60 lines
1.2 KiB
GLSL
60 lines
1.2 KiB
GLSL
[vertex]
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layout(location=0) in highp vec4 vertex_attrib;
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layout(location=4) in vec2 uv_in;
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uniform float offset_x;
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out vec2 uv_interp;
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void main() {
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uv_interp = uv_in;
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gl_Position = vec4(vertex_attrib.x + offset_x, vertex_attrib.y, 0.0, 1.0);
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}
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[fragment]
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uniform sampler2D source; //texunit:0
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uniform vec2 eye_center;
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uniform float k1;
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uniform float k2;
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uniform float upscale;
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uniform float aspect_ratio;
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in vec2 uv_interp;
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layout(location = 0) out vec4 frag_color;
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void main() {
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vec2 coords = uv_interp;
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vec2 offset = coords - eye_center;
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// take aspect ratio into account
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offset.y /= aspect_ratio;
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// distort
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vec2 offset_sq = offset * offset;
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float radius_sq = offset_sq.x + offset_sq.y;
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float radius_s4 = radius_sq * radius_sq;
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float distortion_scale = 1.0 + (k1 * radius_sq) + (k2 * radius_s4);
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offset *= distortion_scale;
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// reapply aspect ratio
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offset.y *= aspect_ratio;
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// add our eye center back in
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coords = offset + eye_center;
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coords /= upscale;
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// and check our color
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if (coords.x < -1.0 || coords.y < -1.0 || coords.x > 1.0 || coords.y > 1.0) {
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frag_color = vec4(0.0, 0.0, 0.0, 1.0);
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} else {
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coords = (coords + vec2(1.0)) / vec2(2.0);
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frag_color = textureLod(source, coords, 0.0);
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}
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}
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