lineloop: add test for checking behavior with many immediate mode verts

line loops are difficult to handle because when trying to accumulate vertex
data in a buffer the loop must be closed at the end - this is problematic if
using any kind of fixed size buffer. With immediate mode api (presumably
display lists have similar problems) this exposes a bug in mesa when the
buffer gets full and data is wrapped around (each buffer forms its own
incorrect line loop) (actually it seems to expose two bugs, one in vbo,
one in draw). See https://bugs.freedesktop.org/show_bug.cgi?id=81174.
This only tests line loops, not the primitive-from-hell, GL_POLYGON, which
should have the same problem but only with fill mode line...

Reviewed-by: Jose Fonseca <jfonseca@vmware.com>

2 files changed, 100 insertions, 0 deletions

diff --git a/tests/general/CMakeLists.gl.txt b/tests/general/CMakeLists.gl.txt
index cd251242a..5917df2b2 100644
--- a/tests/general/CMakeLists.gl.txt
+++ b/tests/general/CMakeLists.gl.txt
@@ -74,6 +74,7 @@ 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 (lineloop lineloop.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/lineloop.c b/tests/general/lineloop.c
new file mode 100644
index 000000000..734743f7f
--- /dev/null
+++ b/tests/general/lineloop.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 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.
+ */
+
+/**
+ * @file lineloop.c
+ *
+ * Test line loop with many vertices.
+ * No additional lines should appear due to buffer splitting.
+ */
+
+#include "piglit-util-gl-common.h"
+
+#define WSIZE 400
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+
+	config.supports_gl_compat_version = 10;
+        config.window_width = WSIZE;
+        config.window_height = WSIZE;
+	config.window_visual = PIGLIT_GL_VISUAL_RGB | PIGLIT_GL_VISUAL_DOUBLE;
+
+PIGLIT_GL_TEST_CONFIG_END
+
+static const char *TestName = "lineloop";
+static int vert_count = 10000;
+
+static void
+draw(GLuint numVerts)
+{
+   GLuint i;
+
+   glColor3f(1,0,1);
+   glBegin(GL_LINE_LOOP);
+   for (i = 0; i < numVerts; i++) {
+      glVertex3f(sin(i*M_PI*2/numVerts), cos(i*M_PI*2/numVerts),0);
+   }
+   glEnd();
+}
+
+static void
+test_prims(void)
+{
+   if (!piglit_automatic)
+      printf("%s: %u vertices\n", TestName, vert_count);
+   glClear(GL_COLOR_BUFFER_BIT);
+   draw(vert_count);
+   piglit_present_results();
+}
+
+
+enum piglit_result
+piglit_display(void)
+{
+   float expected[4] = {0.0f, 0.0f, 0.0f, 0.0f};
+   int pass;
+   int half_quad = (int)((float)(WSIZE/2) / sqrt(2.0f) - 1.0f);
+   test_prims();
+   pass = piglit_probe_rect_rgb(WSIZE / 2 - half_quad,
+                                WSIZE / 2 - half_quad,
+                                half_quad, half_quad, expected);
+   return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+}
+
+
+void
+piglit_init(int argc, char**argv)
+{
+   int i;
+   for (i = 1; i < argc; ++i) {
+      if (i + 1 < argc) {
+         if (strcmp(argv[i], "-count") == 0) {
+            vert_count = strtoul(argv[++i], NULL, 0);
+         }
+      }
+   }
+ 
+   glViewport(0,0, WSIZE, WSIZE);
+   glOrtho(-1,1,-1,1,-1,1);
+}