OpenGL Memory allocation problems for drawing

I'm very new to Android and I'm writing my first app which consists of drawing STL data (a bunch of triangles). For a small number of triangles (~ 4000), my app works great. But as soon as I try to load large data (~ 100000 triangles), I get memory allocation problems. Here is basically what I do:

I am using a GLSurfaceView for my rendering

a) I read in my data, creating a list of triangles (3 * X/Y/Z and a normal vector for each triangle) b) I create ByteBuffers using allocateDirect() for the vertex data, the normals and the indices. c) I add the data into the ByteBuffers d) I call glVertexPointe开发者_高级运维r, glNormalPointer and I assign the bytebuffers e) I call glDrawElements() using the indexBuffer

As soon as I try to allocate around 10MB by calling allocateDirect(), my application crashes. I tried to calll allocate() instead, which works, but then the glVertexPointer method crashes (even for a small number of triangles)

Am I doing something wrong?

Also, do I have to call glVertexPointer, glNormalPointer every time I redraw or is it enough to call it in the surfaceChanged method?

Thanks a lot,

Mark

You should only create the VBOs once. After that if you need to load new data into them you do it in local arrays, and then load it in to the VBOs all at once using a "put" call.

The largest type that you can use for the index VBO is "short", so you can only draw 64k vertexes at a time. If you are drawing 100k vertexes, you will have to do it in two passes.

Edit: regarding your memory limitations, find out what the heap limit is for your device. The heap limit can be 16, 24, 32, or 48 MB. You can use the "android:largeHeap="true"" option to greatly increase the limits, but I'm not sure if that option is available for pre-Honeycomb versions of Android or not.

I'm not expert with 3D rendering, but 10MB of vertex data strikes me as quite a lot, especially for a mobile application, so I'm not surprised you're encountering memory allocation issues! Even if they did successfully get allocated, you'd likely find it unusable due to poor performance.

Does the entire scene really need to be in video memory all the time? You may want to explore techniques to cull vertices that are far away from the camera and only upload/draw what is necessary.