test: More coverage coverage.

A couple of different shapes that aim to test the tessellation side of
the rasterisers more... And worryingly there does seem to be an
unexpected systematic error.

10 files changed, 251 insertions, 6 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index bc43e480..836b1b40 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -345,6 +345,14 @@ REFERENCE_IMAGES = \
 	copy-path.ref.png \
 	coverage-rectangles.ref.png \
 	coverage-rectangles.xlib.xfail.png \
+	coverage-intersecting-triangles.ref.png \
+	coverage-intersecting-triangles.xlib.xfail.png \
+	coverage-intersecting-quads.ref.png \
+	coverage-intersecting-quads.xlib.xfail.png \
+	coverage-row-trianges.ref.png \
+	coverage-row-trianges.xlib.xfail.png \
+	coverage-column-trianges.ref.png \
+	coverage-column-trianges.xlib.xfail.png \
 	coverage-triangles.ref.png \
 	coverage-triangles.xlib.xfail.png \
 	create-from-png-stream.ref.png \
diff --git a/test/coverage-column-triangles.ref.png b/test/coverage-column-triangles.ref.png
new file mode 100644
index 00000000..aa61031b
--- /dev/null
+++ b/test/coverage-column-triangles.ref.png
diff --git a/test/coverage-column-triangles.xlib.xfail.png b/test/coverage-column-triangles.xlib.xfail.png
new file mode 100644
index 00000000..f433b7a8
--- /dev/null
+++ b/test/coverage-column-triangles.xlib.xfail.png
diff --git a/test/coverage-intersecting-quads.ref.png b/test/coverage-intersecting-quads.ref.png
new file mode 100644
index 00000000..f56cb557
--- /dev/null
+++ b/test/coverage-intersecting-quads.ref.png
diff --git a/test/coverage-intersecting-quads.xlib.xfail.png b/test/coverage-intersecting-quads.xlib.xfail.png
new file mode 100644
index 00000000..d6b8c2ef
--- /dev/null
+++ b/test/coverage-intersecting-quads.xlib.xfail.png
diff --git a/test/coverage-intersecting-triangles.ref.png b/test/coverage-intersecting-triangles.ref.png
new file mode 100644
index 00000000..40a48c13
--- /dev/null
+++ b/test/coverage-intersecting-triangles.ref.png
diff --git a/test/coverage-intersecting-triangles.xlib.xfail.png b/test/coverage-intersecting-triangles.xlib.xfail.png
new file mode 100644
index 00000000..e64cd474
--- /dev/null
+++ b/test/coverage-intersecting-triangles.xlib.xfail.png
diff --git a/test/coverage-row-triangles.ref.png b/test/coverage-row-triangles.ref.png
new file mode 100644
index 00000000..aa61031b
--- /dev/null
+++ b/test/coverage-row-triangles.ref.png
diff --git a/test/coverage-row-triangles.xlib.xfail.png b/test/coverage-row-triangles.xlib.xfail.png
new file mode 100644
index 00000000..f8582fbb
--- /dev/null
+++ b/test/coverage-row-triangles.xlib.xfail.png
diff --git a/test/coverage.c b/test/coverage.c
index 70ef97b7..198ebae8 100644
--- a/test/coverage.c
+++ b/test/coverage.c
@@ -30,12 +30,15 @@
  * driver test suite.
  */
 
+#define GENERATE_REFERENCE 0
+
 #define WIDTH 256
 #define HEIGHT 40
 
 #include "../src/cairo-fixed-type-private.h"
 #define PRECISION (1 << CAIRO_FIXED_FRAC_BITS)
 
+/* XXX beware multithreading! */
 static uint32_t state;
 
 static uint32_t
@@ -47,10 +50,12 @@ hars_petruska_f54_1_random (void)
 }
 
 static double
-random_offset (int range)
+random_offset (int range, int precise)
 {
     double x = hars_petruska_f54_1_random() / (double) UINT32_MAX * range / WIDTH;
-    return floor (x * PRECISION) / PRECISION;
+    if (precise)
+	x = floor (x * PRECISION) / PRECISION;
+    return x;
 }
 
 static cairo_test_status_t
@@ -63,6 +68,13 @@ rectangles (cairo_t *cr, int width, int height)
     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
     cairo_paint (cr);
 
+#if GENERATE_REFERENCE
+    for (x = 0; x < WIDTH; x++) {
+	cairo_set_source_rgba (cr, 1, 1, 1, x * x * 1.0 / (WIDTH * WIDTH));
+	cairo_rectangle (cr, x, 0, 1, HEIGHT);
+	cairo_fill (cr);
+    }
+#else
     cairo_set_operator (cr, CAIRO_OPERATOR_ADD);
     for (channel = 0; channel < 3; channel++) {
 	switch (channel) {
@@ -74,13 +86,111 @@ rectangles (cairo_t *cr, int width, int height)
 
