command_buffer: Implement path rendering functions for CHROMIUM_path_rendering

gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc

Index: gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
diff --git a/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc b/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
index 6aab2e5399ea142e18625a7cc93c16cbe060eb1c..1759c894f7e853aceef75a23291b45c9ee9274a9 100644
--- a/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
+++ b/gpu/command_buffer/tests/gl_chromium_path_rendering_unittest.cc
@@ -7,11 +7,13 @@
 #include <GLES2/gl2extchromium.h>
 #include <cmath>
 
+#include "base/strings/stringprintf.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 {
 
@@ -38,7 +40,125 @@ class CHROMIUMPathRenderingTest : public testing::Test {
       EXPECT_EQ(static_cast<GLint>(round(expected[i])), actual[i]);
     }
   }
+
+  void SetupStateForTestPattern() {
+    glViewport(0, 0, kResolution, kResolution);
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    glStencilMask(0xffffffff);
+    glClearStencil(0);
+    glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+
+    static const char* v_shader_src =
+        SHADER(void main() { gl_Position = vec4(1); });
+    static const char* f_shader_src =
+        "#extension GL_CHROMIUM_path_rendering: require\n" SHADER(
+            precision mediump float;
+            void main() { gl_FragColor = gl_TexCoord[0] + gl_TexCoord[1]; });
+
+    GLuint program = GLTestHelper::LoadProgram(v_shader_src, f_shader_src);
+    glUseProgram(program);
+    glDeleteProgram(program);
+
+    // Set up orthogonal projection with near/far plane distance of 2.
+    static GLfloat matrix[16] = {
+        2.0f / (kResolution - 1), 0.0f,                     0.0f,  0.0f,
+        0.0f,                     2.0f / (kResolution - 1), 0.0f,  0.0f,
+        0.0f,                     0.0f,                     -1.0f, 0.0f,
+        -1.0f,                    -1.0f,                    0.0f,  1.0f};
+    glMatrixLoadfCHROMIUM(GL_PROJECTION_CHROMIUM, matrix);
+    glMatrixLoadIdentityCHROMIUM(GL_MODELVIEW_CHROMIUM);
+
+    glEnable(GL_STENCIL_TEST);
+
+    GLTestHelper::CheckGLError("no errors at state setup", __LINE__);
+  }
+
+  void SetupPathStateForTestPattern(GLuint path) {
+    GLubyte commands[] = {GL_MOVE_TO_CHROMIUM, GL_LINE_TO_CHROMIUM,
+                          GL_QUADRATIC_CURVE_TO_CHROMIUM,
+                          GL_CUBIC_CURVE_TO_CHROMIUM, GL_CLOSE_PATH_CHROMIUM};
+
+    GLfloat coords[] = {50.0f, 50.0f, 75.0f, 75.0f, 100.0f, 62.5f, 50.0f,
+                        25.5f, 0.0f,  62.5f, 50.0f, 50.0f,  25.0f, 75.0f};
+
+    glPathCommandsCHROMIUM(path,
+                           arraysize(commands),
+                           commands,
+                           arraysize(coords),
+                           GL_FLOAT,
+                           coords);
+
