fbo-maxsize: minor test improvements

Clear the large FBO to a non-black color and probe for it in the
final test.

This uncovers a bug in Mesa's llvmpipe driver where we ran out of
bin commmand memory and skipped some tiles, leaving them black.

Setting the clear color to white (and actually clearing the FBO)
helps to detect that.

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/fbo/fbo-maxsize.c b/tests/fbo/fbo-maxsize.c
index ef886007..905afc05 100644
--- a/tests/fbo/fbo-maxsize.c
+++ b/tests/fbo/fbo-maxsize.c
@@ -140,6 +140,9 @@ static int create_fbo(void)
 	glViewport(0, 0, maxsize, maxsize);
 	piglit_ortho_projection(maxsize, maxsize, GL_FALSE);
 
+	glClearColor(1.0, 1.0, 1.0, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+
 	x0 = maxsize / 4;
 	x1 = maxsize * 3 / 4;
 	y0 = maxsize / 4;
@@ -188,10 +191,13 @@ piglit_display(void)
 	int x2 = (piglit_width / 4) * 3;
 	int y1 = piglit_height / 4;
 	int y2 = (piglit_height / 4) * 3;
+	int cx = piglit_width / 2;
+	int cy = piglit_height / 2;
 	float c1[3] = {0.25, 0.25, 0.25};
 	float c2[3] = {0.75, 0.25, 0.25};
 	float c3[3] = {0.25, 0.75, 0.75};
 	float c4[3] = {0.75, 0.75, 0.75};
+	float white[3] = {1.0, 1.0, 1.0};
 
 	glClearColor(0.5, 0.5, 0.5, 0.5);
 	glClear(GL_COLOR_BUFFER_BIT);
@@ -212,11 +218,13 @@ piglit_display(void)
 	draw_tex_sub_rect(x2, y1);
 	draw_tex_sub_rect(x1, y2);
 	draw_tex_sub_rect(x2, y2);
+	draw_tex_sub_rect(cx, cy);
 
 	pass &= piglit_probe_pixel_rgb(x1, y1, c1);
 	pass &= piglit_probe_pixel_rgb(x2, y1, c2);
 	pass &= piglit_probe_pixel_rgb(x1, y2, c3);
 	pass &= piglit_probe_pixel_rgb(x2, y2, c4);
+	pass &= piglit_probe_pixel_rgb(cx, cy, white);
 
 	glDeleteTextures(1, &tex);
 	glDisable(GL_TEXTURE_2D);