Application crash when using VBO

[julien.1486]

Hi !

I try to use the VBOs in order to render a model but my application crash when I call glDrawRangeElements.

I have a "ObjectGL" class which can contain several "Materials" objects (which are polygons with specific materials datas).

Firstly, I generate the VBO id for each Materials (they are stored in the ArrayList "mats") :

public void genVBOS() throws IOException{
		if(GLContext.getCapabilities().GL_ARB_vertex_buffer_object){			
			for (int i = 0; i < mats.size(); i+=2) {						//One for datas, one for indices
				IntBuffer vbo = BufferUtils.createIntBuffer(2);
				ARBVertexBufferObject.glGenBuffersARB(vbo);
				ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, vbo.get(i));
				ARBVertexBufferObject.glBufferDataARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, vvtvn, ARBVertexBufferObject.GL_STATIC_DRAW_ARB); //vvtvn is an interleaved array of vertices, tex coords and normals
				
				ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB, vbo.get(i+1));
				ARBVertexBufferObject.glBufferDataARB(ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB, mats.get(i).getIndices(), ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB);
				
				mats.get(i).setVbo(vbo);
			}
		}

And after I call the ObjectGL.draw function :

public void draw(){		
		for (int i = 0; i < mats.size(); i++) {
			int stride = (3+2+3)*4;                       // Order : Vertices, Tex Coords, Normals
			ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, mats.get(i).getVbo().get(0));    //The first ID contain the datas
			GL11.glEnableClientState(GL11.GL_VERTEX_ARRAY);				
			int offset = 0;
			GL11.glVertexPointer(3, GL11.GL_FLOAT, stride, offset);
			
			if(normals){
				GL11.glEnableClientState(GL11.GL_NORMAL_ARRAY);
				offset = 2 * 4;
				GL11.glTexCoordPointer(2, GL11.GL_FLOAT, stride, offset);
			}
			if(text){
				GL11.glEnableClientState(GL11.GL_TEXTURE_COORD_ARRAY);
				offset = (3 + 2) * 4;
				GL11.glNormalPointer(GL11.GL_FLOAT, stride, offset);
			}		
			
			ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, mats.get(i).getVbo().get(1));
			GL12.glDrawRangeElements(GL11.GL_TRIANGLES, 0, mats.get(i).getIndices().capacity(), mats.get(i).getIndices().capacity(), GL11.GL_UNSIGNED_INT, 0);    //At this point the application crashes
		}
		
	}

I read some tutorials (including LWJGL documentation) about VBO but I guess something is wrong in my code 

Do you have any idea ?
Thanks for your help 

[Kai]

Hi,

it seems that you are running out of index range in genVBOS() when doing

ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, vbo.get(i));

and

ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB, vbo.get(i+1));

because the counter i is not guaranteed to be always in [0, 1], which is required, because the vbo names you are allocating are only 2 in size.

I guess you might use 0 as index for the first vbo.get() and 1 for the second one.