Fullscreen window blinking

dougbinks · April 29, 2020, 3:49pm

I wouldn’t call it a ‘trick’ - it is a robust and workable approach.

I have submitted an issue for this:

github.com/glfw/glfw

Feature request / discussion: multiple contexts for a window

opened 03:48PM - 29 Apr 20 UTC

dougbinks

enhancement macOS Windows X11 Wayland EGL

The following thread on discourse discusses a need for multiple contexts for a w…indow: https://discourse.glfw.org/t/fullscreen-window-blinking/1538/4 I am unsure about the overall benefit of multiple contexts for OpenGL these days, and I think it's best to keep GLFW as lean as possible, however this is something which is currently not possible to do with GLFW without altering core GLFW code so I think it's reasonable to consider. Potential approaches: 1. Expose the required OS specific information via the GLFW native API, for example on Windows WGL requires the device context `window->context.wgl.dc` which is not currently exposed. Users could then write their own OS specific code to create contexts. 2. Add `GLFWUserContext* glfwCreateUserGLContext(GLFWwindow* window)` and supporting functions, see below. I have named these User Contexts to differentiate from the GLFW context created along with the window. For 2 we would need ``` // Create a new context for a window GLFWUserContext* glfwCreateUserGLContext(GLFWwindow* window); // Delete a context void glfwDestroyUserContext(GLFWUserContext* context); // Make a context current void glfwMakeUserContextCurrent(GLFWUserContext* context); // Get current context - returns NULL if primary window context is current, // in which case glfwGetCurrentContext would return window, and // glfwGetCurrentContext will return NULL if a user context is current. GLFWUserContext* glfwGetCurrentUserContext(void); ``` I can create the Windows versions of the API, and sdegrande can help with the GLX and potentially Mac. This is potentially related to #1501

However I am unsure adding to the GLFW API for this is a good idea given that there are other, perhaps better, solutions.