[SOLVED] DrawVertexPrimitiveList not working

[ItsBritneyBitch]

Hi everyone, here's a code snippet used to render a cube adapted from a DirectX sample, but it doesn't work with Irrlicht using either (DX or OpenGL) drivers:

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        irr::video::S3DVertex vertices[8] =
        {
                irr::video::S3DVertex(vector3df(-30.0f, 30.0f, -30.0f), vector3df(), SColor(255, 0, 0, 255), vector2df()),
                irr::video::S3DVertex(vector3df(30.0f, 30.0f, -30.0f), vector3df(), SColor(255, 0, 255, 0), vector2df()),
                irr::video::S3DVertex(vector3df(-30.0f, -30.0f, -30.0f), vector3df(), SColor(255, 255, 0, 0), vector2df()),
                irr::video::S3DVertex(vector3df(30.0f, -30.0f, -30.0f), vector3df(), SColor(255, 0, 255, 255), vector2df()),
                irr::video::S3DVertex(vector3df(-30.0f, 30.0f, 30.0f), vector3df(), SColor(255, 0, 0, 255), vector2df()),
                irr::video::S3DVertex(vector3df(30.0f, 30.0f, 30.0f), vector3df(), SColor(255, 255, 0, 0), vector2df()),
                irr::video::S3DVertex(vector3df(-30.0f, -30.0f, 30.0f), vector3df(), SColor(255, 0, 255, 0), vector2df()),
                irr::video::S3DVertex(vector3df(30.0f, -30.0f, 30.0f), vector3df(), SColor(255, 0, 255, 255), vector2df())
        };
        int indices[36] =
        {
                0, 1, 2,    // side 1
                2, 1, 3,
                4, 0, 6,    // side 2
                6, 0, 2,
                7, 5, 6,    // side 3
                6, 5, 4,
                3, 1, 7,    // side 4
                7, 1, 5,
                4, 5, 0,    // side 5
                0, 5, 1,
                3, 7, 2,    // side 6
                2, 7, 6,
        };
        driver->drawVertexPrimitiveList(&vertices[0], 8, &indices[0], 12, irr::video::EVT_STANDARD, irr::scene::EPT_TRIANGLES);
 

This shows some random triangles being rendered, but it's like it doesn't follow the index order
What's funny, this function never works as its supposed to, and given the poor documentation (in particular regarding the 4th parameter) this is driving me nuts.
Help anyone?

[hybrid]

I guess it's the winding order, but didn't check this actually. Just make sure that all your tris are properly oriented. Since you also don't pass normals make sure that lighting is turned off.

[ItsBritneyBitch]

Got it working now. I was using int as the type for the indices, which is 32 bits instead of u16, which is the format (EIT_16BIT) specified by default. I changed the index array declaration to

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u16 indices[36]

and it works like a charm now. I could also have changed the 7th parameter to EIT_32BIT, if I wanted to have more than 65536 indices.

I guess it's the winding order, but didn't check this actually. Just make sure that all your tris are properly oriented. Since you also don't pass normals make sure that lighting is turned off.

Thanks anyway for your reply. I was aware i was setting the normals to 0 because i wasn't particularly caring about the lighting. Regarding the winding order, it's correct, and I think Irrlicht is using the same winding order convention as DirectX (not sure if it is CW or CCW) for backface culling, because these indices where taken from a DX sample using default settings.

[hybrid]

Yeah, same winding order as in DirectX. I also have to check for the correct order from time to time. IIRC, it's clock-wise.