Get the GLHandle for a the Vertices VBO in TGLMeshObject.

[dyspd]

Hi,

I am looking to get the GLHandle for a VBO buffer object suitable for a call to clCreateFromGLBuffer in OpenCL.

I realise that this is not in the interface of any class I have found so far that deals with VBOs, but cannot determine which private member of which class actually holds the GLHandle so I can hack the code to expose it for some performance testing of directly manipulating the mesh vertex points from OpenCL kernels.

Peter

[Jerome.D (BeanzMaster)]

Hi, Peter you can't gain acces to VBO directly but you can through TFGVertexIndexList (private property FIndex ) for verticeslist.

Also with VBO for multi-texturing you must pass through a TextureEX

see :*procedure TFGVertexIndexList.BuildList(var mrci: TGLRenderContextInfo); *

In GLVectorFileObject.pas in private section of TGLMeshObject you can see

    FUseVBO: boolean;
    FVerticesVBO: TGLVBOHandle;
    FNormalsVBO: TGLVBOHandle;
    FColorsVBO: TGLVBOHandle;
    FTexCoordsVBO: array of TGLVBOHandle;
    FLightmapTexCoordsVBO: TGLVBOHandle;
    FValidBuffers: TVBOBuffers;

You can also take a look to the demos in Examples\SceneObjects\cube\

For doing what you want i think the best it will create Own Object derived from GLMeshObject (like your GLFreeFormRevolution ) or the other solution it will to create public properties in GLMeshObject

Just little question Have you resolved the bug with the TabControl and TGLSceneViewer under Linux ?

Jérôme

[dyspd]

Hi Jérôme,

Thanks for the info, may try that at some time in the near future, but as I have gained acceptable performance through sparse array and and multi-threading it may go on the back burner for a while, until my list of vertices grows much larger. (brute force was ~ 8 sec - now less than a second for twice the work). The work unit is quite small and am now memory bandwidth limited on 8 cpu cores, so this probably means that GPU increase will only be in the order of 3-5 and only IF I can work out a decent partitioning algo for my problem that would work with GPU kernels.

The bug with gtk2 linux seems worse than first described, I tried placing a TGLSceneViewer on a panel on a form and the scene was rendering to the form with a blank panel on top . I t would seem that the 'HDC' equivalent is not set/valid when the scene viewer is trying to store all the handles it requires. To be honest I am not very au fait with gtk2 internals and do not have a clue how to trace it down.

Peter