(Trees) 3Ds vers. sprites
Blitz3D Forums/Blitz3D Programming/(Trees) 3Ds vers. sprites
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| Hi. I am doing a speed test for an outdoor scene. I am switching between Trees as sprites and tress as low-poly 3Ds models. When the camera moves near a bunch of sprite trees, my frames per second drop to half. However, with the models it stays the same. Why is this? I thought sprites render faster? Is it the way I made my tree-sprites? Thanks, Fader |
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| do you use sprites with alpha or mask ? .. alpha always hit performance a lot |
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| Yeah, large alpha sprites up close to the camera really hammers your fillrate. Because you're essentially drawing those pixels multiple times ( depending on how many trees are in line with each pixel ) Alpha sprite trees are great for distance trees ( just added a few to ABB ) but low poly mesh trees might be better up close. |
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| Fader What you're experiencing is fill rate bottleneck. When the screen is full of pixels, it takes longer to draw. If there are lots of overlapping polygons that take up the entire screen, the video card has to work it's butt off to fill the entire screen over and over again. There's not much you can do other than controlling the camera so it can't get that close to clusters of overlapping polygons that fill the screen. I'm curious, what sort of video card do you have? I'm guessing something old-ish, since newer cards should be able to handle a few simple tree sprites without a real hitch. |
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| Oh, a good test to see if it IS fillrate related is to drop your resolution. If the game gets faster simply because the screen is smaller, you're limited by fill rate. |
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| Maybe you could use a mixture to keep up your fram route |
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| Use a Level of Detail (LOD) function which replaces 3D meshes with sprites when they are a certain distance from the camera. You could then use autofading to give it a professional finish. |
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