我对制作一个不依赖于X11的OpenGL应用程序感兴趣。我看到了这可以通过EGL实现，甚至在互联网上有相关的示例。但是我该如何控制上下文版本呢？下面的示例代码在wayland中创建了一个OpenGL上下文(版本为2.1)，但在我的电脑上显示支持的最高OpenGL版本是3.3(可以使用GLX和xlib在X服务器中使用glXCreateContextAttribsARB创建此类上下文)。所以我的问题是：我是否可以通过EGL创建一个更高版本的OpenGL上下文，如果可以，该如何实现呢？
示例代码:
示例代码:
#include <wayland-client.h>
#include <wayland-egl.h>
#include <EGL/egl.h>
#include <GL/gl.h>
#include <string.h>
#include <stdio.h>
#define WIDTH 256
#define HEIGHT 256
static struct wl_display *display;
static struct wl_compositor *compositor = NULL;
static struct wl_shell *shell = NULL;
static EGLDisplay egl_display;
static char running = 1;
struct window {
EGLContext egl_context;
struct wl_surface *surface;
struct wl_shell_surface *shell_surface;
struct wl_egl_window *egl_window;
EGLSurface egl_surface;
};
// listeners
static void registry_add_object (void *data, struct wl_registry *registry, uint32_t name, const char *interface, uint32_t version) {
if (!strcmp(interface,"wl_compositor")) {
compositor = wl_registry_bind (registry, name, &wl_compositor_interface, 0);
}
else if (!strcmp(interface,"wl_shell")) {
shell = wl_registry_bind (registry, name, &wl_shell_interface, 0);
}
}
static void registry_remove_object (void *data, struct wl_registry *registry, uint32_t name) {
}
static struct wl_registry_listener registry_listener = {®istry_add_object, ®istry_remove_object};
static void shell_surface_ping (void *data, struct wl_shell_surface *shell_surface, uint32_t serial) {
wl_shell_surface_pong (shell_surface, serial);
}
static void shell_surface_configure (void *data, struct wl_shell_surface *shell_surface, uint32_t edges, int32_t width, int32_t height) {
struct window *window = data;
wl_egl_window_resize (window->egl_window, width, height, 0, 0);
}
static void shell_surface_popup_done (void *data, struct wl_shell_surface *shell_surface) {
}
static struct wl_shell_surface_listener shell_surface_listener = {&shell_surface_ping, &shell_surface_configure, &shell_surface_popup_done};
static void create_window (struct window *window, int32_t width, int32_t height) {
eglBindAPI (EGL_OPENGL_API);
EGLint attributes[] = {
EGL_RED_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_BLUE_SIZE, 8,
EGL_NONE};
EGLConfig config;
EGLint num_config;
eglChooseConfig (egl_display, attributes, &config, 1, &num_config);
window->egl_context = eglCreateContext (egl_display, config, EGL_NO_CONTEXT, NULL);
window->surface = wl_compositor_create_surface (compositor);
window->shell_surface = wl_shell_get_shell_surface (shell, window->surface);
wl_shell_surface_add_listener (window->shell_surface, &shell_surface_listener, window);
wl_shell_surface_set_toplevel (window->shell_surface);
window->egl_window = wl_egl_window_create (window->surface, width, height);
window->egl_surface = eglCreateWindowSurface (egl_display, config, window->egl_window, NULL);
eglMakeCurrent (egl_display, window->egl_surface, window->egl_surface, window->egl_context);
}
static void delete_window (struct window *window) {
eglDestroySurface (egl_display, window->egl_surface);
wl_egl_window_destroy (window->egl_window);
wl_shell_surface_destroy (window->shell_surface);
wl_surface_destroy (window->surface);
eglDestroyContext (egl_display, window->egl_context);
}
static void draw_window (struct window *window) {
glClearColor (0.0, 1.0, 0.0, 1.0);
glClear (GL_COLOR_BUFFER_BIT);
printf("%s\n", glGetString(GL_VERSION));
eglSwapBuffers (egl_display, window->egl_surface);
}
int main () {
display = wl_display_connect (NULL);
struct wl_registry *registry = wl_display_get_registry (display);
wl_registry_add_listener (registry, ®istry_listener, NULL);
wl_display_dispatch (display);
egl_display = eglGetDisplay (display);
eglInitialize (egl_display, NULL, NULL);
struct window window;
create_window (&window, WIDTH, HEIGHT);
while (running) {
wl_display_dispatch_pending (display);
draw_window (&window);
}
delete_window (&window);
eglTerminate (egl_display);
wl_display_disconnect (display);
return 0;
}