+    glPathParameterfCHROMIUM(path, GL_PATH_STROKE_WIDTH_CHROMIUM, 5.0f);
+    glPathParameterfCHROMIUM(path, GL_PATH_MITER_LIMIT_CHROMIUM, 1.0f);
+    glPathParameteriCHROMIUM(
+        path, GL_PATH_JOIN_STYLE_CHROMIUM, GL_ROUND_CHROMIUM);
+    glPathParameteriCHROMIUM(
+        path, GL_PATH_INITIAL_END_CAP_CHROMIUM, GL_SQUARE_CHROMIUM);
+    glPathParameteriCHROMIUM(
+        path, GL_PATH_TERMINAL_END_CAP_CHROMIUM, GL_FLAT_CHROMIUM);
+  }
+
+  void VerifyTestPatternFill(float x, float y) {
+    // Inside the fill we should have color formed by the texture coordinate set
+    // coefficients.
+    const float fill_coords[] = {55.0f, 55.0f, 50.0f, 28.0f, 66.0f, 63.0f};
+
+    for (size_t i = 0; i < arraysize(fill_coords); i += 2) {
+      float fx = fill_coords[i];
+      float fy = fill_coords[i + 1];
+      uint8 expected_color[] = {
+          255 * (fx * 1.0f / kResolution - fx * 0.2f / kResolution),
+          255 * (fy * 1.0f / kResolution - fy * 0.2f / kResolution),
+          0,  // The calculations cancel each other.
+          255};
+      // Note: we compare with a bit of tolerance, since CPU float computation
+      // will not always match the shader computation.
+      EXPECT_TRUE(
+          GLTestHelper::CheckPixels(x + fx, y + fy, 1, 1, 2, expected_color));
+    }
+  }
+
+  void VerifyTestPatternBg(float x, float y) {
+    const float bg_coords[] = {80.0f, 80.0f, 20.0f, 20.0f, 90.0f, 1.0f};
+    uint8 expected_color[] = {0, 0, 0, 0};
+
+    for (size_t i = 0; i < arraysize(bg_coords); i += 2) {
+      float bx = bg_coords[i];
+      float by = bg_coords[i + 1];
+
+      EXPECT_TRUE(
+          GLTestHelper::CheckPixels(x + bx, y + by, 1, 1, 0, expected_color));
+    }
+  }
+
+  void VerifyTestPatternStroke(float x, float y) {
+    // Inside the stroke we should have green.
+    const uint8 green[] = {0, 255, 0, 255};
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 50, y + 53, 1, 1, 0, green));
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 26, y + 76, 1, 1, 0, green));
+
+    // Outside the path we should have black.
+    const uint8 black[] = {0, 0, 0, 0};
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 10, y + 10, 1, 1, 0, black));
+    EXPECT_TRUE(GLTestHelper::CheckPixels(x + 80, y + 80, 1, 1, 0, black));
+  }
+
   GLManager gl_;
+  static GLfloat fill_coefficients_[3 * 3 * 2];
+  static GLfloat stroke_coefficients_[3 * 3];
+};
+
+GLfloat CHROMIUMPathRenderingTest::fill_coefficients_[] = {
+    1.0f / kResolution,  0.0f,                0.0f,
+    0.0f,                1.0f / kResolution,  0.0f,
+    1.0f / kResolution,  1.0f / kResolution,  0.0f,
+    -0.2f / kResolution, 0.0f,                0.0f,
+    0.0f,                -0.2f / kResolution, 0.0f,
+    -1.0f / kResolution, -1.0f / kResolution, 0.0};
+
+// Stroke should be constant green.
+GLfloat CHROMIUMPathRenderingTest::stroke_coefficients_[] = {
+    0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
 };
 
