1 files changed, 166 insertions, 0 deletions
diff --git a/themes/src/autumn/LeafParticleRender.cpp b/themes/src/autumn/LeafParticleRender.cpp
new file mode 100644
index 0000000..fee3df2
--- /dev/null
+++ b/themes/src/autumn/LeafParticleRender.cpp
@@ -0,0 +1,166 @@
+#include "LeafParticleRender.h"
+#include "../Renderer2d.h"
+#include "../mathlib.h"
+#include "TreeShape.h"
+#include "../types.h"
+#include <math.h>
+
+const i32 verticesPerLeaf = 6; 
+const f32 leafRadius = 3.f;
+const i32 fallChanceMax = 100;
+
+inline void updateLeaf(Vertex2D* vertices, Vector2 position, Vector4 color, f32 scale) {
+    f32 radius = scale * leafRadius;
+    Vector2 bottomLeft = Vector2(-radius, -radius) + position;
+    Vector2 bottomRight = Vector2(radius, -radius) + position;
+    Vector2 topLeft = Vector2(-radius, radius) + position;
+    Vector2 topRight = Vector2(radius, radius) + position;
+
+    vertices[0] = { bottomLeft, color, Mat4x4() };
+    vertices[1] = { bottomRight, color, Mat4x4() };
+    vertices[2] = { topLeft, color, Mat4x4() };
+    vertices[3] = { topLeft, color, Mat4x4() };
+    vertices[4] = { topRight, color, Mat4x4() };
+    vertices[5] = { bottomRight, color, Mat4x4() };
+}
+
+void LeafParticleRender::load(Renderer2d *renderer, TreeShapeLoadResult* lr) {
+    LeafParticleLoadData ld;
+    ld.numLeaves = 256;
+    numLeaves = ld.numLeaves;
+    numVertices = ld.numLeaves * verticesPerLeaf;
+
+    updateData = new LeafParticleUpdateData[numLeaves];
+    vertices = new Vertex2D[numVertices];
+
+    for (i32 leafIdx = 0; leafIdx < numLeaves; leafIdx++) {
+        i32 randomBranch = randomIntBetween(0, lr->numBranches);
+        i32 randomVertex = randomIntBetween(0, 6); // TODO: Manually entering num vertices per branch.
+        updateData[leafIdx].vertexToFollow = &lr->updateData[randomBranch].vertices[randomVertex];
+        updateData[leafIdx].fallChance = randomIntBetween(0, fallChanceMax);
+        updateData[leafIdx].color = Vector4(randomFloatBetween(0.3, 0.9), randomFloatBetween(0.1, 0.6), 0, 1);
+        updateData[leafIdx].vertexPtr = &vertices[leafIdx * verticesPerLeaf];
+        updateData[leafIdx].resetTime = randomFloatBetween(4.f, 6.f);
+    }
+
+    useShader(renderer->shader);
+
+    glGenVertexArrays(1, &vao);
+    glBindVertexArray(vao);
+
+    glGenBuffers(1, &vbo);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(Vertex2D), &vertices[0], GL_DYNAMIC_DRAW);
+
+    glEnableVertexAttribArray(renderer->attributes.position);
+    glVertexAttribPointer(renderer->attributes.position, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex2D), (GLvoid *)0);
+
+    glEnableVertexAttribArray(renderer->attributes.color);
+    glVertexAttribPointer(renderer->attributes.color, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex2D), (GLvoid *)offsetof(Vertex2D, color));
+
+	for (i32 idx = 0; idx < 4; idx++) {
+		glEnableVertexAttribArray(renderer->attributes.vMatrix + idx);
+		glVertexAttribPointer(renderer->attributes.vMatrix + idx, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex2D), (GLvoid *)(offsetof(Vertex2D, vMatrix) + (idx * 16)));
+	}
+	
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindVertexArray(0);
+}
+
+void LeafParticleRender::update(f32 dtSeconds) {
+    elapsedTimeSeconds += dtSeconds;
+
+    // Every time the fallIntervalSeconds passes, we remove one leaf
+    // from the tree and send it barrelling towards the earth.
