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thebookofshaders/09/tmp/grid-warp.frag

34 lines
755 B
GLSL

// Author @patriciogv ( patriciogonzalezvivo.com ) - 2015
#ifdef GL_ES
precision mediump float;
#endif
uniform vec2 u_resolution;
uniform float u_time;
vec2 tile(vec2 _st, float _zoom){
_st *= _zoom;
return fract(_st);
}
float X(vec2 _st, float _width){
float pct0 = smoothstep(_st.x-_width,_st.x,_st.y);
pct0 *= 1.-smoothstep(_st.x,_st.x+_width,_st.y);
float pct1 = smoothstep(_st.x-_width,_st.x,1.0-_st.y);
pct1 *= 1.-smoothstep(_st.x,_st.x+_width,1.0-_st.y);
return pct0+pct1;
}
void main(void){
vec2 st = gl_FragCoord.xy/u_resolution.xy;
st.y *= u_resolution.y/u_resolution.x;
vec2 xy = st-vec2(.5);
float grid = 1.0-X(tile(xy,10.+20.0*dot(xy,xy)),0.05);
gl_FragColor = vec4(vec3(grid),1.0);
}