[Piglit] [PATCH] arb-fragment-coord-conventions: test center shift correctness

[Jose Fonseca]

looks good to me.  I ran into a similar problem using graw's examples for frag coord properties to bring up this functionality on llvmpipe, but I didn't notice piglit test behaved similarly at the time.

Jose

----- Original Message -----
> Modifies the pixel center tests to check that the pixel coordinates
> actually start at 0 / 0.5.
> Catches sign errors in center shift calculation (+-0.5).
> ---
>  .../shaders/glsl-arb-fragment-coord-conventions.c  |   18 ++++++++++--------
>  1 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/tests/shaders/glsl-arb-fragment-coord-conventions.c
> b/tests/shaders/glsl-arb-fragment-coord-conventions.c
> index 28c44a0..297b0e8 100644
> --- a/tests/shaders/glsl-arb-fragment-coord-conventions.c
> +++ b/tests/shaders/glsl-arb-fragment-coord-conventions.c
> @@ -51,8 +51,10 @@ static const float black[4] = {0.0, 0.0, 0.0, 0.0};
>  static const float red[4] = {1.0, 0.0, 0.0, 0.0};
>  static const float green[4] = {0.0, 1.0, 0.0, 0.0};
>  static const float yellow[4] = {1.0, 1.0, 0.0, 0.0};
> -static const float gray25[4] = {0.25, 0.25, 0.0, 0.0};
> -static const float gray75[4] = {0.75, 0.75, 0.0, 0.0};
> +static const float gray25_l[4] = {0.25, 0.25, 0.0, 0.0};
> +static const float gray25_r[4] = {0.25, 0.25, 1.0, 0.0};
> +static const float gray75_l[4] = {0.75, 0.75, 0.5, 0.0};
> +static const float gray75_r[4] = {0.75, 0.75, 1.0, 0.0};
>  
>  static int test = 0;
>  
> @@ -111,7 +113,7 @@ piglit_display(void)
>           "void main(void) \n"
>           "{ \n"
>           "   gl_FragColor = fract(gl_FragCoord) + 0.25; \n"
> -         "   gl_FragColor.z = 0.0; \n"
> +         "   gl_FragColor.z = (gl_FragCoord.x + gl_FragCoord.y) * 0.5; \n"
>           "} \n";
>  
>        printf("Pixel center half integer\n");
> @@ -125,10 +127,10 @@ piglit_display(void)
>        piglit_draw_rect(0, 0, WIDTH, HEIGHT);
>  
>        /* lower-left corner */
> -      pass = piglit_probe_pixel_rgb(0, 0, gray75) && pass;
> +      pass = piglit_probe_pixel_rgb(0, 0, gray75_l) && pass;
>  
>        /* upper-right corner */
> -      pass = piglit_probe_pixel_rgb(WIDTH - 1, HEIGHT - 1, gray75) && pass;
> +      pass = piglit_probe_pixel_rgb(WIDTH - 1, HEIGHT - 1, gray75_r) &&
> pass;
>     }
>  
>     /* Pixel center integer */
> @@ -140,7 +142,7 @@ piglit_display(void)
>           "void main(void) \n"
>           "{ \n"
>           "   gl_FragColor = fract(gl_FragCoord) + 0.25; \n"
> -         "   gl_FragColor.z = 0.0; \n"
> +         "   gl_FragColor.z = (gl_FragCoord.x + gl_FragCoord.y) * 0.5; \n"
>           "} \n";
>  
>        printf("Pixel center integer\n");
> @@ -154,10 +156,10 @@ piglit_display(void)
>        piglit_draw_rect(0, 0, WIDTH, HEIGHT);
>  
>        /* lower-left corner */
> -      pass = piglit_probe_pixel_rgb(0, 0, gray25) && pass;
> +      pass = piglit_probe_pixel_rgb(0, 0, gray25_l) && pass;
>  
>        /* upper-right corner */
> -      pass = piglit_probe_pixel_rgb(WIDTH - 1, HEIGHT - 1, gray25) && pass;
> +      pass = piglit_probe_pixel_rgb(WIDTH - 1, HEIGHT - 1, gray25_r) &&
> pass;
>     }
>  
>     /* Pixel origin upper left */
> --
> 1.7.3.4
> 
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