SHADER } 
 
     ]); 
 
     progPost.inPos = gl.getAttribLocation(progPost.prog, "inPos"); 
 
     if (!progPost.prog) 
 
      return; 
 
     
 
     // create cube 
 
     var cubePos = [ 
 
     -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 
 
     -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0 ]; 
 
     var cubeCol = [ 1.0, 0.0, 0.0, 1.0, 0.5, 0.0, 1.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0 ]; 
 
     var cubeHlpInx = [ 0, 1, 2, 3, 1, 5, 6, 2, 5, 4, 7, 6, 4, 0, 3, 7, 3, 2, 6, 7, 1, 0, 4, 5 ]; 
 
     var cubePosData = []; 
 
     for (var i = 0; i < cubeHlpInx.length; ++ i) { 
 
     cubePosData.push(cubePos[cubeHlpInx[i]*3], cubePos[cubeHlpInx[i]*3+1], cubePos[cubeHlpInx[i]*3+2]); 
 
     } 
 
     var cubeNVData = []; 
 
     for (var i1 = 0; i1 < cubeHlpInx.length; i1 += 4) { 
 
     var nv = [0, 0, 0]; 
 
     for (i2 = 0; i2 < 4; ++ i2) { 
 
      var i = i1 + i2; 
 
      nv[0] += cubePosData[i*3]; nv[1] += cubePosData[i*3+1]; nv[2] += cubePosData[i*3+2]; 
 
     } 
 
     for (i2 = 0; i2 < 4; ++ i2) 
 
     cubeNVData.push(nv[0], nv[1], nv[2]); 
 
     } 
 
     var cubeColData = []; 
 
     for (var is = 0; is < 6; ++ is) { 
 
     for (var ip = 0; ip < 4; ++ ip) { 
 
     cubeColData.push(cubeCol[is*3], cubeCol[is*3+1], cubeCol[is*3+2]); 
 
     } 
 
     } 
 
     var cubeInxData = []; 
 
     for (var i = 0; i < cubeHlpInx.length; i += 4) { 
 
     cubeInxData.push(i, i+1, i+2, i, i+2, i+3); 
 
     } 
 
     bufCube = VertexBuffer.Create(
 
     [ { data : cubePosData, attrSize : 3, attrLoc : progDraw.inPos }, 
 
     { data : cubeNVData, attrSize : 3, attrLoc : progDraw.inNV }, 
 
     { data : cubeColData, attrSize : 3, attrLoc : progDraw.inCol } ], 
 
     cubeInxData); 
 

 
     bufQuad.pos = gl.createBuffer(); 
 
     gl.bindBuffer(gl.ARRAY_BUFFER, bufQuad.pos); 
 
     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([ -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0 ]), gl.STATIC_DRAW); 
 
     bufQuad.inx = gl.createBuffer(); 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx); 
 
     gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array([ 0, 1, 2, 0, 2, 3 ]), gl.STATIC_DRAW); 
 
     
 
     window.onresize = resize; 
 
     resize(); 
 
     requestAnimationFrame(render); 
 
    } 
 
    
 
    function Fract(val) { 
 
     return val - Math.trunc(val); 
 
    } 
 
    function CalcAng(deltaTime, intervall) { 
 
     return Fract(deltaTime/(1000*intervall)) * 2.0 * Math.PI; 
 
    } 
 
    function CalcMove(deltaTime, intervall, range) { 
 
     var pos = self.Fract(deltaTime/(1000*intervall)) * 2.0 
 
     var pos = pos < 1.0 ? pos : (2.0-pos) 
 
     return range[0] + (range[1] - range[0]) * pos; 
 
    }  
 
    function EllipticalPosition(a, b, angRag) { 
 
     var a_b = a * a - b * b 
 
     var ea = (a_b <= 0) ? 0 : Math.sqrt(a_b); 
 
     var eb = (a_b >= 0) ? 0 : Math.sqrt(-a_b); 
 
     return [ a * Math.sin(angRag) - ea, b * Math.cos(angRag) - eb, 0 ]; 
 
