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							361 lines
						
					
					
						
							11 KiB
						
					
					
				<script src=lib1.js></script>
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<script src="https://pagecdn.io/lib/ace/1.4.12/ace.js" crossorigin="anonymous"></script>
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<script src="https://pagecdn.io/lib/ace/1.4.12/ext-language_tools.js" crossorigin="anonymous"></script>
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<style>
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 .ace_gutter-layer {
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   /* original width is 48px */
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   width: 25px !important;
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 }
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 .ace_gutter-layer > * {
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   /* 48 - 32 = 16 */
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   margin-left: 0;
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 }
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 .ace_gutter-cell {
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  padding-left: 0 !important;
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  padding-right: 3px !important;
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 }
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 .code{ 
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    font-family: "monaco, menlo, ubuntu mono, consolas, source-code-pro" ;
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    }
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 </style>
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<body bgcolor=white text=black link=black alink=blue vlink=blue>
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<center>
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<canvas id='canvas1' width=600 height=600></canvas>
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</center>
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</body>
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<!!-------- VERTEX SHADER: YOU PROBABLY DON'T WANT TO CHANGE THIS RIGHT NOW -------->
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<script id='my_vertex_shader' type='x-shader/x-vertex'>
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   attribute vec3 aPos;
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   varying   vec3 vPos;
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   void main() {
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      gl_Position = vec4(aPos, 1.);
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      vPos = aPos;
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   }
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</script>
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<!!-------- FRAGMENT SHADER: THIS IS WHERE YOU WILL DO YOUR WORK -------->
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<script id='my_fragment_shader' type='x-shader/x-fragment'>
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 uniform float uTime;   // TIME, IN SECONDS
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 uniform int flags;
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 varying vec3 vPos;     // -1 < vPos.x < +1
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                        // -1 < vPos.y < +1
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                        //      vPos.z == 0
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uniform sampler2D uSampler;
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 // YOU MUST DEFINE A main() FUNCTION.
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 void main() {
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 ////////////////////////////////////////////////
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 //
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 // HERE, FOR YOUR HOMEWORK, YOU CAN WRITE ANY
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 // CODE YOU LIKE
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    //DEFINE A COLOR FOR THIS FRAGMENT.
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    // LIGHT DIRECTION AND COLOR
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    vec3 LDir = vec3(1, 1, 1);
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    vec3 LCol = vec3(1.,.98,.9);
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    vec3 VDir = vec3(0., 0., 1.);
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    float R = 0.5 + 0.3*sin(uTime/10.);
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    // vPos IS THE 3D LOCATION OF THIS FRAGMENT.
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    // SURFACE REFLECTANCE PROPERTIES
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    vec3 diffuse = vec3(.7,.7,.6);
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    vec3 ambient = vec3(.1,.1,.09);
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    vec3 specular = vec3(.35,.35,.3);
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    // CREATE A WACKY BACKGROUND PATTERN.
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    vec3 color = vec3(.5 + .5 * sin(20. * vPos.x + sin(10. * vPos.y + 5. * uTime)),
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                      .5,
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                      .5 + .5 * sin(20. * vPos.y + sin(10. * vPos.x + 5. * uTime)));
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    vec3 specularlight; //specular light should disregard object color.
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    float x = vPos.x;
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    float y = vPos.y;
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    // CREATE BOUNCING ANIMATION.
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    y += .5 - 2. * abs(.5 * sin(uTime));
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    // FIGURE OUT WHETHER THIS PIXEL IS ON THE SPHERE.
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    float rr = x * x + y * y;
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    // IF SO, THEN SHADE THE SPHERE.
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    if (rr < R*R) {
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       // COMPUTE THE z AND NORMAL OF THE SPHERE.
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       float z = R * sqrt(1. - rr/(R*R));
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       vec3 N = vec3(x,y,z) / R;
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       // APPLY SHADING AND LIGHTING.
