Recording data from StretchBlt to disk
Disregard my previous thread. It appears that the problem I'm having is completely different. When I use StretchBlt to scale an image down, why is the buffer containing the output always black? How do I read the data? Even though I can see everything fine in my game engine, when I try looking at the data in the buffers right after all the drawing is finished, the only value I see is zero, pointing to a black image. Yet, the image, as I'm seeing it in the game engine is not black, it's vivid and detailed without very little black in sight.
My question is, how do I read the data contained in buffers, for recording screenshots and the like to disk? Why do I only see 0's for the data in the buffers even though the scene is rich and vibrant in color?
This sample is the rough idea. Why is DebugTest in this case reporting zero when the value should be 204? This explains why fwrite is writing all-black images. Any ideas on what's going on?
unsigned char Buffer
unsigned char DebugTest;
// other stuff and initialization
// within a function - draw the bright test image
AlphaBlend(BufferHandle, 0, 0, 1024, 768, ImageToDraw, 0, 0, 1024,768, BlendMode);
DebugTest = Buffer; // outputs 0 when it should be 204