msaa: Rewrite sample-alpha-to-one test to utilize shared code

Lot of the functions defined in this test case are also shared by
draw-buffers-common.cpp. So this refactoring is done to avoid code
duplication.

Reviewed-by: Paul Berry<stereotype441@gmail.com>

2 files changed, 46 insertions, 213 deletions

diff --git a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
index 36b680056..ec5d05fdf 100644
--- a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
+++ b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
@@ -50,7 +50,8 @@ piglit_add_executable (ext_framebuffer_multisample-samples samples.c)
 piglit_add_executable (ext_framebuffer_multisample-sample-coverage common.cpp sample-coverage.cpp)
 piglit_add_executable (ext_framebuffer_multisample-sample-alpha-to-coverage common.cpp
 		       draw-buffers-common.cpp sample-alpha-to-coverage.cpp)
-piglit_add_executable (ext_framebuffer_multisample-sample-alpha-to-one common.cpp sample-alpha-to-one.cpp)
+piglit_add_executable (ext_framebuffer_multisample-sample-alpha-to-one common.cpp
+		       draw-buffers-common.cpp sample-alpha-to-one.cpp)
 piglit_add_executable (ext_framebuffer_multisample-turn-on-off common.cpp turn-on-off.cpp)
 piglit_add_executable (ext_framebuffer_multisample-unaligned-blit common.cpp unaligned-blit.cpp)
 piglit_add_executable (ext_framebuffer_multisample-upsample common.cpp upsample.cpp)
diff --git a/tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp b/tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp
index 6f203cbb1..76d056feb 100644
--- a/tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp
+++ b/tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp
@@ -7,7 +7,6 @@
  * 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:
-static float coverage[4];
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
@@ -22,25 +21,20 @@ static float coverage[4];
  * IN THE SOFTWARE.
  */
 
-#include "common.h"
+#include "draw-buffers-common.h"
 
 /**
  * \file sample-alpha-to-one.cpp
  *
- * This test operates by computing the expected color values when
- * GL_SAMPLE_ALPHA_TO_ONE is disabled.
+ * Verify that alpha values are modified if GL_SAMPLE_ALPHA_TO_ONE is
+ * enabled in a multisample buffer.
  *
- * Draw a test pattern with GL_SAMPLE_ALPHA_TO_ONE disabled and blit it to
- * the right half of window system framebuffer. Probe the right half of
- * framebuffer and compare with expected values.
+ * This test operates by drawing a pattern in multisample FBO to generate
+ * reference and test image. Reference image is drawn to right half of window
+ * system frame buffer and test image to left half.
  *
- * Compute the expected color values when GL_SAMPLE_ALPHA_TO_ONE is enabled.
- * Draws the same test pattern for the second time in multisample buffer with
- * GL_SAMPLE_ALPHA_TO_ONE enabled. Blits it in to left half of window system
- * framebuffer.
- *
- * Probe the left half of window syetem framebuffer and compare with expected
- * color values.
+ * Compare the left and right halves of window system frame buffer to verify
+ * the test image.
  *
  * Author: Anuj Phogat <anuj.phogat@gmail.com>
  */
@@ -49,208 +43,50 @@ PIGLIT_GL_TEST_MAIN(512 /*window_width*/,
 		    256 /*window_height*/,
 		    GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA)
 
