73 lines
2 KiB
Text
73 lines
2 KiB
Text
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uniform int nr_lights;
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varying vec3 q_tilde;
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varying vec3 inv_T_square_v;
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varying vec3 inv_T_square_e_c;
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varying vec4 ev_clip;
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varying vec3 v;
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//varying vec3 h[4];
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//varying vec3 l[4];
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varying vec4 a;
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//varying vec4 d;
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varying vec4 s;
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void main()
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{
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// decompress the matrix T
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float R = gl_Vertex.w;
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float inv_R = 1.0/R;
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// determine eye point in parameter space
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vec3 e = gl_ModelViewMatrixInverse[3].xyz;
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vec3 e_tilde = inv_R*(e - gl_Vertex.xyz);
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// compute helper
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float inv_e_square = 1.0/dot(e_tilde,e_tilde);
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// determine silhoutte center in parameter space
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vec3 m_tilde = inv_e_square*e_tilde;
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// determine radius of silhouette in parameter space
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float r = sqrt(1.0-inv_e_square);
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// compute vector x of length r orthogonal to e in parameter space
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vec3 x_tilde = r*normalize(cross(gl_ModelViewMatrixInverse[1].xyz,e_tilde));
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// compute vector y of length r orthogonal to x and e in parameter space
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vec3 y_tilde = r*normalize(cross(e_tilde,x_tilde));
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// compute the corner point in homogeneous object coordinates
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vec3 V_tilde = m_tilde+gl_MultiTexCoord2.x*x_tilde+gl_MultiTexCoord2.y*y_tilde;
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vec3 v_tilde = V_tilde - e_tilde;
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vec4 V;
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V.xyz = R*V_tilde+gl_Vertex.xyz;
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V.w = 1.0;
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q_tilde.xy = gl_MultiTexCoord2.xy;
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q_tilde.z = sqrt(inv_e_square);
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// compute vector from eye to vertex in eye space
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v = (gl_ModelViewMatrix*V).xyz;
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// compute components to compute normal in eye space
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inv_T_square_e_c = gl_NormalMatrix*(e_tilde);
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inv_T_square_v = gl_NormalMatrix*(v_tilde);
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v = -normalize(v);
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gl_Position = gl_ModelViewProjectionMatrix * V;
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ev_clip.xy = (gl_ModelViewProjectionMatrix * gl_ModelViewMatrixInverse[3]).zw;
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ev_clip.zw = gl_Position.zw - ev_clip.xy;
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a = vec4(0.0,0.0,0.0,0.0);
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vec4 lpos;
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for (int i=0; i<nr_lights; ++i) {
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a += gl_LightSource[i].ambient*gl_Color;
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}
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gl_FrontColor = gl_Color;
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//d = gl_Color;
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s = gl_FrontMaterial.specular;
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}
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