ARB_sample_shading: Add test for gl_SampleMask in combination with MRTs and alpha-to-coverage.

This test currently fails on the i965 driver because when writing the
color output to a non-zero RT it incorrectly passes the sample mask
where the alpha component from the zeroth RT should be.

3 files changed, 196 insertions, 0 deletions

diff --git a/tests/all.py b/tests/all.py
index c92289a4a..9af40a1ac 100644
--- a/tests/all.py
+++ b/tests/all.py
@@ -2164,6 +2164,8 @@ with profile.group_manager(
            str(num_samples)],
           'builtin-gl-sample-mask-simple {}'.format(num_samples))
 
+    g(['arb_sample_shading-builtin-gl-sample-mask-mrt-alpha'])
+
 # Group ARB_debug_output
 with profile.group_manager(
         PiglitGLTest,
diff --git a/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt b/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
index 84e25468f..ede97f7b7 100644
--- a/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
+++ b/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
@@ -15,6 +15,7 @@ piglit_add_executable (arb_sample_shading-builtin-gl-num-samples builtin-gl-num-
 piglit_add_executable (arb_sample_shading-builtin-gl-sample-id builtin-gl-sample-id.cpp)
 piglit_add_executable (arb_sample_shading-builtin-gl-sample-mask builtin-gl-sample-mask.cpp)
 piglit_add_executable (arb_sample_shading-builtin-gl-sample-mask-simple builtin-gl-sample-mask-simple.cpp)
+piglit_add_executable (arb_sample_shading-builtin-gl-sample-mask-mrt-alpha builtin-gl-sample-mask-mrt-alpha.cpp)
 piglit_add_executable (arb_sample_shading-builtin-gl-sample-position builtin-gl-sample-position.cpp)
 piglit_add_executable (arb_sample_shading-interpolate-at-sample-position interpolate-at-sample-position.cpp)
 piglit_add_executable (arb_sample_shading-ignore-centroid-qualifier ignore-centroid-qualifier.cpp)
diff --git a/tests/spec/arb_sample_shading/execution/builtin-gl-sample-mask-mrt-alpha.cpp b/tests/spec/arb_sample_shading/execution/builtin-gl-sample-mask-mrt-alpha.cpp
new file mode 100644
index 000000000..ce5f6c3e1
--- /dev/null
+++ b/tests/spec/arb_sample_shading/execution/builtin-gl-sample-mask-mrt-alpha.cpp
@@ -0,0 +1,193 @@
+/*
+ * Copyright (c) 2015 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.
+ */
+
+/** \file builtin-gl-sample-mask-mrt-alpha.cpp
+ *
+ *  This test verifies that assigning gl_SampleMask[] from the
+ *  fragment shader works as expected in cases where the
+ *  implementation is required to supply an additional alpha component
+ *  previously written to a different color attachment to render to a
+ *  non-zero attachment of a multisample FBO (e.g. while using
+ *  alpha-to-coverage).
+ */
+
+#include "piglit-fbo.h"
+using namespace piglit_util_fbo;
+
+#define NUM_SAMPLES 4
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+
+        config.supports_gl_compat_version = 21;
+        config.supports_gl_core_version = 31;
+
+        config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGBA;
+
+PIGLIT_GL_TEST_CONFIG_END
+
+static Fbo
+make_fbo()
+{
+        FboConfig config(NUM_SAMPLES, piglit_width, piglit_height);
+        config.num_rb_attachments = 0;
+        config.num_tex_attachments = 2;
+        config.tex_attachment[0] = GL_COLOR_ATTACHMENT0;
+        config.tex_attachment[1] = GL_COLOR_ATTACHMENT1;
+
+        Fbo fbo;
+        fbo.setup(config);
+
+        if (!piglit_check_gl_error(GL_NO_ERROR))
+                piglit_report_result(PIGLIT_FAIL);
+
+        return fbo;
+}
+
+/**
+ * Render to both texture attachments of the multisample fbo enabling
+ * alpha-to-coverage to make the implementation pass the additional
+ * alpha component from the first attachment when rendering into the
+ * second.  The resulting sample mask will still be 5 as specified in
+ * the fragment shader because an alpha value of 1.0 maps to the
+ * coverage mask ~0.
