43 lines
974 B
GLSL
43 lines
974 B
GLSL
#version GLSL_VERSION
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#define left -1.0f
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#define top 1.0f
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#define right 1.0f
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#define bottom -1.0f
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#define tex_left 0
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#define tex_top 0
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#define tex_right 1
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#define tex_bottom 1
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uniform float tiled;
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uniform vec4 sizes; // [ window_width, window_height, image_width, image_height ]
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out vec2 texcoord;
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const vec2 pos_map[] = vec2[4](
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vec2(left, top),
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vec2(left, bottom),
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vec2(right, bottom),
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vec2(right, top)
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);
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const vec2 tex_map[] = vec2[4](
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vec2(tex_left, tex_top),
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vec2(tex_left, tex_bottom),
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vec2(tex_right, tex_bottom),
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vec2(tex_right, tex_top)
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);
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float scale_factor(float window, float image) {
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return window / image;
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}
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float tiling_factor(int i) {
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return tiled * scale_factor(sizes[i], sizes[i + 2]) + (1 - tiled);
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}
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void main() {
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vec2 tex_coords = tex_map[gl_VertexID];
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texcoord = vec2(tex_coords[0] * tiling_factor(0), tex_coords[1] * tiling_factor(1));
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gl_Position = vec4(pos_map[gl_VertexID], 0, 1);
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}
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