As what I am aware of, VBOs do not need direct buffers (and indirect buffers might be handled faster), but this is just a detail. I also tried GL_FIXED but it did not make much difference for me. I assume that it gives performance gains only if you have a) static data that is converted to fixed format once and then re-rendered or b) do all calculations with fixed number precision (which is making things a lot more complicated and less readable when you need to update data). So I switched back to Float because I hat to convert most values to fixed before uploading them in GL calls.
I wonder if your offsets are correct? Is _pos_size_bytes the correct offset? For safety, I would stick to non-interleaved arrays for testing. Also I'm not sure when to array-copying in the bufferdata call takes place - have you tried a glFlush call or a buffer rebind (bind VBO to 0 and the ID again) after all the buffering? Somebody with knowledge about the native part of of this buffering could help you better with this, I guess. T. On Feb 16, 8:43 pm, Viktor Linder <[email protected]> wrote: > As you say, the most likely explanation is that I have a bad pointer > being used somewhere. The thing is I have gone over this code a bunch > of times and tried lots of different checks and I just can't find > what's wrong. > Do you have any pointers on ways to debug the crash in the GL library? > > I forgot to mention: I bind the array buffer to 0 after the call to > glDrawElements(), so any future draw calls that are not using VBOs > will not break. Also, I am not using VBOs for all draw calls. > > You keep a different VBO for each channel; is using a single VBO for > several channels not allowed? > > If its possible to use a single buffer that would reduce the needed > calls to glBindBuffer() and allowed interleaved data which would > improve cache locality. > > Curious; did using GL_FIXED give a large performance gain? > > Thanks for your help. > > /Viktor > On 16 Feb, 21:25, Robert Green <[email protected]> wrote: > > > > > You're probably pointing something to some bad memory location > > somewhere. I know you didn't post all of your real code so I can't > > really say for sure but it looks to me like you may be doing something > > wrong with your buffers. Here's how I do it: > > > -- Load -- > > GL11 gl11 = (GL11) gl; > > if (modelData.normals != null) { > > int[] vboIds = new int[5]; > > gl11.glGenBuffers(5, vboIds, 0); > > vertexVBOId = vboIds[0]; > > texVBOId = vboIds[1]; > > normalVBOId = vboIds[2]; > > indexVBOId = vboIds[3]; > > lightmapVBOId = vboIds[4]; > > } else { > > int[] vboIds = new int[4]; > > gl11.glGenBuffers(4, vboIds, 0); > > vertexVBOId = vboIds[0]; > > texVBOId = vboIds[1]; > > indexVBOId = vboIds[2]; > > lightmapVBOId = vboIds[3]; > > } > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, > > vertexVBOId); > > gl11.glBufferData(GL11.GL_ARRAY_BUFFER, > > modelData.vertices.length * > > 4, BufferUtil.createDirectIntBuffer(modelData.vertices), > > GL11.GL_STATIC_DRAW); > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, texVBOId); > > gl11.glBufferData(GL11.GL_ARRAY_BUFFER, > > modelData.tex.length * 4, > > BufferUtil.createDirectIntBuffer(modelData.tex), GL11.GL_STATIC_DRAW); > > if (modelData.normals != null) { > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, > > normalVBOId); > > gl11.glBufferData(GL11.GL_ARRAY_BUFFER, > > modelData.normals.length * > > 4, BufferUtil.createDirectIntBuffer(modelData.normals), > > GL11.GL_STATIC_DRAW); > > } > > gl11.glBindBuffer(GL11.GL_ELEMENT_ARRAY_BUFFER, > > indexVBOId); > > gl11.glBufferData(GL11.GL_ELEMENT_ARRAY_BUFFER, > > modelData.indices.length * 2, > > BufferUtil.createDirectShortBuffer(modelData.indices), > > GL11.GL_STATIC_DRAW); > > if (hasLightMap) { > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, > > lightmapVBOId); > > gl11.glBufferData(GL11.GL_ARRAY_BUFFER, > > lightMapModelData.tex.length * 4, > > BufferUtil.createDirectIntBuffer(lightMapModelData.tex), > > GL11.GL_STATIC_DRAW); > > } > > BaseRenderer.checkErrors(gl11); > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, 0); > > gl11.glBindBuffer(GL11.GL_ELEMENT_ARRAY_BUFFER, 0); > > > -- Draw -- > > > // use VBOs > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, > > vertexVBOId); > > gl11.glVertexPointer(3, GL10.GL_FIXED, 0, 0); > > if (modelData.normals != null) { > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, > > normalVBOId); > > gl11.glNormalPointer(GL10.GL_FIXED, 0, 0); > > } > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, > > texVBOId); > > gl11.glTexCoordPointer(2, GL10.GL_FIXED, 0, > > 0); > > //gl11.glBindBuffer(GL11.GL_ELEMENT_ARRAY_BUFFER, > > indexVBOId); > > // the main draw call > > gl11.glDrawArrays(GL11.GL_TRIANGLES, 