Advanced OpenGL Vertex Buffer Object

toneburst

Hi,

has anyone tried using VAOs in Processing?

I'm attempting to add a VAO to the Advanced OpenGL example from the Wiki, but I can't work out how to set it up.

My plan is to create and populate the VBOs and bind them to a VAO in setup(), then I just need to bind and draw the VAO in draw(), rather than having to bind the 3 VBOs individually before drawing. That's the plan, anyway.

So far, I've changed 'gl' to be an instance of the 'GL3', rather than 'GL2ES2' JOGL objects, as I think VAOs aren't part of the GL2ES2 spec.

I've changed gl = pgl.gl.getGL2ES2(); to gl = pgl.gl.getGL3(); to match.

I've also generated an extra IntBuffer in setup()

gl.glGenBuffers(4, intBuffer); vaoId = intBuffer.get(0); posVboId = intBuffer.get(1); colorVboId = intBuffer.get(2); indexVboId = intBuffer.get(3);

as according to the the jogamp docs for GL3, the glGenVertexArrays() function requires an IntBuffer as its 2nd argument.

What I can't work out is what should be in the IntBuffer that's passed in, and how to get the data into it.

Apologies if this is a stupid question. I have a basic concept of what VAOs are for, but have never tried implementing them before.

Any tips or pointers gratefully accepted.

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nabr

@toneburst IntBuffer vao = GLBuffers.newDirectIntBuffer(1); gl3.glGenVertexArrays(1, vao); gl3.glBindVertexArray(vao.get(0));

https://github.com/tolkanabroski/pshader-processing/blob/master/basics/iknowopengl.pde

toneburst

Hi @nabr sorry for the late reply. I'll try that, thanks very much, once again!

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toneburst

Unless I'm missing something, he doesn't seem to be using the VAO he created, in the draw method.

Maybe I'm wrong, though...

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nabr

@toneburst yes. becourse the example use drawelements https://www.google.de/search?q=gldrawelements+vs+gldrawarrays
you have to figure out, what works best in your project.

glDrawArrays(enum mode, int first, sizei count)
glDrawElements(enum mode, sizei count, enum type, const void *indices)
glDrawRangeElements(enum mode, uint start, uint end, sizei count, enum type, const void *indices)
glDrawArraysInstanced(enum mode, int first, sizei count, sizei primcount)
glDrawElementsInstanced(enum mode, sizei count, enum type, const void *indices, sizei primcount)
glDrawElementsBaseVertex(enum mode, sizei count, enum type, const void *indices, int basevertex)
glDrawRangeElementsBaseVertex(enum mode, uint start, uint end, sizei count, enum type, ...
glDrawArraysInstancedBaseInstance(enum mode, int first, sizei count, sizei primcount, uint baseinstance)
glDrawArraysIndirect(enum mode, const void *indirect) // GL_DRAW_INDIRECT_BUFFER
glDrawElementsInstancedBaseVertex(enum mode, sizei count, enum type, const void *indices, ...
glDrawElementsInstancedBaseInstance(enum mode, sizei count, enum type, const void *indices, ...
glDrawElementsInstancedBaseVertexBaseInstance(enum mode, sizei count, enum type, ...
glDrawElementsIndirect(enum mode, enum type, const void *indirect) // GL_DRAW_INDIRECT_BUFFER
glDrawTransformFeedback(enum mode, uint id)
glDrawTransformFeedbackStream(enum mode, uint id, uint stream)
glDrawTransformFeedbackInstanced(enum mode, uint id, sizei primcount)
glDrawTransformFeedbackStreamInstanced(enum mode, uint id, uint stream, sizei primcount)

toneburst

Ah, I see. Thanks @nabr.

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