wgl

Regular window screen capture using openGL

由 不问归期 提交于 2021-02-08 10:55:38
问题 I'm trying to my desktop image capture. (All images, including the desktop output to the monitor) It's easy using window API (BitBlt or CImageClass) and it's not the way I want. I want do it using opengl. so I found glReadPixel funtion and window TRANSPARENT. But it just read pixel own Windows application screen.(Save as bmp file and check) Initialize() glfwSetErrorCallback(errorCallback); if (!glfwInit()) { std::cerr << "Error: GLFW " << std::endl; exit(EXIT_FAILURE); } glfwWindowHint(GLFW

wglGetProcAddress returns NULL

由 拈花ヽ惹草 提交于 2020-01-01 03:46:14
问题 I was trying to use WGL_ARB_pbuffer for offscreen rendering with OpenGL, but I was failed during initialization. Here is my code. wglGetExtensionsStringARB = (PFNWGLGETEXTENSIONSSTRINGARBPROC) wglGetProcAddress("wglGetExtensionsStringARB"); if(!wglGetExtensionsStringARB) return; const GLubyte* extensions = (const GLubyte*) wglGetExtensionsStringARB(wglGetCurrentDC()); So actually this ends at 2nd line because wglGetExtensionsStringARB got NULL. I have no idea why wglGetProcAddress doesn't

Will `wglCreateContext` fail safely if a DirectX context already exists for the given `HDC` (device context)

由 对着背影说爱祢 提交于 2019-12-25 10:57:15
问题 I'm attempting to contribute to a cross-platform, memory-safe API for creating and using OpenGL contexts in Rust called glutin. There is an effort to redesign the API in a way that will allow users to create a GL context for a pre-existing window. One of the concerns raised was that this might not be memory safe if a user attempts to create a GL context for a window that has a pre-existing DirectX context. The documentation for wglCreateContext suggests that it will return NULL upon failure,

Will `wglCreateContext` fail safely if a DirectX context already exists for the given `HDC` (device context)

由 拥有回忆 提交于 2019-12-25 10:56:03
问题 I'm attempting to contribute to a cross-platform, memory-safe API for creating and using OpenGL contexts in Rust called glutin. There is an effort to redesign the API in a way that will allow users to create a GL context for a pre-existing window. One of the concerns raised was that this might not be memory safe if a user attempts to create a GL context for a window that has a pre-existing DirectX context. The documentation for wglCreateContext suggests that it will return NULL upon failure,

Minimal Windowless OpenGL Context Initialization

由 一笑奈何 提交于 2019-12-18 16:47:29
问题 How can I initialize a windowless OpenGL context with the minimal amount of code? I've read here that you can use wglCreateContextAttribsARB to create windowless context, however it doesn't explain how? 回答1: From the link: Creating a context without a window, for off-screen rendering. This may not actually work. That second sentence is important. From the WGL_ARB_create_context specification: 4) Should there be a way to make a context current without binding it to a window system drawable at

changing GLUT calls to work with MFC/C++

由 …衆ロ難τιáo~ 提交于 2019-12-07 17:20:17
问题 I have a program that uses GLUT for its OpenGL rendering. Now I need it to be inside of a MFC project so that it can work with another program component. I've followed this tutorial: http://www.codeguru.com/cpp/g-m/opengl/openfaq/article.php/c10975__1/Setting-Up-OpenGL-in-an-MFC-Control.htm I am calling the function that was the GLUT display callback when the timer fires, but that's not working because the rendering depends on something that happens in the GLUT idle callback. I don't

changing GLUT calls to work with MFC/C++

由 半腔热情 提交于 2019-12-05 21:36:36
I have a program that uses GLUT for its OpenGL rendering. Now I need it to be inside of a MFC project so that it can work with another program component. I've followed this tutorial: http://www.codeguru.com/cpp/g-m/opengl/openfaq/article.php/c10975__1/Setting-Up-OpenGL-in-an-MFC-Control.htm I am calling the function that was the GLUT display callback when the timer fires, but that's not working because the rendering depends on something that happens in the GLUT idle callback. I don't understand where I should call the GLUT idle callback in my MFC program. Is there a separate event handler I

WGL: No double buffering + multi sampling = FAIL?

由 对着背影说爱祢 提交于 2019-12-04 07:25:07
I usually create a pixel format using wglChoosePixelFormatARB() with these arguments (among others): WGL_DOUBLE_BUFFER_ARB = GL_TRUE WGL_SAMPLE_BUFFERS_ARB = GL_TRUE WGL_SAMPLES_ARB = 4 i.e. double buffering on and x4 multisampling. This works just fine. But when I try to turn of the double buffering: WGL_DOUBLE_BUFFER_ARB = GL_FALSE WGL_SAMPLE_BUFFERS_ARB = GL_TRUE WGL_SAMPLES_ARB = 4 The call to wglChoosePixelFormatARB() fails (or rather indicates it didn't create anything) When I effectively turn multisampling off: WGL_DOUBLE_BUFFER_ARB = GL_FALSE WGL_SAMPLE_BUFFERS_ARB = GL_TRUE WGL

wglGetProcAddress returns NULL

由 大城市里の小女人 提交于 2019-12-03 08:36:13
I was trying to use WGL_ARB_pbuffer for offscreen rendering with OpenGL, but I was failed during initialization. Here is my code. wglGetExtensionsStringARB = (PFNWGLGETEXTENSIONSSTRINGARBPROC) wglGetProcAddress("wglGetExtensionsStringARB"); if(!wglGetExtensionsStringARB) return; const GLubyte* extensions = (const GLubyte*) wglGetExtensionsStringARB(wglGetCurrentDC()); So actually this ends at 2nd line because wglGetExtensionsStringARB got NULL. I have no idea why wglGetProcAddress doesn't work. I included "wglext.h" and also I defined as below at the header. PFNWGLGETEXTENSIONSSTRINGARBPROC
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