26.5 OpenGL in the Pop Framework

[ Team LiB ]

26.5 OpenGL in the Pop Framework Look back at the code for CPopView::OnDraw(CDC* pDC) that we gave in Section 24.4: Graphics in the Pop Framework. Here is a bulleted list showing some of the corresponding OpenGL calls made by the _pgraphics member of CPopView if _pgraphics is of the type cGraphicsOpenGL*. Wake up the graphics with _pgraphics->activate(). This calls ::wglMakeCurrent( _pDC->GetSafeHdc(), _hRC ) Clear the graphics background with _pgraphics->clear(targetrect). This calls ::glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); Install the projection and view matrices with these lines. _pviewpointcritter->loadProjectionMatrix(); _pviewpointcritter->loadViewMatrix(); These in turn call: ::glMatrixMode(GL_MODELVIEW) ::glLoadMatrixf(_pviewpointcritter->attitude().inverse()); ::glMatrixMode(GL_PROJECTION) ::gluPerspective (fieldofviewangleindegrees, xtoyaspectratio, nearzclip, farzclip); //Values from _pviewpointcritter Draw your game world and then the critters with pgame()->drawCritters(_pgraphics, _drawflags). This generates a variety of ::gl and ::glu calls like, in the case of polygons ::glEnableClientState(GL_VERTEX_ARRAY); ::glVertexPointer(...); ::glDrawArrays(...); Send the graphics to your video display with _pgraphics->display(this, pDC) This calls ::glFinish();// Tell OpenGL to flush its pipeline ::SwapBuffers( _pDC->GetSafeHdc() ); // Now Swap the buffers

[ Team LiB ]