[Piglit] [PATCH] line-flat-clip-color: test flat-shaded line clipping color

[Brian Paul]

This exercises a bug found in Mesa with softpipe, llvmpipe and swrast
---
 tests/all.py                         |    1 +
 tests/general/CMakeLists.gl.txt      |    1 +
 tests/general/line-flat-clip-color.c |  156 ++++++++++++++++++++++++++++++++++
 3 files changed, 158 insertions(+)
 create mode 100644 tests/general/line-flat-clip-color.c

diff --git a/tests/all.py b/tests/all.py
index 5d6ef9a..d1bd617 100644
--- a/tests/all.py
+++ b/tests/all.py
@@ -861,6 +861,7 @@ add_concurrent_test(gl11, 'glinfo')
 add_plain_test(gl11, 'hiz')
 add_plain_test(gl11, 'infinite-spot-light')
 add_plain_test(gl11, 'line-aa-width')
+add_concurrent_test(gl11, 'line-flat-clip-color')
 add_plain_test(gl11, 'linestipple')
 add_plain_test(gl11, 'longprim')
 add_concurrent_test(gl11, 'masked-clear')
diff --git a/tests/general/CMakeLists.gl.txt b/tests/general/CMakeLists.gl.txt
index 1933b13..69ed167 100644
--- a/tests/general/CMakeLists.gl.txt
+++ b/tests/general/CMakeLists.gl.txt
@@ -81,6 +81,7 @@ piglit_add_executable (line-aa-width line-aa-width.c)
 IF (UNIX)
 	target_link_libraries (line-aa-width m)
 ENDIF (UNIX)
+piglit_add_executable (line-flat-clip-color line-flat-clip-color.c)
 piglit_add_executable (longprim longprim.c)
 piglit_add_executable (masked-clear masked-clear.c)
 piglit_add_executable (pos-array pos-array.c)
diff --git a/tests/general/line-flat-clip-color.c b/tests/general/line-flat-clip-color.c
new file mode 100644
index 0000000..4cf37b2
--- /dev/null
+++ b/tests/general/line-flat-clip-color.c
@@ -0,0 +1,156 @@
+/*
+ * Copyright © 2014 VMware, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * Test flat-shaded clipped line color.
+ * Exercises provoking vertex, line smooth, line width, etc.
+ *
+ * Author: Brian Paul
+ */
+
+
+#include "piglit-util-gl-common.h"
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+	config.supports_gl_compat_version = 10;
+	config.window_visual = PIGLIT_GL_VISUAL_RGB | PIGLIT_GL_VISUAL_DOUBLE;
+PIGLIT_GL_TEST_CONFIG_END
+
+
+/* far left, far right verts */
+static const float verts[2][2] = {
+	{ -10.0, 0.0 }, { 10.0, 0.0 }
+};
+
+static const float colors[2][3] = {
+	{ 1.0, 0.0, 0.0 }, { 0.0, 1.0, 0.0 }
+};
+
+static const GLuint forward_order[2] = { 0, 1 };
+static const GLuint backward_order[2] = { 1, 0 };
+
+static bool have_pv = false;
+
+
+static bool
+test_one(int order, const float expected[3])
+{
+	bool pass;
+	int dy, y = piglit_height / 2;
+
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	/* draw horizontal line across middle of window */
+	if (order == 0)
+		glDrawElements(GL_LINES, 2, GL_UNSIGNED_INT, forward_order);
+	else
+		glDrawElements(GL_LINES, 2, GL_UNSIGNED_INT, backward_order);
+
+	/* To be resilient in the face of different line rasterization,
+	 * try several Y values to find where the line was drawn.
+	 */
+	for (dy = -1; dy <= 1; dy++) {
+		GLfloat color[3];
+		glReadPixels(0, y + dy, 1, 1, GL_RGB, GL_FLOAT, color);
+		if (color[0] || color[1] || color[2]) {
+			/* found non-black pixel */
+			/* test all pixels across middle of window */
+			pass = piglit_probe_rect_rgb(0, y + dy, /* x, y */
+						     piglit_width, 1, /* w, h */
+						     expected);
+			break;
+		}
+	}
+
+	piglit_present_results();
+
+	return pass;
+}
+
+
+void
+piglit_init(int argc, char **argv)
+{
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	glMatrixMode(GL_MODELVIEW);
+	glLoadIdentity();
+
+	glEnable(GL_VERTEX_ARRAY);
+	glEnable(GL_COLOR_ARRAY);
+	glVertexPointer(2, GL_FLOAT, 0, verts);
+	glColorPointer(3, GL_FLOAT, 0, colors);
+
+	glShadeModel(GL_FLAT);
+
+	if (piglit_is_extension_supported("GL_ARB_provoking_vertex")) {
+		have_pv = true;
+	}
+	else if (piglit_is_extension_supported("GL_EXT_provoking_vertex")) {
+		have_pv = true;
+	}
+
+	if (have_pv)
+		printf("Have provoking vertex.\n");
+}
+
+
+enum piglit_result
+piglit_display(void)
+{
+	int direction, smooth, pv, width;
+	bool p, pass = true;
+
+	for (pv = 0; pv <= (int) have_pv; pv++) {
+		if (pv == 1)
+			glProvokingVertex(GL_FIRST_VERTEX_CONVENTION_EXT);
+
+		for (width = 1; width <= 5; width += 4) {
+			glLineWidth((float) width);
+
+			for (smooth = 0; smooth <= 1; smooth++) {
+				if (smooth)
+					glEnable(GL_LINE_SMOOTH);
+				else
+					glDisable(GL_LINE_SMOOTH);
+
+				for (direction = 0; direction <= 1; direction++) {
+					/* Determine which vertex color should
+					 * have been used for the line.
+					 */
+					int c = !(direction ^ pv);
+
+					p = test_one(direction, colors[c]);
+					if (!p) {
+						printf("failure (pv = %d, dir = %d,"
+						       " smooth = %d, width = %d)\n",
+						       pv, direction, smooth, width);
+					}
+					pass = pass && p;
+				}
+			}
+		}
+	}
+
+	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+}
-- 
1.7.10.4