100 sprites or 100 renderworlds?

Blitz3D Forums/Blitz3D Programming/100 sprites or 100 renderworlds?

Craig H. Nisbet (Posted 2004) [#1]

I'm doing a glowing overlay effect and I'm wondering if it is less intensive to do one sprite moving around being redrawn over and over on top of the render, or to have a sprite at avery position and render once. The only concern I have is that my level would have and boatload of sprites if I did that.

Rob (Posted 2004) [#2]

I think that it's slower to do the multiple renderworlds.

Difference (Posted 2004) [#3]

When I do 50-100 alpha'ed quads at the same position, I get a massive performance hit.

Afrohorse (Posted 2004) [#4]

Both choices will be very slow, its probably worth thinking of another way of doing it. Glowing can be done by rendering the scene to a lower resolution texture, then stretching it over the screen using one full-screen sprite, this will use the hardware's bilinear filtering to blur the image. Sometimes though, this can still look too pixelated so extra blending can be done by rendering 3 or 4 full-screen sprites slightly offset from each other - but this can be quite a hit (because it's really heavy on fill-rate). You can speed things up a little by feeding back the low-res texture into itself using a number of offset sprites like you would in full-screen, but rendering it into the small texture instead before applying it as a full-screen sprite :)