    } 
 
    
 
    glArrayType = typeof Float32Array !="undefined" ? Float32Array : (typeof WebGLFloatArray != "undefined" ? WebGLFloatArray : Array); 
 
    
 
    function IdentityMat44() { 
 
    var m = new glArrayType(16); 
 
    m[0] = 1; m[1] = 0; m[2] = 0; m[3] = 0; 
 
    m[4] = 0; m[5] = 1; m[6] = 0; m[7] = 0; 
 
    m[8] = 0; m[9] = 0; m[10] = 1; m[11] = 0; 
 
    m[12] = 0; m[13] = 0; m[14] = 0; m[15] = 1; 
 
    return m; 
 
    }; 
 
    
 
    function RotateAxis(matA, angRad, axis) { 
 
     var aMap = [ [1, 2], [2, 0], [0, 1] ]; 
 
     var a0 = aMap[axis][0], a1 = aMap[axis][1]; 
 
     var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad); 
 
     var matB = new glArrayType(16); 
 
     for (var i = 0; i < 16; ++ i) matB[i] = matA[i]; 
 
     for (var i = 0; i < 3; ++ i) { 
 
      matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng; 
 
      matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng; 
 
     } 
 
     return matB; 
 
    } 
 
    
 
    function Cross(a, b) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; } 
 
    function Dot(a, b) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; } 
 
    function Normalize(v) { 
 
     var len = Math.sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]); 
 
     return [ v[0]/len, v[1]/len, v[2]/len ]; 
 
    } 
 
    
 
    var Camera = {}; 
 
    Camera.create = function() { 
 
     this.pos = [0, 3, 0.0]; 
 
     this.target = [0, 0, 0]; 
 
     this.up  = [0, 0, 1]; 
 
     this.fov_y = 90; 
 
     this.vp  = [800, 600]; 
 
     this.near = 0.5; 
 
     this.far = 100.0; 
 
    } 
 
    Camera.Perspective = function() { 
 
     var fn = this.far + this.near; 
 
     var f_n = this.far - this.near; 
 
     var r = this.vp[0]/this.vp[1]; 
 
     var t = 1/Math.tan(Math.PI * this.fov_y/360); 
 
     var m = IdentityMat44(); 
 
     m[0] = t/r; m[1] = 0; m[2] = 0;        m[3] = 0; 
 
     m[4] = 0; m[5] = t; m[6] = 0;        m[7] = 0; 
 
     m[8] = 0; m[9] = 0; m[10] = -fn/f_n;      m[11] = -1; 
 
     m[12] = 0; m[13] = 0; m[14] = -2 * this.far * this.near/f_n; m[15] = 0; 
 
     return m; 
 
    } 
 
    Camera.LookAt = function() { 
 
     var mz = Normalize([ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ]); 
 
     var mx = Normalize(Cross(this.up, mz)); 
 
     var my = Normalize(Cross(mz, mx)); 
 
     var tx = Dot(mx, this.pos); 
 
     var ty = Dot(my, this.pos); 
 
     var tz = Dot([-mz[0], -mz[1], -mz[2]], this.pos); 
 
     var m = IdentityMat44(); 
 
     m[0] = mx[0]; m[1] = my[0]; m[2] = mz[0]; m[3] = 0; 
 
     m[4] = mx[1]; m[5] = my[1]; m[6] = mz[1]; m[7] = 0; 
 
     m[8] = mx[2]; m[9] = my[2]; m[10] = mz[2]; m[11] = 0; 
 
     m[12] = tx; m[13] = ty; m[14] = tz; m[15] = 1; 
 
     return m; 
 
    } 
 
    
 
    var ShaderProgram = {}; 
 
    ShaderProgram.Create = function(shaderList) { 
 
     var shaderObjs = []; 
 
     for (var i_sh = 0; i_sh < shaderList.length; ++ i_sh) { 
 
      var shderObj = this.CompileShader(shaderList[i_sh].source, shaderList[i_sh].stage); 
 
      if (shderObj == 0) 
 
       return 0; 
 
      shaderObjs.push(shderObj); 
 