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       vec3 realVPos = vec3(vPos.x, vPos.y, z);
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       //*DIRECTIONS ARE NORMALIZED TO GET THE CORRECT PHONG LIGHTING
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       LDir = normalize(LDir - realVPos);
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       VDir = normalize(VDir - realVPos);
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       vec3 lcolor = ambient;
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       lcolor += diffuse * max(0., dot(N, LDir)) * LCol;
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       //*SPECULAR LIGHTS ARE ADDED
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       specularlight = specular * 
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                  pow(max(0.,dot(2.*dot(N, LDir) * N - LDir, VDir)),3.) * LCol;
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       // ROTATE THE TEXTURE OVER TIME.
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       float angle = 0.4 * uTime;
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       float px =  cos(angle) * N.x + sin(angle) * N.z;
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       float pz = -sin(angle) * N.x + cos(angle) * N.z;
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       vec3 P = vec3(px, N.y, pz);
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       // APPLY PROCEDURAL NOISE TEXTURE.
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       float cloud = min(0.85, max(-0.05, 2. * noise(1.1 * P)));
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       //const float rspeed = 10.;
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      //*CALCULATING THE TEXTURE COORDINATE.
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      const float pi = 3.14159265359;
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      float tex_x = acos(abs(x)/sqrt(R*R-y*y));
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      if(x > 0.)
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         tex_x = pi - tex_x;
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      tex_x = R * tex_x;
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      tex_x *= 1.5708;//*Correct aspect ratio of texture 2:1 -> 2pir:2r
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      tex_x = tex_x + float(uTime)*R;
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      float _2pir = 2. * pi * R;
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      float quo = float(int(tex_x/_2pir));
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      tex_x = (tex_x - quo * _2pir) / _2pir;
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      //*TEXTURE MAPPING
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      vec3 texture_color;
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      if(flags /*& 0x1*/ == 0)
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         texture_color = texture2D(uSampler, vec2(tex_x, ((R - y)/(2.*R)))).xyz;
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      else
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         texture_color = vec3(.0841, .5329, .9604);
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      color = lcolor * 
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            (cloud + texture_color) + specularlight;
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    }
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    //*CALCULATING LIGHTING AND SHADOWS FOR THE BACKGROUND
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    else{
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      vec3 realVPos = vec3(vPos.x, vPos.y, -1.);
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      vec3 N = vec3(0., 0., 1.);
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      vec3 C = vec3(0., vPos.y - y, 0.);
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      // APPLY SHADING AND LIGHTING.
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      vec3 lcolor = 6.*ambient;
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      //*CALCULATING DISTANCE BETWEEN SPHERE CENTER TO THE RAY 
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       //BETWEEN THE POINT TO LIGHT SOURCE
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      vec3 LV = realVPos - LDir;
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      vec3 LC = C - LDir;
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      vec3 VC = C - realVPos;
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      float lLV = dot(LV, LV);
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      float lLC = dot(LC, LC);
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      float lVC = dot(VC, VC);
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      float RR = R*R;
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      float d_VCVL = -dot(VC, LV);
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      float dist = min(lLC, lVC);
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      if (d_VCVL > 0.)
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         dist = min(dist, lVC - d_VCVL*d_VCVL/lLV);
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      //*CALCULATE DISTANCE BETWEEN SPHERE CENTER TO THE RAY BETWEEN POINT TO CAMERA
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      vec3 EV = realVPos - VDir;
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      vec3 EC = C - VDir;
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      float lEV = dot(EV, EV);
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      float lEC = dot(EC, EC);
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      float d_VCVE = -dot(VC, EV);
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      float dist2 = min(lEC, lVC);
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      if (d_VCVE > 0.)
