I am new to this list, and SDL programming, but I have been through the
documentation and the archives to find answer to these questions, and have
not found the information I was looking for.
I am using SDL with OpenGL in SDL_OPENGLBLIT mode so I can use 2D graphics
for decoration and gui without the hassle of setting up OpenGl textures.
From the work I have done so far it seems it is not possible to BLIT
an SDL surface onto the screen on top of a GL rendered background with
ALPHA blending. Any part of the image that is transparent does not
show the rendered image that was behind it, but instead shows what was
in the video surface before the rendering was done. Is this correct?
The other problem I am having is related to the fact that my window
is set to be resizable, and I use SDL_SetVideoMode() to change the size
whenever I get a resize event. It seems from observed behavoir, and
reading comments in the SDL source code that calling SDL_SetVideoMode()
with SDL_OPENGLBLIT leaks at least one surface each time, with the
consequence that if the window is resized frequently, the program rapidly
uses up all available memory. Is this behavoir likely to be fixed,
or is it likely to be a long-term problem? If noone is likely to be able to
do it soon, I will volunteer, but I will need some pointers on what needs
to be done.
Al Riddoch–
WorldForge Developer http://www.worldforge.org/