 	for (x = 0; x < WIDTH; x++) {
 	    for (y = 0; y < HEIGHT; y++) {
-		double dx = random_offset (WIDTH - x);
-		double dy = random_offset (WIDTH - x);
+		double dx = random_offset (WIDTH - x, TRUE);
+		double dy = random_offset (WIDTH - x, TRUE);
 		cairo_rectangle (cr, x + dx, y + dy, x / (double) WIDTH, x / (double) WIDTH);
 	    }
 	}
 	cairo_fill (cr);
     }
+#endif
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+static cairo_test_status_t
+intersecting_quads (cairo_t *cr, int width, int height)
+{
+    int x, y, channel;
+
+    state = 0x12345678;
+
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_paint (cr);
+
+#if GENERATE_REFERENCE
+    for (x = 0; x < WIDTH; x++) {
+	cairo_set_source_rgba (cr, 1, 1, 1, x * x * 0.5 / (WIDTH * WIDTH));
+	cairo_rectangle (cr, x, 0, 1, HEIGHT);
+	cairo_fill (cr);
+    }
+#else
+    cairo_set_operator (cr, CAIRO_OPERATOR_ADD);
+    for (channel = 0; channel < 3; channel++) {
+	switch (channel) {
+	default:
+	case 0: cairo_set_source_rgb (cr, 1.0, 0.0, 0.0); break;
+	case 1: cairo_set_source_rgb (cr, 0.0, 1.0, 0.0); break;
+	case 2: cairo_set_source_rgb (cr, 0.0, 0.0, 1.0); break;
+	}
+
+	for (x = 0; x < WIDTH; x++) {
+	    double step = x / (double) WIDTH;
+	    for (y = 0; y < HEIGHT; y++) {
+		double dx = random_offset (WIDTH - x, TRUE);
+		double dy = random_offset (WIDTH - x, TRUE);
+		cairo_move_to (cr, x + dx, y + dy);
+		cairo_rel_line_to (cr, step, step);
+		cairo_rel_line_to (cr, 0, -step);
+		cairo_rel_line_to (cr, -step, step);
+		cairo_close_path (cr);
+	    }
+	}
+	cairo_fill (cr);
+    }
+#endif
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+static cairo_test_status_t
+intersecting_triangles (cairo_t *cr, int width, int height)
+{
+    int x, y, channel;
+
+    state = 0x12345678;
+
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_paint (cr);
+
+#if GENERATE_REFERENCE
+    for (x = 0; x < WIDTH; x++) {
+	cairo_set_source_rgba (cr, 1, 1, 1, x * 0.75 / WIDTH);
+	cairo_rectangle (cr, x, 0, 1, HEIGHT);
+	cairo_fill (cr);
+    }
+#else
+    cairo_set_operator (cr, CAIRO_OPERATOR_ADD);
+    for (channel = 0; channel < 3; channel++) {
+	switch (channel) {
+	default:
+	case 0: cairo_set_source_rgb (cr, 1.0, 0.0, 0.0); break;
+	case 1: cairo_set_source_rgb (cr, 0.0, 1.0, 0.0); break;
+	case 2: cairo_set_source_rgb (cr, 0.0, 0.0, 1.0); break;
+	}
+
+	for (x = 0; x < WIDTH; x++) {
+	    double step = x / (double) WIDTH;
+	    for (y = 0; y < HEIGHT; y++) {
+		double dx = random_offset (WIDTH - x, TRUE);
+		double dy = random_offset (WIDTH - x, TRUE);
+
+		/* left */
+		cairo_move_to (cr, x + dx, y + dy);
+		cairo_rel_line_to (cr, 0, step);
+		cairo_rel_line_to (cr, step, 0);
+		cairo_close_path (cr);
+
+		/* right, mirrored */
+		cairo_move_to (cr, x + dx + step, y + dy + step);
+		cairo_rel_line_to (cr, 0, -step);
+		cairo_rel_line_to (cr, -step, step);
+		cairo_close_path (cr);
+	    }
+	}
+	cairo_fill (cr);
+    }
+#endif
 
     return CAIRO_TEST_SUCCESS;
 }
@@ -95,6 +205,13 @@ triangles (cairo_t *cr, int width, int height)
     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
     cairo_paint (cr);
 
+#if GENERATE_REFERENCE
+    for (x = 0; x < WIDTH; x++) {
+	cairo_set_source_rgba (cr, 1, 1, 1, x * x * 0.5 / (WIDTH * WIDTH));
+	cairo_rectangle (cr, x, 0, 1, HEIGHT);
+	cairo_fill (cr);
+    }
+#else
     cairo_set_operator (cr, CAIRO_OPERATOR_ADD);
     for (channel = 0; channel < 3; channel++) {
 	switch (channel) {
@@ -106,8 +223,8 @@ triangles (cairo_t *cr, int width, int height)
 
