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perlin.cc
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perlin.cc
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/** This creates a random flow field using my noise implementation
* and then uses OpenGL to render particles that travel in said flow field */
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <ctime>
#include <cmath>
#include <shader.h>
#include <noise.h> // My noise implementation
#include <random>
const int W = 1366;
const int H = 768;
const int xSize = 112; // Amount of vectors along x
const int ySize = 64; // Amount of vectors along y
const double frameStep = 0.0001; // Determines how fast the "z-axis" of the noise changes
const double axisStep = 0.01; // Magnitude of x and y axis of noise
const int lineCount = 10000; // How many particles
const double maxVel = 0.001; // Max velocity of particles
const double pi = 3.1415926535;
/** A bare minimum vector class
* Capable of creating a vector 1/10th of
* maxVel in magnitude from a given angle
* operator+= is used to move particles */
class Vector{
public:
GLfloat x, y;
Vector(): x(0), y(0) {}
void setAngle(double angle){
x = cos(angle)*maxVel*0.01;
y = sin(angle)*maxVel*0.01;
// cout << "Angle: " << angle << " -> " << x << ", " << y << endl;
}
void operator+=(Vector other){
x += other.x;
y += other.y;
double mag = sqrt(x*x+y*y);
if(mag > maxVel){
x *= maxVel/mag;
y *= maxVel/mag;
}
}
};
/** Line struct used to pass line vertices to
* graphics card through vbo */
struct Line{
GLfloat x1;
GLfloat y1;
GLfloat x2;
GLfloat y2;
};
/** Lines class to keep track of all particles
* Named Lines since a particle is a line to OpenGL */
class Lines{
public:
Line *lines; // Particles
Vector *vels; // Current velocities
int size;
/** Creates count number of particles and gives then random positions */
Lines(int count): size(count){
std::mt19937 rand(time(0));
lines = new Line[count];
vels = new Vector[count];
for(int i=0; i<count; ++i){
lines[i].x1 = lines[i].x2 = (float)rand()*2/rand.max()-1.0;
lines[i].y1 = lines[i].y2 = (float)rand()*2/rand.max()-1.0;
}
}
/** Updates all particles according to flow field
* param: vectors - flow field vectors */
void update(Vector **vectors){
for(int i=0, x, y; i<size; ++i){
// cout << lines[i].x1 << ", " << lines[i].y1 << " -> ";
// cout << (lines[i].x1+1.0)*(float)W/2 << ", " << (lines[i].y1+1.0)*(float)H/2 << " -> ";
x = (lines[i].x1 >= 1.0) ? xSize-1 : (int)((lines[i].x1+1.0)*(float)(W/2)/(float)(W/xSize));
y = (lines[i].y1 >= 1.0) ? ySize-1 : (int)((lines[i].y1+1.0)*(float)(H/2)/(float)(H/ySize));
// cout << x << ", " << y << endl;
vels[i] += vectors[y][x];
// cout << vels[i].x << ", " << vels[i].y << endl;
setPrev(i);
lines[i].x1 += vels[i].x;
lines[i].y1 += vels[i].y;
if(lines[i].x1 > 1.0f && vels[i].x > 0){
lines[i].x1 = -1.0f;
setPrev(i);
}
else if(lines[i].x1 < -1.0f && vels[i].x < 0){
lines[i].x1 = 1.0f;
setPrev(i);
}
if(lines[i].y1 > 1.0f && vels[i].y > 0){
lines[i].y1 = -1.0f;
setPrev(i);
}
else if(lines[i].y1 < -1.0f && vels[i].y < 0){
lines[i].y1 = 1.0f;
setPrev(i);
}
// cout << lines[i].x1 << ", " << lines[i].y1 << " <- " << lines[i].x2 << ", " << lines[i].y2 << endl;
}
}
/** Just a little helper for updating previous particle positions */
void setPrev(int index){
lines[index].x2 = lines[index].x1;
lines[index].y2 = lines[index].y1;
}
~Lines(){
delete[] lines;
delete[] vels;
}
};
/** Key callback for closing window when esc is pressed */
void keyCallback(GLFWwindow *window, int key, int scancode, int action, int mode){
if(key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) glfwSetWindowShouldClose(window, GL_TRUE);
}
int main(){
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 5);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow *window = glfwCreateWindow(W, H, "Perlin", glfwGetPrimaryMonitor(), nullptr);
glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, keyCallback);
glewExperimental = GL_TRUE;
glewInit();
glViewport(0, 0, W, H);
Lines particles(lineCount);
GLuint vao, vbo; // Make OpenGL vertex buffer and vertex array
glGenBuffers(1, &vbo);
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(Line)*lineCount, particles.lines, GL_STREAM_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(0);
glBindVertexArray(0);
NoiseGenerator perlin(time(0));
Vector **vectors = new Vector*[ySize];
for(int i=0; i<ySize; ++i) vectors[i] = new Vector[xSize];
shader sp("vertex.shader", "fragment.shader"); // Shader program
sp.use();
int frames = 0;
glEnable(GL_ALPHA_TEST); // enable alpha test and blending
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glClearColor(1.0, 1.0, 1.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
while(!glfwWindowShouldClose(window)){
glfwPollEvents();
for(int i=0; i<ySize; ++i){
for(int j=0; j<xSize; ++j){ // Update vectors according to noise
vectors[i][j].setAngle(perlin(j*axisStep/*+i*frameStep*/, i*axisStep/*+j*frameStep*/, frames*frameStep)*2*pi);
// cout << perlin(j*frameStep, i*frameStep, frames*frameStep) << endl;
}
}
particles.update(vectors); // Update particles
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(Line)*lineCount, particles.lines); // Update VBO
glDrawArrays(GL_LINES, 0, lineCount*2);
glBindVertexArray(0);
glfwSwapBuffers(window);
++frames;
}
glDeleteVertexArrays(1, &vao);
glDeleteBuffers(1, &vbo);
glfwTerminate();
for(int i=0; i<ySize; ++i) delete[] vectors[i];
delete[] vectors;
return 0;
}