1 files changed, 114 insertions, 0 deletions
diff --git a/front/src/components/animated_bg.tsx b/front/src/components/animated_bg.tsx
new file mode 100644
index 0000000..6a8ab3a
--- /dev/null
+++ b/front/src/components/animated_bg.tsx
@@ -0,0 +1,114 @@
+import { Shaders, Node, GLSL } from "gl-react";
+import { Surface } from "gl-react-dom";
+import React from "preact/compat";
+import { PropsWithChildren } from "preact/compat";
+
+const shaders = Shaders.create({
+    letters: {
+        frag: GLSL`
+precision highp float;
+varying vec2 uv;
+uniform vec3 color;
+uniform sampler2D t;
+uniform float time;
+uniform vec2 tiles;
+uniform float symbol_count;
+
+vec2 map_to_symbol_uv(vec2 image_coord, float symbol_index) {
+    float symbol_width = 1.0 / symbol_count;
+    float symbol_height = 1.0;
+    float symbol_x = symbol_index * symbol_width;
+    return vec2(symbol_x + image_coord.x * symbol_width, image_coord.y * symbol_height);
+}
+
+vec2 tile_index(vec2 p, vec2 tiles) {
+    return vec2(floor(p.x * tiles.x), floor(p.y * tiles.y));
+}
+
+vec2 tilefy (vec2 p, vec2 tiles) {
+    return vec2(fract(p.x * tiles.x), fract(p.y * tiles.y));
+}
+
+float randf(float n) {
+    return fract(sin(n) * 43758.5453123);
+}
+
+void main() {
+    vec2 tile = tile_index(uv, tiles);
+    float tilerand = randf(tile.x + tile.y * tiles.x);
+    float v = tilerand + randf(floor(tilerand * time));
+    float diff = fract(tilerand * time);
+    float s = floor(v * 9.0);
+    vec2 tp = tilefy(uv, tiles);
+    vec2 tp_center = vec2(0.5, 0.5);
+    float d = distance(tp, tp_center);
+    float scale = min(sin(diff * 3.1415) * 1.2, 1.0);
+    tp = tp_center + (tp - tp_center) / scale;
+    if (tp.x < 0.0 || tp.x > 1.0 || tp.y < 0.0 || tp.y > 1.0) {
+        gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);
+        return;
+    }
+    vec2 p = map_to_symbol_uv(tp, mod(s, symbol_count));
+    vec4 c = texture2D(t, p);
+    c.rgb *= color;
+    c.a *= uv.y * 4.0;
+    gl_FragColor = vec4(c.rgb * c.a, c.a);
+}
+`
+    }
+});
+
+const fps = 60;
+
+const AnimatedBgInternal = ({ tick }: { tick: number }) => {
+    const t = "/assets/images/symbols.png";
+
+    return (
+        <div style={{ position: "absolute", top: 0, left: 0, width: "100%", height: "100%", zIndex: -10 }}>
+            <Surface width={window.innerWidth} height={window.innerHeight / 2}>
+                <Node
+                    shader={shaders.letters}
+                    uniforms={{
+                        t,
+                        color: [42 / 255, 42 / 255, 80 / 255],
+                        tiles: [Math.ceil(window.innerWidth / 32), Math.ceil(window.innerHeight / 64)],
+                        symbol_count: 9,
+                        time: tick / 60
+                    }}
+                    uniformsOptions={{
+                        t: { interpolation: "nearest" }
+                    }} />
+            </Surface>
+        </div>
+    );
+}
+
+// a higher order component that provides a tick prop
+// that updates every 1/refreshRate seconds
+//
+// accepts a JSX component as an argument
+const timeLoop = (
+    C: (props: PropsWithChildren<{ tick: number }>) => React.JSX.Element,
+    { refreshRate }: { refreshRate: number }
+) => {
+    return class TimeLoop extends React.Component {
+        interval: any;
+        state = { tick: 0 };
+
+        componentDidMount() {
+            this.interval = setInterval(() => {
+                this.setState({ tick: this.state.tick + 1 });
+            }, 1000 / refreshRate);
+        }
+
+        componentWillUnmount() {
+            clearInterval(this.interval);
+        }
+
+        render() {
+            return <C {...this.props} tick={this.state.tick} />;
+        }
+    };
+}
+
+export const AnimatedBg = timeLoop(AnimatedBgInternal, { refreshRate: fps });