[Piglit] [PATCH] swapbuffers-behavior: check if swapbuffers swaps or copies

[Brian Paul]

From: Brian Paul <brianp at vmware.com>

Probe front/back buffers after a SwapBuffers() call to see if the
implementation does a true swap or a back-to-front copy.

There is no pass/fail (except for one sanity check).  This is just
to find out what GL does.
---
 tests/all.py                             |    1 +
 tests/spec/gl-1.0/CMakeLists.gl.txt      |    1 +
 tests/spec/gl-1.0/swapbuffers-behavior.c |  121 ++++++++++++++++++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 tests/spec/gl-1.0/swapbuffers-behavior.c

diff --git a/tests/all.py b/tests/all.py
index 4b1316a..e7430af 100644
--- a/tests/all.py
+++ b/tests/all.py
@@ -928,6 +928,7 @@ add_concurrent_test(gl10, 'gl-1.0-edgeflag-quads')
 add_concurrent_test(gl10, 'gl-1.0-long-dlist')
 add_concurrent_test(gl10, 'gl-1.0-rendermode-feedback')
 add_plain_test(gl10, 'gl-1.0-front-invalidate-back')
+add_plain_test(gl10, 'gl-1.0-swapbuffers-behavior')
 
 gl12 = Group()
 spec['!OpenGL 1.2'] = gl12
diff --git a/tests/spec/gl-1.0/CMakeLists.gl.txt b/tests/spec/gl-1.0/CMakeLists.gl.txt
index e2a450f..2717864 100644
--- a/tests/spec/gl-1.0/CMakeLists.gl.txt
+++ b/tests/spec/gl-1.0/CMakeLists.gl.txt
@@ -18,5 +18,6 @@ piglit_add_executable (gl-1.0-dlist-shademodel dlist-shademodel.c)
 piglit_add_executable (gl-1.0-front-invalidate-back front-invalidate-back.c)
 piglit_add_executable (gl-1.0-long-dlist long-dlist.c)
 piglit_add_executable (gl-1.0-rendermode-feedback rendermode-feedback.c)
+piglit_add_executable (gl-1.0-swapbuffers-behavior swapbuffers-behavior.c)
 
 # vim: ft=cmake:
diff --git a/tests/spec/gl-1.0/swapbuffers-behavior.c b/tests/spec/gl-1.0/swapbuffers-behavior.c
new file mode 100644
index 0000000..4c161ba
--- /dev/null
+++ b/tests/spec/gl-1.0/swapbuffers-behavior.c
@@ -0,0 +1,121 @@
+/*
+ * 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.
+ */
+
+/**
+ * @file swapbuffers-behavior.c
+ *
+ * Test/check behavior of SwapBuffers.  In some environments, SwapBuffers
+ * just copies the back buffer to the front.  Other times it's a true swap.
+ * This test just checks and reports which behavior is found.
+ */
+
+#include "piglit-util-gl-common.h"
+
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+	config.supports_gl_compat_version = 10;
+	config.window_visual = PIGLIT_GL_VISUAL_RGBA | PIGLIT_GL_VISUAL_DOUBLE;
+	config.requires_displayed_window = true;
+PIGLIT_GL_TEST_CONFIG_END
+
+
+static const float blue[4] = { 0.0f, 0.0f, 1.0f, 0.0f };
+static const float green[4] = { 0.0f, 1.0f, 0.0f, 0.0f };
+
+
+static bool
+match(const float c1[4], const float c2[4])
+{
+	return (c1[0] == c2[0] &&
+		c1[1] == c2[1] &&
+		c1[2] == c2[2] &&
+		c1[3] == c2[3]);
+}
+
+
+enum piglit_result
+piglit_display(void)
+{
+	GLfloat color[4];
+
+	glViewport(0, 0, piglit_width, piglit_height);
+
+	/* Clear back buffer to green */
+	glDrawBuffer(GL_BACK);
+	glClearColor(green[0], green[1], green[2], green[3]);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+        /* First swap */
+	piglit_swap_buffers();
+
+        /* Front buffer sanity-check */
+	glReadBuffer(GL_FRONT);
+	if (!piglit_probe_rect_rgb_silent(0, 0, piglit_width, piglit_height,
+					  green)) {
+		printf("SwapBuffers apparently failed!\n");
+                return PIGLIT_FAIL;
+	}
+
+	/* Read back buffer */
+	glReadBuffer(GL_BACK);
+	if (!piglit_probe_rect_rgb_silent(0, 0, piglit_width, piglit_height,
+					  green)) {
+		printf("After 1st swap, back buffer is no longer green.\n");
+	}
+
+	/* Clear front buffer to blue */
+	glDrawBuffer(GL_FRONT);
+	glClearColor(blue[0], blue[1], blue[2], blue[3]);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+        /* Second swap */
+	piglit_swap_buffers();
+
+	/* Read back buffer */
+	glReadBuffer(GL_BACK);
+	glReadPixels(piglit_width/2, piglit_height/2, 1, 1, GL_RGBA, GL_FLOAT,
+		     color);
+	if (match(color, green)) {
+	        printf("After 2nd swap: back buffer is green. "
+		       "SwapBuffers is a back-to-front copy.\n");
+	}
+	else if (match(color, blue)) {
+	        printf("After 2nd swap: back buffer is blue. "
+		       "SwapBuffers is a true swap.\n");
+	}
+	else {
+		printf("Back color: %g, %g, %g, %g. Back buffer undefined.\n",
+		       color[0], color[1], color[2], color[3]);
+	}
+
+	fflush(stdout);
+
+	return PIGLIT_PASS;
+}
+
+
+void
+piglit_init(int argc, char **argv)
+{
+	/* nothing */
+}
-- 
1.7.10.4