diff options
Diffstat (limited to 'pass1.frag')
-rw-r--r-- | pass1.frag | 31 |
1 files changed, 25 insertions, 6 deletions
@@ -9,16 +9,35 @@ layout(location = U_LOC_TIME) uniform float time; layout(location = U_LOC_PASS1) uniform sampler2D buf; ivec2 res = ivec2(RES_H, RES_V); +const float step = 0.04; +const float turns = 9.0; + void main() { - vec2 point = vec2(sin(time), cos(time)) * 0.7; - point.x *= float(res.y) / float(res.x); // adjust for aspect ratio - point = ((point + 1.0) / 2.0) * res.xy; // convert to screen coords + vec2 uv = gl_FragCoord.xy / res.xy; float r = 20.0; // circle radius + + vec2 norm = (uv - 0.5) * 2.0; + norm.x *= float(res.x) / float(res.y); // adjust for aspect ratio + + float offset = time * 7.0; + + float mag = 1.3 + 0.5 * sin(2 * time); + float size = 0.4 + 0.1 * sin(3 * time); color = vec4(0.0); - if (length(gl_FragCoord.xy - point) < r) - color = vec4(1.0); - color += texture(buf, gl_FragCoord.xy / res.xy) * 0.95; + for (float t = 0.0; t < PI_2; t += step) { + // <https://www.desmos.com/calculator/e0kq6z1ndd> + vec2 f = vec2( + cos(t) + mag * cos(turns * t + offset), + sin(t) + mag * sin(turns * t + offset) + ); + f *= size; + if (length(f - norm) < 0.01) { + color = vec4(1.0, 1.0, 1.0, 1.0); + } + } + + color += texture(buf, ((uv - 0.5) * 0.99) + 0.5) * 0.97; } |