 TEST_F(CHROMIUMPathRenderingTest, TestMatrix) {
@@ -107,4 +227,323 @@ TEST_F(CHROMIUMPathRenderingTest, TestMatrixErrors) {
   EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
 }
 
+TEST_F(CHROMIUMPathRenderingTest, TestTexCoordShader) {

[piman, 2014/04/24 22:26:36]

We'll have to skip those tests if the extension isn't present

+  static const char* fs_str =
+      "#extension GL_CHROMIUM_path_rendering: require\n" SHADER(
+          precision mediump float;
+          void main() { gl_FragColor = gl_TexCoord[0] + gl_TexCoord[% d]; });
+
+  GLint maxTextureCoords = -1;
+  glGetIntegerv(GL_MAX_TEXTURE_COORDS_CHROMIUM, &maxTextureCoords);
+  EXPECT_LT(static_cast<GLint>(0), maxTextureCoords);
+
+  std::string fs_str_max = base::StringPrintf(fs_str, maxTextureCoords - 1);
+
+  const char* shader_str = fs_str_max.c_str();
+  GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+  glShaderSource(fs, 1, &shader_str, NULL);
+  glCompileShader(fs);
+  GLint value = 0;
+  glGetShaderiv(fs, GL_COMPILE_STATUS, &value);
+  if (value == 0) {
+    char buffer[1024];
+    GLsizei length = 0;
+    glGetShaderInfoLog(fs, sizeof(buffer), &length, buffer);
+    std::string log(buffer, length);
+    EXPECT_EQ(1, value) << "Error compiling shader: " << log;
+  }
+
+  EXPECT_EQ(static_cast<GLint>(1), value);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glDeleteShader(fs);
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TooBigTexCoordShaderFails) {
+  static const char* fs_str =
+      "#extension GL_CHROMIUM_path_rendering: require\n" SHADER(
+          precision mediump float;
+          void main() { gl_FragColor = gl_TexCoord[0] + gl_TexCoord[% d]; });
+
+  GLint maxTextureCoords = -1;
+  glGetIntegerv(GL_MAX_TEXTURE_COORDS_CHROMIUM, &maxTextureCoords);
+  EXPECT_LT(static_cast<GLint>(0), maxTextureCoords);
+
+  // Using too big TexCoord index should fail.
+  std::string fs_str_too_big = base::StringPrintf(fs_str, maxTextureCoords);
+
+  const char* shader_str = fs_str_too_big.c_str();
+  GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+  GLint value = 0;
+  glShaderSource(fs, 1, &shader_str, NULL);
+  glCompileShader(fs);
+  glGetShaderiv(fs, GL_COMPILE_STATUS, &value);
+  EXPECT_EQ(static_cast<GLint>(0), value);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glDeleteShader(fs);
+}
+
+TEST_F(CHROMIUMPathRenderingTest, NoExtensionTexCoordShaderFails) {
+  static const char* shader_str = SHADER(
+      precision mediump float; void main() { gl_FragColor = gl_TexCoord[0]; });
+  GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+  GLint value = 0;
+  glShaderSource(fs, 1, &shader_str, NULL);
+  glCompileShader(fs);
+  glGetShaderiv(fs, GL_COMPILE_STATUS, &value);
+  EXPECT_EQ(static_cast<GLint>(0), value);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glDeleteShader(fs);
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestSimpleCalls) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering")) {
+    return;
+  }
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  EXPECT_TRUE(path != 0);
+  glDeletePathsCHROMIUM(path, 1);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  GLuint firstPath = glGenPathsCHROMIUM(5);
+  EXPECT_TRUE(firstPath != 0);
+  glDeletePathsCHROMIUM(firstPath, 5);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Test deleting paths that are not actually allocated:
+  // "unused names in /paths/ are silently ignored"
+  firstPath = glGenPathsCHROMIUM(5);
+  EXPECT_TRUE(firstPath != 0);
+  glDeletePathsCHROMIUM(firstPath, 6);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  GLint maxTextureCoords = -1;
+  glGetIntegerv(GL_MAX_TEXTURE_COORDS_CHROMIUM, &maxTextureCoords);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  EXPECT_LT(static_cast<GLint>(0), maxTextureCoords);
+}
+
+TEST_F(CHROMIUMPathRenderingTest, TestErrors) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering")) {
+    return;
+  }
+
+  // This is unspecified.
+  EXPECT_EQ(static_cast<GLuint>(-1), glGenPathsCHROMIUM(0));
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+
+  // Using non-existing path object produces error.
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glPathParameterfCHROMIUM(555, GL_PATH_STROKE_WIDTH_CHROMIUM, 5.0f);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glPathParameteriCHROMIUM(555, GL_PATH_JOIN_STYLE_CHROMIUM, GL_ROUND_CHROMIUM);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  // Trying to create a path object with non-existing path name produces error.
