[Piglit] [PATCH] Triangles should be clipped to the clip volume and therefore shouldn't end up being rasterized outside the viewport.

[Stuart Abercrombie]

Apologies -- still learning the submission process.  I sent a version
with the correct subject, so ignore this.

On Mon, Nov 12, 2012 at 1:21 PM, Stuart Abercrombie
<sabercrombie at chromium.org> wrote:
> This was failing on Sandy Bridge with guard band clipping enabled.
>
> v2 with a new name, more comments and addition to all.tests.
>
> Reviewed-by: Brian Paul <brianp at vmware.com>
> ---
>  tests/all.tests                             |    1 +
>  tests/general/CMakeLists.gl.txt             |    1 +
>  tests/general/triangle-guardband-viewport.c |   62 +++++++++++++++++++++++++++
>  3 files changed, 64 insertions(+), 0 deletions(-)
>  create mode 100644 tests/general/triangle-guardband-viewport.c
>
> diff --git a/tests/all.tests b/tests/all.tests
> index 0a8a5aa..954a96c 100644
> --- a/tests/all.tests
> +++ b/tests/all.tests
> @@ -556,6 +556,7 @@ add_plain_test(gl11, 'streaming-texture-leak')
>  add_plain_test(gl11, 'texredefine')
>  add_plain_test(gl11, 'texsubimage')
>  add_plain_test(gl11, 'texture-al')
> +add_plain_test(gl11, 'triangle-guardband-viewport')
>
>  gl10 = Group()
>  spec['!OpenGL 1.0'] = gl10
> diff --git a/tests/general/CMakeLists.gl.txt b/tests/general/CMakeLists.gl.txt
> index 11da25f..a26371c 100644
> --- a/tests/general/CMakeLists.gl.txt
> +++ b/tests/general/CMakeLists.gl.txt
> @@ -134,5 +134,6 @@ piglit_add_executable (occlusion-query-discard occlusion-query-discard.c)
>  piglit_add_executable (quad-invariance quad-invariance.c)
>  piglit_add_executable (clear-accum clear-accum.c)
>  piglit_add_executable (vs-point_size-zero vs-point_size-zero.c)
> +piglit_add_executable (triangle-guardband-viewport triangle-guardband-viewport.c)
>
>  # vim: ft=cmake:
> diff --git a/tests/general/triangle-guardband-viewport.c b/tests/general/triangle-guardband-viewport.c
> new file mode 100644
> index 0000000..fcd11fe
> --- /dev/null
> +++ b/tests/general/triangle-guardband-viewport.c
> @@ -0,0 +1,62 @@
> +/** @file triangle-guardband-vewport.c
> + *
> + * Tests whether clipping of triangles to the clip volume
> + * is reflected in what is rasterized. Specifically,
> + * triangles (unlike some other primitives) should not be
> + * rasterized outside the viewport extents because they should
> + * have been clipped to the clip volume mapping to the viewport.
> + *
> + * Faulty guard-band clipping optimizations have been known to
> + * not honor this requirement.
> + */
> +
> +#include "piglit-util-gl-common.h"
> +
> +PIGLIT_GL_TEST_CONFIG_BEGIN
> +
> +       config.supports_gl_compat_version = 10;
> +
> +       config.window_width = 100;
> +       config.window_height = 100;
> +       config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGB;
> +
> +PIGLIT_GL_TEST_CONFIG_END
> +
> +enum piglit_result
> +piglit_display(void)
> +{
> +       GLboolean pass = GL_TRUE;
> +       static float green[] = {0.0, 1.0, 0.0, 0.0};
> +       static float blue[]  = {0.0, 0.0, 1.0, 0.0};
> +
> +       /* make the whole window green. */
> +       glClearColor(0.0, 1.0, 0.0, 0.0);
> +       glClear(GL_COLOR_BUFFER_BIT);
> +
> +       /* set viewport to the left half of the window */
> +       glViewport(0, 0, piglit_width / 2, piglit_height);
> +
> +       /* draw blue rect extending beyond the right edge of the
> +          frustrum, notionally across the whole window */
> +       glColor4fv(blue);
> +       piglit_draw_rect(-1.0, -1.0, 4.0, 2.0);
> +
> +       /* check that the right half of the window, outside
> +          the viewport, still has the clear color */
> +       pass &= piglit_probe_rect_rgb(piglit_width/2, 0,
> +                               piglit_width/2, piglit_height, green);
> +
> +       piglit_present_results();
> +
> +       return pass ? PIGLIT_PASS : PIGLIT_FAIL;
> +}
> +
> +void
> +piglit_init(int argc, char **argv)
> +{
> +       glMatrixMode(GL_PROJECTION);
> +       glLoadIdentity();
> +
> +       glMatrixMode(GL_MODELVIEW);
> +       glLoadIdentity();
> +}
> --
> 1.7.7.3
>