shaders

commit 7d0c03b6af58f17e430ca6d0f0a911328aef59b9
parent d608712bb19f4732d4b835a9c6623562c54b1d2a
Author: mpizzzle <m@michaelpercival.xyz>
Date:   Tue,  8 Sep 2020 11:38:39 +0100

???

Diffstat:
A
combo.frag
 | 
43
+++++++++++++++++++++++++++++++++++++++++++
M
miyagi2.frag
 | 
3
---

2 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/combo.frag b/combo.frag
@@ -0,0 +1,43 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+#define PI 3.14159265359
+
+uniform vec2 u_resolution;
+uniform vec2 u_mouse;
+uniform float u_time;
+
+float quadraticBezier(float x, vec2 ab) {
+  float epsilon = 0.00001;
+  float a = max(0.0, min(1.0, ab.x)); 
+  float b = max(0.0, min(1.0, ab.y)); 
+
+  if (a == 0.5) {
+    a += epsilon;
+  }
+  
+  // solve t from x (an inverse operation)
+  float om2a = 1.0 - 2.0 * a;
+  float t = (sqrt(a * a + om2a * x) - a) / om2a;
+  return (1.0 - 2.0 * b) * (t * t) + (2.0 * b) * t;
+}
+
+void main() {
+    vec2 st = gl_FragCoord.xy / u_resolution;
+
+    float y = quadraticBezier(st.x, u_mouse / u_resolution);
+    float yy = (sin(st.x * PI / 2.0 + (u_time * 1.5)) / 2.0) + 0.5;
+    vec3 color = vec3(y);
+    vec3 color2 = vec3(yy);
+    float thickness = 0.02;
+
+    float plot = smoothstep(y - thickness, y, st.y) - smoothstep(y, y + thickness, st.y);
+    float plot2 = smoothstep(yy - thickness, yy, st.y) - smoothstep(yy, yy + thickness, st.y);
+
+    color = (1.0 - plot) + plot * vec3(1.0, 0.0, 1.0);
+    color2 = (1.0 - plot2) + plot2 * vec3(0.0, 1.0, 0.0);
+
+    gl_FragColor = vec4(color * color2, 1.0);
+}
+
diff --git a/miyagi2.frag b/miyagi2.frag
@@ -11,9 +11,6 @@ uniform float u_time;
 void main() {
     vec2 st = gl_FragCoord.xy / u_resolution;
 
-    //float y = (sin(st.x * PI / 2.0 + (u_time * 1.5)) / 2.0) + 0.5;
-    //float y = abs(sin(st.x * PI / 2.0 + (u_time * 1.5)));
-    //float y = fract(sin(st.x * PI / 2.0 + (u_time * 1.5)));
     float y = (sin(st.x * PI / 2.0 + (u_time * 1.5)) / 2.0) + 0.5;
 
     vec3 color = vec3(y);