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#include <particle.hpp>
#include <engine.hpp>
#include <render.hpp>
#include <world.hpp>
ParticleSystem::ParticleSystem(int count, bool m)
: max(m)
{
parts.reserve(count);
}
void ParticleSystem::add(const vec2& pos, const ParticleType& type)
{
// TODO not enforce max
if (/*max &&*/ parts.size() + 1 >= parts.capacity())
return;
parts.emplace_back(pos, type);
}
void ParticleSystem::addMultiple(const int& count, const ParticleType& type, std::function<vec2(void)> f)
{
int togo = count;
while (togo-- > 0)
parts.emplace_back(f(), type);
}
void ParticleSystem::render(void) const
{
static GLuint particleVBO = 9999, texVBO = 0;
if (particleVBO == 9999) {
glGenBuffers(1, &particleVBO);
glBindBuffer(GL_ARRAY_BUFFER, particleVBO);
glBufferData(GL_ARRAY_BUFFER, parts.capacity() * 18 * sizeof(GLfloat), nullptr,
GL_STREAM_DRAW);
glGenBuffers(1, &texVBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, texVBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, parts.capacity() * 12 * sizeof(GLfloat), nullptr,
GL_STATIC_DRAW);
int top = (parts.capacity() - 1) * 12 * sizeof(GLfloat), i = 0;
unsigned char zero = 0;
while (i < top) {
glBufferSubData(GL_ELEMENT_ARRAY_BUFFER, i, 1, &zero);
i++;
}
}
glBindBuffer(GL_ARRAY_BUFFER, particleVBO);
// copy data into VBO
int offset = 0;
for (const auto& p : parts) {
GLfloat coords[18] = {
p.location.x, p.location.y, -1,
p.location.x, p.location.y + 5, -1,
p.location.x + 5, p.location.y + 5, -1,
p.location.x + 5, p.location.y + 5, -1,
p.location.x + 5, p.location.y, -1,
p.location.x, p.location.y, -1
};
glBufferSubData(GL_ARRAY_BUFFER, offset, 18 * sizeof(GLfloat), coords);
offset += 18 * sizeof(GLfloat);
}
Render::worldShader.use();
Render::worldShader.enable();
Colors::blue.use();
//glUniform4f(Render::worldShader.uniform[WU_tex_color], 0.0f, 0.0f, 1.0f, 1.0f);
glEnableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER, particleVBO);
glVertexAttribPointer(Render::worldShader.coord, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, texVBO);
glVertexAttribPointer(Render::worldShader.tex, 2, GL_FLOAT, GL_FALSE, 0, 0);
glDrawArrays(GL_TRIANGLES, 0, parts.size() * 6);
glDisableClientState(GL_VERTEX_ARRAY);
Render::worldShader.disable();
Render::worldShader.unuse();
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}
void ParticleSystem::update(entityx::EntityManager &en, entityx::EventManager &ev, entityx::TimeDelta dt)
{
(void)en;
(void)ev;
(void)dt; // TODO use for time to die
auto& worldSystem = *game::engine.getSystem<WorldSystem>();
for (auto part = std::begin(parts); part != std::end(parts); part++) {
auto& p = *part;
// update timers
p.timeLeft -= dt;
if (p.timeLeft <= 0)
parts.erase(part);
// update movement
switch (p.type) {
case ParticleType::Drop:
if (p.velocity.y > -.6)
p.velocity.y -= 0.001f;
break;
case ParticleType::Confetti:
break;
}
// really update movement
p.location.x += p.velocity.x * dt;
p.location.y += p.velocity.y * dt;
// world collision
auto height = worldSystem.isAboveGround(p.location);
if (height != 0)
p.location.y = height + 5, p.velocity.y = randGet() % 10 / 40.0f;
}
}
int ParticleSystem::getCount(void) const
{
return parts.size();
}
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