[PATCH weston v2 04/14] tests: Add surface checks

[Bryce Harrington]

Introduce helper routines for testing surfaces against specific
conditions.  These allow tests to validate screen captures as displaying
the correct rendering results.

Signed-off-by: Bryce Harrington <bryce at osg.samsung.com>
---
 tests/weston-test-client-helper.c | 116 ++++++++++++++++++++++++++++++++++++++
 tests/weston-test-client-helper.h |  15 +++++
 2 files changed, 131 insertions(+)

diff --git a/tests/weston-test-client-helper.c b/tests/weston-test-client-helper.c
index 080bb62..04b77d5 100644
--- a/tests/weston-test-client-helper.c
+++ b/tests/weston-test-client-helper.c
@@ -32,6 +32,10 @@
 #include "../shared/os-compatibility.h"
 #include "weston-test-client-helper.h"
 
+#define max(a, b) (((a) > (b)) ? (a) : (b))
+#define min(a, b) (((a) > (b)) ? (b) : (a))
+#define clip(x, a, b)  min(max(x, a), b)
+
 void *
 fail_on_null(void *p)
 {
@@ -861,3 +865,115 @@ screenshot_reference_filename(const char *basename, uint32_t seq) {
 		return NULL;
 	return filename;
 }
+
+/**
+ * check_surfaces_equal() - tests if two surfaces are pixel-identical
+ *
+ * Returns true if surface buffers have all the same byte values,
+ * false if the surfaces don't match or can't be compared due to
+ * different dimensions.
+ */
+bool
+check_surfaces_equal(const struct surface *a, const struct surface *b)
+{
+	int y;
+	void *p, *q;
+
+	if (a == NULL || b == NULL)
+		return false;
+	if (a->width != b->width || a->height != a->height)
+		return false;
+
+	if (a->stride == b->stride) {
+		printf("Checking data for equivalent strides\n");
+		return (memcmp(a->data, b->data, a->stride * a->height) == 0);
+	} else {
+		printf("Manually comparing due to differing strides\n");
+		for (y = 0; y < a->height; y++) {
+			p = a->data + (y * a->stride);
+			q = b->data + (y * b->stride);
+			if (memcmp(p, q, a->stride) != 0)
+				return false;
+		}
+		return true;
+	}
+}
+
+/**
+ * check_surfaces_match_in_clip() - tests if a given region within two
+ * surfaces are pixel-identical.
+ *
+ * Returns true if the two surfaces have the same byte values within the
+ * given clipping region, or false if they don't match or the surfaces
+ * can't be compared.
+ */
+bool
+check_surfaces_match_in_clip(const struct surface *a, const struct surface *b, const struct rectangle *clip_rect)
+{
+	int i, j;
+	int a_bpp, b_bpp;
+	int x0, y0, x1, y1;
+	void *p, *q;
+	char a_char, b_char;
+
+	if (a == NULL || b == NULL || clip_rect == NULL)
+		return false;
+
+	if (a->data == NULL || b->data == NULL) {
+		printf("Undefined data\n");
+		return false;
+	}
+	if (a->width != b->width || a->height != b->height) {
+		printf("Mismatched dimensions:  %d,%d != %d,%d\n",
+		       a->width, a->height, b->width, b->height);
+		return false;
+	}
+	if (clip_rect->x > a->width || clip_rect->y > a->height) {
+		printf("Clip outside image boundaries\n");
+		return true;
+	}
+
+	x0 = max(0, clip_rect->x);
+	y0 = max(0, clip_rect->y);
+	x1 = min(a->width,  clip_rect->x + clip_rect->width);
+	y1 = min(a->height, clip_rect->y + clip_rect->height);
+
+	if (x0 == x1 || y0 == y1) {
+		printf("Degenerate comparison\n");
+		return true;
+	}
+
+	printf("Bytewise comparison inside clip\n");
+	a_bpp = a->stride / a->width;
+	b_bpp = b->stride / b->width;
+	for (i=y0; i<y1; i++) {
+		p = a->data + i * a->stride + x0 * a_bpp;
+		q = b->data + i * b->stride + x0 * b_bpp;
+		if (a->stride == b->stride) {
+			if (memcmp(p, q, (x1-x0)*a_bpp) != 0) {
+				// Dump the bad row
+				printf("Mismatched image on row %d\n", i);
+				for (j=0; j<(x1-x0)*a_bpp; j++) {
+					a_char = *((char*)(p+j*a_bpp));
+					b_char = *((char*)(q+j*b_bpp));
+					printf("%d,%d: %8x %8x %s\n", i, j, a_char, b_char,
+					       (a_char != b_char)? " <---": "");
+				}
+				return false;
+			}
+		} else {
+			/* account for bpp differences */
+			for (j=0; j<x1-x0; j++) {
+				a_char = *((char*)(p+j*a_bpp));
+				b_char = *((char*)(q+j*b_bpp));
+				if (a_char != b_char) {
+					printf("%d,%d: %8x %8x %s\n", i, j, a_char, b_char,
+					       (a_char != b_char)? " <---": "");
+					return false;
+				}
+			}
+		}
+	}
+
+	return true;
+}
diff --git a/tests/weston-test-client-helper.h b/tests/weston-test-client-helper.h
index 43a5aa7..8cbd4ba 100644
--- a/tests/weston-test-client-helper.h
+++ b/tests/weston-test-client-helper.h
@@ -27,6 +27,7 @@
 
 #include <assert.h>
 #include <stdbool.h>
+
 #include "weston-test-runner.h"
 #include "weston-test-client-protocol.h"
 
@@ -129,9 +130,17 @@ struct surface {
 	int y;
 	int width;
 	int height;
+	int stride;
 	void *data;
 };
 
+struct rectangle {
+	int x;
+	int y;
+	int width;
+	int height;
+};
+
 void *
 fail_on_null(void *p);
 
@@ -190,4 +199,10 @@ screenshot_output_filename(const char *basename, uint32_t seq);
 char*
 screenshot_reference_filename(const char *basename, uint32_t seq);
 
+bool
+check_surfaces_equal(const struct surface *a, const struct surface *b);
+
+bool
+check_surfaces_match_in_clip(const struct surface *a, const struct surface *b, const struct rectangle *clip);
+
 #endif
-- 
1.9.1