Reland: Add ETC1 powered SSE encoder for tile texture compression

cc/resources/texture_compressor_unittest.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.

[reveman, 2015/05/05 15:30:11]

If this is supposed to contain generic texture compression tests (as the file
name suggest) please have them be parameterized just like the perf tests. If
they are ETC specific, then they belong in a texture_compressor_etc1_unittest.cc
file.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/resources/texture_compressor.h"
+
+#include "cc/base/util.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace cc {
+namespace {
+
+#define TEST_IMAGE_WIDTH 256
+#define TEST_IMAGE_HEIGHT 256
+#define TEST_IMAGE_CHANNELS 4
+#define TEST_IMAGE_SIZE \
+  (TEST_IMAGE_WIDTH * TEST_IMAGE_HEIGHT * TEST_IMAGE_CHANNELS)
+
+#define TEST_IMAGE_POISON 0xDEADBEEF
+#define TEST_PIXEL_LIMIT 256

[reveman, 2015/05/05 15:30:11]

please use constants instead of defines. and maybe move them into the test
function that use them instead of having them be global

+
+TEST(TextureCompressorTest, CreateETC1) {
+  scoped_ptr<TextureCompressor> compressor =
+      TextureCompressor::Create(TextureCompressor::kFormatETC1);
+  EXPECT_NE(nullptr, compressor);
+}
+
+TEST(TextureCompressorTest, CompressRatioETC1) {
+  scoped_ptr<TextureCompressor> compressor =
+      TextureCompressor::Create(TextureCompressor::kFormatETC1);
+  uint8_t src[TEST_IMAGE_SIZE];
+  uint8_t dst[TEST_IMAGE_SIZE];
+  int compressed_size = 0;
+
+  /* Poison destination bytes */
+  uint32_t* dst_32 = reinterpret_cast<uint32_t*>(dst);
+  for (int i = 0; i < TEST_IMAGE_WIDTH * TEST_IMAGE_HEIGHT; i++) {
+    dst_32[i] = TEST_IMAGE_POISON;
+  }
+
+  /* Generate test texture */
+  for (int i = 0; i < TEST_IMAGE_SIZE; i++) {
+    src[i] = i % TEST_PIXEL_LIMIT;
+  }
+
+  compressor->Compress(src, dst, TEST_IMAGE_WIDTH, TEST_IMAGE_HEIGHT,
+                       (TextureCompressor::Quality)0);
+  for (compressed_size = 0;
+       compressed_size < TEST_IMAGE_WIDTH * TEST_IMAGE_HEIGHT;
+       compressed_size++) {
+    if (dst_32[compressed_size] == TEST_IMAGE_POISON) {
+      compressed_size =
+          compressed_size * 4; /* size in bytes of the compressed block */
+      break;
+    }
+  }
+
+  /* Check if compression ratio is 8:1 for RGBA or BGRA images, after discarding
+   * alpha channel */
+  EXPECT_EQ(compressed_size * 8, TEST_IMAGE_SIZE);
+}
+
+}  // namespace
+}  // namespace cc