43 lines
1.6 KiB
GLSL
43 lines
1.6 KiB
GLSL
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/**
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* Draw the icons, leaving a semi-transparent rectangle on top of the icon.
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*
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* The top-left corner of the rectangle is rounded and drawned with anti-alias.
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* The anti-alias is done by transitioning from the outer to the inner radius of
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* the rounded corner, and the rectangle sides.
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*/
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void main()
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{
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/* Top-left rounded corner parameters. */
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const float circle_radius_outer = 0.1;
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const float circle_radius_inner = 0.075;
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/**
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* Add a bit transparency to see a bit of the icon, without
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* getting on the way of readability. */
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const float mask_transparency = 0.25;
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vec2 circle_center = vec2(circle_radius_outer - text_width, 0.5);
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fragColor = texture(image, texCoord_interp) * color;
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/* radius in icon space (1 is the icon width). */
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float radius = length(mask_coord_interp - circle_center);
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float mask = smoothstep(circle_radius_inner, circle_radius_outer, radius);
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bool lower_half = mask_coord_interp.y < circle_center.y;
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bool right_half = mask_coord_interp.x > circle_center.x;
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if (right_half && mask_coord_interp.t < circle_center.y + circle_radius_outer) {
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mask = smoothstep(circle_center.y + circle_radius_inner,
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circle_center.y + circle_radius_outer,
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mask_coord_interp.t);
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}
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if (lower_half && mask_coord_interp.s > circle_center.x - circle_radius_outer) {
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mask = smoothstep(circle_center.x - circle_radius_inner,
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circle_center.x - circle_radius_outer,
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mask_coord_interp.s);
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}
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fragColor = mix(vec4(0.0), fragColor, max(mask_transparency, mask));
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}
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