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Fix X11: test/gl_overlay stale overlay rendering (#1111)

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ManoloFLTK 2024-11-08 13:00:51 +01:00
parent d932c0de4f
commit 9560740b8e
1 changed files with 27 additions and 0 deletions
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27
src/Fl_Gl_Window.cxx
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@ -236,6 +236,33 @@ void Fl_Gl_Window::ortho() {
*/
void Fl_Gl_Window::swap_buffers() {
#if defined(USE_X11)
if (overlay) {
int wo = w(), ho = h();
GLint matrixmode;
GLfloat pos[4];
glGetIntegerv(GL_MATRIX_MODE, &matrixmode);
glGetFloatv(GL_CURRENT_RASTER_POSITION, pos); // save original glRasterPos
glMatrixMode(GL_PROJECTION); // save proj/model matrices
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glScalef(2.0f/wo, 2.0f/ho, 1.0f);
glTranslatef(-wo/2.0f, -ho/2.0f, 0.0f); // set transform so 0,0 is bottom/left of Gl_Window
glRasterPos2i(0,0); // set glRasterPos to bottom left corner
{
// Emulate overlay by doing copypixels
glReadBuffer(GL_BACK);
glDrawBuffer(GL_FRONT);
glCopyPixels(0, 0, wo, ho, GL_COLOR); // copy GL_BACK to GL_FRONT
}
glPopMatrix(); // GL_MODELVIEW // restore model/proj matrices
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(matrixmode);
glRasterPos3f(pos[0], pos[1], pos[2]); // restore original glRasterPos
} else
glXSwapBuffers(fl_display, fl_xid(this));
#elif defined(WIN32)
# if HAVE_GL_OVERLAY