0-1 or -1 to 1 ...

experiments/draw_poly/test.frag

@@ -0,0 +1,31 @@
+#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)); }
+
+float dot2(vec2 v) {
+  return dot(v,v);
+}
+
+
+float fill(float x, float size) { return 1.-step(size, x); }
+
+void main() {
+  vec2 st = (gl_FragCoord.xy*2.-u_resolution.xy)/u_resolution.y;
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+
+  gl_FragColor = vec4(color, alpha);
+}

experiments/holo/holo.frag

@@ -12,6 +12,8 @@ const vec3 uBColor = vec3(.5,.5,.5);
 const vec3 uCColor = vec3(1.,1.,1.);
 const vec3 uDColor = vec3(.0,.33,.67);
 
+float fill(float x, float size) { return 1.-step(size, x); }
+
 //get colors from http://dev.thi.ng/gradients/
 vec3 cosPalette(float t) {
   return uAColor + uBColor*cos(6.28318*(uCColor*t+uDColor));
@@ -30,33 +32,133 @@ float rhombSDF(vec2 st) {
   return max(triangle1, triangle2);
 }
 
-float fill(float x, float size) {
-  return 1.-step(size, x);
+float sdRhombus(in vec2 p, in vec2 b) {
+  p = abs(p);
+  vec2 a = b-2.*p;
+  float h = clamp((a.x*b.x-a.y*b.y)/dot(b,b),-1.,1.);
+  float d = length(p-.5*b*vec2(1.-h,1.+h));
+  return d*sign(p.x*b.y+p.y*b.x-b.x*b.y);
 }
 
+//2d perlin noise fn via stegu/webgl-noise
+vec4 mod289(vec4 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; }
+
+vec4 permute(vec4 x) { return mod289(((x*34.0)+10.0)*x);}
+
+vec4 taylorInvSqrt(vec4 r){ return 1.79284291400159 - 0.85373472095314 * r; }
+
+vec2 fade(vec2 t) { return t*t*t*(t*(t*6.0-15.0)+10.0); }
+
+
+
+// Classic Perlin noise
+float cnoise(vec2 P) {
+  vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
+  vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
+  Pi = mod289(Pi); // To avoid truncation effects in permutation
+  vec4 ix = Pi.xzxz;
+  vec4 iy = Pi.yyww;
+  vec4 fx = Pf.xzxz;
+  vec4 fy = Pf.yyww;
+
+  vec4 i = permute(permute(ix) + iy);
+
+  vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
+  vec4 gy = abs(gx) - 0.5 ;
+  vec4 tx = floor(gx + 0.5);
+  gx = gx - tx;
+
+  vec2 g00 = vec2(gx.x,gy.x);
+  vec2 g10 = vec2(gx.y,gy.y);
+  vec2 g01 = vec2(gx.z,gy.z);
+  vec2 g11 = vec2(gx.w,gy.w);
+
+  vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
+  g00 *= norm.x;  
+  g01 *= norm.y;  
+  g10 *= norm.z;  
+  g11 *= norm.w;  
+
+  float n00 = dot(g00, vec2(fx.x, fy.x));
+  float n10 = dot(g10, vec2(fx.y, fy.y));
+  float n01 = dot(g01, vec2(fx.z, fy.z));
+  float n11 = dot(g11, vec2(fx.w, fy.w));
+
+  vec2 fade_xy = fade(Pf.xy);
+  vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
+  float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
+  return 2.3 * n_xy;
+}
+
+// Classic Perlin noise, periodic variant
+float pnoise(vec2 P, vec2 rep) {
+  vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);
+  vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);
+  Pi = mod(Pi, rep.xyxy); // To create noise with explicit period
+  Pi = mod289(Pi);        // To avoid truncation effects in permutation
+  vec4 ix = Pi.xzxz;
+  vec4 iy = Pi.yyww;
+  vec4 fx = Pf.xzxz;
+  vec4 fy = Pf.yyww;
+
+  vec4 i = permute(permute(ix) + iy);
+
+  vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;
+  vec4 gy = abs(gx) - 0.5 ;
+  vec4 tx = floor(gx + 0.5);
+  gx = gx - tx;
+
+  vec2 g00 = vec2(gx.x,gy.x);
+  vec2 g10 = vec2(gx.y,gy.y);
+  vec2 g01 = vec2(gx.z,gy.z);
+  vec2 g11 = vec2(gx.w,gy.w);
+
+  vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));
+  g00 *= norm.x;  
+  g01 *= norm.y;  
+  g10 *= norm.z;  
+  g11 *= norm.w;  
+
+  float n00 = dot(g00, vec2(fx.x, fy.x));
+  float n10 = dot(g10, vec2(fx.y, fy.y));
+  float n01 = dot(g01, vec2(fx.z, fy.z));
+  float n11 = dot(g11, vec2(fx.w, fy.w));
+
+  vec2 fade_xy = fade(Pf.xy);
+  vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);
+  float n_xy = mix(n_x.x, n_x.y, fade_xy.y);
+  return 2.3 * n_xy;
+}
+
+
+
 void main() {
-  vec2 st = gl_FragCoord.xy/u_resolution;
+  vec2 st = (gl_FragCoord.xy*2.-u_resolution.xy)/u_resolution.y;
   vec3 color = vec3(0.0,0.0,0.0);
   float alpha = 1.0;
-  float size = 1.;
+  float size = .00001;
   float final_color = 0.5;
   float amount = 1.;
   float off = .3;
   float max_int = .5;
   float mouse_dist = distance(u_mouse.xy/u_resolution.xy,vec2(.5,.5));
   float speed = 1.;
+  float s = u_time/120.;
   int iterations = 2;
   st = fract(st*amount);
   for (int i = 0; i<iterations;i++) {
-    float n = fill(rhombSDF(st+vec2(0.,off)),size);
-    float e = fill(rhombSDF(st+vec2(off,0.)),size);
-    float s = fill(rhombSDF(st+vec2(0.,off*-1.)),size);
-    float w = fill(rhombSDF(st+vec2(off*-1.,.0)),size);
+    vec2 b = vec2(1.);
+    float n = fill(sdRhombus(st+vec2(.0,off),b),size);
+    float e = fill(sdRhombus(st+vec2(off,.0),b),size);
+    float s = fill(sdRhombus(st+vec2(.0,off*-1.),b),size);
+    float w = fill(sdRhombus(st+vec2(off*-1.,.0),b),size);
     float comb = n+e+s+w;
     vec2 central = st - vec2(.5);
 
     comb = comb *(max_int-(abs(central.x+central.y)*sin(u_time*speed)+.3));
-    final_color = mix(final_color, comb, (st.x+st.y)/2.);
+    //final_color = mix(final_color, comb, (st.x+st.y)/2.);
+    final_color = mix(final_color, comb,.5);
+    final_color = mix(final_color,pnoise(u_mouse.xx*sin(u_time), st),.1);
     //final_color = mix(final_color,(n+e+s+w)*(max_int-(st.x*(.3+(sin(u_time*speed)*.7))),st.x);
     off += .3;
     rotate(st, radians(90.));
@@ -64,5 +166,5 @@ void main() {
     //color += fill(n, .2);
   
   color += cosPalette(final_color);
-  gl_FragColor = vec4(color, alpha);
+  gl_FragColor = vec4(color,1.);
 }