     } 
 
     var progObj = this.LinkProgram(shaderObjs) 
 
     if (progObj != 0) { 
 
      progObj.attribIndex = {}; 
 
      var noOfAttributes = gl.getProgramParameter(progObj, gl.ACTIVE_ATTRIBUTES); 
 
      for (var i_n = 0; i_n < noOfAttributes; ++ i_n) { 
 
       var name = gl.getActiveAttrib(progObj, i_n).name; 
 
       progObj.attribIndex[name] = gl.getAttribLocation(progObj, name); 
 
      } 
 
      progObj.unifomLocation = {}; 
 
      var noOfUniforms = gl.getProgramParameter(progObj, gl.ACTIVE_UNIFORMS); 
 
      for (var i_n = 0; i_n < noOfUniforms; ++ i_n) { 
 
       var name = gl.getActiveUniform(progObj, i_n).name; 
 
       progObj.unifomLocation[name] = gl.getUniformLocation(progObj, name); 
 
      } 
 
     } 
 
     return progObj; 
 
    } 
 
    ShaderProgram.AttributeIndex = function(progObj, name) { return progObj.attribIndex[name]; } 
 
    ShaderProgram.UniformLocation = function(progObj, name) { return progObj.unifomLocation[name]; } 
 
    ShaderProgram.Use = function(progObj) { gl.useProgram(progObj); } 
 
    ShaderProgram.SetUniformI1 = function(progObj, name, val) { if(progObj.unifomLocation[name]) gl.uniform1i(progObj.unifomLocation[name], val); } 
 
    ShaderProgram.SetUniformF1 = function(progObj, name, val) { if(progObj.unifomLocation[name]) gl.uniform1f(progObj.unifomLocation[name], val); } 
 
    ShaderProgram.SetUniformF2 = function(progObj, name, arr) { if(progObj.unifomLocation[name]) gl.uniform2fv(progObj.unifomLocation[name], arr); } 
 
    ShaderProgram.SetUniformF3 = function(progObj, name, arr) { if(progObj.unifomLocation[name]) gl.uniform3fv(progObj.unifomLocation[name], arr); } 
 
    ShaderProgram.SetUniformF4 = function(progObj, name, arr) { if(progObj.unifomLocation[name]) gl.uniform4fv(progObj.unifomLocation[name], arr); } 
 
    ShaderProgram.SetUniformM33 = function(progObj, name, mat) { if(progObj.unifomLocation[name]) gl.uniformMatrix3fv(progObj.unifomLocation[name], false, mat); } 
 
    ShaderProgram.SetUniformM44 = function(progObj, name, mat) { if(progObj.unifomLocation[name]) gl.uniformMatrix4fv(progObj.unifomLocation[name], false, mat); } 
 
    ShaderProgram.CompileShader = function(source, shaderStage) { 
 
     var shaderScript = document.getElementById(source); 
 
     if (shaderScript) 
 
     source = shaderScript.text; 
 
     var shaderObj = gl.createShader(shaderStage); 
 
     gl.shaderSource(shaderObj, source); 
 
     gl.compileShader(shaderObj); 
 
     var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS); 
 
     if (!status) alert(gl.getShaderInfoLog(shaderObj)); 
 
     return status ? shaderObj : null; 
 
    } 
 
    ShaderProgram.LinkProgram = function(shaderObjs) { 
 
     var prog = gl.createProgram(); 
 
     for (var i_sh = 0; i_sh < shaderObjs.length; ++ i_sh) 
 
      gl.attachShader(prog, shaderObjs[i_sh]); 
 
     gl.linkProgram(prog); 
 
     status = gl.getProgramParameter(prog, gl.LINK_STATUS); 
 
     if (!status) alert("Could not initialise shaders"); 
 
     gl.useProgram(null); 
 
     return status ? prog : null; 
 
    } 
 
    
 
    var VertexBuffer = {}; 
 
    VertexBuffer.Create = function(attributes, indices) { 
 
     var buffer = {}; 
 
     buffer.buf = []; 
 
     buffer.attr = [] 
 
     for (var i = 0; i < attributes.length; ++ i) { 
 
      buffer.buf.push(gl.createBuffer()); 
 
      buffer.attr.push({ size : attributes[i].attrSize, loc : attributes[i].attrLoc }); 
 
      gl.bindBuffer(gl.ARRAY_BUFFER, buffer.buf[i]); 
 
      gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(attributes[i].data), gl.STATIC_DRAW); 
 
