I want to use OpenGL graphics on subregions of both dialog forms and child forms of a MDI application. I have a multiple rendering context version working, rendering onto TPanels on both kinds of form and calling wglMakeCurrent frequently to activate/deactivate appropriately. I use wglShareLists so that textures are common to all rendering contexts. I was very happy at getting this all working when I discovered that a number of Intel graphics drivers fail to deal with wglShareLists.
This made me wonder if somehow I could get the results I want with a single rendering context.Can anyone suggest how I achieve this? My idea is to render to single window positioned to match the region of the active child form (or dialog box), and bitblt this to a bitmap as each child deactivates. The non-active forms thus display a bitmap image of the rendering. Initially I tried using a Tpanel on the main form as the OGL window, which paints infront of the MDI child forms but I have to "cut" a hole in the diaglog boxes to show it. Then I used a borderless form shown SW_SHOWNOACTIVATE and setting the WMNCHitTest message result to HTTRANSPARENT to prevent mouse clicks giving it focus. Where my idea runs into difficulty is with floating toolbars etc. I need to manage the zorder of the OGL window so that it is temporarily topmost before the bitblt, then located just infront of the form it is rendering so floating toolbars etc. are painted infront of it. Managing the zorder is giving me problems. And perhaps using a form provides more funcationality than I need. Maybe a simple control, something more like a THintWindow, would be better?
Long question I know, but interesting (I hope) and a good solution would have all kinds of uses.