msaa: Add test to verify alpha to coverage with dual source blending

src0_alpha should be used for the fragment coverage.
Both src0 and src1 can be used to determine src/dst color blending factors.

Note: Test is verified using NVIDIA and AMD's proprietary linux drivers. Test
also passes on mesa i965 drivers.

Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

3 files changed, 136 insertions, 0 deletions

diff --git a/tests/all.tests b/tests/all.tests
index ad65b285c..b827cd443 100644
--- a/tests/all.tests
+++ b/tests/all.tests
@@ -1487,6 +1487,12 @@ for num_samples in MSAA_SAMPLE_COUNTS:
         ext_framebuffer_multisample[test_name] = PlainExecTest(executable)
 
 for num_samples in MSAA_SAMPLE_COUNTS:
+        test_name = ' '.join(['alpha-to-coverage-dual-src-blend', str(num_samples)])
+        executable = 'ext_framebuffer_multisample-{0} -auto'.format(
+                test_name)
+        ext_framebuffer_multisample[test_name] = PlainExecTest(executable)
+
+for num_samples in MSAA_SAMPLE_COUNTS:
         test_name = ' '.join(['int-draw-buffers-alpha-to-one', str(num_samples)])
         executable = 'ext_framebuffer_multisample-{0} -auto'.format(
                 test_name)
diff --git a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
index 8abbb43ce..694148b13 100644
--- a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
+++ b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
@@ -12,6 +12,8 @@ link_libraries (
 piglit_add_executable (ext_framebuffer_multisample-accuracy common.cpp accuracy.cpp)
 piglit_add_executable (ext_framebuffer_multisample-alpha-to-coverage-no-draw-buffer-zero common.cpp
                        draw-buffers-common.cpp alpha-to-coverage-no-draw-buffer-zero.cpp)
+piglit_add_executable (ext_framebuffer_multisample-alpha-to-coverage-dual-src-blend common.cpp
+		       draw-buffers-common.cpp alpha-to-coverage-dual-src-blend.cpp)
 piglit_add_executable (ext_framebuffer_multisample-alpha-blending alpha-blending.c)
 piglit_add_executable (ext_framebuffer_multisample-alpha-to-one-msaa-disabled common.cpp
 		       draw-buffers-common.cpp alpha-to-one-msaa-disabled.cpp)
diff --git a/tests/spec/ext_framebuffer_multisample/alpha-to-coverage-dual-src-blend.cpp b/tests/spec/ext_framebuffer_multisample/alpha-to-coverage-dual-src-blend.cpp
new file mode 100644
index 000000000..ffd90e923
--- /dev/null
+++ b/tests/spec/ext_framebuffer_multisample/alpha-to-coverage-dual-src-blend.cpp
@@ -0,0 +1,128 @@
+/*
+ * Copyright © 2012 Intel Corporation
+ *
+ * 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.
+ */
+
+#include "draw-buffers-common.h"
+
+/**
+ * \file alpha-to-coverage-dual-src-blend.cpp
+ *
+ * Verify sample-alpha-to-coverage with dual source blending.
+ *
+ * This test operates by drawing a pattern in single sample FBO to generate
+ * a reference and test image. Reference image is drawn to the right half of
+ * window system draw buffer and test image to the left half.
+ *
+ * Compute the expected color values. Probe window system color buffer and
+ * compare against expected color values.
+ *
+ * Author: Anuj Phogat <anuj.phogat@gmail.com>
+ */
+
+PIGLIT_GL_TEST_MAIN(512 /*window_width*/,
+		    256 /*window_height*/,
+		    GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA)
+void
+print_usage_and_exit(char *prog_name)
+{
+        printf("Usage: %s <num_samples>\n", prog_name);
+	piglit_report_result(PIGLIT_FAIL);
+}
+
+void
+piglit_init(int argc, char **argv)
+{
+	int samples;
+	const int num_attachments = 1;
+
+	if (argc < 2)
+		print_usage_and_exit(argv[0]);
+	{
+		char *endptr = NULL;
+		samples = strtol(argv[1], &endptr, 0);
+		if (endptr != argv[1] + strlen(argv[1]))
+			print_usage_and_exit(argv[0]);
+	}
+
+	piglit_require_gl_version(30);
+
+	int pattern_width = piglit_width / 2;
+	int pattern_height = piglit_height / num_attachments;
+
+	piglit_ortho_projection(pattern_width,
+				pattern_height,
+				GL_TRUE);
+
+	ms_fbo_and_draw_buffers_setup(samples,
+				      pattern_width,
+				      pattern_height,
+				      num_attachments,
+				      GL_COLOR_BUFFER_BIT,
+				      GL_RGBA);
+
+	shader_compile(true /* sample_alpha_to_coverage */,
+		       true /* dual_src_blend */);
+}
+
+enum piglit_result
+piglit_display()
+{
+	bool pass = true;
+	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+	glClearColor(0.0, 0.0, 0.0, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+	allocate_data_arrays();
+
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC1_ALPHA);
+
+	/* Reference image drawn when sample_alpha_to_coverage is enabled,
+	 * doesn't represent an expected image. Reference image is drawn only
+	 * to visualize the image difference caused by enabling
+	 * sample_alpha_to_coverage
+	 */
+	draw_reference_image(true /* sample_alpha_to_coverage */,
+			     false /* sample_alpha_to_one */);
+
+	draw_test_image(true /* sample_alpha_to_coverage */,
+			false /* sample_alpha_to_one */);
+
+	glDisable(GL_BLEND);
+	pass = piglit_check_gl_error(GL_NO_ERROR) && pass;
+
+	/* Probe test images of all the draw_buffers blitted to resolve fbo
+	 * and compare with expected color values.  This method of verification
+	 * is appropriate for tests with sample-alpha-to-coverage enabled.
+	 * Possibility of dithering effect when the coverage value is not a
+	 * strict multiple of 1 / num_samples makes image compare (test /
+	 * reference image) unsuitable for this test.
+	 */
+	pass = probe_framebuffer_color() && pass;
+
+	/* Free the memory allocated for data arrays */
+	free_data_arrays();
+
+	if (!piglit_automatic)
+		piglit_present_results();
+
+	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+}