+  // (Not a error in real NV_path_rendering).
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLubyte commands[] = {GL_MOVE_TO_CHROMIUM, GL_CLOSE_PATH_CHROMIUM};
+  GLfloat coords[] = {50.0f, 50.0f};
+  glPathCommandsCHROMIUM(555, arraysize(commands), commands, arraysize(coords),
+                         GL_FLOAT, coords);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
+
+  // Try creating a path object with non-GLfloat coords
+  GLint path = glGenPathsCHROMIUM(1);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLbyte coords_b[] = {0, 0};
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands,
+                         arraysize(coords_b), GL_BYTE, coords_b);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLshort coords_s[] = {0, 0};
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands,
+                         arraysize(coords_s), GL_SHORT, coords_s);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  // Test that using other pathNameType than GL_UNSIGNED_INT fails for Instanced
+  // functions.
+  glPathCommandsCHROMIUM(path, arraysize(commands), commands, arraysize(coords),
+                         GL_FLOAT, coords);
+
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLbyte pathsb[] = {1, 1, 1, 1, 1};
+  glStencilStrokePathInstancedCHROMIUM(arraysize(pathsb), GL_BYTE, pathsb,
+                                       path - 1, 0x80, 0x80, GL_NONE, NULL);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLint pathssi[] = {1, 1, 1, 1, 1};
+  glStencilStrokePathInstancedCHROMIUM(arraysize(pathssi), GL_INT, pathssi,
+                                       path - 1, 0x80, 0x80, GL_NONE, NULL);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+  // Test that using pathNameType GL_UNSIGNED_INT succeeds.
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  GLuint pathsui[] = {1, 1, 1, 1, 1};
+  glStencilStrokePathInstancedCHROMIUM(arraysize(pathsui), GL_UNSIGNED_INT,
+                                       pathsui, path - 1, 0x80, 0x80, GL_NONE,
+                                       NULL);
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+
+  // Test that using bogus transform enum (GL_FASTEST) fails.
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  glStencilStrokePathInstancedCHROMIUM(arraysize(pathsui), GL_UNSIGNED_INT,
+                                       pathsui, path - 1, 0x80, 0x80,
+                                       GL_FASTEST,
+                                       NULL);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), glGetError());
+
+
+  glDeletePathsCHROMIUM(path, 1);
+}
+
+// Tests that drawing with CHROMIUM_path_rendering functions work.
+TEST_F(CHROMIUMPathRenderingTest, TestPathRendering) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering")) {
+    return;
+  }
+
+  SetupStateForTestPattern();
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  SetupPathStateForTestPattern(path);
+
+  // Do the stencil fill, cover fill, stencil stroke, cover stroke
+  // in unconventional order:
+  // 1) stencil the stroke in stencil high bit
+  // 2) stencil the fill in low bits
+  // 3) cover the fill
+  // 4) cover the stroke
+  // This is done to check that glPathStencilFunc works, eg the mask
+  // goes through. Stencil func is not tested ATM, for simplicity.
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0xFF);
+  glStencilStrokePathCHROMIUM(path, 0x80, 0x80);
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0x7F);
+  glStencilFillPathCHROMIUM(path, GL_COUNT_UP_CHROMIUM, 0x7F);
+
+  // TexCoord generation is tested by using the TexCoord values
+  // as pixel values. Transform object coords, eg. [0..width], to [0..1].
+  // Setup two texture coordinate sets so that we check the support
+  // for multiple TexCoords. See the verification section on how the
+  // pixel color should look like.
+  glPathTexGenCHROMIUM(
+      GL_TEXTURE0, GL_OBJECT_LINEAR_CHROMIUM, 3, fill_coefficients_);
+  glPathTexGenCHROMIUM(GL_TEXTURE0 + 1,
+                       GL_OBJECT_LINEAR_CHROMIUM,
+                       3,
+                       &fill_coefficients_[3 * 3]);
+
+  glStencilFunc(GL_LESS, 0, 0x7F);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glCoverFillPathCHROMIUM(path, GL_BOUNDING_BOX_CHROMIUM);
