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OpenGL New technique better than parralax mapping

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Relief mapping : Seen on opengl.org In fact it's "simply" some raytracing into an heightmap using the pixel shader. You can even raytrace self-shadows (and local reflections I guess). It look awesome, but considering the high amount of pixel shader instructions needed ( Compared to parralax mapping in example ) I don't know if it's yet usable in some game engine ( Even on GeForce 6800 ). Maybe the solution is to use this technique near the camera, and to use parralax or standard bump-mapping instead farther. The problem will be to smoothly transition between these LODs (especially between relief mapping and others)

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Hmmm... after a quick read, it looks like a more advanced version of parallax mapping, but it requires many instructions and it's pretty slow even on hi-end cards. The beauty of parallax mapping is that you get a surprisingly good result with just 2-3 instructions.

I will definately check it out later, though.

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You got it ! It's like choosing between 3 added instructions and tenths/hundreds added instructions ( depending on the precision you want, you can have more or less iteration steps for the ray tracing linear and binary search ).

The only common point with parralax mapping tough is that both techniques perturbates in some way the UV coordinate used to sample the diffuse and normal maps ( and gloss etc maps ).

However I consider parralax mapping has being a hack ( while still being a cheap and good hack in some situations ) while relief mapping is more physicaly correct.





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yeah who couldnt see that coming...

still cool it works in realtime tho. it will really add some badass realism to games. all hail to raytracing i suppose.

on the other hand, a card built for rasterizing isnt likely to be better at raytracing than at rasterizing. if youd use that power to crunch some triangles instead of raytracing one quad, youd get the same with much less effort id wager.

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yeah who couldnt see that coming...

still cool it works in realtime tho. it will really add some badass realism to games. all hail to raytracing i suppose.

on the other hand, a card built for rasterizing isnt likely to be better at raytracing than at rasterizing. if youd use that power to crunch some triangles instead of raytracing one quad, youd get the same with much less effort id wager.

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I've followed the topic on opengl.org from the beginning and I'm very impressed with results it gives. But even with all the improvements posted so far, I doubt we'll see this in games any time soon. The cost, compated to bumpmapping and parallax mapping is just way to high for now, even if used in shader LOD chain. I'll try to implement it in my engine just to see how it performs on 100k tris scene. [grin]

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cool, of course... i had similar(if not same) idea about implementing terrain from voxel world on GPU, but i have GeForce FX 5200 only... :(

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It's a neat technique but I think we're likely to see mainstream hardware that can do true displacement mapping with adaptive tesselation before it becomes really practical for real time use. With hardware support that's likely to be a more efficient way to do things. The nice thing about parallax mapping is that it looks significantly better than normal mapping without costing too much more. This looks significantly better again but is significantly more expensive as well.

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Quote:
Original post by mattnewport
It's a neat technique but I think we're likely to see mainstream hardware that can do true displacement mapping with adaptive tesselation before it becomes really practical for real time use.
Aye. To be honest, I'm having trouble getting really excited about all these texture-space effects because they don't solve the biggest problem - the silhouette.

Once someone shows me a method which does virtual displacement, with silhouette correction, on a single quad, then I'll be excited. [grin]

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superpig> this one does produce correct silhouettes, not like parallax mapping, it's just that these screenshots don't show it.

the bumps don't stick out of the surface, but dig inside it.
if the pixels that connect the quad edges to the rest are rendered transparently, you get proper silhouettes. (your meshes faces need to be pushed along their normals so they enclose the highest possible bump).

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