[PATCH 4/5] d3dx9_36: Implemented ID3DXConstantTable_SetMatrix and ID3DXConstantTable_SetMatrixArray

[Matteo Bruni]

2011/1/21 Michael Stefaniuc <mstefani at redhat.com>:
> On 01/21/2011 06:56 AM, Travis Athougies wrote:
>> On Thu, Jan 20, 2011 at 7:27 AM, Matteo Bruni<matteo.mystral at gmail.com>
>>  wrote:
>>>
>>> 2011/1/20 Travis Athougies<iammisc at gmail.com>:
>>>>
>>>> +            /* D3DXMATRIX is a union, one of whose elements is an
>>>> array, so it can be cast to a float pointer */
>>>> +           if (is_vertex_shader(This->desc.Version))
>>>> +               IDirect3DDevice9_SetVertexShaderConstantF(device,
>>>> desc.RegisterIndex + i, (float *)(matrix + i),
>>>> +                        desc.RegisterCount);
>>>> +           else
>>>> +               IDirect3DDevice9_SetPixelShaderConstantF(device,
>>>> desc.RegisterIndex + i, (float *)(matrix + i),
>>>> +                        desc.RegisterCount);
>>>
>>> Can't you just pass matrix->m[i] as parameter, instead of that cast?
>>>
>>
>> Uh no. If I were to do that, matrix->m[1] would be the second row, not
>> the second matrix. I'm trying to get at the second matrix. To
>> illustrate this, suppose the matrix were at 0x8000 (not going to
>> happen, but just pretend). matrix->m[1] would be at 0x8010, since
>> floats are 4 bytes. However, the next matrix is actually at 0x8040
>> (since sizeof(float) * 16 [the number of elements in the matrix] =
>> 64).
>
> So you want a pointer to the first element of the "i"th matrix, right?
>    &matrix[i]._11
> No cast, no explicit pointer arithmetic.
>

Oh, right, I misread that (and Michael's suggestion is good). But then
I would expect the register index to be incremented by
desc.RegisterCount at each iteration. RegisterCount is supposedly 4,
but what if it is not? This calls for some SetMatrixArray tests.