From 7f83d0d65acba1c1a5b65a8258b75d1f318c22f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A1s=20Schmelczer?= <andras@schmelczer.dev>
Date: Sat, 29 Jan 2022 21:11:32 +0100
Subject: [PATCH] Add hexagons
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Signed-off-by: András Schmelczer <andras@schmelczer.dev>
---
 src/drawables/shapes/hexagon-factory.ts | 69 +++++++++++++++++++++++++
 src/main.ts                             |  1 +
 2 files changed, 70 insertions(+)
 create mode 100644 src/drawables/shapes/hexagon-factory.ts

diff --git a/src/drawables/shapes/hexagon-factory.ts b/src/drawables/shapes/hexagon-factory.ts
new file mode 100644
index 0000000..19d0df1
--- /dev/null
+++ b/src/drawables/shapes/hexagon-factory.ts
@@ -0,0 +1,69 @@
+import { mat2d, vec2, vec3, vec4 } from 'gl-matrix';
+import { codeForColorAccess } from '../../helper/code-for-color-access';
+import { DrawableDescriptor } from '../drawable-descriptor';
+import { EmptyDrawable } from '../empty-drawable';
+
+/**
+ * @category Drawable
+ */
+class HexagonBase extends EmptyDrawable {
+  constructor(public center: vec2, public radius: number) {
+    super();
+  }
+}
+
+/**
+ * @category Drawable
+ */
+export const HexagonFactory = (color: vec3 | vec4 | number): typeof HexagonBase => {
+  class Hexagon extends HexagonBase {
+    public static descriptor: DrawableDescriptor = {
+      sdf: {
+        shader: `
+            uniform vec2 circleCenters[CIRCLE_COUNT];
+            uniform float circleRadii[CIRCLE_COUNT];
+  
+            float circleMinDistance(vec2 target, out vec4 color) {
+              color = ${codeForColorAccess(color)};
+              float minDistance = 1000.0;
+              for (int i = 0; i < CIRCLE_COUNT; i++) {
+                const vec3 k = vec3(-0.866025404,0.5,0.577350269);
+                float r = circleRadii[i];
+                vec2 p = abs(target - circleCenters[i]);
+                float cosa = 0.8660;
+                float sina = 0.5;
+                p = vec2(cosa * p.x - sina * p.y, sina * p.x + cosa * p.y);
+                p -= 2.0*min(dot(k.xy,p),0.0)*k.xy;
+                p -= vec2(clamp(p.x, -k.z*r, k.z*r), r);
+                float dist = length(p)*sign(p.y);
+                minDistance = min(minDistance, dist);
+              }
+  
+              return minDistance;
+            }
+          `,
+        distanceFunctionName: 'circleMinDistance',
+      },
+      propertyUniformMapping: {
+        center: 'circleCenters',
+        radius: 'circleRadii',
+      },
+      uniformCountMacroName: 'CIRCLE_COUNT',
+      shaderCombinationSteps: [0, 1, 2, 3, 8, 16],
+      empty: new Hexagon(vec2.create(), 0),
+    };
+
+    public minDistance(target: vec2): number {
+      return vec2.dist(this.center, target) - this.radius;
+    }
+
+    protected getObjectToSerialize(transform2d: mat2d, transform1d: number): any {
+      return {
+        center: vec2.transformMat2d(vec2.create(), this.center, transform2d),
+        radius: this.radius * transform1d,
+      };
+    }
+  }
+
+  return Hexagon;
+};
diff --git a/src/main.ts b/src/main.ts
index 2dbdd0f..c98086c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -33,6 +33,7 @@ export * from './drawables/drawable-descriptor';
 export * from './drawables/lights/circle-light';
 export * from './drawables/lights/flashlight';
 export * from './drawables/shapes/circle-factory';
+export * from './drawables/shapes/hexagon-factory';
 export * from './drawables/shapes/colorful-circle';
 export * from './drawables/shapes/droplet-factory';
 export * from './drawables/shapes/inverted-tunnel-factory';