[Piglit] [PATCH] fbo-maxsize: Try to avoid allocating miplevels.

[Kenneth Graunke]

A 16384x16384 RGBA8888 buffer takes 1GB of RAM.  If the driver allocates
mipmap levels, that increases our storage requirements to 1.5GB.  The
test doesn't use mipmapping, so this seems like a waste.

Disabling mipmap filtering before allocating the texture provides a hint
to the driver, suggesting that it should only allocate space for the
base level.  Most Mesa drivers (Gallium and i965) follow this practice.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 tests/fbo/fbo-maxsize.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/fbo/fbo-maxsize.c b/tests/fbo/fbo-maxsize.c
index 64dcd99..cec6716 100644
--- a/tests/fbo/fbo-maxsize.c
+++ b/tests/fbo/fbo-maxsize.c
@@ -107,6 +107,11 @@ static int create_fbo(void)
 	glGenTextures(1, &tex);
 	glBindTexture(GL_TEXTURE_2D, tex);
 
+	/* Turn off mipmap filtering as a hint to the driver that we don't
+	 * need multiple mipmap levels (as those can increase the memory
+	 * requirements by 50%, and we don't need them in this test.
+	 */
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, maxsize, maxsize,
 		     0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 
-- 
2.10.2