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#include <iostream>
#include <glad/gl.h>
#include <GLFW/glfw3.h>
// Function prototypes
GLFWwindow* create_window(const char *name, int major, int minor);
GladGLContext* create_context(GLFWwindow *window);
void free_context(GladGLContext *context);
void draw(GLFWwindow *window, GladGLContext *context, float r, float g, float b);
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
// Window dimensions
const GLuint WIDTH = 400, HEIGHT = 300;
int main()
{
glfwInit();
GLFWwindow *window1 = create_window("Window 1", 3, 3);
GLFWwindow *window2 = create_window("Window 2", 3, 2);
if (!window1 || !window2) {
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwSetKeyCallback(window1, key_callback);
glfwSetKeyCallback(window2, key_callback);
GladGLContext *context1 = create_context(window1);
GladGLContext *context2 = create_context(window2);
if (!context1 || !context2) {
std::cout << "Failed to initialize GL contexts" << std::endl;
free_context(context1);
free_context(context2);
}
glfwMakeContextCurrent(window1);
context1->Viewport(0, 0, WIDTH, HEIGHT);
glfwMakeContextCurrent(window2);
context2->Viewport(0, 0, WIDTH, HEIGHT);
while (!glfwWindowShouldClose(window1) && !glfwWindowShouldClose(window2))
{
glfwPollEvents();
draw(window1, context1, 0.5, 0.2, 0.6);
draw(window2, context2, 0.0, 0.1, 0.8);
}
free_context(context1);
free_context(context2);
glfwTerminate();
return 0;
}
GLFWwindow* create_window(const char *name, int major, int minor) {
std::cout << "Creating Window, OpenGL " << major << "." << minor << ": " << name << std::endl;
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, major);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, minor);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, name, NULL, NULL);
return window;
}
GladGLContext* create_context(GLFWwindow *window) {
glfwMakeContextCurrent(window);
GladGLContext* context = (GladGLContext*) calloc(1, sizeof(GladGLContext));
if (!context) return NULL;
int version = gladLoadGLContext(context, glfwGetProcAddress);
std::cout << "Loaded OpenGL " << GLAD_VERSION_MAJOR(version) << "." << GLAD_VERSION_MINOR(version) << std::endl;
return context;
}
void free_context(GladGLContext *context) {
free(context);
}
void draw(GLFWwindow *window, GladGLContext *gl, float r, float g, float b) {
glfwMakeContextCurrent(window);
gl->ClearColor(r, g, b, 1.0f);
gl->Clear(GL_COLOR_BUFFER_BIT);
glfwSwapBuffers(window);
}
// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
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