[Piglit] [PATCH v3 2/4] fbo-pbo-readpixels-small: make it endian-safe

[Oded Gabbay]

In this test we use GL_BGRA + GL_UNSIGNED_BYTE. However, the probe
function receives two 4-byte values to compare, expected and observed.
This is wrong as the correct way to compare array_of_bytes
(GL_UNSIGNED_BYTE) in an endian-safe way is by comparing memory (and not
values).

This patch fixes this bug by changing the function to receive two
pointers instead of values. It also corrects the way the expected values
are constructed to be in endian-safe way for array-of-bytes

This fixes the test in llvmpipe, softpipe and r600g in big-endian machine.

v2: Changed initialization of expected results to be more clear
v3: Changed printing of results to display individual components

Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
---
 tests/fbo/fbo-pbo-readpixels-small.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/tests/fbo/fbo-pbo-readpixels-small.c b/tests/fbo/fbo-pbo-readpixels-small.c
index c7730b2..8e363e0 100644
--- a/tests/fbo/fbo-pbo-readpixels-small.c
+++ b/tests/fbo/fbo-pbo-readpixels-small.c
@@ -80,12 +80,16 @@ make_fbo(GLuint *fbo, GLuint *tex)
 }
 
 static GLboolean
-probe(int x, int y, uint32_t expected, uint32_t observed)
+probe(int x, int y, uint8_t *expected, uint8_t *observed)
 {
-	if ((expected & 0xffffff) != (observed & 0xffffff)) {
+	if (expected[0] != observed[0] ||
+		 expected[1] != observed[1] ||
+		 expected[2] != observed[2]) {
 		printf("Probe color at (%i,%i)\n", x, y);
-		printf("  Expected: 0x%08x\n", expected);
-		printf("  Observed: 0x%08x\n", observed);
+		printf("  Expected: b = 0x%02x  g = 0x%02x  r = 0x%02x  a = 0x%02x\n",
+				expected[0], expected[1], expected[2], expected[3]);
+		printf("  Observed: b = 0x%02x  g = 0x%02x  r = 0x%02x  a = 0x%02x\n",
+				observed[0], observed[1], observed[2], observed[3]);
 
 		return GL_FALSE;
 	} else {
@@ -98,7 +102,9 @@ piglit_display(void)
 {
 	GLboolean pass = GL_TRUE;
 	GLuint fbo, tex, pbo;
-	uint32_t *addr;
+	uint8_t *addr;
+	static uint8_t green[] = {0x00, 0xFF, 0x00, 0x00};
+	static uint8_t blue[]  = {0xFF, 0x00, 0x00, 0x00};
 
 	make_fbo(&fbo, &tex);
 
@@ -122,24 +128,25 @@ piglit_display(void)
 	glReadPixels(0, 0, 2, 2,
 		     GL_BGRA, GL_UNSIGNED_BYTE, (void *)(uintptr_t)0);
 	addr = glMapBufferARB(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY_ARB);
-	pass &= probe(0, 0, 0x0000ff00, addr[0]);
-	pass &= probe(1, 0, 0x0000ff00, addr[1]);
-	pass &= probe(0, 1, 0x000000ff, addr[2]);
-	pass &= probe(1, 1, 0x000000ff, addr[3]);
+
+	pass &= probe(0, 0, green, addr);
+	pass &= probe(1, 0, green, addr + 4);
+	pass &= probe(0, 1, blue,  addr + 8);
+	pass &= probe(1, 1, blue,  addr + 12);
 	glUnmapBufferARB(GL_PIXEL_PACK_BUFFER);
 
 	/* Read with an offset. */
 	glReadPixels(1, 0, 1, 1,
 		     GL_BGRA, GL_UNSIGNED_BYTE, (void *)(uintptr_t)4);
 	addr = glMapBufferARB(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY_ARB);
-	pass &= probe(1, 0, 0x0000ff00, addr[1]);
+	pass &= probe(1, 0, green, addr + 4);
 	glUnmapBufferARB(GL_PIXEL_PACK_BUFFER);
 
 	/* Read with an offset. */
 	glReadPixels(1, 1, 1, 1,
 		     GL_BGRA, GL_UNSIGNED_BYTE, (void *)(uintptr_t)4);
 	addr = glMapBufferARB(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY_ARB);
-	pass &= probe(1, 1, 0x000000ff, addr[1]);
+	pass &= probe(1, 1, blue, addr + 4);
 	glUnmapBufferARB(GL_PIXEL_PACK_BUFFER);
 
 	glDeleteBuffersARB(1, &pbo);
-- 
2.5.5