Fix indexed PNG loading.

The issue for indexed images is the bits per channel is how many bits are used to look up the value
in the palette. The value that comes out is an RGB value.

Review URL: http://codereview.chromium.org/149060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19543 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 58 insertions, 6 deletions

diff --git a/o3d/core/cross/bitmap_png.cc b/o3d/core/cross/bitmap_png.cc
index de86a5d..ea8a9ac 100644
--- a/o3d/core/cross/bitmap_png.cc
+++ b/o3d/core/cross/bitmap_png.cc
@@ -164,9 +164,8 @@ bool Bitmap::LoadFromPNGStream(MemoryReadStream *stream,
   if (png_color_type == PNG_COLOR_TYPE_PALETTE) {
     // Expand paletted colors into RGB{A} triplets
     png_set_palette_to_rgb(png_ptr);
-  }
   // Gray vs RGB.
-  if ((png_color_type & PNG_COLOR_MASK_COLOR) == PNG_COLOR_TYPE_RGB) {
+  } else if ((png_color_type & PNG_COLOR_MASK_COLOR) == PNG_COLOR_TYPE_RGB) {
     if (png_bits_per_channel != 8) {
       png_error(png_ptr, "PNG image type not recognized");
     }
@@ -176,7 +175,7 @@ bool Bitmap::LoadFromPNGStream(MemoryReadStream *stream,
       png_error(png_ptr, "PNG image type not recognized");
     }
     // Expand grayscale images to the full 8 bits from 2, or 4 bits/pixel
-    // TODO: Do we want to expose L/A/LA texture formats ?
+    // TODO(o3d): Do we want to expose L/A/LA texture formats ?
     png_set_gray_1_2_4_to_8(png_ptr);
     png_set_gray_to_rgb(png_ptr);
   }
diff --git a/o3d/core/cross/bitmap_test.cc b/o3d/core/cross/bitmap_test.cc
index 0a3e5c4..0c3766d 100644
--- a/o3d/core/cross/bitmap_test.cc
+++ b/o3d/core/cross/bitmap_test.cc
@@ -137,6 +137,25 @@ static unsigned char kpng256x256_24bit_interlaced_BGRX[128] = {
   0x1d, 0x8d, 0x96, 0xff, 0x1b, 0x8f, 0x90, 0xff,
 };
 
+static unsigned char kpng256x256_32bit_BGRA[128] = {
+  0x36, 0x87, 0xbc, 0xd4, 0x36, 0x87, 0xbc, 0xfa,
+  0x35, 0x83, 0xb5, 0xff, 0x34, 0x83, 0xb5, 0xfe,
+  0x35, 0x83, 0xb5, 0xf3, 0x35, 0x82, 0xb5, 0xcf,
+  0x35, 0x82, 0xb4, 0x9a, 0x35, 0x82, 0xb4, 0x75,
+  0x35, 0x82, 0xb4, 0x67, 0x35, 0x82, 0xb4, 0x7d,
+  0x35, 0x82, 0xb4, 0xa8, 0x35, 0x82, 0xb4, 0xdd,
+  0x35, 0x82, 0xb4, 0xf7, 0x35, 0x82, 0xb4, 0xff,
+  0x35, 0x82, 0xb4, 0xff, 0x35, 0x82, 0xb4, 0xf8,
+  0x35, 0x82, 0xb4, 0xaf, 0x35, 0x82, 0xb4, 0x68,
+  0x35, 0x83, 0xb5, 0x5a, 0x37, 0x85, 0xb8, 0x6a,
+  0x36, 0x85, 0xb8, 0xaf, 0x35, 0x86, 0xb7, 0xf8,
+  0x35, 0x87, 0xb7, 0xff, 0x35, 0x88, 0xb7, 0xff,
+  0x35, 0x89, 0xb7, 0xff, 0x34, 0x8a, 0xb7, 0xff,
+  0x34, 0x8b, 0xb7, 0xff, 0x32, 0x8c, 0xb5, 0xff,
+  0x31, 0x8c, 0xb1, 0xff, 0x2f, 0x8d, 0xaf, 0xff,
+  0x1d, 0x8d, 0x96, 0xff, 0x1b, 0x8f, 0x90, 0xff,
+};
+
 static unsigned char kpng256x256_8bit_palette_BGRX[128] = {
   0x36, 0x89, 0xbb, 0xff, 0x36, 0x89, 0xbb, 0xff,
   0x35, 0x81, 0xb5, 0xff, 0x32, 0x84, 0xb5, 0xff,
@@ -156,6 +175,25 @@ static unsigned char kpng256x256_8bit_palette_BGRX[128] = {
   0x1f, 0x8d, 0x91, 0xff, 0x1f, 0x8d, 0x91, 0xff,
 };
 
