Accessing display memory

you can get a pointer to the video buffer with DirectDraw, but this is not always the same address. You have to request the pointer everytime you want to draw a frame by locking the primary surface, and release it after that by unlocking it. you can find a documentation of directdraw in the msdn librarie

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That''s not directly though, I want to do it without DirectX or other graphics library. I know they can do it, so there must be someway I can too.

DirectDraw is very direct. You only have to do quite some initialization, but once you have the pointer, you can just write to like any other memory address. it''s a bit slower than writing to normal memory, because the data needs to go over the agp bus, but that''s something you will always have if you are writing to the video buffer.
I am sure it''s not just an offscreen buffer that''s copied to the screen once you unlock it, because if you just change one byte, the pixels on the screen changes immediately (unless you are drawing to a backbuffer)

I don''t think it''s possible to draw to the videobuffer without DirectDraw or maybe something similar, because windows runs in protected mode, and with that, memory addresses are virtual addresses. Virtual addresses don''t have to be the same as their physical address, so there''s no fixed pointer that will always point to the video memory, surely not one that will work on different video cards. The only way to get a pointer to that buffer is via the card specific drivers, and to use that, you need directdraw or so

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I''ve used DirectDraw/3D/OpenGL and I know how to do this stuff in those. I know that it would be complicated, but if those libraries can do it, it''s obviously not impossible. What is it that they do to get the address and the right to access the memory?

Win if you can, lose if you must, but always cheat.

directdraw and similar are basically wrappers for the drivers. And the drivers are specially writtin for one type of video hardware, and they know how to interact with the hardware directly, but this differs from card to card, so you can''t make something that will work on different computer, and also, hardware vendors keep it a secret how their hardware works, so I think it''s nearly impossible to do it without directdraw or so.

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I guess it''s back to the handhelds then...thanx for the info.

Win if you can, lose if you must, but always cheat.