 	for (x = 0; x < WIDTH; x++) {
 	    for (y = 0; y < HEIGHT; y++) {
-		double dx = random_offset (WIDTH - x);
-		double dy = random_offset (WIDTH - x);
+		double dx = random_offset (WIDTH - x, TRUE);
+		double dy = random_offset (WIDTH - x, TRUE);
 		cairo_move_to (cr, x + dx, y + dy);
 		cairo_rel_line_to (cr, x / (double) WIDTH, 0);
 		cairo_rel_line_to (cr, 0, x / (double) WIDTH);
@@ -116,6 +233,101 @@ triangles (cairo_t *cr, int width, int height)
 	}
 	cairo_fill (cr);
     }
+#endif
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+static cairo_test_status_t
+column_triangles (cairo_t *cr, int width, int height)
+{
+    int x, y, i, channel;
+
+    state = 0x12345678;
+
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_paint (cr);
+
+#if GENERATE_REFERENCE
+    for (x = 0; x < WIDTH; x++) {
+	cairo_set_source_rgba (cr, 1, 1, 1, x * 0.5 / WIDTH);
+	cairo_rectangle (cr, x, 0, 1, HEIGHT);
+	cairo_fill (cr);
+    }
+#else
+    cairo_set_operator (cr, CAIRO_OPERATOR_ADD);
+    for (channel = 0; channel < 3; channel++) {
+	switch (channel) {
+	default:
+	case 0: cairo_set_source_rgb (cr, 1.0, 0.0, 0.0); break;
+	case 1: cairo_set_source_rgb (cr, 0.0, 1.0, 0.0); break;
+	case 2: cairo_set_source_rgb (cr, 0.0, 0.0, 1.0); break;
+	}
+
+	for (x = 0; x < WIDTH; x++) {
+	    double step = x / (double) (2 * WIDTH);
+	    for (y = 0; y < HEIGHT; y++) {
+		for (i = 0; i < PRECISION; i++) {
+		    double dy = random_offset (WIDTH - x, FALSE);
+
+		    cairo_move_to (cr, x + i / (double) PRECISION, y + dy);
+		    cairo_rel_line_to (cr, 0, step);
+		    cairo_rel_line_to (cr, 1 / (double) PRECISION, step);
+		    cairo_rel_line_to (cr, 0, -step);
+		    cairo_close_path (cr);
+		}
+		cairo_fill (cr); /* do these per-pixel due to the extra volume of edges */
+	    }
+	}
+    }
+#endif
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+static cairo_test_status_t
+row_triangles (cairo_t *cr, int width, int height)
+{
+    int x, y, i, channel;
+
+    state = 0x12345678;
+
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_paint (cr);
+
+#if GENERATE_REFERENCE
+    for (x = 0; x < WIDTH; x++) {
+	cairo_set_source_rgba (cr, 1, 1, 1, x * 0.5 / WIDTH);
+	cairo_rectangle (cr, x, 0, 1, HEIGHT);
+	cairo_fill (cr);
+    }
+#else
+    cairo_set_operator (cr, CAIRO_OPERATOR_ADD);
+    for (channel = 0; channel < 3; channel++) {
+	switch (channel) {
+	default:
+	case 0: cairo_set_source_rgb (cr, 1.0, 0.0, 0.0); break;
+	case 1: cairo_set_source_rgb (cr, 0.0, 1.0, 0.0); break;
+	case 2: cairo_set_source_rgb (cr, 0.0, 0.0, 1.0); break;
+	}
+
+	for (x = 0; x < WIDTH; x++) {
+	    double step = x / (double) (2 * WIDTH);
+	    for (y = 0; y < HEIGHT; y++) {
+		for (i = 0; i < PRECISION; i++) {
+		    double dx = random_offset (WIDTH - x, FALSE);
+
+		    cairo_move_to (cr, x + dx, y + i / (double) PRECISION);
+		    cairo_rel_line_to (cr,  step, 0);
+		    cairo_rel_line_to (cr,  step, 1 / (double) PRECISION);
+		    cairo_rel_line_to (cr, -step, 0);
+		    cairo_close_path (cr);
+		}
+		cairo_fill (cr); /* do these per-pixel due to the extra volume of edges */
+	    }
+	}
+    }
+#endif
 
     return CAIRO_TEST_SUCCESS;
 }
@@ -127,6 +339,31 @@ CAIRO_TEST (coverage_rectangles,
 	    WIDTH, HEIGHT,
 	    NULL, rectangles)
 
+CAIRO_TEST (coverage_intersecting_quads,
+	    "Check the fidelity of the rasterisation.",
+	    NULL, /* keywords */
+	    "target=raster", /* requirements */
+	    WIDTH, HEIGHT,
+	    NULL, intersecting_quads)
+
+CAIRO_TEST (coverage_intersecting_triangles,
+	    "Check the fidelity of the rasterisation.",
+	    NULL, /* keywords */
+	    "target=raster", /* requirements */
+	    WIDTH, HEIGHT,
+	    NULL, intersecting_triangles)
+CAIRO_TEST (coverage_row_triangles,
+	    "Check the fidelity of the rasterisation.",
+	    NULL, /* keywords */
+	    "target=raster", /* requirements */
+	    WIDTH, HEIGHT,
+	    NULL, row_triangles)
+CAIRO_TEST (coverage_column_triangles,
+	    "Check the fidelity of the rasterisation.",
+	    NULL, /* keywords */
+	    "target=raster", /* requirements */
+	    WIDTH, HEIGHT,
+	    NULL, column_triangles)
 CAIRO_TEST (coverage_triangles,
 	    "Check the fidelity of the rasterisation.",
 	    NULL, /* keywords */