+static unsigned char kpng20x14_4bit_palette_BGRX[128] = {
+  0xed, 0xed, 0xed, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0xed, 0xed, 0xed, 0xff,
+  0xff, 0xff, 0xff, 0xff, 0x54, 0x54, 0x54, 0xff,
+  0x33, 0x33, 0x33, 0xff, 0x33, 0x33, 0x33, 0xff,
+  0x33, 0x33, 0x33, 0xff, 0x33, 0x33, 0x33, 0xff,
+  0x33, 0x33, 0x33, 0xff, 0x33, 0x33, 0x33, 0xff,
+  0x33, 0x33, 0x33, 0xff, 0x33, 0x33, 0x33, 0xff,
+  0x54, 0x54, 0x54, 0xff, 0x33, 0x33, 0x33, 0xff,
+};
+
 static unsigned char kdxt1_256x256[128] = {
   0x47, 0xbc, 0x06, 0xb4, 0x5a, 0x6a, 0x6a, 0xea,
   0x27, 0xb4, 0x06, 0xb4, 0x57, 0x57, 0x57, 0x5e,
@@ -413,8 +451,6 @@ TEST_F(BitmapTest, LoadPNGFile24bitInterlaced) {
   EXPECT_TRUE(TestBitmapData(bitmap, kpng256x256_24bit_interlaced_BGRX));
 }
 
-// NOTE: unable to get Photoshop to export an PNG file with alpha.
-/*
 TEST_F(BitmapTest, LoadPNGFile32bit) {
   String filename = *g_program_path + "/bitmap_test/png-256x256-32bit.png";
   FilePath filepath = UTF8ToFilePath(filename);
@@ -426,8 +462,8 @@ TEST_F(BitmapTest, LoadPNGFile32bit) {
   EXPECT_EQ(256, bitmap.width());
   EXPECT_EQ(256, bitmap.height());
   EXPECT_EQ(1, bitmap.num_mipmaps());
+  EXPECT_TRUE(TestBitmapData(bitmap, kpng256x256_32bit_BGRA));
 }
-*/
 
 // Loads a palettized PNG file, checks it against the known data.
 TEST_F(BitmapTest, LoadPNGFile8bitPalette) {
@@ -445,6 +481,23 @@ TEST_F(BitmapTest, LoadPNGFile8bitPalette) {
   EXPECT_TRUE(TestBitmapData(bitmap, kpng256x256_8bit_palette_BGRX));
 }
 
+// Loads a palettized PNG file, checks it against the known data.
+TEST_F(BitmapTest, LoadPNGFile4bitPalette) {
+  String filename = *g_program_path +
+                    "/bitmap_test/png-20x14-4bit-palette.png";
+  FilePath filepath = UTF8ToFilePath(filename);
+  Bitmap bitmap;
+  EXPECT_TRUE(bitmap.LoadFromFile(filepath, Bitmap::PNG, false));
+  EXPECT_TRUE(bitmap.image_data() != NULL);
+  EXPECT_FALSE(bitmap.is_cubemap());
+  EXPECT_EQ(Texture::XRGB8, bitmap.format());
+  EXPECT_EQ(20, bitmap.width());
+  EXPECT_EQ(14, bitmap.height());
+  EXPECT_EQ(1, bitmap.num_mipmaps());
+  EXPECT_TRUE(TestBitmapData(bitmap, kpng20x14_4bit_palette_BGRX));
+}
+
+
 // Tries to load a 5kx5k PNG file, which should fail.
 TEST_F(BitmapTest, LoadPNGFileTooLarge) {
   String filename = *g_program_path + "/bitmap_test/5kx5k.png";