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         dist2 = min(dist2, lVC - d_VCVE*d_VCVE/lEV);
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      //*AMBIENT LIGHT WILL DECAY WHEN BACKGROUND POINT IS CLOSER TO THE SPHERE
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      //*FIRST THE DISTANCE IS NORMALIZED, THEN I CURVED IT WITH LOGISTIC FUNCTION
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      float aratio0 = 1./(1.+pow(2.71828,15.*(.2-(sqrt(lVC) - R - .4806)/1.381)));
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      lcolor *= aratio0;
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      diffuse *= pow(aratio0, 0.3);
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      //*TEST IF CAMERA CAN SEE THE POINT
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      if(dist2 < RR)
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      {
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         specular *= 0.;
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         float d = sqrt(dist2);
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         float ratio = pow(2., sqrt(dist2)/R) - 1.;
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         diffuse *= ratio;
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      }
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      //*TEST IF THE LIGHT CAN REACH THE BACKGROUND POINT DIRECTLY
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      if(dist < RR)
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      {
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         specular *= 0.;
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         float ratio = pow(2.7, sqrt(dist)/R) - 1.7;
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         float aratio = pow(2., sqrt(dist)/R) - 1.;
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         if(ratio < 0.)
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            ratio = 0.;
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         diffuse *= ratio;
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         lcolor *= aratio;
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      }
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      LDir = normalize(LDir - realVPos);
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      VDir = normalize(VDir - realVPos); 
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      lcolor += 1.2*diffuse * max(0., dot(N, LDir)) * LCol;
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      specularlight = 0.3*specular * 
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            pow(max(0., dot(2.*dot(N, LDir) * N - LDir, VDir)),32.) * LCol;
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      color = color * lcolor + specularlight;
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    }
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    // APPLY GAMMA CORRECTION AND SET THE PIXEL COLOR.
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    gl_FragColor = vec4(sqrt(color), 1.0);
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 }
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</script>
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<!!-------- CREATE A PROPERLY DESCRIPTIVE TITLE BELOW -------->
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<script id='my_title' type='text/html'>
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The Bouncing Earth
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</script>
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<!!-------- HERE IS WHERE YOU CAN PROVIDE A LONGER TEXT DESCRIPTION -------->
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<script id='my_instructions' type='text/html'><font color=#909090>
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<p style="font-size:30px; ">This is a description 
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of my cool homework 
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that you are seeing now.</p>
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<p>
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<i style="font-size:25px;">Here is how it works:</i>
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<ul>
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   <li>First, I added <a href="http://planetpixelemporium.com/download/download.php?earthmap1k.jpg">texture</a> to the sphere. The code to load the texture is from 
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      <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Tutorial/Using_textures_in_WebGL">here</a>. Please wait a sec for the texture to download.</li>
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   <li>Then, I mapped the 3D sphere surface to the rectangular 2D texture picture.  </li>
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   <li>I also make it look like it's rotating by adding uTime to the offset of the texture and reset the offset to 0 whenever it exceeds
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       the width of the texture.</li>
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   <li>I used Perlin Noise to generate fake clouds.</li>
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   <li> I modified the lighting so that the light source won't move with the sphere and 
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      the lighting will change when the sphere moves. I also added specular lights to make it shinier.</li>
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   <li> I tried to add some 'soft shadow' to it. I used a mix of methods inspired by Ambient Occlusion and Ray Tracing.<br>
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      <ul>
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         <li>The Ambient lights and diffusion lights are reduced with respect to the distance between the background point and the sphere.</li>
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         <li>The specular light of the background wall is eliminated and the diffusion factor is reduced when the ray shooting from the background point 
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         towards the light source or from the background point towards the camera position intersect with the sphere.</li>
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      </ul>
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   <li>I added basic interactions such as press ctrl + 't' key to hide/show texture, click on the above canvas to pause/unpause animations. 
