I have some idea about programming graphic, but...

Elod · Post by **Elod** » Sat Mar 24, 2007 3:26 am

Hi, everybody! I have some idea about programming graphic, but i don't know that will have any problem or not.

1. Draw several same scene with different detail (Bump, color, light and shade, etc.) in different secne buffer

2. Then use VFPU to compute (compute it in one pixel by one pixel) each buffer mix in one scene buffer, then print that scene buffer out.

Does that idea have problem or not?

Why i think that idea? i want to program something same as PC pixel shader.

If that idea is no problem, then do it will pay many time to finish it? It will make FPS lower?

Bytrix · Post by **Bytrix** » Sat Mar 24, 2007 9:47 am

That would be extremely slow on the PSPs hardware. While the PSP is very good for most uses it does lack some features that are common in modern graphics hardware of PCs but to be honest features like that would only get in the way of creating good gameplay in portable games.

rapso · Post by **rapso** » Sat Mar 24, 2007 11:07 am

somethin similar is called multipass rendering, it's very common sind the quake2 engine. It's working for me kinda well and I've still smooth 60hz.

Raphael · Post by **Raphael** » Sat Mar 24, 2007 7:37 pm

Why would you want to use the VFPU to compute the composite image? Use the GU and use it's hardware blending FFS! You spare your CPU from loading/storing millions of values from/to VRAM and converting each from RGBA8888 to float color format and back. There's no way this could ever be fast!
Read up on multipass rendering as my preposter already mentioned. It's the common way to do things like that on single-texture hardware.

EDIT: Btw, the only thing to make something along the lines of a shader for PSP would be a vertex shader, by writing a shader code -> VFPU compiler and running that shader before sending the vertex data to GE. However, since most interesting stuff is achieved by a pixel shader, this is not so tempting.