210 lines
7.0 KiB
C++
210 lines
7.0 KiB
C++
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#include <stdio.h>
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#include <iostream>
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#include "shader.h"
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#include <cmath>
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#include <GL/glew.h>
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#include <GLFW/glfw3.h>
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#include <glm/glm.hpp>
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#include <glm/gtc/matrix_transform.hpp>
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#include <glm/gtc/type_ptr.hpp>
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GLFWwindow* window;
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#define PI 3.141592 // PI approximate value
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#define HEIGHT 0.0025 // step length for numerical integration
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#define ROD_LENGHT 0.5 // length of rod
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#define GRAVITY 9.81 // gravitational constant
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#define theta_0 PI / 2 // Initial angle
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#define omega_0 0 // Initial angular velocity
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#define time_0 0 // Initial time
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#define RADIUS 0.10 // Radius of pendulum circle
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#define A 1.4 // Amplitude of the driving force
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#define k 0.67 // Frequency of the driving force
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#define CIRCLE_AMOUNT 10
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// Function for angular velocity (f function for numerical integration)
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float f(float time, float theta, float omega) {
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return omega;
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}
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// Function for angular acceleration (g function for numerical integration)
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float g(float time, float theta, float omega) {
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return -(GRAVITY / ROD_LENGHT) * sin(theta);
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}
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// Function to draw the circle (pendulum ball)
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void drawCircle(float array[]) {
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const int circle_offset = 2160;
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for(int i = 0; i < CIRCLE_AMOUNT; i++){
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int corner_one, corner_two, corner_three; // corners of triangles. GL_TRIANGLES starts to draw counterclockwise.
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corner_one = -6;
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corner_two = -4;
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corner_three = -2;
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for (int angle = 1; angle <= 360; angle++) {
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corner_one = corner_one + 6;
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corner_two = corner_two + 6;
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corner_three = corner_three + 6;
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array[circle_offset * i + corner_one] = 0.1f + 0.1f * i;
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array[circle_offset * i + corner_one + 1] = 0.1f + 0.1f * i;
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array[circle_offset * i + corner_two] = RADIUS * cos((angle - 1) * PI / 180);
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array[circle_offset * i + corner_two + 1] = RADIUS * sin((angle - 1) * PI / 180);
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array[circle_offset * i + corner_three] = RADIUS * cos(angle * PI / 180);
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array[circle_offset * i + corner_three + 1] = RADIUS * sin(angle * PI / 180);
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}
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}
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}
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void RungeKuttaIntegration(float& theta, float& omega, float& time) {
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float h = HEIGHT; // Step size
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float k1_theta = h * f(time, theta, omega);
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float k1_omega = h * g(time, theta, omega);
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float k2_theta = h * f(time + h / 2, theta + k1_theta / 2, omega + k1_omega / 2);
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float k2_omega = h * g(time + h / 2, theta + k1_theta / 2, omega + k1_omega / 2);
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float k3_theta = h * f(time + h / 2, theta + k2_theta / 2, omega + k2_omega / 2);
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float k3_omega = h * g(time + h / 2, theta + k2_theta / 2, omega + k2_omega / 2);
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float k4_theta = h * f(time + h, theta + k3_theta, omega + k3_omega);
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float k4_omega = h * g(time + h, theta + k3_theta, omega + k3_omega);
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// Update theta and omega
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theta += (k1_theta + 2 * k2_theta + 2 * k3_theta + k4_theta) / 6;
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omega += (k1_omega + 2 * k2_omega + 2 * k3_omega + k4_omega) / 6;
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// Keep theta in the range of -2PI to 2PI
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if (theta > 2 * PI) theta -= 2 * PI;
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if (theta < -2 * PI) theta += 2 * PI;
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time += h; // Increment time
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}
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int main()
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{
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if( !glfwInit() )
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{
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fprintf( stderr, "Failed to initialize GLFW\n" );
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getchar();
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return -1;
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}
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glfwWindowHint(GLFW_SAMPLES, 4);
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glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
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glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
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glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
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window = glfwCreateWindow( 630, 600, "ZADANIE 2", NULL, NULL);
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if( window == NULL ){
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fprintf( stderr, "Failed to open GLFW window. If you have an Intel GPU, they are not 3.3 compatible. Try the 2.1 version of the tutorials.\n" );
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getchar();
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glfwTerminate();
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return -1;
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}
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glfwMakeContextCurrent(window);
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glewExperimental = true;
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if (glewInit() != GLEW_OK) {
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fprintf(stderr, "Failed to initialize GLEW\n");
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getchar();
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glfwTerminate();
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return -1;
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}
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glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE);
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glClearColor(1.0f, 0.8f, 0.0f, 0.0f);
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Shader myshader("pendulum_vs.glsl" , "pendulum_fs.glsl");
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unsigned int shaderProgram = myshader.programID();
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float vertices[2160 * CIRCLE_AMOUNT];
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float vertices2[] = { //vertices2 gives us the rod of the pendulum.
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-0.01f, 0.0f,
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0.01f, 0.0f,
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0.01f, 0.8f,
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-0.01f, 0.8f,
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-0.01, 0.0f
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};
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drawCircle(vertices); //draws the pendulum ball.
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unsigned int VBO, VAO, VAO2;
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glGenVertexArrays(1, &VAO);
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glGenBuffers(1, &VBO);
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glBindVertexArray(VAO);
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_DYNAMIC_DRAW);
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//position attribute for 'vertices'(ball of the pendulum)
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glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0);
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glEnableVertexAttribArray(0);
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glGenVertexArrays(1, &VAO2);
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glGenBuffers(1, &VBO);
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glBindVertexArray(VAO2);
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices2), vertices2, GL_STATIC_DRAW);
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//position attribute for 'vertices2'(rod of the pendulum)
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glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0);
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glEnableVertexAttribArray(0);
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float theta= theta_0;
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float omega= omega_0;
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float time = time_0;
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float driving_force;
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//Initialize f and g functions.
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f(time,theta,omega);
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g(time,theta,omega);
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float current_angle;
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do{
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driving_force = A * cos(k * time);
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current_angle = theta * 180 / PI; //converts theta(radian) to degree
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std::cout <<current_angle << std::endl;
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RungeKuttaIntegration(theta, omega, time);
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glClear( GL_COLOR_BUFFER_BIT );
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glBindVertexArray(VAO);
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for(int i = 0; i < CIRCLE_AMOUNT; i++){
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glm::mat4 model = glm::mat4(0.0f + i * 0.1f);
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glm::mat4 projection = glm::mat4(1.0f);
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glm::mat4 view = glm::mat4(0.9f);
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glUseProgram(shaderProgram);
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glDrawArrays(GL_TRIANGLES, 2160 * i, 2160);
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view = glm::rotate(view, glm::radians(current_angle), glm::vec3(0.0f, 0.0f, 1.0f));
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view = glm::translate(view, glm::vec3(0.0f, -0.8f, 0.0f));
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glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
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glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "view"), 1, GL_FALSE, glm::value_ptr(view));
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glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "model"), 1, GL_FALSE, glm::value_ptr(model));
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}
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glBindVertexArray(VAO2);
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glDrawArrays(GL_TRIANGLE_STRIP, 0, 5);
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glfwSwapBuffers(window);
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glfwPollEvents();
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}
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while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
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glfwWindowShouldClose(window) == 0);
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glfwTerminate();
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return 0;
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}
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