-const int pattern_width = 256; const int pattern_height = 256;
-static Fbo ms_fbo;
-static GLint num_samples;
-static float expected[4][4];
-static GLbitfield buffer_to_test;
-
-static const float bg_color[4] =
-	{0.0, 0.0, 1.0, 0.8};
-
-static const float color[4][4] = {
-	/* Red */
-	{1.0, 0.0, 0.0, 0.0},
-	/* Green */
-	{0.0, 1.0, 0.0, 0.25},
-	/* Yellow */
-	{1.0, 1.0, 0.0, 0.75},
-	/* Cyan */
-	{0.0, 1.0, 1.0, 1.0} };
-
-static GLint prog;
-static GLint color_loc;
-static GLint depth_loc;
-
-static const char *vert =
-	"#version 130\n"
-	"in vec2 pos;\n"
-	"uniform float depth;\n"
-	"void main()\n"
-	"{\n"
-	"  vec4 eye_pos = gl_ModelViewProjectionMatrix * vec4(pos, 0.0, 1.0);\n"
-	"  gl_Position = vec4(eye_pos.xy, depth, 1.0);\n"
-	"}\n";
-
-static const char *frag =
-	"#version 130\n"
-	"uniform vec4 color;\n"
-	"void main()\n"
-	"{\n"
-	"  gl_FragColor = color;\n"
-	"}\n";
-
-void
-shader_compile()
-{
-	/* Compile program */
-	GLint vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vert);
-	GLint fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, frag);
-	prog = piglit_link_simple_program(vs, fs);
-
-	if (!piglit_link_check_status(prog)) {
-		piglit_report_result(PIGLIT_FAIL);
-	}
-
-	glBindAttribLocation(prog, 0, "pos");
-	glEnableVertexAttribArray(0);
-
-	/* Set up uniforms */
-	glUseProgram(prog);
-	color_loc = glGetUniformLocation(prog, "color");
-	depth_loc = glGetUniformLocation(prog, "depth");
-}
-
-void
-draw_pattern(bool sample_alpha_to_one)
-{
-	float vertex_data[10][2] = {
-		{ 0,			 0 },
-		{ 0,			 pattern_height },
-		{ pattern_width / 4,	 pattern_height },
-		{ pattern_width / 4,	 0 },
-		{ pattern_width / 2,	 pattern_height },
-		{ pattern_width / 2,	 0 },
-		{ 3 * pattern_width / 4, pattern_height },
-		{ 3 * pattern_width / 4, 0 },
-		{ pattern_width,	 pattern_height },
-		{ pattern_width,	 0 },
-	};
-
-	unsigned int indices[24] = {0, 1, 2, 0, 2, 3,
-				    3, 2, 4, 3, 4, 5,
-				    5, 4, 6, 5, 6, 7,
-				    7, 6, 8, 7, 8, 9};
-	glUseProgram(prog);
-
-	glClearColor(bg_color[0], bg_color[1],
-		     bg_color[2], bg_color[3]);
-	glClear(buffer_to_test);
-
-	if (sample_alpha_to_one)
-		glEnable(GL_SAMPLE_ALPHA_TO_ONE);
-
-	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(vertex_data[0]),
-			      (void *) vertex_data);
-
-	for (int i = 0; i < 4; ++i) {
-		glUniform4fv(color_loc, 1, color[i]);
-		glUniform1f(depth_loc, 0.0);
-		glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT,
-			       (void *) (indices + 6 * i));
-	}
-	if (sample_alpha_to_one)
-		glDisable (GL_SAMPLE_ALPHA_TO_ONE);
-}
-
 void
 print_usage_and_exit(char *prog_name)
 {
-	printf("Usage: %s <num_samples>\n", prog_name);
+        printf("Usage: %s <num_samples>\n", prog_name);
 	piglit_report_result(PIGLIT_FAIL);
 }
 
 void
-compute_expected(void)
-{
-
-	/* Page 242 (page 258 of the PDF) of the OpenGL 3.0 spec says:
-	 * Next, if SAMPLE ALPHA TO ONE is enabled, each alpha value is
-	 * replaced by the maximum representable alpha value. Otherwise,
-	 * the alpha values are not changed.
-	 */
-	for(int i = 0; i < 4; i++) {
-		expected[i][0] = color[i][0];
-		expected[i][1] = color[i][1];
-		expected[i][2] = color[i][2];
-		expected[i][3] = 1.0 ;
-	}
-}
-
-bool probe_framebuffer_color(GLint x_offset, const float *expected)
-{
-	bool result = true;
-
-	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
-	for(int i = 0; i< 4; i++) {
-		result = piglit_probe_rect_rgba(x_offset + i * (pattern_width / 4),
-						0,
-						pattern_width / 4,
-						pattern_height,
-						expected + 4 * i)
-			 && result;
-	}
-	return result;
-}
-
-bool
-test_sample_alpha_to_one(void)
-{
-	bool result = true;
-	compute_expected();
-	/* Draw test pattern in multisample ms_fbo with GL_SAMPLE_COVERAGE
-	 * enabled
-	 */
-	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
-	draw_pattern(true);
-
-	/* Blit ms_fbo to the left half of window system framebuffer. This
-	 * is the test image.
-	 */
-	glBindFramebuffer(GL_READ_FRAMEBUFFER, ms_fbo.handle);
-	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
-	glBlitFramebuffer(0, 0, pattern_width, pattern_height,
-			  0, 0, pattern_width, pattern_height,
-			  buffer_to_test, GL_NEAREST);
-
-	/* Probe the left half of default framebuffer and compare to the
-	 * expected values */
-	if (buffer_to_test == GL_COLOR_BUFFER_BIT)
-		result = probe_framebuffer_color(0, expected[0]) && result;
-
-	result = piglit_check_gl_error(GL_NO_ERROR) && result;
-	return result;
-}
-void
 piglit_init(int argc, char **argv)
 {
+	int num_attachments = 1;
+	int samples;
+
 	if (argc < 2)
 		print_usage_and_exit(argv[0]);
 	{
 		char *endptr = NULL;
-		num_samples = strtol(argv[1], &endptr, 0);
+		samples = strtol(argv[1], &endptr, 0);
 		if (endptr != argv[1] + strlen(argv[1]))
 			print_usage_and_exit(argv[0]);
 	}
 
