[Piglit] [PATCH 4/4] util: Set tolerance according to alpha channel bit depth.

[Mario Kleiner]

Make sure piglit_set_tolerance_for_bits() doesn't ask for a
alpha tolerance impossible to achieve for the given alpha
bit depth of the context, e.g., in case of 2 bit alpha channels
with ARGB2101010 visuals or fbconfigs.

Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
---
 tests/util/piglit-framework-gl/piglit_winsys_framework.c | 6 +++++-
 tests/util/piglit-util-gl.c                              | 7 +++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/tests/util/piglit-framework-gl/piglit_winsys_framework.c b/tests/util/piglit-framework-gl/piglit_winsys_framework.c
index 5713f5c..9dc4944 100644
--- a/tests/util/piglit-framework-gl/piglit_winsys_framework.c
+++ b/tests/util/piglit-framework-gl/piglit_winsys_framework.c
@@ -56,7 +56,6 @@ run_test(struct piglit_gl_framework *gl_fw,
 	bool no_window = false;
 	const char *env_no_window = getenv("PIGLIT_NO_WINDOW");
 
-
 	if (env_no_window != NULL) {
 		if (strcmp(env_no_window, "0") == 0) {
 			no_window = false;
@@ -69,6 +68,11 @@ run_test(struct piglit_gl_framework *gl_fw,
 		}
 	}
 
+	/* Init tolerance. This will make sure we don't request too strict
+	 * tolerance for contexts alpha bit depth.
+	 */
+	piglit_set_tolerance_for_bits(8, 8, 8, 8);
+
 	if (gl_fw->test_config->init)
 		gl_fw->test_config->init(argc, argv);
 
diff --git a/tests/util/piglit-util-gl.c b/tests/util/piglit-util-gl.c
index d8b8f85..8b16482 100644
--- a/tests/util/piglit-util-gl.c
+++ b/tests/util/piglit-util-gl.c
@@ -278,6 +278,13 @@ piglit_set_tolerance_for_bits(int rbits, int gbits, int bbits, int abits)
 	int bits[4] = {rbits, gbits, bbits, abits};
 	int i;
 
+	/* Make sure we don't set a alpha tolerance impossible to achieve with
+	 * given alpha channel bit depths.
+	 */
+	glGetIntegerv(GL_ALPHA_BITS, &abits);
+	if (abits < bits[3])
+		bits[3] = abits;
+
 	for (i = 0; i < 4; i++) {
 		if (bits[i] == 0) {
 			/* With 0 bits of storage, we still want to
-- 
2.7.4