143 lines
4.4 KiB
C++
143 lines
4.4 KiB
C++
#pragma once
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#include "glew.h"
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#include <GLFW/glfw3.h>
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#include "glm.hpp"
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#include <list>
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#include "ext.hpp"
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struct Particle
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{
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public:
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float birthTime;
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glm::vec3 startPosition;
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glm::vec3 direction;
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glm::vec3 randomPointOnCircle;
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float getAge(float time) {
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return time - birthTime;
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}
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};
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class ParticleSystem
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{
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private:
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std::list<Particle> particles;
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GLuint VBO;
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GLuint VAO;
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GLfloat vertices[9];
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float lastGenerated = -1.f;
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bool shouldGenerateNewParticle(float time) {
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return lastGenerated == -1.f || time - lastGenerated > generationInterval;
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}
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glm::vec3 generateRandomPointOnCircle() {
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float distanceFromCenter = static_cast <float> (rand()) / static_cast <float> (RAND_MAX/sourceRadius);
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float radians = static_cast <float> (rand()) / static_cast <float> (RAND_MAX / 6.28f);
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glm::vec3 referenceVector(0.0f, 1.0f, 0.0f);
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glm::vec3 output = glm::normalize(glm::cross(sourceDirection, referenceVector)) * distanceFromCenter;
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glm::mat4 rotationMatrix = glm::rotate(glm::mat4(1.0f), radians, sourceDirection);
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output = glm::vec3(rotationMatrix * glm::vec4(output, 1.0f));
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return output;
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}
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void generateNewParticle(float time) {
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Particle newParticle;
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newParticle.birthTime = time;
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newParticle.startPosition = sourcePosition;
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newParticle.randomPointOnCircle = generateRandomPointOnCircle();
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newParticle.direction = sourceDirection;
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particles.push_back(newParticle);
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lastGenerated = time;
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}
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void deleteOld(float time) {
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auto it = particles.begin();
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while (it != particles.end()) {
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if ((*it).getAge(time) > lifetime) {
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it = particles.erase(it);
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}
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else {
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++it;
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}
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}
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}
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glm::vec3 calculateParticleColor(float age) {
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float rate = glm::clamp(age / lifetime, 0.f, 1.f);
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glm::vec3 mixedColor = (1.0f - rate) * startColor + rate * endColor;
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return mixedColor;
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}
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public:
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glm::vec3 sourcePosition;
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float sourceRadius = 0.02f;
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glm::vec3 sourceDirection = glm::vec3(1.f, 0.f, 0.f);
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float generationInterval = 0.0025f;
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float lifetime = 0.5f;
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float speed = 100.f;
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glm::vec3 startColor = glm::vec3(1.f, 0.f, 0.f);
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glm::vec3 endColor = glm::vec3(1.f, 1.f, 0.f);
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ParticleSystem() {
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// Inicjalizacja wierzcho<68>k<EFBFBD>w tr<74>jk<6A>ta w 3D
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vertices[0] = -0.5f; vertices[1] = -0.5f; vertices[2] = 0.0f;
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vertices[3] = 0.5f; vertices[4] = -0.5f; vertices[5] = 0.0f;
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vertices[6] = 0.0f; vertices[7] = 0.5f; vertices[8] = 0.0f;
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glGenBuffers(1, &VBO);
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
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glGenVertexArrays(1, &VAO);
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glBindVertexArray(VAO);
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (void*)0);
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glEnableVertexAttribArray(0);
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glBindVertexArray(0);
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}
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void drawParticles(GLuint program, glm::mat4 view, glm::mat4 projection, float time) {
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if (shouldGenerateNewParticle(time)) {
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generateNewParticle(time);
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}
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deleteOld(time);
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glUseProgram(program);
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GLuint modelLoc = glGetUniformLocation(program, "model");
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GLuint viewLoc = glGetUniformLocation(program, "view");
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GLuint projectionLoc = glGetUniformLocation(program, "projection");
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GLuint colorLoc = glGetUniformLocation(program, "color");
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int i = 0;
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for (auto particle : particles) {
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glm::vec3 color = calculateParticleColor(particle.getAge(time));
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glUniform3f(colorLoc, color.x, color.y, color.z);
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glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
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glUniformMatrix4fv(projectionLoc, 1, GL_FALSE, glm::value_ptr(projection));
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glm::mat4 model = glm::translate(glm::mat4(1.0f), sourcePosition + particle.randomPointOnCircle);
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model = glm::scale(model, glm::vec3(0.005f, 0.005f, 0.005f));
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model = glm::translate(model, particle.direction * speed * (time - particle.birthTime));
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glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
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glBindVertexArray(VAO);
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glDrawArrays(GL_TRIANGLES, 0, 3);
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i++;
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}
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glBindVertexArray(0);
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}
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};
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