27 lines
801 B
Plaintext
27 lines
801 B
Plaintext
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uniform mat4 U; // Undistortion
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uniform float maxRadSq;
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// GoogleVR Distortion using Vertex Displacement
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float distortionFactor(const float rSquared) {
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float ret = 0.0;
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ret = rSquared * (ret + U[1][1]);
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ret = rSquared * (ret + U[0][1]);
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ret = rSquared * (ret + U[3][0]);
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ret = rSquared * (ret + U[2][0]);
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ret = rSquared * (ret + U[1][0]);
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ret = rSquared * (ret + U[0][0]);
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return ret + 1.0;
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}
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// Convert point from world space to undistorted camera space
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vec4 undistort(const mat4 WV, vec4 pos) {
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// Go to camera space
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pos = WV * pos;
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const float nearClip = 0.1;
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if (pos.z <= -nearClip) { // Reminder: Forward is -Z
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// Undistort the point's coordinates in XY
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float r2 = clamp(dot(pos.xy, pos.xy) / (pos.z * pos.z), 0.0, maxRadSq);
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pos.xy *= distortionFactor(r2);
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}
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return pos;
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}
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