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#include "LeafParticleRender.h"
#include "Renderer2d.h"
#include "mathlib.h"
#include "TreeShape.h"
#include "types.h"
#include <math.h>
const int32 verticesPerLeaf = 6;
const float32 leafRadius = 3.f;
const int32 fallChanceMax = 100;
inline void updateLeaf(Renderer2dVertex* vertices, Vector2 position, Vector4 color, float32 scale) {
float32 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 };
vertices[1] = { bottomRight, color };
vertices[2] = { topLeft, color };
vertices[3] = { topLeft, color };
vertices[4] = { topRight, color };
vertices[5] = { bottomRight, color };
}
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 Renderer2dVertex[numVertices];
for (int32 leafIdx = 0; leafIdx < numLeaves; leafIdx++) {
int32 randomBranch = randomIntBetween(0, lr->numBranches);
int32 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(Renderer2dVertex), &vertices[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));
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
void LeafParticleRender::update(float32 dtSeconds) {
elapsedTimeSeconds += dtSeconds;
// Every time the fallIntervalSeconds passes, we remove one leaf
// from the tree and send it barrelling towards the earth.
int32 fallRoll;
bool didGenerateFall = false;
if (elapsedTimeSeconds >= fallIntervalSeconds) {
fallRoll = randomIntBetween(0, fallChanceMax);
didGenerateFall = true;
elapsedTimeSeconds = 0;
}
for (int32 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 float32 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(Renderer2dVertex), &vertices[0]);
glBindVertexArray(vao);
glDrawArrays(GL_TRIANGLES, 0, numVertices);
glBindVertexArray(0);
}
void LeafParticleRender::unload() {
glDeleteVertexArrays(1, &vao);
glDeleteBuffers(1, &vbo);
delete [] vertices;
delete [] updateData;
elapsedTimeSeconds = 0;
}
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