[Piglit] [PATCH] fbo-blit-after-swap: New test for partial blits after a buffer swap

[Federico Mena Quintero]

From: Federico Mena Quintero <federico at suse.com>

The clutter/cogl libraries try to minimize the area that gets updated on every frame.
They do this by doing glBlitFramebufferEXT() from the back buffer to the front buffer.

However, this is buggy with software rendering if there has been a buffer swap
*before* the first blit from the back buffer to the front buffer.  In this case,
Mesa copies the whole back buffer into the front buffer, instead of just the
requested region.
---
 tests/all.tests                 |   1 +
 tests/fbo/CMakeLists.gl.txt     |   1 +
 tests/fbo/fbo-blit-after-swap.c | 136 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 138 insertions(+)
 create mode 100644 tests/fbo/fbo-blit-after-swap.c

diff --git a/tests/all.tests b/tests/all.tests
index 7ab841e..6c92ebf 100644
--- a/tests/all.tests
+++ b/tests/all.tests
@@ -1163,6 +1163,7 @@ for format in ('rgba', 'depth', 'stencil'):
         test_name = ' '.join(['framebuffer-blit-levels', test_mode, format])
         arb_framebuffer_object[test_name] = PlainExecTest(test_name + ' -auto')
 add_plain_test(arb_framebuffer_object, 'fbo-alpha')
+add_plain_test(arb_framebuffer_object, 'fbo-blit-after-swap')
 add_plain_test(arb_framebuffer_object, 'fbo-blit-stretch')
 add_plain_test(arb_framebuffer_object, 'fbo-blit-scaled-linear')
 add_plain_test(arb_framebuffer_object, 'fbo-attachments-blit-scaled-linear')
diff --git a/tests/fbo/CMakeLists.gl.txt b/tests/fbo/CMakeLists.gl.txt
index 588fe26..3ad9ec0 100644
--- a/tests/fbo/CMakeLists.gl.txt
+++ b/tests/fbo/CMakeLists.gl.txt
@@ -31,6 +31,7 @@ piglit_add_executable (fbo-alpha fbo-alpha.c)
 piglit_add_executable (fbo-luminance-alpha fbo-luminance-alpha.c)
 piglit_add_executable (fbo-bind-renderbuffer fbo-bind-renderbuffer.c)
 piglit_add_executable (fbo-blit fbo-blit.c)
+piglit_add_executable (fbo-blit-after-swap fbo-blit-after-swap.c)
 piglit_add_executable (fbo-blit-d24s8 fbo-blit-d24s8.c)
 piglit_add_executable (fbo-blit-stretch fbo-blit-stretch.cpp)
 piglit_add_executable (fbo-blending-formats fbo-blending-formats.c)
diff --git a/tests/fbo/fbo-blit-after-swap.c b/tests/fbo/fbo-blit-after-swap.c
new file mode 100644
index 0000000..38fc870
--- /dev/null
+++ b/tests/fbo/fbo-blit-after-swap.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2013 Suse, Inc. 
+ * Copyright © 2011 Henri Verbeet <hverbeet at gmail.com>
+ * Copyright 2011 Red Hat, 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 fbo-blit-after-swap.c
+ *
+ * Test a glBlitFrameBuffer() with a smaller-than-the-window region after doing a buffer swap
+ */
+
+#include "piglit-util-gl-common.h"
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+
+	config.supports_gl_compat_version = 10;
+
+	config.window_width = 128;
+	config.window_height = 128;
+	config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGB;
+	config.requires_displayed_window = true;
+
+PIGLIT_GL_TEST_CONFIG_END
+
+#define SWAP_BUFFERS_BEFORE_BLIT 1
+
+static const float red[]   = {1.0f, 0.0f, 0.0f, 1.0f};
+static const float blue[]  = {0.0f, 0.0f, 1.0f, 1.0f};
+static const float black[] = {0.0f, 0.0f, 0.0f, 1.0f};
+
+static void
+setup_front_buffer(void)
+{
+	glDrawBuffer(GL_BACK);
+
+	glClearColor(blue[0], blue[1], blue[2], blue[3]);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+#if SWAP_BUFFERS_BEFORE_BLIT
+	piglit_swap_buffers();
+#else
+	glDrawBuffer(GL_FRONT);
+	glReadBuffer(GL_BACK);
+	glBlitFramebufferEXT(0, 0, piglit_width, piglit_height,
+			     0, 0, piglit_width, piglit_height,
+			     GL_COLOR_BUFFER_BIT, GL_NEAREST);
+#endif
+}
+
+static void
+setup_back_buffer(void)
+{
+	int w = piglit_width;
+	int h = piglit_height;
+
+	glDrawBuffer(GL_BACK);
+
+	/* Clear to black */
+	glClearColor(black[0], black[1], black[2], black[3]);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	/* Paint a red square in the middle of the back buffer */
+	glColor4f(red[0], red[1], red[2], red[3]);
+	piglit_draw_rect(w / 4, h / 4, w / 2, h / 2);
+}
+
+static void
+blit_from_back_to_front(void)
+{
+	int w = piglit_width;
+	int h = piglit_height;
+
+	/* Copy just the red square from the back buffer to the blue front buffer */
+	glDrawBuffer(GL_FRONT);
+	glReadBuffer(GL_BACK);
+	glBlitFramebufferEXT(w / 4, h / 4, 3 * w / 4, 3 * h / 4,
+			     w / 4, h / 4, 3 * w / 4, 3 * h / 4,
+			     GL_COLOR_BUFFER_BIT, GL_NEAREST);
+}
+
+enum piglit_result piglit_display(void)
+{
+	int w = piglit_width;
+	int h = piglit_height;
+	bool success = 1;
+
+	piglit_ortho_projection(w, h, GL_FALSE);
+
+	setup_front_buffer();
+	setup_back_buffer();
+
+	blit_from_back_to_front();
+
+	glFlush();
+
+	/* Now see how we did... */
+
+	glReadBuffer(GL_FRONT);
+
+	/* the middle should be red */
+	success &= piglit_probe_pixel_rgb(w / 2, h / 2, red);
+
+	/* the corners should be blue */
+	success &= piglit_probe_pixel_rgb(0, 0, blue);
+	success &= piglit_probe_pixel_rgb(w - 1, 0, blue);
+	success &= piglit_probe_pixel_rgb(0, h - 1, blue);
+	success &= piglit_probe_pixel_rgb(w - 1, h - 1, blue);
+
+	return success ? PIGLIT_PASS : PIGLIT_FAIL;
+}
+
+void piglit_init(int argc, char **argv)
+{
+	piglit_require_extension("GL_EXT_framebuffer_object");
+	piglit_require_extension("GL_EXT_framebuffer_blit");
+}
-- 
1.8.1.4