1 files changed, 128 insertions, 8 deletions

diff --git a/themes/Snowflake.cpp b/themes/Snowflake.cpp
index 54654f0..3c9afa4 100644
--- a/themes/Snowflake.cpp
+++ b/themes/Snowflake.cpp
@@ -1,26 +1,146 @@
 #include "Snowflake.h"
+#include "Renderer2d.h"
+#include "mathlib.h"
+#include "List.h"
+
+const Vector4 snowColor = Vector4(1.0, 0.98, 0.98, 1);
+
+inline void generateSnowflakeShape(List<Renderer2dVertex>* vertices, int32 numArms, float32 radius) {
+	float32 dx = ((2 * PI) / numArms) / 3.0;
+	for (int32 centerIdx = 0; centerIdx < (3 * numArms); centerIdx+=3) {
+	    float32 degreeStart = dx * centerIdx;
+		float32 degreeEnd = dx * (centerIdx + 1);
+
+		float32 cosStart = cosf(degreeStart);
+		float32 cosEnd = cosf(degreeEnd);
+
+		float32 sinStart = sinf(degreeStart);
+		float32 sinEnd = sinf(degreeEnd);
+
+		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;
+
+		vertices->add({ leftStart, snowColor, Mat4x4() });
+		vertices->add({ leftEnd, snowColor, Mat4x4() });
+		vertices->add({ rightEnd, snowColor, Mat4x4() });
+		vertices->add({ rightEnd, snowColor, Mat4x4() });
+		vertices->add({ rightStart, snowColor, Mat4x4() });
+		vertices->add({ leftStart, snowColor, Mat4x4() });
+	}
+}
+
+inline void initFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud) {
+	ud->vtxIdx = renderer->vertices.numElements;
+	generateSnowflakeShape(&renderer->vertices, 6, randomFloatBetween(8.f, 24.f);
+	ud->numVertices = renderer->vertices.numElements - ud->vtxIdx;
+}
+
+inline void spawnFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud) {
+	ud->velocity = Vector2(randomFloatBetween(-10, 10), randomFloatBetween(-100, -85));
+	ud->position = Vector2(randomFloatBetween(0, renderer->xMax), randomFloatBetween(renderer->yMax, renderer->yMax + 256));
+}
+
+inline void findAndSpawnNextFlake(SnowflakeParticleRenderer* renderer) {
+    do {
+	    renderer->endIndex++;
+
+		if (renderer->endIndex >= renderer->numSnowflakes)
+			renderer->endIndex = 0;
+	} while (renderer->updateData[renderer->endIndex].onGround);
+
+	spawnFlake(renderer, &renderer->updateData[renderer->endIndex]);
+}
 
 void SnowflakeParticleRenderer::load(SnowflakeLoadParameters params, Renderer2d* renderer) {
-	updateData = new SnowflakeUpdateData[maxSnowflakes];
-    renderData = new SnowflakeRenderData[maxSnowflakes];
-	activeIndex = 0;
+	startIndex = 0;
+	spawnIntervalSeconds = params.spawnIntervalSeconds;
+	endIndex = params.initialSnowflakeCount;
+	numSnowflakes = params.maxSnowflakes;
+
+	updateData = new SnowflakeUpdateData[params.maxSnowflakes];
 
-	for (int32 s = 0; s < maxSnowflakes; s++) {
+	xMax = static_cast<float32>(renderer->context->width);
+    yMax = static_cast<float32>(renderer->context->height);
+	
+	// Initialize each snow flake with its shape
+	for (int32 s = 0; s < numSnowflakes; s++) {
 		auto ud = &updateData[s];
-		auto rd = &renderData[s];
+	    initFlake(this, ud);
+
+		if (s < endIndex) {
+			spawnFlake(this, ud);
+		}
+	}
+
+	useShader(renderer->shader);
+
+    glGenVertexArrays(1, &vao);
+    glBindVertexArray(vao);
+
+    glGenBuffers(1, &vbo);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, vertices.numElements * sizeof(Renderer2dVertex), &vertices.data[0], GL_DYNAMIC_DRAW);
+
+    glEnableVertexAttribArray(renderer->attributes.position);
+    glVertexAttribPointer(renderer->attributes.position, 2, GL_FLOAT, GL_FALSE, sizeof(Renderer2dVertex), (GLvoid *)0);
+
+    glEnableVertexAttribArray(renderer->attributes.color);
+    glVertexAttribPointer(renderer->attributes.color, 4, GL_FLOAT, GL_FALSE, sizeof(Renderer2dVertex), (GLvoid *)offsetof(Renderer2dVertex, color));
 
-		ud->velocity = params->flakeV0;
+	for (int32 idx = 0; idx < 4; idx++) {
+		int32 offset = (4 * sizeof(float32)) * idx;
+		glEnableVertexAttribArray(renderer->attributes.vMatrix + idx);
+		glVertexAttribPointer(renderer->attributes.vMatrix + idx,
+							  4,
+							  GL_FLOAT,
+							  GL_FALSE,
+							  sizeof(Renderer2dVertex),
+							  (GLvoid *)(offsetof(Renderer2dVertex, vMatrix) + offset));
+		//glVertexAttribDivisor(renderer->attributes.vMatrix + idx, 1);
 	}
+
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindVertexArray(0);
 }
 
 void SnowflakeParticleRenderer::update(float32 dtSeconds) {
-	
+	timeUntilNextSpawnSeconds -= dtSeconds;
+	if (timeUntilNextSpawnSeconds < 0) {
+		timeUntilNextSpawnSeconds = spawnIntervalSeconds;
+		findAndSpawnNextFlake(this);
+	}
+
+	for (int32 s = startIndex; s < endIndex; s++) {
+		SnowflakeUpdateData* ud = &updateData[s];
+		ud->position += ud->velocity * dtSeconds;
+
+		Mat4x4 m = Mat4x4().translateByVec2(ud->position);
+		for (int32 v = ud->vtxIdx; v < (ud->vtxIdx + ud->numVertices); v++) {
+		    vertices.data[v].vMatrix = m;
+		}
+	}
 }
 
 void SnowflakeParticleRenderer::render(Renderer2d* renderer) {
+	auto startVertex = &updateData[startIndex];
+	auto endVertex = &updateData[endIndex];
+	int32 numVertices = (endVertex->vtxIdx + endVertex->numVertices) - startVertex->vtxIdx;
+	setShaderMat4(renderer->uniforms.model, model);
 
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferSubData(GL_ARRAY_BUFFER, 0, numVertices * sizeof(Renderer2dVertex), &vertices.data[startVertex->vtxIdx]);
+
+    glBindVertexArray(vao);
+    glDrawArrays(GL_TRIANGLES, 0, numVertices);
+    glBindVertexArray(0);
 }
 
 void SnowflakeParticleRenderer::unload() {
-
+	glDeleteVertexArrays(1, &vao);
+    glDeleteBuffers(1, &vbo);
+	vertices.deallocate();
+	delete [] updateData;
 }