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two squares in a circle
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| // uses love2d 'effect' entry point | |
| uniform float time = 0.0f; | |
| float pi = 3.14159; | |
| float intersect(float value1, float value2) | |
| { | |
| return value1 * value2; | |
| } | |
| float merge(float value1, float value2) | |
| { | |
| return 1-((1-value1) * (1-value2)); | |
| } | |
| float halfspace(vec2 origin, vec2 direction, float feather, vec2 point) | |
| { | |
| return smoothstep( | |
| feather/2, | |
| -feather/2, | |
| dot(point - origin, direction)); | |
| } | |
| vec2 rotate(vec2 v, float a) | |
| { | |
| float cos_a = cos(a); | |
| float sin_a = sin(a); | |
| return vec2( | |
| cos_a * v.x - sin_a * v.y, | |
| cos_a * v.y + sin_a * v.x); | |
| } | |
| float square(vec2 point, float size, float feather) | |
| { | |
| return | |
| halfspace(vec2(size/2, 0), vec2(1, 0), feather, point) * | |
| halfspace(vec2(0, size/2), vec2(0, 1), feather, point) * | |
| halfspace(vec2(-size/2, 0), vec2(-1, 0), feather, point) * | |
| halfspace(vec2(0, -size/2), vec2(0, -1), feather, point); | |
| } | |
| float circle(vec2 point, float feather) | |
| { | |
| return smoothstep(-feather/2, feather/2, 0.8 - length(point)); | |
| } | |
| vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords) | |
| { | |
| vec2 point = texture_coords.xy * 2 - vec2(1, 1); | |
| vec2 axle = vec2(cos(-time*2*pi/6), sin(-time*2*pi/6)); | |
| float value = merge( | |
| square(rotate(point - 0.2*axle, -time*2*pi/4 / 3), 0.7, 0.2), | |
| square(rotate(point + 0.3*axle, time*2*pi/4 / 1.5), 0.5, 0.2)); | |
| value = merge(value, circle(point, 0.2)/2); | |
| return vec4(color.xyz, | |
| smoothstep(0.15, 0.25, value) * | |
| smoothstep(0.85, 0.75, value)); | |
| } |
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