Question

I am writing a simple 3D rendering engine.
The end result of my 3D processing is pixel data. Next I need to display it on the screen with GDI+.
I am using WinForms and Visual Basic. I am drawing directly on form’s ClientRectangle.

I have some questions.
After I process a pixel, should I be writing pixel data to a buffer first, instead of sending each pixel to GDI+ individually?
– If so, how much of a screen should I buffer at one time? Full screen, half, quarter, eighth? I think there may be RAM usage / performance trade-offs here.
– What is the best data structure for the pixel buffer?
– Which GDI+ command do I use to render the pixel buffer (or the individual pixel)? Is it possible to avoid creating the bitmap as an intermediate step and send pixel data directly to screen?

Maximum screen size I anticipate is 1600×1200. RAM could be as low as 1GB.

Thanks.

Answer 1

Hope you can find some of those answers here

1. Write the data into a buffer of RGBA structs first. This will make it easy if, for example you want to render multiple “layers” and then composite those as well. It will also make it easy if you want to perform any deferred processing at some point. Once a full (tile?) render is complete, you can flush it to the output bitmap/file.
2. This depends on what resolutions you allow the user to render to. If you want to render gigapixel images, you will need to tile it at some reasonable size. I would recommend that the tile size be configurable and then you can set it at a reasonable default after testing.
3. I would recommend starting out with a simple RGBA buffer if you’re not looking to perform any deferred shading.
4. If you are NOT performing tiled rendering/rendering images that can fit in memory, you can simply use Bitmap.LockBits and write the data that way. If you are using tiled rendering, you will need to either find a library that allows you to render a scanline at a time (and make that a “tile”) or fix the file format you want to write TGA, PNG and seek/write directly to the file. Dumping the image as a RAW file and then using a command-line tool to convert it would also be another option.

Hope this helps!