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      Just a proof of concept.</li>   
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   <li>Finally, I made some small changes like changing R over time and refined the UI a little bit. I used 
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      <a href="https://ace.c9.io">Ace</a> for code highlighting and autocompletion on the edit panel.</li>
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   <li>Comments begin with '//*' are added by me.</li>
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   <li>Repo on <a href="https://github.com/sunyinqi0508/graphics_hw1">Github</a>.</li>
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   </li>
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 </ul>
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<p>
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</script>
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<!!-------- YOU PROBABLY DON'T WANT TO CHANGE ANYTHING BELOW FOR NOW -------->
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<script>
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// CREATE THE HTML DOCUMENT
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let flags = 0x0;
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let vs = my_vertex_shader.innerHTML,
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    fs = my_fragment_shader.innerHTML;
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    fs = fs.substring(1, fs.length);
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document.body.innerHTML = [''
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   ,'<font size=7 color=#909090>' + my_title.innerHTML
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   ,'<TABLE cellspacing=0 cellpadding=0><TR>'
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   ,'<td><font color=red size=5><div id=errorMessage></div></font></td>'
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   ,'</TR><TR>'
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   ,'<table cellspacing=0>'
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   ,'<tr>'
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   ,'<td valign=top>'
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   ,'<div id="ace" style="width:800px;height:1780px;"></div>'
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   ,'</td><td valign=top>' + document.body.innerHTML  + '<div style=\'font-size:25px\'>' + my_instructions.innerHTML + '</div>' + '</td>'
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   ,'</tr></table>'
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   ,'</TR></TABLE>'
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   ].join('');
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// SET UP THE EDITABLE TEXT AREA ON THE LEFT SIDE.
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let text = fs.split('\n'), cols = 0;
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for (let i = 0 ; i < text.length ; i++)
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   cols = Math.max(cols, text[i].length);
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ace.require("ace/ext/language_tools");
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var editor = ace.edit("ace", {
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   mode:"ace/mode/glsl",
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   theme:"ace/theme/crimson_editor"
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});
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editor.setOptions({
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   enableBasicAutocompletion: true,
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   enableSnippets: true,
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   enableLiveAutocompletion: true,
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   fontSize: 14,
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						|
   fontFamily: "monaco, menlo, ubuntu mono, consolas, source-code-pro",
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   fixedWidthGutter: true,
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   showGutter: true,
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   showPrintMargin: false,
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});
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editor.setAutoScrollEditorIntoView(true);
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editor.getSession().setValue(fs);
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// REPARSE THE SHADER PROGRAM AFTER EVERY KEYSTROKE.
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editor.session.on('change', function(delta) {
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   canvas1.setShaders(vs, editor.getSession().getValue());
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});
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let lastTime = Date.now();
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let animating = true;
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let ctrl = false;
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canvas1.addEventListener('click',function(ev){
 | 
						|
   if(animating)
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						|
      lastTime = Date.now();
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						|
   else
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						|
      startTime += Date.now() - lastTime;   
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						|
   animating = !animating;
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						|
});
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						|
document.addEventListener('keydown',(e)=>{
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						|
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						|
if(e.code.startsWith('Control'))
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						|
{
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						|
   ctrl = true;
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						|
}
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else if(ctrl && e.code == 'KeyT')
 | 
						|
   {
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						|
      mask = 0x1;
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						|
      flags = flags&!mask | (!(flags&mask)*mask);
 | 
						|
      setUniform('1i', 'flags', flags);
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						|
   }
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						|
});
 | 
						|
 | 
						|
document.addEventListener('keyup',(e)=>{
 | 
						|
   if(e.code.startsWith('Control'))
 | 
						|
   {
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						|
      ctrl = false;
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						|
   }
 | 
						|
});
 | 
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// SET THE CURRENT TIME IN SECONDS BEFORE RENDERING EACH FRAME.
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						|
 | 
						|
let startTime = Date.now();
 | 
						|
 | 
						|
function animate(gl) {
 | 
						|
   if(animating)
 | 
						|
      setUniform('1f', 'uTime', (Date.now() - startTime) / 1000);
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						|
   else
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      setUniform('1f', 'uTime', (lastTime - startTime) / 1000);
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}
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// START EVERYTHING.
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						|
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gl_start(canvas1, vs, fs);
 | 
						|
</script>
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 |