     } 
 
     buffer.inx = gl.createBuffer(); 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffer.inx); 
 
     gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(indices), gl.STATIC_DRAW); 
 
     buffer.inxLen = indices.length; 
 
     gl.bindBuffer(gl.ARRAY_BUFFER, null); 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null); 
 
     return buffer; 
 
    } 
 
    VertexBuffer.Draw = function(bufObj) { 
 
    for (var i = 0; i < bufObj.buf.length; ++ i) { 
 
      gl.bindBuffer(gl.ARRAY_BUFFER, bufObj.buf[i]); 
 
      gl.vertexAttribPointer(bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0); 
 
      gl.enableVertexAttribArray(bufObj.attr[i].loc); 
 
     } 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufObj.inx); 
 
     gl.drawElements(gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0); 
 
     for (var i = 0; i < bufObj.buf.length; ++ i) 
 
     gl.disableVertexAttribArray(bufObj.attr[i].loc); 
 
     gl.bindBuffer(gl.ARRAY_BUFFER, null); 
 
     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null); 
 
    } 
 
    
 
    initScene(); 
 
    
 
})();

html,body { 
 
    height: 100%; 
 
    width: 100%; 
 
    margin: 0; 
 
    overflow: hidden; 
 
} 
 

 
#gui { 
 
    position : absolute; 
 
    top : 0; 
 
    left : 0; 
 
}

<script id="draw-shader-vs" type="x-shader/x-vertex"> 
 
    precision highp float; 
 
    
 
    attribute vec3 inPos; 
 
    attribute vec3 inNV; 
 
    attribute vec3 inCol; 
 
    
 
    varying vec3 vertPos; 
 
    varying vec3 vertNV; 
 
    varying vec3 vertCol; 
 
    
 
    uniform mat4 u_projectionMat44; 
 
    uniform mat4 u_viewMat44; 
 
    uniform mat4 u_modelMat44; 
 
    
 
    void main() 
 
    { 
 
     mat4 mv  = u_viewMat44 * u_modelMat44; 
 
     vertCol  = inCol; 
 
     vertNV  = normalize(mat3(mv) * inNV); 
 
     vec4 viewPos = mv * vec4(inPos, 1.0); 
 
     vertPos  = viewPos.xyz; 
 
     gl_Position = u_projectionMat44 * viewPos; 
 
    } 
 
</script> 
 
    
 
<script id="draw-shader-fs" type="x-shader/x-fragment"> 
 
    precision mediump float; 
 

 
    varying vec3 vertPos; 
 
    varying vec3 vertNV; 
 
    varying vec3 vertCol; 
 
    
 
    uniform float u_shininess; 
 
    uniform float u_glow; 
 
    
 
    void main() 
 
    { 
 
     vec3 color = vertCol; 
 
     vec3 normalV = normalize(vertNV); 
 
     vec3 eyeV  = normalize(-vertPos); 
 
     vec3 halfV = normalize(eyeV + normalV); 
 
     float NdotH = max(0.0, dot(normalV, halfV)); 
 
     float shineFac = (u_shininess + 2.0) * pow(NdotH, u_shininess)/(2.0 * 3.14159265); 
 
     gl_FragColor = vec4(color.rgb * u_glow * shineFac * 0.5, 1.0); 
 
    } 
 
</script> 
 
    
 
<script id="post-shader-vs" type="x-shader/x-vertex"> 
 
    precision mediump float; 
 
    
 
    attribute vec2 inPos; 
 
    
 
    varying vec2 pos; 
 
    
 
    void main() 
 
    { 
 
     pos = inPos; 
 
     gl_Position = vec4(inPos, 0.0, 1.0); 
 
    } 
 
</script> 
 
    
 
<script id="blurX-shader-fs" type="x-shader/x-fragment"> 
 
    precision mediump float; 
 
    
 
    varying vec2 pos; 
 
