From c3c2451232bfeeaa0d5fc200e4a5a27e13c258d2 Mon Sep 17 00:00:00 2001
From: mattkae <mattkae@protonmail.com>
Date: Mon, 17 Jan 2022 08:46:49 -0500
Subject: Generating slightly prettier snowflakes

---
 themes/Snowflake.cpp    |  19 +++++++++++++++----
 themes/Snowflake.h      |   7 +++++--
 themes/dist/output.wasm | Bin 82223 -> 82965 bytes
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/themes/Snowflake.cpp b/themes/Snowflake.cpp
index 3c9afa4..da42515 100644
--- a/themes/Snowflake.cpp
+++ b/themes/Snowflake.cpp
@@ -5,7 +5,7 @@
 
 const Vector4 snowColor = Vector4(1.0, 0.98, 0.98, 1);
 
-inline void generateSnowflakeShape(List<Renderer2dVertex>* vertices, int32 numArms, float32 radius) {
+inline void generateSnowflakeShape(List<Renderer2dVertex>* vertices, int32 numArms, float32 radius, float32 innerRadius) {
 	float32 dx = ((2 * PI) / numArms) / 3.0;
 	for (int32 centerIdx = 0; centerIdx < (3 * numArms); centerIdx+=3) {
 	    float32 degreeStart = dx * centerIdx;
@@ -20,8 +20,8 @@ inline void generateSnowflakeShape(List<Renderer2dVertex>* vertices, int32 numAr
 		Vector2 leftEnd = Vector2(radius * cosStart, radius * sinStart);
 		Vector2 rightEnd = Vector2(radius * cosEnd, radius * sinEnd);
 		Vector2 diff = (rightEnd - leftEnd) / 2.0;
-		Vector2 leftStart = Vector2(-diff.x, -diff.y);
-		Vector2 rightStart = diff;
+		Vector2 leftStart = Vector2(-diff.x, -diff.y) + Vector2(innerRadius * cosStart, innerRadius * sinStart);
+		Vector2 rightStart = diff + Vector2(innerRadius * cosEnd, innerRadius * sinEnd);
 
 		vertices->add({ leftStart, snowColor, Mat4x4() });
 		vertices->add({ leftEnd, snowColor, Mat4x4() });
@@ -34,7 +34,7 @@ inline void generateSnowflakeShape(List<Renderer2dVertex>* vertices, int32 numAr
 
 inline void initFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud) {
 	ud->vtxIdx = renderer->vertices.numElements;
-	generateSnowflakeShape(&renderer->vertices, 6, randomFloatBetween(8.f, 24.f);
+	generateSnowflakeShape(&renderer->vertices, randomIntBetween(4, 16), randomFloatBetween(8.f, 16.f), randomFloatBetween(2.f, 6.f));
 	ud->numVertices = renderer->vertices.numElements - ud->vtxIdx;
 }
 
@@ -113,8 +113,19 @@ void SnowflakeParticleRenderer::update(float32 dtSeconds) {
 		findAndSpawnNextFlake(this);
 	}
 
+	bool addWind = false;
+	timeUntilNextWindSeconds -= dtSeconds;
+	if (timeUntilNextWindSeconds < 0) {
+		timeUntilNextWindSeconds = windIntervalSeconds;
+		windSpeed = Vector2(randomFloatBetween(-10, 10), randomFloatBetween(-10, 0));
+		addWind = true;
+	}
+
 	for (int32 s = startIndex; s < endIndex; s++) {
 		SnowflakeUpdateData* ud = &updateData[s];
+
+		if (addWind) ud->velocity += windSpeed;
+		
 		ud->position += ud->velocity * dtSeconds;
 
 		Mat4x4 m = Mat4x4().translateByVec2(ud->position);
diff --git a/themes/Snowflake.h b/themes/Snowflake.h
index 08f1c0c..d44851b 100644
--- a/themes/Snowflake.h
+++ b/themes/Snowflake.h
@@ -14,6 +14,7 @@ struct SnowflakeLoadParameters {
 	float32 flakeSizeDeviation = 1.f;
 	Vector4 snowColor = { 0.8, 0.8, 0.8, 1.0 };
 	float32 spawnIntervalSeconds = 0.3;
+	float32 windIntervalSeconds = 1.5;
 };
 
 struct SnowflakeUpdateData {
@@ -31,12 +32,14 @@ struct SnowflakeParticleRenderer {
 	float32 xMax = 0;
 	float32 yMax = 0;
 	float32 spawnIntervalSeconds = 0.3;
+	float32 windIntervalSeconds = 1.5;
 	int32 startIndex = 0;
 	int32 endIndex = 0;
 	int32 numSnowflakes = 0;
-    Vector3 windSpeed = { 0, 0, 0 };
+    Vector2 windSpeed;
 	SnowflakeUpdateData* updateData;
-	float32 timeUntilNextSpawnSeconds = 0;;
+	float32 timeUntilNextSpawnSeconds = 0;
+	float32 timeUntilNextWindSeconds = 0;
 
 	uint32 vao;
 	uint32 vbo;
diff --git a/themes/dist/output.wasm b/themes/dist/output.wasm
index 427f834..776adba 100755
Binary files a/themes/dist/output.wasm and b/themes/dist/output.wasm differ
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