command_buffer: Implement CHROMIUM_framebuffer_mixed_samples extension

gpu/command_buffer/tests/gl_chromium_framebuffer_mixed_samples_unittest.cc

Index: gpu/command_buffer/tests/gl_chromium_framebuffer_mixed_samples_unittest.cc
diff --git a/gpu/command_buffer/tests/gl_chromium_framebuffer_mixed_samples_unittest.cc b/gpu/command_buffer/tests/gl_chromium_framebuffer_mixed_samples_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2297aee15da8a57773b84529523627d293f1c453
--- /dev/null
+++ b/gpu/command_buffer/tests/gl_chromium_framebuffer_mixed_samples_unittest.cc
@@ -0,0 +1,243 @@
+// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#include <GLES2/gl2extchromium.h>
+
+#include "base/command_line.h"
+#include "gpu/command_buffer/service/gpu_switches.h"
+#include "gpu/command_buffer/tests/gl_manager.h"
+#include "gpu/command_buffer/tests/gl_test_utils.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+#define SHADER(Src) #Src
+
+namespace gpu {
+
+class CHROMIUMFramebufferMixedSamplesTest : public testing::Test {
+ protected:
+  const GLuint kWidth = 100;
+  const GLuint kHeight = 100;
+
+  void SetUp() override {
+    base::CommandLine command_line(*base::CommandLine::ForCurrentProcess());
+    command_line.AppendSwitch(switches::kEnableGLPathRendering);
+    gl_.InitializeWithCommandLine(GLManager::Options(), &command_line);
+  }
+
+  void TearDown() override { gl_.Destroy(); }
+
+  bool IsApplicable() const {
+    return GLTestHelper::HasExtension(
+               "GL_CHROMIUM_framebuffer_mixed_samples") &&
+           GLTestHelper::HasExtension("GL_OES_rgb8_rgba8");
+  }
+
+  enum SetupFBOType {
+    MixedSampleFBO,   // 1 color sample, N stencil samples.
+    SingleSampleFBO,  // 1 color sample, 1 stencil sample.
+  };
+
+  void SetupState(SetupFBOType fbo_type) {
+    // clang-format off
+    static const char* kVertexShaderSource = SHADER(
+        attribute mediump vec4 position;
+        void main() {
+          gl_Position = position;
+        });
+    static const char* kFragmentShaderSource = SHADER(
+        uniform mediump vec4 color;
+        void main() {
+          gl_FragColor = color;
+        });
+    // clang-format on
+    GLuint program =
+        GLTestHelper::LoadProgram(kVertexShaderSource, kFragmentShaderSource);
+    glUseProgram(program);
+    GLuint position_loc = glGetAttribLocation(program, "position");
+    color_loc_ = glGetUniformLocation(program, "color");
+
+    GLuint vbo = 0;
+    glGenBuffers(1, &vbo);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    static float vertices[] = {
+        1.0f,  1.0f, -1.0f, 1.0f,  -1.0f, -1.0f, -1.0f, 1.0f, -1.0f,
+        -1.0f, 1.0f, -1.0f, -1.0f, -1.0f, 1.0f,  -1.0f, 1.0f, 1.0f,
+    };
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+    glEnableVertexAttribArray(position_loc);
+    glVertexAttribPointer(position_loc, 2, GL_FLOAT, GL_FALSE, 0, 0);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+    GLuint texture = 0;
+    glActiveTexture(GL_TEXTURE0);
+    glGenTextures(1, &texture);
+    glBindTexture(GL_TEXTURE_2D, texture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kWidth, kHeight, 0, GL_RGBA,
+                 GL_UNSIGNED_BYTE, NULL);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    GLuint stencil_rb = 0;
+    glGenRenderbuffers(1, &stencil_rb);
+    glBindRenderbuffer(GL_RENDERBUFFER, stencil_rb);
+
+    if (fbo_type == MixedSampleFBO) {
+      // Create a sample buffer.
