Refactor rendering

frontend/src/scripts/drawing/shaders/random.frag

@@ -0,0 +1,48 @@
+#version 300 es
+
+precision mediump float;
+
+const float inf = 1000000.0;
+const float pi = atan(1.0) * 4.0;
+
+float interpolate(float from, float to, float quotient) {
+    float steppedQ = sin(quotient * pi - pi * 0.5) * 0.5 + 0.5;
+    return from + (to - from) * clamp(steppedQ, 0.0, 1.0);
+}
+
+float noise(float x){
+    return fract(sin(x) * 43758.5453123);
+}
+
+float terrain(float x) {
+    float result = 0.0;
+
+    float frequency = 0.01;
+    float amplitude = 1.0;
+
+    for (int i = 0; i < 8; i++) {
+        result += sin(2.0 * pi * x * frequency - 2.0 * pi * noise(float(i) * 200.0)) * amplitude;
+        frequency *= 1.5;
+        amplitude /= 1.2;
+    }
+
+    return result;
+}
+
+vec2 random2(vec2 st){
+    st = vec2( dot(st,vec2(127.1,311.7)),
+              dot(st,vec2(269.5,183.3)) );
+    return -1.0 + 2.0*fract(sin(st)*43758.5453123);
+}
+
+float noise(vec2 st) {
+    vec2 i = floor(st);
+    vec2 f = fract(st);
+
+    vec2 u = f*f*(3.0-2.0*f);
+
+    return mix( mix( dot( random2(i + vec2(0.0,0.0) ), f - vec2(0.0,0.0) ),
+                     dot( random2(i + vec2(1.0,0.0) ), f - vec2(1.0,0.0) ), u.x),
+                mix( dot( random2(i + vec2(0.0,1.0) ), f - vec2(0.0,1.0) ),
+                     dot( random2(i + vec2(1.0,1.0) ), f - vec2(1.0,1.0) ), u.x), u.y);
+}