# FrameBuffer Heightmaps Poor Performance

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multifractal    306

Hello,

I have been trying to render height maps to a texture using a frame buffer object. This works...although the performance is simply awful (3 fps). I think the problem rests in the fact the that the quad is still attached to the viewport after the terrain is rendered yet calling viewPort.detach(quad) results in the following, distorted image:

Here is the code I use to create the frame buffer, attach it to a viewport, and render the height map to a texture. The shader is running improved, texture-based, perlin noise.

                Texture2D hm = new Texture2D(1024,1024,Format.RGBA32F);
mat = new Material(assetManager, "NoiseProgram.j3md");
geom.setMaterial(mat);
mat.setTexture("permSampler2d", permutationTexture());
FrameBuffer fbo = new FrameBuffer(1024,1024,1);
fbo.setColorTexture(hm);
vp.setOutputFrameBuffer(fbo);
vp.attachScene(ge);


I may have not done a great job explaining the problem. Thanks for any help.

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Seabolt    781

Sir, optimization without finding the bottleneck is pushishable by death.

Take a look at Pix to see where the majority of your frame count is going, take a look at what warnings may be displayed, try cutting out parts of the algorithm and see what gives you the biggest frame boost; but do not ever, **EVER**, guess. I say this from experience. You always eliminate the bottleneck first.

That being said, what does rendering the height map entail? And you say the quad may still be attached, what do you mean? Your fullscreen quad that you used to rasterize the screen with? Because if that's still drawing then you'll definitely take a hit.

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BornToCode    1185

Sir, optimization without finding the bottleneck is pushishable by death.

Take a look at Pix to see where the majority of your frame count is going, take a look at what warnings may be displayed, try cutting out parts of the algorithm and see what gives you the biggest frame boost; but do not ever, **EVER**, guess. I say this from experience. You always eliminate the bottleneck first.

That being said, what does rendering the height map entail? And you say the quad may still be attached, what do you mean? Your fullscreen quad that you used to rasterize the screen with? Because if that's still drawing then you'll definitely take a hit.

It looks like he is using OpenGL and not DirectX. So pix will not work in that case. You can use gDebugger for OpenGL. here is a link to where you can download it.

http://www.gremedy.com/

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Seabolt    781

Doh! Sorry I thought I was still in the DX forum, I apologize for that OP.