+      GLsizei num_samples = 8, max_samples = 0;
+      glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
+      num_samples = std::min(num_samples, max_samples);
+      glRenderbufferStorageMultisampleCHROMIUM(
+          GL_RENDERBUFFER, num_samples, GL_STENCIL_INDEX8, kWidth, kHeight);
+      GLint param = 0;
+      glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_SAMPLES,
+                                   &param);
+      EXPECT_GT(param, 1);
+    } else {
+      glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, kWidth,
+                            kHeight);
+    }
+    glBindRenderbuffer(GL_RENDERBUFFER, 0);
+
+    GLuint sample_fbo = 0;
+    glGenFramebuffers(1, &sample_fbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, sample_fbo);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                           texture, 0);
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
+                              GL_RENDERBUFFER, stencil_rb);
+    EXPECT_EQ(static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE),
+              glCheckFramebufferStatus(GL_FRAMEBUFFER));
+
+    glViewport(0, 0, kWidth, kHeight);
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    glClearStencil(1);
+    glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+    glEnable(GL_STENCIL_TEST);
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glStencilMask(0xffffffff);
+    glStencilFunc(GL_EQUAL, 1, 0xffffffff);
+    glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  }
+
+  GLManager gl_;
+  GLint color_loc_;
+};
+
+TEST_F(CHROMIUMFramebufferMixedSamplesTest, Simple) {
+  if (!IsApplicable()) {
+    return;
+  }
+  GLint value = -1;
+  glGetIntegerv(GL_COVERAGE_MODULATION_CHROMIUM, &value);
+  EXPECT_EQ(0, value);
+  GLenum kValues[] = {GL_NONE, GL_RGB, GL_RGBA, GL_ALPHA};
+  for (auto expect : kValues) {
+    glCoverageModulationCHROMIUM(expect);
+    value = -1;
+    glGetIntegerv(GL_COVERAGE_MODULATION_CHROMIUM, &value);
+    EXPECT_EQ(expect, static_cast<GLenum>(value));
+    EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  }
+
+  glCoverageModulationCHROMIUM(GL_BYTE);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+  value = -1;
+  glGetIntegerv(GL_COVERAGE_MODULATION_CHROMIUM, &value);
+  EXPECT_EQ(static_cast<GLenum>(GL_ALPHA), static_cast<GLenum>(value));
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+}
+
+// The test pattern is as follows:
+// A green triangle (bottom left, top right, top left).
+// A blue triangle (top left, bottom right, bottom left).
+// The triangles will overlap but overlap only contains green pixels,
+// due to each draw erasing its area from stencil.
+// The blue triangle will fill only the area (bottom left, center,
+// bottom right).
+
+// The test tests that CoverageModulation call works.
+// The fractional pixels of both triangles end up being modulated
+// by the coverage of the fragment. Test that drawing with and without
+// CoverageModulation causes the result to be different.
+TEST_F(CHROMIUMFramebufferMixedSamplesTest, CoverageModulation) {
+  if (!IsApplicable()) {
+    return;
+  }
+  static const float kBlue[] = {0.0f, 0.0f, 1.0f, 1.0f};
+  static const float kGreen[] = {0.0f, 1.0f, 0.0f, 1.0f};
+  scoped_ptr<uint8[]> results[3];
+  const GLint kResultSize = kWidth * kHeight * 4;
+
+  for (int pass = 0; pass < 3; ++pass) {
+    SetupState(MixedSampleFBO);
+    if (pass == 1) {
+      glCoverageModulationCHROMIUM(GL_RGBA);
+    }
+    glUniform4fv(color_loc_, 1, kGreen);
+    glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    glUniform4fv(color_loc_, 1, kBlue);
+    glDrawArrays(GL_TRIANGLES, 3, 3);
+    if (pass == 1) {
+      glCoverageModulationCHROMIUM(GL_NONE);
+    }
+
+    results[pass].reset(new uint8[kResultSize]);
+    memset(results[pass].get(), GLTestHelper::kCheckClearValue, kResultSize);
+    glReadPixels(0, 0, kWidth, kHeight, GL_RGBA, GL_UNSIGNED_BYTE,
+                 results[pass].get());
+  }
+
+  EXPECT_NE(0, memcmp(results[0].get(), results[1].get(), kResultSize));
+  // Verify that rendering is deterministic, so that the pass above does not
+  // come from non-deterministic rendering.
+  EXPECT_EQ(0, memcmp(results[0].get(), results[2].get(), kResultSize));
+}
+
+// The test tests that the stencil buffer can be multisampled, even though the
+// color buffer is single-sampled. Draws the same pattern with single-sample
+// stencil buffer and with multisample stencil buffer. The images should differ.
+TEST_F(CHROMIUMFramebufferMixedSamplesTest, MultisampleStencilEffective) {
+  if (!IsApplicable()) {
+    return;
+  }
+
+  static const float kBlue[] = {0.0f, 0.0f, 1.0f, 1.0f};
+  static const float kGreen[] = {0.0f, 1.0f, 0.0f, 1.0f};
+
+  scoped_ptr<uint8[]> results[3];
+  const GLint kResultSize = kWidth * kHeight * 4;
+
+  for (int pass = 0; pass < 3; ++pass) {
+    if (pass == 1) {
+      SetupState(MixedSampleFBO);
+    } else {
+      SetupState(SingleSampleFBO);
+    }
+    glUniform4fv(color_loc_, 1, kGreen);
+    glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    glUniform4fv(color_loc_, 1, kBlue);
+    glDrawArrays(GL_TRIANGLES, 3, 3);
+
+    results[pass].reset(new uint8[kResultSize]);
+    memset(results[pass].get(), GLTestHelper::kCheckClearValue, kResultSize);
+    glReadPixels(0, 0, kWidth, kHeight, GL_RGBA, GL_UNSIGNED_BYTE,
+                 results[pass].get());
+  }
+
+  EXPECT_NE(0, memcmp(results[0].get(), results[1].get(), kResultSize));
+  // Verify that rendering is deterministic, so that the pass above does not
+  // come from non-deterministic rendering.
+  EXPECT_EQ(0, memcmp(results[0].get(), results[2].get(), kResultSize));
+}
+
+}  // namespace gpu