+    i32 fallRoll;
+    bool didGenerateFall = false;
+    if (elapsedTimeSeconds >= fallIntervalSeconds) {
+        fallRoll = randomIntBetween(0, fallChanceMax);
+        didGenerateFall = true;
+        elapsedTimeSeconds = 0;
+    }
+
+    for (i32 leafIdx = 0; leafIdx < numLeaves; leafIdx++) {
+        auto updateDataItem = &updateData[leafIdx];
+
+        if (didGenerateFall) {
+            if (updateDataItem->state == LeafParticleState::OnTree && updateDataItem->fallChance == fallRoll) {
+                updateDataItem->state = LeafParticleState::Falling;
+                updateDataItem->fallPosition = updateDataItem->vertexToFollow->position;
+                updateDataItem->fallVerticalVelocity = -randomFloatBetween(15.f, 25.f);
+                updateDataItem->fallHorizontalFrequency = randomFloatBetween(3.f, 5.f);
+            }
+        }
+
+        switch (updateDataItem->state) {
+        case (LeafParticleState::Remerging): {
+            updateDataItem->timeElapsedSeconds += dtSeconds;
+
+            if (updateDataItem->timeElapsedSeconds >= updateDataItem->resetTime) {
+                updateDataItem->timeElapsedSeconds = 0.f;
+                updateDataItem->state = LeafParticleState::OnTree;
+                updateDataItem->color.w = 1.f;
+                updateDataItem->scale = 1.f;
+            }
+            else {
+                updateDataItem->color.w = (updateDataItem->timeElapsedSeconds / updateDataItem->resetTime);
+                updateDataItem->scale = (updateDataItem->timeElapsedSeconds / updateDataItem->resetTime);
+            }
+
+            updateLeaf(updateDataItem->vertexPtr, updateDataItem->vertexToFollow->position, updateDataItem->color, updateDataItem->scale);
+            break;
+        }
+        case (LeafParticleState::OnGround): {
+            updateDataItem->timeElapsedSeconds += dtSeconds;
+
+            if (updateDataItem->timeElapsedSeconds >= updateDataItem->resetTime) {
+                updateDataItem->timeElapsedSeconds = 0.f;
+                updateDataItem->color.w = 0.f;
+                updateDataItem->state = LeafParticleState::Remerging;
+            }
+            else {
+                updateDataItem->color.w = 1.f - (updateDataItem->timeElapsedSeconds / updateDataItem->resetTime);
+                updateLeaf(updateDataItem->vertexPtr, updateDataItem->fallPosition, updateDataItem->color, updateDataItem->scale);
+            }
+            break;
+        }
+        case (LeafParticleState::Falling): {
+            updateDataItem->timeElapsedSeconds += dtSeconds;
+            const f32 xPosUpdate = cosf(updateDataItem->fallHorizontalFrequency * updateDataItem->timeElapsedSeconds);
+            updateDataItem->fallPosition.x += xPosUpdate;
+            updateDataItem->fallPosition.y += updateDataItem->fallVerticalVelocity * dtSeconds;
+            if (updateDataItem->fallPosition.y <= 50.f) { // TODO: Hardcoded ground for now
+                updateDataItem->fallPosition.y = 50.f;
+                updateDataItem->state = LeafParticleState::OnGround;
+                updateDataItem->timeElapsedSeconds = 0;
+                updateDataItem->resetTime = randomFloatBetween(2.f, 5.f); // TODO: Hardcoded reset interval
+            }
+            updateLeaf(updateDataItem->vertexPtr, updateDataItem->fallPosition, updateDataItem->color, updateDataItem->scale);
+            break;
+        }
+        case (LeafParticleState::OnTree): {
+            updateLeaf(updateDataItem->vertexPtr, updateDataItem->vertexToFollow->position, updateDataItem->color, updateDataItem->scale);
+            break;
+        }
+        }
+    }
+}
+
+void LeafParticleRender::render(Renderer2d *renderer) {
+    setShaderMat4(renderer->uniforms.model, model);
+
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferSubData(GL_ARRAY_BUFFER, 0, numVertices * sizeof(Vertex2D), &vertices[0]);
+
+    glBindVertexArray(vao);
+    glDrawArrays(GL_TRIANGLES, 0, numVertices);
+    glBindVertexArray(0);
+}
+
+void LeafParticleRender::unload() {
+    glDeleteVertexArrays(1, &vao);
+    glDeleteBuffers(1, &vbo);
+    delete [] vertices;
+
+    elapsedTimeSeconds = 0;
+}