OrthoPosHLines completed.

1 files changed, 62 insertions, 0 deletions

diff --git a/tests/spec/laura_orthpos/orthpos.c b/tests/spec/laura_orthpos/orthpos.c
index d558d6df7..68a517e92 100644
--- a/tests/spec/laura_orthpos/orthpos.c
+++ b/tests/spec/laura_orthpos/orthpos.c
@@ -420,6 +420,67 @@ orthoPosVLines() {
 	return verifyOrthPos(img, imgBytes/windowSize, "Immediate-mode vertical lines");
 } /* orthoPosVLines */
 
+/**
+ * This test checks the positioning of unit-width horizontal lines
+ * under orthographic projection.	(This is important for apps
+ * that want to use OpenGL for precise 2D drawing.)  It fills in
+ * an entire rectangle with a stack of horizontal lines, drawing
+ * adjacent lines with different colors and with blending enabled.
+ * If there are gaps (pixels that are the background color, and
+ * thus haven't been filled), overlaps (pixels that show a blend
+ * of more than one color), or improper edges (pixels around the
+ * edge of the rectangle that haven't been filled, or pixels just
+ * outside the edge that have), then the test fails.
+ * 
+ * This test generally fails for one of several reasons.  First,
+ * the coordinate transformation process may have an incorrect bias;
+ * this usually will cause a bad edge.  Second, the coordinate
+ * transformation process may round pixel coordinates incorrectly;
+ * this will usually cause gaps and/or overlaps.  Third, the
+ * line rasterization process may not be filling the correct
+ * pixels; this can cause gaps, overlaps, or bad edges.  Fourth,
+ * the OpenGL implementation may not handle the diamond-exit rule
+ * (section 3.4.1 in version 1.2.1 of the OpenGL spec) correctly;
+ * this should cause a bad border or bad right edge.
+ * 
+ * It can be argued that this test is more strict that the OpenGL
+ * specification requires.  However, it is necessary to be this
+ * strict in order for the results to be useful to app developers
+ * using OpenGL for 2D drawing.
+ */
+bool
+orthoPosHLines() {
+	/*
+	 * Immediate-mode horizontal lines
+	 * See the comments in the vertical line case above.
+	 */
+	int y;
+	
+	/* Draw the image */
+	glClear(GL_COLOR_BUFFER_BIT);
+	glBegin(GL_LINES);
+	for (y = 1; y <= drawingSize; ++y) {
+		if (y & 1)
+			glColor4f(0.0, 1.0, 0.0, 0.5);
+		else
+			glColor4f(1.0, 0.0, 0.0, 0.5);
+		glVertex2i(1, y);
+		glVertex2i(drawingSize + 1, y);
+	}
+	glEnd();
+
+	/* Read the image */
+	glReadPixels(0, 0, windowSize, windowSize, GL_RGB, GL_UNSIGNED_BYTE, img);
+
+	/* Show the image */
+	if (!piglit_automatic) {
+		piglit_present_results();
+	}
+
+	/* Check the results */
+	return verifyOrthPos(img, imgBytes/windowSize, "Immediate-mode horizontal lines");
+} /* orthoPosHLines */
+
 enum piglit_result
 piglit_display(void)
 {
@@ -427,6 +488,7 @@ piglit_display(void)
 
 	pass &= orthoPosPoints();
 	pass &= orthoPosVLines();
+	pass &= orthoPosHLines();
 
 	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
 }