Add support for half float alpha textures.

include/gpu/GrTypes.h

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
@@ skipping 284 matching lines @@
      * having RGBA values. However, there are single-channel encodings which set
      * the alpha to opaque and all three RGB channels equal effectively making the
      * compression format a single channel such as R11 EAC and LATC.
      */
     kASTC_12x12_GrPixelConfig,
 
     /**
      * Byte order is r, g, b, a.  This color format is 32 bits per channel
      */
     kRGBA_float_GrPixelConfig,
-    kLast_GrPixelConfig = kRGBA_float_GrPixelConfig
+
+    /**
+     * This color format is a single 16 bit float channel
+     */
+    kAlpha_half_GrPixelConfig,
+
+    kLast_GrPixelConfig = kAlpha_half_GrPixelConfig
 };
 static const int kGrPixelConfigCnt = kLast_GrPixelConfig + 1;
 
 // Aliases for pixel configs that match skia's byte order.
 #ifndef SK_CPU_LENDIAN
     #error "Skia gpu currently assumes little endian"
 #endif
 #if SK_PMCOLOR_BYTE_ORDER(B,G,R,A)
     static const GrPixelConfig kSkia8888_GrPixelConfig = kBGRA_8888_GrPixelConfig;
 #elif SK_PMCOLOR_BYTE_ORDER(R,G,B,A)
@@ skipping 41 matching lines @@
     }
 }
 
 static inline size_t GrBytesPerPixel(GrPixelConfig config) {
     SkASSERT(!GrPixelConfigIsCompressed(config));
     switch (config) {
         case kAlpha_8_GrPixelConfig:
             return 1;
         case kRGB_565_GrPixelConfig:
         case kRGBA_4444_GrPixelConfig:
+        case kAlpha_half_GrPixelConfig:
             return 2;
         case kRGBA_8888_GrPixelConfig:
         case kBGRA_8888_GrPixelConfig:
             return 4;
         case kRGBA_float_GrPixelConfig:
             return 16;
         default:
             return 0;
     }
 }
 
 static inline size_t GrUnpackAlignment(GrPixelConfig config) {
     SkASSERT(!GrPixelConfigIsCompressed(config));
     switch (config) {
         case kAlpha_8_GrPixelConfig:
             return 1;
         case kRGB_565_GrPixelConfig:
         case kRGBA_4444_GrPixelConfig:
+        case kAlpha_half_GrPixelConfig:
             return 2;
         case kRGBA_8888_GrPixelConfig:
         case kBGRA_8888_GrPixelConfig:
         case kRGBA_float_GrPixelConfig:
             return 4;
         default:
             return 0;
     }
 }
 
 static inline bool GrPixelConfigIsOpaque(GrPixelConfig config) {
     switch (config) {
         case kETC1_GrPixelConfig:
         case kRGB_565_GrPixelConfig:
             return true;
         default:
             return false;
     }
 }
 
 static inline bool GrPixelConfigIsAlphaOnly(GrPixelConfig config) {
     switch (config) {
         case kR11_EAC_GrPixelConfig:
         case kLATC_GrPixelConfig:
         case kASTC_12x12_GrPixelConfig:
         case kAlpha_8_GrPixelConfig:
+        case kAlpha_half_GrPixelConfig:
             return true;
         default:
             return false;
     }
 }
 
 /**
  * Optional bitfield flags that can be set on GrSurfaceDesc (below).
  */
 enum GrSurfaceFlags {
@@ skipping 295 matching lines @@
 public:
     GrAutoMalloc() : INHERITED() {}
     explicit GrAutoMalloc(size_t size) : INHERITED(size) {}
     virtual ~GrAutoMalloc() {}
 private:
     typedef GrAutoMallocBaseType INHERITED;
 };
 
 #undef GrAutoMallocBaseType
 #endif