19 lines
572 B
Plaintext
19 lines
572 B
Plaintext
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#version 330
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in vec2 uv;
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in vec2 position_background;
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out vec4 frag_color;
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uniform sampler2D image;
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uniform vec4 background_color;
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void main() {
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vec2 frac = position_background - floor(position_background);
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float checkerboard = ((frac.x > .5) == (frac.y > .5)) ? 0.4 : 0.5;
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vec4 background = (1.0 - background_color.a) * vec4(vec3(checkerboard), 1.0) +
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background_color.a * vec4(background_color.rgb, 1.0);
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vec4 value = texture(image, uv);
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frag_color = (1.0 - value.a) * background + value.a * vec4(value.rgb, 1.0);
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}
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