+
+  glPathTexGenCHROMIUM(
+      GL_TEXTURE0, GL_OBJECT_LINEAR_CHROMIUM, 3, stroke_coefficients_);
+  glPathTexGenCHROMIUM(
+      GL_TEXTURE0 + 1, GL_OBJECT_LINEAR_CHROMIUM, 3, stroke_coefficients_);
+  glStencilFunc(GL_EQUAL, 0x80, 0x80);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glCoverStrokePathCHROMIUM(path, GL_BOUNDING_BOX_CHROMIUM);
+
+  glDeletePathsCHROMIUM(path, 1);
+
+  // Verify the image.
+  VerifyTestPatternFill(0.f, 0.f);
+  VerifyTestPatternBg(0.f, 0.f);
+  VerifyTestPatternStroke(0.f, 0.f);
+}
+
+// Tests that drawing with *Instanced functions work.
+TEST_F(CHROMIUMPathRenderingTest, TestPathRenderingInstanced) {
+  if (!GLTestHelper::HasExtension("GL_CHROMIUM_path_rendering")) {
+    return;
+  }
+
+  SetupStateForTestPattern();
+
+  GLuint path = glGenPathsCHROMIUM(1);
+  SetupPathStateForTestPattern(path);
+
+  GLuint paths[] = {1, 1, 1, 1, 1};
+  GLfloat transforms[] = {
+      1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,  0.0f,  0.0f,
+      1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 20.0f, 20.0f, 0.0f,
+      1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 30.0f, 30.0f, 0.0f,
+      1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 40.0f, 40.0f, 0.0f,
+      1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 50.0f, 50.0f, 0.0f,
+      1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 60.0f, 60.0f, 0.0f,
+  };
+
+  // The test pattern is the same as in the simple draw case above,
+  // except that the path is drawn 5 times with different offsets.
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0xFF);
+  glStencilStrokePathInstancedCHROMIUM(5,
+                                       GL_UNSIGNED_INT,
+                                       paths,
+                                       path - 1,
+                                       0x80,
+                                       0x80,
+                                       GL_AFFINE_3D_CHROMIUM,
+                                       transforms);
+
+  glPathStencilFuncCHROMIUM(GL_ALWAYS, 0, 0x7F);
+  glStencilFillPathInstancedCHROMIUM(5,
+                                     GL_UNSIGNED_INT,
+                                     paths,
+                                     path - 1,
+                                     GL_COUNT_UP_CHROMIUM,
+                                     0x7F,
+                                     GL_AFFINE_3D_CHROMIUM,
+                                     transforms);
+
+  glPathTexGenCHROMIUM(
+      GL_TEXTURE0, GL_OBJECT_LINEAR_CHROMIUM, 3, fill_coefficients_);
+  glPathTexGenCHROMIUM(GL_TEXTURE0 + 1,
+                       GL_OBJECT_LINEAR_CHROMIUM,
+                       3,
+                       &fill_coefficients_[3 * 3]);
+
+  glStencilFunc(GL_LESS, 0, 0x7F);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glCoverFillPathInstancedCHROMIUM(5,
+                                   GL_UNSIGNED_INT,
+                                   paths,
+                                   path - 1,
+                                   GL_BOUNDING_BOX_OF_BOUNDING_BOXES_CHROMIUM,
+                                   GL_AFFINE_3D_CHROMIUM,
+                                   transforms);
+
+  glPathTexGenCHROMIUM(
+      GL_TEXTURE0, GL_OBJECT_LINEAR_CHROMIUM, 3, stroke_coefficients_);
+  glPathTexGenCHROMIUM(
+      GL_TEXTURE0 + 1, GL_OBJECT_LINEAR_CHROMIUM, 3, stroke_coefficients_);
+  glStencilFunc(GL_EQUAL, 0x80, 0x80);
+  glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
+  glCoverStrokePathInstancedCHROMIUM(5,
+                                     GL_UNSIGNED_INT,
+                                     paths,
+                                     path - 1,
+                                     GL_BOUNDING_BOX_OF_BOUNDING_BOXES_CHROMIUM,
+                                     GL_AFFINE_3D_CHROMIUM,
+                                     transforms);
+
+  glDeletePathsCHROMIUM(path, 1);
+#if 0
+  // FIXME: the instanced picture is not set up to be correct yet,
+  // and neither is the verification.
+  GLTestHelper::SaveBackbufferAsBMP("nvpr-unittest.bmp", kResolution,
+                                    kResolution);
+  // Verify the image.
+  VerifyTestPatternFill(0.f, 0.f);
+  VerifyTestPatternBg(0.f, 0.f);
+  VerifyTestPatternStroke(0.f, 0.f);
+#endif
+}
+
 }  // namespace gpu