+ */
+static bool
+run_test(Fbo &fbo)
+{
+        const GLuint prog = piglit_build_simple_program(
+                "#version 130\n"
+                "in vec4 piglit_vertex;\n"
+                "\n"
+                "void main()\n"
+                "{\n"
+                "   gl_Position = piglit_vertex;\n"
+                "}\n",
+                "#version 130\n"
+                "#extension GL_ARB_sample_shading : enable\n"
+                "\n"
+                "out vec4 out_color[2];"
+                "\n"
+                "void main()\n"
+                "{\n"
+                "   gl_SampleMask[0] = 5;\n"
+                "   out_color[0] = vec4(1.0, 0.0, 0.0, 1.0);\n"
+                "   out_color[1] = vec4(1.0, 0.0, 0.0, 0.0);\n"
+                "}\n");
+
+        glUseProgram(prog);
+
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo.handle);
+        glDrawBuffers(fbo.config.num_tex_attachments,
+                      fbo.config.tex_attachment);
+        glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+        fbo.set_viewport();
+
+        glClear(GL_COLOR_BUFFER_BIT);
+        piglit_draw_rect(-1, -1, 2, 2);
+
+        glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
+        glDeleteProgram(prog);
+
+        return piglit_check_gl_error(GL_NO_ERROR);
+}
+
+/**
+ * Resolve the red component of each sample from the texture
+ * previously bound to color attachment i as the RGBA components of
+ * the actual framebuffer.  Return true if only the first and third
+ * samples were written according to the coverage mask set by the
+ * shader.
+ */
+static bool
+check(const Fbo &fbo, unsigned i)
+{
+        const float expected[] = { 1, 0, 1, 0 };
+        const GLuint prog = piglit_build_simple_program(
+                "#version 130\n"
+                "in vec4 piglit_vertex;\n"
+                "\n"
+                "void main()\n"
+                "{\n"
+                "   gl_Position = piglit_vertex;\n"
+                "}\n",
+                "#version 130\n"
+                "#extension GL_ARB_texture_multisample : require\n"
+                "\n"
+                "uniform sampler2DMS tex;\n"
+                "out vec4 out_color;\n"
+                "\n"
+                "void main()\n"
+                "{\n"
+                "   vec4 v;\n"
+                "\n"
+                "   for (int i = 0; i < 4; i++)\n"
+                "      v[i] = texelFetch(tex, ivec2(gl_FragCoord.x,\n"
+                "                                   gl_FragCoord.y), i).x;\n"
+                "\n"
+                "   out_color = v;\n"
+                "}\n");
+
+        glUseProgram(prog);
+        glUniform1i(glGetUniformLocation(prog, "tex"), 0);
+
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
+        glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, fbo.color_tex[i]);
+        glViewport(0, 0, piglit_width, piglit_height);
+
+        glClear(GL_COLOR_BUFFER_BIT);
+        piglit_draw_rect(-1, -1, 2, 2);
+
+        glDeleteProgram(prog);
+
+        if (!piglit_check_gl_error(GL_NO_ERROR))
+                return false;
+
+        if (!piglit_probe_rect_rgba(0, 0, piglit_width, piglit_height,
+                                    expected)) {
+                printf("  Attachment: %d\n", i);
+                return false;
+        }
+
+        return true;
+}
+
+void
+piglit_init(int argc, char **argv)
+{
+        piglit_require_extension("GL_ARB_texture_multisample");
+        piglit_require_extension("GL_ARB_sample_shading");
+        piglit_require_GLSL_version(130);
+
+        Fbo fbo = make_fbo();
+
+        if (run_test(fbo) && check(fbo, 0) && check(fbo, 1))
+                piglit_report_result(PIGLIT_PASS);
+        else
+                piglit_report_result(PIGLIT_FAIL);
+}
+
+piglit_result
+piglit_display()
+{
+        return PIGLIT_FAIL;
+}