mirror of
https://github.com/bvanroll/shaders.git
synced 2025-08-29 03:52:47 +00:00
47 lines
1.1 KiB
GLSL
47 lines
1.1 KiB
GLSL
#ifdef GL_ES
|
|
precision mediump float;
|
|
#endif
|
|
uniform vec2 u_resolution;
|
|
uniform vec2 u_mouse;
|
|
uniform float u_time;
|
|
|
|
#define PI 3.14159265359
|
|
|
|
const vec3 uAColor = vec3(.5,.5,.5);
|
|
const vec3 uBColor = vec3(.5,.5,.5);
|
|
const vec3 uCColor = vec3(1.,1.,1.);
|
|
const vec3 uDColor = vec3(.0,.33,.67);
|
|
|
|
//get colors from http://dev.thi.ng/gradients/
|
|
vec3 cosPalette(float t) {
|
|
return uAColor + uBColor*cos(6.28318*(uCColor*t+uDColor));
|
|
}
|
|
|
|
vec2 rotate(vec2 st, float a) {
|
|
st = mat2(cos(a),-sin(a),sin(a),cos(a))*(st-.5);
|
|
return st+.5;
|
|
}
|
|
|
|
float triSDF(vec2 st) {
|
|
st = (st*2.-1.)*2.;
|
|
return max(abs(st.x)*.866025+st.y*.5,-st.y*.5);
|
|
}
|
|
|
|
float fill(float x, float size) {
|
|
return 1.-step(size, x);
|
|
}
|
|
|
|
void main() {
|
|
vec2 st = gl_FragCoord.xy/u_resolution;
|
|
vec3 color = vec3(0.0,0.0,0.0);
|
|
float alpha = 1.0;
|
|
|
|
st = rotate(st, radians(-25.));
|
|
float sdf = triSDF(st);
|
|
//why does dividing the triangle with a larger triangle create a smaller black triangle area at the bottom?
|
|
sdf /= triSDF(st+vec2(.0,.2));
|
|
color += sdf; //fill(abs(sdf),.56);
|
|
|
|
gl_FragColor = vec4(color, alpha);
|
|
}
|