Add ETC1 format to SkTextureCompressor

src/utils/SkTextureCompressor.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTextureCompressor.h"
 #include "SkTextureCompressor_ASTC.h"
 #include "SkTextureCompressor_LATC.h"
 #include "SkTextureCompressor_R11EAC.h"
 
 #include "SkBitmap.h"
 #include "SkData.h"
 #include "SkEndian.h"
 
 #include "SkTextureCompression_opts.h"
 
+#ifndef SK_IGNORE_ETC1_SUPPORT
+#  include "etc1.h"
+#endif
+
+// Convert ETC1 functions to our function signatures
+static bool compress_etc1_565(uint8_t* dst, const uint8_t* src,
+                              int width, int height, int rowBytes) {
+#ifndef SK_IGNORE_ETC1_SUPPORT
+    return 0 == etc1_encode_image(src, width, height, 2, rowBytes, dst);
+#else
+    return false;
+#endif
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 namespace SkTextureCompressor {
 
 void GetBlockDimensions(Format format, int* dimX, int* dimY, bool matchSpec) {
     if (NULL == dimX || NULL == dimY) {
         return;
     }
 
     if (!matchSpec && SkTextureCompressorGetPlatformDims(format, dimX, dimY)) {
         return;
     }
 
     // No specialized arguments, return the dimensions as they are in the spec.
     switch(format) {
         // These formats are 64 bits per 4x4 block.
         default:
             SkDEBUGFAIL("Unknown compression format!");
             // fall through
+        case kLATC_Format:
         case kR11_EAC_Format:
-        case kLATC_Format:
+        case kETC1_Format: 
             *dimX = 4;
             *dimY = 4;
             break;
 
         // This format is 12x12 blocks to 128 bits.
         case kASTC_12x12_Format:
             *dimX = 12;
             *dimY = 12;
             break;        
     }
 }
 
 int GetCompressedDataSize(Format fmt, int width, int height) {
     int dimX, dimY;
     GetBlockDimensions(fmt, &dimX, &dimY, true);
 
     int encodedBlockSize = 0;
             
     switch (fmt) {
         // These formats are 64 bits per 4x4 block.
+        case kLATC_Format:
         case kR11_EAC_Format:
-        case kLATC_Format:
+        case kETC1_Format:
             encodedBlockSize = 8;
             break;
 
         // This format is 12x12 blocks to 128 bits.
         case kASTC_12x12_Format:
             encodedBlockSize = 16;
             break;
 
         default:
             SkFAIL("Unknown compressed format!");
@@ skipping 31 matching lines @@
                     case kASTC_12x12_Format:
                         proc = CompressA8To12x12ASTC;
                         break;
                     default:
                         // Do nothing...
                         break;
                 }
             }
             break;
 
+            case kRGB_565_SkColorType:
+            {
+                switch (format) {
+                    case kETC1_Format:
+                        proc = compress_etc1_565;
+                        break;
+                    default:
+                        // Do nothing...
+                        break;
+                }
+            }
+            break;
+
             default:
                 // Do nothing...
                 break;
         }
     }
 
     if (NULL != proc) {
         return proc(dst, src, width, height, rowBytes);
     }
 
@@ skipping 49 matching lines @@
 
     switch(format) {
         case kLATC_Format:
             DecompressLATC(dst, dstRowBytes, src, width, height);
             return true;
 
         case kR11_EAC_Format:
             DecompressR11EAC(dst, dstRowBytes, src, width, height);
             return true;
 
+#ifndef SK_IGNORE_ETC1_SUPPORT
+        case kETC1_Format:
+            return 0 == etc1_decode_image(src, dst, width, height, 3, dstRowBytes);
+#endif
         case kASTC_12x12_Format:
             // TODO(krajcevski) .. right now just fall through and return false.
             return false;
+
+        default:
+            // Do nothing...
+            break;
     }
 
     return false;
 }
 
 }  // namespace SkTextureCompressor