[Piglit] [PATCH] depth-clamp-range: make sure clamping actually makes a difference

[sroland at vmware.com]

From: Roland Scheidegger <sroland at vmware.com>

The problem with the chosen depth values was that the depth values
naturally got viewport-transformed to values below 0.5 (for those
quads drawn) or above 0.5 (for those not drawn).
This allowed buggy implementations (in particular llvmpipe) to pass
the test, even though llvmpipe a) couldn't handle swapped near/far and
b) didn't actually do any clamping whatsoever in this particular case.
So change the depth values so that transformed values actually end up
"on the wrong side" of the depth range.
---
 tests/general/depth-clamp-range.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/tests/general/depth-clamp-range.c b/tests/general/depth-clamp-range.c
index dd93000..d61d351 100644
--- a/tests/general/depth-clamp-range.c
+++ b/tests/general/depth-clamp-range.c
@@ -89,17 +89,17 @@ piglit_display(void)
 	/* Now, test that near depth clamping works.*/
 	glEnable(GL_DEPTH_CLAMP);
 	glDepthRange(0.25, 1.0);
-	quad(30, 10, 2); /* 0.25 - drawn. */
+	quad(30, 10, 4); /* 0.25 - drawn. */
 
 	glDepthRange(0.75, 1.0);
-	quad(30, 30, 2); /* 0.75 - not drawn. */
+	quad(30, 30, 4); /* 0.75 - not drawn. */
 
 	/* Test that far clamping works.*/
 	glDepthRange(0.0, 0.25);
-	quad(50, 10, -2); /* 0.25 - drawn. */
+	quad(50, 10, -4); /* 0.25 - drawn. */
 
 	glDepthRange(0.0, 0.75);
-	quad(50, 30, -2); /* 0.75 - not drawn. */
+	quad(50, 30, -4); /* 0.75 - not drawn. */
 
 	/* Now, flip near and far around and make sure that it's doing the
 	 * min/max of near and far in the clamping.
@@ -107,17 +107,17 @@ piglit_display(void)
 
 	/* Test that near (max) clamping works. */
 	glDepthRange(0.25, 0.0);
-	quad(70, 10, 2); /* 0.25 - drawn. */
+	quad(70, 10, 4); /* 0.25 - drawn. */
 
 	glDepthRange(0.75, 0.0);
-	quad(70, 30, 2); /* 0.75 - not drawn. */
+	quad(70, 30, 4); /* 0.75 - not drawn. */
 
 	/* Now, test far (min) clamping works. */
 	glDepthRange(1.0, 0.0);
-	quad(90, 10, -2); /* 0.0 - drawn */
+	quad(90, 10, -4); /* 0.0 - drawn */
 
 	glDepthRange(1.0, 0.75);
-	quad(90, 30, -2); /* 0.75 - not drawn*/
+	quad(90, 30, -4); /* 0.75 - not drawn*/
 
 	pass = piglit_probe_pixel_rgb(15, 15, white) && pass;
 	pass = piglit_probe_pixel_rgb(15, 35, clear) && pass;
-- 
2.7.4