Lightmaps, bumpmaps and oojimeflops
Blitz3D Forums/Blitz3D Beginners Area/Lightmaps, bumpmaps and oojimeflops
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| Just say I create a terrain, or a mesh. Then I texture that mesh. How do I lightmap it. What is a lightmap (I assume the following: it's an additional texture, that enhances/diminishes the colour of the material texture slightly to give the effect of lighting.) And what's bumpmapping? I assume this is adding an effect to the texture to give it the impression of contours and embossing to emphasize the detail |
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| How do I lightmap it. What is a lightmap (I assume the following: it's an additional texture, that enhances/diminishes the colour of the material texture slightly to give the effect of lighting.) Right, that's what it is. It's a texture on another texture layer, above the base texture which is usually applied with Mod 2x blending ( because mod 2x blending allows you to both brighten and darken the base texture. colors above 128,128,128 lighten and colors below darken. ) You generally apply EntityFX flag 1 ( full bright ) which will disable realtime lighting on the object. ( You're already lit it, so you don't want the effect ruined by having it affected by realtime lights as well. ) The short answer to how you do it is to buy Gile[s] which generates fantastic lightmaps and applies them for you. There are other lightmappers, and if you're looking for a free way of creating lightmaps, perhaps JFK's Slim Shady would suit you. http://www.blitzbasic.com/toolbox/toolbox.php?cat=4 And what's bumpmapping? I assume this is adding an effect to the texture to give it the impression of contours and embossing to emphasize the detail Basically, yeah. A traditional bump map ( which Blitz cannot use ) is highest at a pixel which is 255,255,255 and lowest on a pixel which is 0,0,0. Blitz has no support for these. All it does have support for is for dot 3 normal maps, but without shaders, these have a big drawback. Essentially you have to color your faces to reflect the angle between the light and the surface so that the bumps will be accurate. On a static entity, you can do this will entity colors and vertex colors ( but I guess it gets kinda slow doing it with vertex colors on lots of geometry ) and you can't really do it on animated objects because Blitz doesn't keep track of animated entities. |
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| Thanks, Syb - nearly lost me when you mentioned shaders and things, but I think I've got it. Just curious on the Lightmapping, though. Surely if you had a lightmapped mesh representing a castle, and within the castle you placed sprites to appear that torches were burning at the correct places to match the ligtmap you used. Now, the player character carries a lantern of his own. This would need to light the mesh as he runs past, so Fullbright would stop this wouldnt it? |
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| Yes, indeed fullbright would stop that. But it's better that way. The best way to simulate local dynamic lights like torches are via decals ( sprites aligned to and overlaid onto a wall ) to brighten them. Halo was working on something like this so you'll probably find some interesting discussion ( and a fair amount of bickering ;) ) in one of those threads. Don't worry too much about shaders. They just allow you to adjust vertex ( and pixel ) colors much faster than you can otherwise. |
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| Thanks loads - really helps! Il get my asbestos suit and check halo's threads too! |
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