Re: [PyOpenGL-Users] glVertexAttribPointer Problem

[Thomas <p_t...@gm...>]

Thank you very much! Problem solved.
If you look too long at a piece of code ...

On 01/30/2011 08:27 PM, Alejandro Segovia wrote:
> Hello Thomas,
>
> On Jan 30, 2011, at 3:19 PM, Thomas<p_t...@gm...>  wrote:
>
>> Hello,
>>
>> I'm trying to use glVertexAttribPointer and interleaved vertex data.
>>
>> // simple coordinate cross: vertex0, color0, ...
>> data = [0.0, 0.0, 0.0, 1.0, 0.0, 0.0, # x0
>>               1.0, 0.0, 0.0, 1.0, 0.0, 0.0, # x1
>>               0.0, 0.0, 0.0, 0.0, 1.0, 0.0, # y0
>>               0.0, 1.0, 0.0, 0.0, 1.0, 0.0, # y1
>>               0.0, 0.0, 0.0, 0.0, 0.0, 1.0, # z0
>>               0.0, 0.0, 1.0, 0.0, 0.0, 1.0] # z1
>>
>> buffer = glGenBuffers(1)
>> glBindBuffer(GL_ARRAY_BUFFER, buffer)
>> glBufferData(GL_ARRAY_BUFFER, numpy.array(cross, numpy.float32),
>> GL_STATIC_DRAW)
>>
>> # attributes are queried by glGetAttribLocation after shaders are linked
>> glVertexAttribPointer(attributes['coord'], GLint(3), GL_FLOAT, GL_FALSE,
>> GLsizei(6 * 4), ctypes.c_void_p(0))
>> glVertexAttribPointer(attributes['color'], GLint(3), GL_FLOAT, GL_FALSE,
>> GLsizei(6 * 4), ctypes.c_void_p(3))
> I'm not 100% sure, but shouldn't this last call to c_void_p receive 3*4 instead of 3? Please check whether a byte offset is expected here by OpenGL.
>
> Good luck,
> Alejandro.-
>
>> for index in attributes.values():
>>              glEnableVertexAttribArray(index)
>>
>> In my vertex shader I have:
>> attribute vec3 coord;
>> attribute vec3 color;
>>
>> Vertex data is correct, but "vec3 color" is always (0.0, 0.0, 0.0)
>>
>> Is it a problem with pyopengl or did I miss something in my setup?
>>
>> -Thomas
>>
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