Added glReadPixels test.

client/deps/glbench/src/main.cc

 // Copyright (c) 2010 The Chromium OS 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 <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
 
@@ skipping 50 matching lines @@
     if (Bench(f, &slope, &bias)) {
       printf("%s: %g\n", name, coefficient * (inverse ? 1.f / slope : slope));
     } else {
       printf("# %s is too slow, returning zero.\n", name);
       printf("%s: 0\n", name);
     }
   }
 }
 
 static int arg1 = 0;
+static void *arg2 = NULL;
 
 void SwapTestFunc(int iter) {
   for (int i = 0 ; i < iter; ++i) {
     SwapBuffers();
   }
 }
 
 void SwapTest() {
   RunTest(SwapTestFunc, "us_swap_swap", 1.f, false);
 }
@@ skipping 701 matching lines @@
 
 void NoFillWindowManagerCompositingTest() {
   glScissor(0, 0, 1, 1);
   glEnable(GL_SCISSOR_TEST);
   InitializeCompositing();
   RunTest(CompositingTestFunc, "1280x768_fps_no_fill_compositing",
           screen_scale_factor, true);
   TeardownCompositing();
 }
 
-// TODO: get resources file from a command line option or something.
+void ReadPixelTestFunc(int iter) {
+  glReadPixels(0, 0, g_width, g_height, GL_RGBA, GL_UNSIGNED_BYTE, arg2);
+  CHECK(glGetError() == 0);
+  for (int i = 0; i < iter; i++)
+    glReadPixels(0, 0, g_width, g_height, GL_RGBA, GL_UNSIGNED_BYTE, arg2);
+}
+
+// TODO: better test names.
+void ReadPixelTest() {
+  // One GL_RGBA pixel takes 4 bytes.
+  const int row_size = g_width * 4;
+  // Default GL_PACK_ALIGNMENT is 4, round up pixel row size to multiple of 4.
+  // This is a no-op because row_size is already divisible by 4.
+  // One is added so that we can test reads into unaligned location.
+  char* pixels = new char[((row_size + 3) & ~3) * g_height + 1];
+
+  arg2 = pixels;
+  RunTest(ReadPixelTestFunc, "mpixels_sec_pixel_read",
+          g_width * g_height, true);
+
+  // Reducing GL_PACK_ALIGNMENT can only make rows smaller.  No need to
+  // reallocate the buffer.
+  glPixelStorei(GL_PACK_ALIGNMENT, 1);
+  RunTest(ReadPixelTestFunc, "mpixels_sec_pixel_read_2",
+          g_width * g_height, true);
+
+  arg2 = static_cast<void*>(pixels + 1);
+  RunTest(ReadPixelTestFunc, "mpixels_sec_pixel_read_3",
+          g_width * g_height, true);
+
+  delete[] pixels;
+}
+
 // TODO: use proper command line parsing library.
 static void ParseArgs(int argc, char *argv[]) {
   const char **enabled_tests_ptr = enabled_tests;
   bool test_name_arg = false;
   bool duration_arg = false;
   for (int i = 0; i < argc; i++) {
     if (test_name_arg) {
       test_name_arg = false;
       *enabled_tests_ptr++ = argv[i];
       if (enabled_tests_ptr - enabled_tests >= enabled_tests_max)
@@ skipping 23 matching lines @@
     SwapTest,
     ClearTest,
     FillRateTest,
     TriangleSetupTest,
     AttributeFetchShaderTest,
     VaryingsAndDdxyShaderTest,
     YuvToRgbShaderTest1,
     YuvToRgbShaderTest2,
     NoFillWindowManagerCompositingTest,
     WindowManagerCompositingTest,
+    ReadPixelTest,
   };
 
   uint64_t done = GetUTime() + 1000000ULL * seconds_to_run;
   do {
     for (unsigned int i = 0; i < sizeof(test) / sizeof(*test); i++) {
       InitContext();
       test[i]();
       GLenum err = glGetError();
       if (err != 0)
         printf("# glGetError returned non-zero: 0x%x\n", err);
       DestroyContext();
     }
   } while (GetUTime() < done);
 
   return 0;
 }