    
 
    uniform sampler2D u_texture; 
 
    uniform vec2  u_textureSize; 
 
    uniform float  u_sigma; 
 
    
 
    float CalcGauss(float x, float sigma) 
 
    { 
 
     float coeff = 1.0/(2.0 * 3.14157 * sigma); 
 
     float expon = -(x*x)/(2.0 * sigma); 
 
     return (coeff*exp(expon)); 
 
    } 
 
    
 
    void main() 
 
    { 
 
     vec2 texC = pos.st * 0.5 + 0.5; 
 
     vec4 texCol = texture2D(u_texture, texC); 
 
     vec4 gaussCol = vec4(texCol.rgb, 1.0); 
 
     float stepX = 1.0/u_textureSize.x; 
 
     for (int i = 1; i <= 20; ++ i) 
 
     { 
 
      float weight = CalcGauss(float(i)/32.0, u_sigma * 0.5); 
 
      texCol = texture2D(u_texture, texC + vec2(float(i) * stepX, 0.0)); 
 
      gaussCol += vec4(texCol.rgb * weight, weight); 
 
      texCol = texture2D(u_texture, texC - vec2(float(i) * stepX, 0.0)); 
 
      gaussCol += vec4(texCol.rgb * weight, weight); 
 
     } 
 
     gaussCol.rgb /= gaussCol.w; 
 
     gl_FragColor = vec4(gaussCol.rgb, 1.0); 
 
    } 
 
</script> 
 
    
 
<script id="blurY-shader-fs" type="x-shader/x-fragment"> 
 
    precision mediump float; 
 
    
 
    varying vec2 pos; 
 
    
 
    uniform sampler2D u_texture; 
 
    uniform vec2  u_textureSize; 
 
    uniform float  u_sigma; 
 
    
 
    float CalcGauss(float x, float sigma) 
 
    { 
 
     float coeff = 1.0/(2.0 * 3.14157 * sigma); 
 
     float expon = -(x*x)/(2.0 * sigma); 
 
     return (coeff*exp(expon)); 
 
    } 
 
    
 
    void main() 
 
    { 
 
     vec2 texC = pos.st * 0.5 + 0.5; 
 
     vec4 texCol = texture2D(u_texture, texC); 
 
     vec4 gaussCol = vec4(texCol.rgb, 1.0); 
 
     float stepY = 1.0/u_textureSize.y; 
 
     for (int i = 1; i <= 20; ++ i) 
 
     { 
 
      float weight = CalcGauss(float(i)/32.0, u_sigma * 0.5); 
 
      texCol = texture2D(u_texture, texC + vec2(0.0, float(i) * stepY)); 
 
      gaussCol += vec4(texCol.rgb * weight, weight); 
 
      texCol = texture2D(u_texture, texC - vec2(0.0, float(i) * stepY)); 
 
      gaussCol += vec4(texCol.rgb * weight, weight); 
 
     } 
 
     vec3 hdrCol = 2.0 * gaussCol.xyz/gaussCol.w; 
 
     vec3 mappedCol = vec3(1.0) - exp(-hdrCol.rgb * 3.0); 
 
     gl_FragColor = vec4(clamp(mappedCol.rgb, 0.0, 1.0), 1.0); 
 
    } 
 
</script> 
 

 
<div> 
 
    <form id="gui" name="inputs"> 
 
     <table> 
 
      <tr> <td> <font color= #CCF>shininess</font> </td> 
 
       <td> <input type="range" id="shine" min="0" max="50" value="10" onchange="changeEventHandler(event);"/></td> </tr> 
 
      <tr> <td> <font color= #CCF>glow</font> </td> 
 
       <td> <input type="range" id="glow" min="100" max="400" value="300" onchange="changeEventHandler(event);"/></td> </tr> 
 
      <tr> <td> <font color= #CCF>blur</font> </td> 
 
       <td> <input type="range" id="sigma" min="1" max="100" value="60" onchange="changeEventHandler(event);"/></td> </tr> 
 
     </table> 
 
    </form> 
 
</div> 
 

 
<canvas id="canvas" style="border: none;" width="100%" height="100%"></canvas>