main.cpp

#include<iostream>
#include<glad/glad.h>
#include<GLFW/glfw3.h>

const float WINDOW_WIDTH = 400;
const float WINDOW_HEIGHT = 225;

int main()
{
	// Initialize GLFW
	glfwInit();

	// Set OpenGL version to 3.3
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);

	// Set version to core to also use new functions
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	// Create 800x800 window with title YoutubeOpenGL
	GLFWwindow* window = glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "I made this!", NULL, NULL);
	if (window == NULL)
	{
		// Terminate GLFW in case window cannot be created
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}

	// Introduce the window in the current context
	glfwMakeContextCurrent(window);

	// Make GLAD configure OpenGL
	gladLoadGL();

	// Specify the OpenGL viewport in the window, 0,0 is the top right corner,
	// 800,800 the bottom corner
	glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);

	float timeElapsedSinceStart = 0.0f;
	float redValue = 1.0f;
	bool updateColor = false;

	while (!glfwWindowShouldClose(window))
	{
		timeElapsedSinceStart = static_cast<float>(glfwGetTime());

		if (std::fmod(timeElapsedSinceStart, 2) == 0) {
			redValue = 0.25f;
			updateColor = true;
		}
		if (std::fmod(timeElapsedSinceStart, 3) == 0) {
			redValue = 0.65f;
			updateColor = true;
		}
		if (std::fmod(timeElapsedSinceStart, 5) == 0) {
			redValue = 10.f;
			updateColor = true;
		}

		if (updateColor) {
			// Set background color according to redValue with opacity 1
			glClearColor(redValue, 0.65f, 0.0f, 1.0f);

			// Clean the back buffer and set the new color
			glClear(GL_COLOR_BUFFER_BIT);

			// Swap the back buffer (original window color)
			// with the front buffer (color just set before)
			glfwSwapBuffers(window);
			updateColor = false;
		}

		glfwPollEvents();
	}

	// Make GLAD destroy the window and terminate itself,
	// then exit without errors
	glfwDestroyWindow(window);
	glfwTerminate();
	return 0;
}