[Mesa-dev] [PATCH] llvmpipe: Don't mess with the provoking vertex when inverting a triangle.

[Jose Fonseca]

Pushed. Thanks.

Jose

----- Original Message -----
> Fixes a bunch of piglit tests related to flat interpolation of
> floats.
> 
> Signed-off-by: Olivier Galibert <galibert at pobox.com>
> ---
>  src/gallium/drivers/llvmpipe/lp_setup_tri.c |   45
>  ++++++++++++++++++++++++---
>  1 file changed, 40 insertions(+), 5 deletions(-)
> 
> diff --git a/src/gallium/drivers/llvmpipe/lp_setup_tri.c
> b/src/gallium/drivers/llvmpipe/lp_setup_tri.c
> index 9916101..97a76d8 100644
> --- a/src/gallium/drivers/llvmpipe/lp_setup_tri.c
> +++ b/src/gallium/drivers/llvmpipe/lp_setup_tri.c
> @@ -815,10 +815,35 @@ calc_fixed_position( struct lp_setup_context
> *setup,
>  
>  /**
>   * Rotate a triangle, flipping its clockwise direction,
> + * Swaps values for xy[0] and xy[1]
> + */
> +static INLINE void
> +rotate_fixed_position_01( struct fixed_position* position )
> +{
> +   int x, y;
> +
> +   x = position->x[1];
> +   y = position->y[1];
> +   position->x[1] = position->x[0];
> +   position->y[1] = position->y[0];
> +   position->x[0] = x;
> +   position->y[0] = y;
> +
> +   position->dx01 = -position->dx01;
> +   position->dy01 = -position->dy01;
> +   position->dx20 = position->x[2] - position->x[0];
> +   position->dy20 = position->y[2] - position->y[0];
> +
> +   position->area = -position->area;
> +}
> +
> +
> +/**
> + * Rotate a triangle, flipping its clockwise direction,
>   * Swaps values for xy[1] and xy[2]
>   */
>  static INLINE void
> -rotate_fixed_position( struct fixed_position* position )
> +rotate_fixed_position_12( struct fixed_position* position )
>  {
>     int x, y;
>  
> @@ -852,8 +877,13 @@ static void triangle_cw( struct lp_setup_context
> *setup,
>     calc_fixed_position(setup, &position, v0, v1, v2);
>  
>     if (position.area < 0) {
> -      rotate_fixed_position(&position);
> -      retry_triangle_ccw(setup, &position, v0, v2, v1,
> !setup->ccw_is_frontface);
> +      if (setup->flatshade_first) {
> +         rotate_fixed_position_12(&position);
> +         retry_triangle_ccw(setup, &position, v0, v2, v1,
> !setup->ccw_is_frontface);
> +      } else {
> +         rotate_fixed_position_01(&position);
> +         retry_triangle_ccw(setup, &position, v1, v0, v2,
> !setup->ccw_is_frontface);
> +      }
>     }
>  }
>  
> @@ -893,8 +923,13 @@ static void triangle_both( struct
> lp_setup_context *setup,
>     if (position.area > 0)
>        retry_triangle_ccw( setup, &position, v0, v1, v2,
>        setup->ccw_is_frontface );
>     else if (position.area < 0) {
> -      rotate_fixed_position( &position );
> -      retry_triangle_ccw( setup, &position, v0, v2, v1,
> !setup->ccw_is_frontface );
> +      if (setup->flatshade_first) {
> +         rotate_fixed_position_12( &position );
> +         retry_triangle_ccw( setup, &position, v0, v2, v1,
> !setup->ccw_is_frontface );
> +      } else {
> +         rotate_fixed_position_01( &position );
> +         retry_triangle_ccw( setup, &position, v1, v0, v2,
> !setup->ccw_is_frontface );
> +      }
>     }
>  }
>  
> --
> 1.7.10.rc3.1.gb306
> 
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