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130 lines
3.7 KiB
130 lines
3.7 KiB
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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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float fl = 3.0;
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const float pi = 3.14159265359;
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const int ns = 2;
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vec4 Sph[ns];
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uniform sampler2D uSampler[ns];
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vec3 Ambient [ns];
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vec3 Diffuse [ns];
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vec4 Specular[ns];
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// YOU MUST DEFINE A main() FUNCTION.
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bool getflag(int flag, int bit){
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float shifted = float(flag) - pow(2., float(bit));
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return fract(shifted / 2.) > 0.;
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}
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float clampv(float val, float l, float h){
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return val < l? l:val > h? h:val;
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}
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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 LIKDEFINE A COLOR FOR THIS FRAGMENT.
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// LIGHT DIRECTION AND COLOR
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vec3 LDir = vec3(.5,.5,.5);
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vec3 LCol = vec3(1.,1.,1.);
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// SPHERE
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Sph[0] = vec4(.5*sin(uTime),0.,.5*cos(uTime), 0.2);
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Sph[1] = vec4(0.,0.,0., 0.2);
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// SURFACE REFLECTANCE PROPERTIES
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Ambient [0] = vec3(.1,.05,.05); // r,g,b
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Diffuse [0] = vec3(1.,.5,.5); // r,g,b
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Specular[0] = vec4(1.,.5,.5, 10.); // r,g,b,power
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Ambient [1] = vec3(.05,.05,.1); // r,g,b
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Diffuse [1] = vec3(.5,.5,1.); // r,g,b
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Specular[1] = vec4(1.,.5,.5, 20.); // r,g,b,power
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// INITIALIZE TO A BACKGROUND COLOR
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vec3 color = vec3(.2, .3, .5);
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// COMPUTE THE RAY ORIGIN AND DIRECTION
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float x = vPos.x;
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float y = vPos.y;
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vec3 V = vec3(0.,0.,fl);
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vec3 W = normalize(vec3(x, y, -fl));
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// RAY TRACE TO ALL OBJECTS IN THE SCENE
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float tMin = 10000.0;
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for (int i = 0 ; i < ns ; i++) {
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// SHIFT COORDINATES, SO THAT SPHERE IS AT (0,0,0)
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vec3 Vp = V - Sph[i].xyz;
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// SOLVE FOR QUADRATIC EQUATION IN t
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float B = dot(W, Vp);
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float C = dot(Vp, Vp) - Sph[i].w * Sph[i].w;
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float D = B*B - C;
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if (D > 0.) {
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float t = -B - sqrt(D);
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// IF RAY HITS SPHERE
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if (t > 0. && t < tMin) {
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float t = -B - sqrt(D);
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// IF RAY HITS SPHERE
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vec3 S = V + t * W;
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if (t > 0. && t < tMin) {
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vec3 tex_sph = S - Sph[i].xyz;
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// FIND SURFACE POINT AND NORMAL, DO SHADING
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float R = Sph[i].w;
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float tex_x = acos(abs(tex_sph.x)/sqrt(R*R-tex_sph.y*tex_sph.y));
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if(tex_sph.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 = clampv((tex_x - quo * _2pir), 0., _2pir) / _2pir;
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//*TEXTURE MAPPING
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vec3 texture_color;
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if(getflag(flags, 0))
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texture_color = texture2D(uSampler[i], vec2(tex_x, ((R - tex_sph.y)/(2.*R)))).xyz;
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vec3 N = normalize(S - Sph[i].xyz);
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vec3 VDir = normalize(Vp);
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//*DIRECTIONS ARE NORMALIZED TO GET THE CORRECT PHONG LIGHTING
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vec3 realLDir = normalize(LDir - S);
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color = (Ambient[i]
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+ Diffuse[i] * max(0.,dot(N,LDir)) * LCol) * texture_color
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// + SPECULAR COMPONENT GOES HERE
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+ Specular[i].xyz*pow(max(0., dot(2.*dot(N, LDir)*N - LDir, VDir)), Specular[i].w)
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;
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tMin = t;
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}
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}
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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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} |