Texture Atlas creation

[MrCoder]

done!

[tduindam]

Hi guys,

I'm trying to use the texture atlas as well. All I get is an index out of bounds exception however.

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Exception in thread "main" java.lang.IndexOutOfBoundsException: 174776
   at java.nio.DirectByteBuffer.get(DirectByteBuffer.java:209)
   at com.ardor3d.extension.atlas.TexturePacker.fillDataBuffer(TexturePacker.java:335)
   at com.ardor3d.extension.atlas.TexturePacker.setDataPixel(TexturePacker.java:327)


The exception is thrown by this part of code. "sourceIndex" gets bigger the capacity of lightData allows.

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dataAsFloatBuffer.put(targetIndex, lightData.get(sourceIndex));
dataAsFloatBuffer.put(targetIndex + 1, lightData.get(sourceIndex + 1));
dataAsFloatBuffer.put(targetIndex + 2, lightData.get(sourceIndex + 2));


Could this maybe have something to do with the type of textures we are using?

[MrCoder]

Could very well be! I'll have a look. What types of textures do you have then?

[tduindam]

What information are you looking for exactly? The result of texture.getTextureStoreFormat() ? In that case there are three types of textures we use: NativeDXT1A, CompressedRGB and RGB8. Also it might be useful to know that we usually have 4 textures per object, for diffuse, specular, illumination and normals.

I'm quite inexperienced when it comes to texturing, so I might not have given the most useful information, just let me know if you need something else.

[MrCoder]

Gotcha, yeah compressed textures won't work since i'm doing the composition of the atlas using the data buffers behind the textures. Should add a check for those formats and fire up a warning. Renanse had an idea on using RTT to compose the atlas instead, which I might try out if i find the time (lets hope so!).

should be possible for you to create atlases for each type of texture you have. issue it once for texture index 0, then once for index 1 etc to create atlases for each of your types (diffuse, specular etc)

[tduindam]

Cool. Now I'm making different atlasses for all different types and skipping all compressed formats. Unfortunately I now get a NullPointerException:

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Exception in thread "main" java.lang.NullPointerException
   at com.ardor3d.extension.atlas.TexturePacker.insert(TexturePacker.java:193)
   at com.ardor3d.extension.atlas.TexturePacker.insert(TexturePacker.java:69)


Which corresponds to this line of code:

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final FloatBuffer destination = parameterObject.getTextureCoords();


It seems that all meshes that I use have no texture coordinates set.. I tried calling mesh.updateGeometricState(0) and mesh.updateWorldRenderStates() as I thought it might be an initialization issue but that didn't work. Should I do something else to initialize the texture coordinates?

Thanks!

[renanse]

Hmm, 193 is this line in my source...

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            destination.put(i, destination.get(i) * diffX + offsetX);

Either way, I can't really see what could be null? In your line, only parameterObject being null would cause NPE, but it wouldn't get that far if it was null. In the line above it would have to be destination, but again, it couldn't get past the line above it (destination.limit()) if it were null.

[tduindam]

I don't think the parameter object is null, I think it is requesting the texture buffer from the mesh, and that buffer is null.

About the line numbers, I think I might have changed some whitespace around by adding and removing some debug statements. I've reverted and double checked. The error occurs at this line:

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for (int i = 0; i < destination.limit(); i += 2) {


Which I think means that this call returns null:

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final FloatBuffer destination = parameterObject.getTextureCoords();


This is the only thing that function does:

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public FloatBuffer getTextureCoords() {
        return mesh.getMeshData().getTextureBuffer(textureIndex);
    }


Also I was thinking, currently I'm skipping compressed textures so that means that for some objects some textures go into the atlas whereas others don't. Might this lead to errors?

[renanse]

What textureIndex are you pointing to? Perhaps there are no tex coords in that channel. Sometimes only channel 0 is setup during import with coords and you need to copy them to the other channels you add textures to.

[MrCoder]

I'll add more error checking, and try to complicate the example a bit more. A question is, if we want it to fail with an exception or instead make it skip meshes without a texture or texturecoord but still work. The latter might feel easier at first, but it's usually better in the long run to force users to use the lib more strictly (only add meshes that they really intend to atlas bake). On the other hand if they use the lib like you do with different types of texture for each index, but some meshes only have a diffuse while others specular etc, then it might be nice to be able to use the same list for the atlas packer and have it automatically skip those that are not valid.