0, > > vertexCount); > > //gl11.glDrawElements(GL10.GL_TRIANGLES, > > vertexCount, > > GL10.GL_UNSIGNED_SHORT, 0); > > // clean up > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, 0); > > //gl11.glBindBuffer(GL11.GL_ELEMENT_ARRAY_BUFFER, > > 0); > > > This code draws without indices but the commented code for indices is > > there. > > I use fixed point coordinates for verts, normals and UVs. You'd want > > to change that to floats for what you're doing. > > > On Feb 16, 1:42 pm, Viktor Linder <[email protected]> wrote: > > > > I am having trouble with implementing VBOs for my game. > > > I get crashes at random when calling glDrawElements() directly after > > > glGenBuffers() / glBufferData(). > > > The crashes disappear when I add printouts which leads me to believe > > > it might be a race condition between glBufferData() and > > > glDrawElements() of some sort. > > > Or I am doing something else that breaks it, but I can't see what. > > > > Here's what I do: > > > > ... > > > gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); > > > gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); > > > ... > > > if(geometry not in cache) { > > > gl11.glGenBuffers(1, _temp_handle, 0); > > > _geo_id = _temp_handle[0]; > > > > // produce text geometry to scratch buffer (allocated with > > > ByteBuffer.allocateDirect()) > > > int off = DynamicBuffer.allocate(_buf_size_floats); > > > TextProducer.create_geometry(_font, _text, DynamicBuffer._buffer, > > > off); > > > > // upload geometry > > > gl11.glBindBuffer(GL11.GL_ARRAY_BUFFER, _geo_id); > > > > DynamicBuffer._buffer.position(off); > > > gl11.glBufferData(GL11.GL_ARRAY_BUFFER, _buf_size_bytes, > > > DynamicBuffer._buffer, GL11.GL_STATIC_DRAW); > > > > DynamicBuffer.deallocate_last(_buf_size_floats); > > > > // set vertex pointer > > > gl11.glVertexPointer(3, GL10.GL_FLOAT, 0, 0); > > > gl11.glTexCoordPointer(2, GL10.GL_FLOAT, 0, _pos_size_bytes); > > > > insert_in_cache();} else { > > > > ... bind + set vertex pointer using existing VBO ... > > > > } > > > > ... > > > gl.glDrawElements(); // <--- sometimes this call crashes, always after > > > buffer was just allocated/produced (ie the geometry-not-in-cache code > > > path) > > > ... > > > > gl.glDisableClientState(VERTEX...); > > > gl.glDisableClientState(TEXCOORD...); > > > > Sometimes the call to glDrawElements() crashes. The crash only happens > > > when glDrawElements() is called right after the buffer has been > > > allocated and written (ie "geometry not in cache" is true). > > > The crash seems more common if the produced buffer is a few kb or more > > > in size. > > > If I insert a Log.d() call in between glVertexPointer3f() and > > > glDrawElements() the crash goes away. > > > > I have double checked that the GL calls are not setting the error > > > flag, and I am not writing past any buffer limit or feeding incorrect > > > sizes etc to glBufferData(). Note that everything renders correctly > > > without artifacts up to the crash. The crash does not happen for the > > > same geometry all the time, a piece of geometry can be produced and > > > rendered correctly, then be re-produced and crash. > > > > Before I make a minimal reproducible example, I thought I would ask > > > this group if anyone else > > > have experienced the same trouble when using a VBO right after call to > > > glBufferData()? > > > > All answers appreciated! > > > /Viktor > > > > PS. > > > This is the crash dump: > > > 02-16 20:23:00.979: INFO/DEBUG(14143): *** *** *** *** *** *** *** *** > > > *** *** *** *** *** *** *** *** > > > 02-16 20:23:00.979: INFO/DEBUG(14143): Build fingerprint: 'android- > > > devphone1/dream_devphone/dream/trout:1.6/DRC83/14721:user/gfh,test- > > > keys' > > > 02-16 20:23:00.979: INFO/DEBUG(14143): pid: 17564, tid: 17580 >>> > > > com.mygame.mygame <<< > > > 02-16 20:23:00.979: INFO/DEBUG(14143): signal 11 (SIGSEGV), fault addr > > > 002df000 > > > 02-16 20:23:00.979: INFO/DEBUG(14143): r0 001b9c28 r1 002deff0 r2 > > > 00000003 r3 001be178 > > > 02-16 20:23:00.979: INFO/DEBUG(14143): r4 002deff4 r5 001be17c r6 > > > 00000044 r7 000003ff > > > 02-16 20:23:00.979: INFO/DEBUG(14143): r8 00000000 r9 001be170 10 > > > 00000003 fp 001b9c14 > > > 02-16 20:23:00.979: INFO/DEBUG(14143): ip 00000002 sp 44944d00 lr > > > 8042b8dc pc 8043fdf8 cpsr 20000010 > > > 02-16 20:23:02.669: INFO/DEBUG(14143): #00 pc 0003fdf8 / > > > system/lib/libhgl.so > > > 02-16 20:23:02.669: INFO/DEBUG(14143): #01 lr 8042b8dc / > > > system/lib/libhgl.so > > > 02-16 20:23:02.669: INFO/DEBUG(14143): stack: > > > 02-16 20:23:02.679: INFO/DEBUG(14143): 44944cc0 > > ... > > read more » -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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