 	piglit_require_gl_version(30);
-	piglit_ortho_projection(pattern_width, pattern_height, GL_TRUE);
 
-	/* Skip the test if num_samples > GL_MAX_SAMPLES */
+	int pattern_width = piglit_width / 2;
+	int pattern_height = piglit_height / num_attachments;
+
+	piglit_ortho_projection(pattern_width,
+				pattern_height,
+				GL_TRUE);
+
+	/* Skip the test if samples > GL_MAX_SAMPLES */
 	GLint max_samples;
 	glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
 
-	if (num_samples > max_samples)
+	if (samples > max_samples)
 		piglit_report_result(PIGLIT_SKIP);
 
-	ms_fbo.setup(FboConfig(num_samples, pattern_width, pattern_height));
-
-	if (!piglit_check_gl_error(GL_NO_ERROR)) {
-                printf("Error setting up frame buffer objects\n");
-		piglit_report_result(PIGLIT_FAIL);
-	}
-
-	buffer_to_test = GL_COLOR_BUFFER_BIT;
+	ms_fbo_and_draw_buffers_setup(samples,
+				      pattern_width,
+				      pattern_height,
+				      num_attachments,
+				      GL_COLOR_BUFFER_BIT,
+				      GL_RGBA);
 	shader_compile();
 }
 
@@ -258,31 +94,27 @@ 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();
 
-	/* Draw test pattern in  multisample ms_fbo with GL_SAMPLE_ALPHA_TO_ONE
-	 * disabled.
-	 */
-	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
-	ms_fbo.set_viewport();
-	draw_pattern(false);
+	/* Set sample_alpha_to_one = true to generate the reference image */
+	draw_reference_image(false /* sample_alpha_to_coverage */,
+			     true /* sample_alpha_to_one */);
 
-	/* Blit ms_fbo to the right half of window system framebuffer. This
-	 * is a reference image to see the visual difference when compared
-	 * to the test image.
-	 */
-	glBindFramebuffer(GL_READ_FRAMEBUFFER, ms_fbo.handle);
-	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
-	glBlitFramebuffer(0, 0, pattern_width, pattern_height,
-			  pattern_width, 0, 2 * pattern_width, pattern_height,
-			  buffer_to_test, GL_NEAREST);
-	/* Probe the right half of default framebuffer and compare to the
-	 * expected values */
-	pass = probe_framebuffer_color(pattern_width, color[0]) && pass;
+	draw_test_image(false /* sample_alpha_to_coverage */,
+			true /* sample_alpha_to_one */);
+
+	pass = piglit_check_gl_error(GL_NO_ERROR) && pass;
 
-	/* Now test multisample fbo with GL_SAMPLE_ALPHA_TO_ONE enabled */
-	pass = test_sample_alpha_to_one() && pass;
+	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+	pass = piglit_probe_rect_halves_equal_rgba(0, 0,
+						   piglit_width,
+						   piglit_height)
+	       && pass;
+	/* Free the memory allocated for data arrays */
+	free_data_arrays();
 
 	if (!piglit_automatic)
 		piglit_present_results();