I rendered some graphics in QGLWidget, it works fine. And i want to store a frame to an QImage, so i add a button and the button code is below:
void VolRenCore::RendrToFBO()
{
GLuint fb;
glGenFramebuffersEXT(1, &fb);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
glGenTextures(1, &tex);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, tex, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, m_ViewPort[0], m_ViewPort[1], 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
bool status = checkFramebufferStatus();
glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
int w = m_ViewPort[0];
int h = m_ViewPort[1];
QImage img(w,h, QImage::Format_ARGB32);
glReadPixels(0,0,w,h,GL_RGBA, GL_UNSIGNED_BYTE, img.bits());
mDisplayDialog fbo(img);
fbo.exec();
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
}
I want the frame image show in the mDisplayDialog, but what i get is a white dialog.