Mesa (gallium-cylindrical-wrap): softpipe: Properly implement cylindrical wrapping.

[Brian Paul]

michal wrote:
> Micha?? Kr??l wrote on 2010-02-05 17:34:
>> Module: Mesa
>> Branch: gallium-cylindrical-wrap
>> Commit: f90399107eb9b54ea2c76f973ab487c38e61a5f0
>> URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f90399107eb9b54ea2c76f973ab487c38e61a5f0
>>
>> Author: Michal Krol <michal at vmware.com>
>> Date:   Fri Feb  5 17:12:48 2010 +0100
>>
>> softpipe: Properly implement cylindrical wrapping.
>>
>> @@ -801,21 +900,23 @@ line_linear_coeff(const struct setup_context *setup,
>>  /**
>>   * Compute a0, dadx and dady for a perspective-corrected interpolant,
>>   * for a line.
>> + * v[0] and v[1] are vmin and vmax, respectively.
>>   */
>>  static void
>>  line_persp_coeff(const struct setup_context *setup,
>>                   struct tgsi_interp_coef *coef,
>> -                 uint vertSlot, uint i)
>> +                 uint i,
>> +                 const float v[2])
>>  {
>>     /* XXX double-check/verify this arithmetic */
>> -   const float a0 = setup->vmin[vertSlot][i] * setup->vmin[0][3];
>> -   const float a1 = setup->vmax[vertSlot][i] * setup->vmax[0][3];
>> +   const float a0 = v[0] * setup->vmin[0][3];
>> +   const float a1 = v[1] * setup->vmax[0][3];
>>     const float da = a1 - a0;
>>     const float dadx = da * setup->emaj.dx * setup->oneoverarea;
>>     const float dady = da * setup->emaj.dy * setup->oneoverarea;
>>     coef->dadx[i] = dadx;
>>     coef->dady[i] = dady;
>> -   coef->a0[i] = (setup->vmin[vertSlot][i] -
>> +   coef->a0[i] = (v[0] - /* XXX: <-- shouldn't that be a0? */
>>   
> I have put this XXX comment, because the code in line_persp_coeff() is 
> not consistent wih tri_persp_coeff(). Can someone double check this?

It works.  I added a line drawing mode to cylwrap.c to test.

-Brian