From 9388ef4adb3c897713b738d722c2858d61a512d9 Mon Sep 17 00:00:00 2001
From: dirk <dirk@git.imagemagick.org>
Date: Mon, 7 Jul 2014 18:39:23 +0000
Subject: [PATCH] Added support for R5G6B5, RGB5A1 and RGBA4 dds files.

---
 coders/dds.c | 120 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 95 insertions(+), 25 deletions(-)

diff --git a/coders/dds.c b/coders/dds.c
index dd6034e82..6bb8ec451 100644
--- a/coders/dds.c
+++ b/coders/dds.c
@@ -748,6 +748,9 @@ if (max - min < steps) \
 #define VectorInit(vector, value) vector.x = vector.y = vector.z = vector.w \
   = value
 #define VectorInit3(vector, value) vector.x = vector.y = vector.z = value
+
+#define IsBitMask(mask, r, g, b, a) (mask.r_bitmask == r && mask.g_bitmask == \
+  g && mask.b_bitmask == b && mask.alpha_bitmask == a)
 
 /*
   Forward declarations
@@ -2170,12 +2173,20 @@ static MagickBooleanType ReadDXT5(Image *image, DDSInfo *dds_info,
 static MagickBooleanType ReadUncompressedRGB(Image *image, DDSInfo *dds_info,
   ExceptionInfo *exception)
 {
-  ssize_t
-    x, y;
-  
   register Quantum
     *q;
-  
+
+  ssize_t
+    x, y;
+
+  unsigned short
+    color;
+
+  if (dds_info->pixelformat.rgb_bitcount == 16 && !IsBitMask(
+    dds_info->pixelformat,0xf800,0x07e0,0x001f,0x0000))
+    ThrowBinaryException(CorruptImageError,"ImageTypeNotSupported",
+      image->filename);
+
   for (y = 0; y < (ssize_t) dds_info->height; y++)
   {
     q = QueueAuthenticPixels(image, 0, y, dds_info->width, 1,exception);
@@ -2185,14 +2196,28 @@ static MagickBooleanType ReadUncompressedRGB(Image *image, DDSInfo *dds_info,
     
     for (x = 0; x < (ssize_t) dds_info->width; x++)
     {
-      SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
-      SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
-      SetPixelRed(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
-      if (dds_info->pixelformat.rgb_bitcount == 32)
-        (void) ReadBlobByte(image);
+
+      if (dds_info->pixelformat.rgb_bitcount == 16)
+        {
+           color=ReadBlobShort(image);
+           SetPixelRed(image,ScaleCharToQuantum((unsigned char)
+             (((color >> 11)/31.0)*255)),q);
+           SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
+             ((((unsigned short)(color << 5) >> 10)/63.0)*255)),q);
+           SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
+             ((((unsigned short)(color << 11) >> 11)/31.0)*255)),q);
+        }
+      else
+        {
+          SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+          SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+          SetPixelRed(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+          if (dds_info->pixelformat.rgb_bitcount == 32)
+            (void) ReadBlobByte(image);
+        }
       q+=GetPixelChannels(image);
     }
     
@@ -2208,12 +2233,29 @@ static MagickBooleanType ReadUncompressedRGB(Image *image, DDSInfo *dds_info,
 static MagickBooleanType ReadUncompressedRGBA(Image *image, DDSInfo *dds_info,
   ExceptionInfo *exception)
 {
-  ssize_t
-    x, y;
-  
   register Quantum
     *q;
-  
+
+  ssize_t
+    alphaBits,
+    x,
+    y;
+
+  unsigned short
+    color;
+
+  alphaBits=0;
+  if (dds_info->pixelformat.rgb_bitcount == 16)
+    {
+      if (IsBitMask(dds_info->pixelformat,0x7c00,0x03e0,0x001f,0x8000))
+        alphaBits=1;
+      else if (IsBitMask(dds_info->pixelformat,0x0f00,0x00f0,0x000f,0xf000))
+        alphaBits=4;
+      else
+        ThrowBinaryException(CorruptImageError,"ImageTypeNotSupported",
+          image->filename);
+    }
+
   for (y = 0; y < (ssize_t) dds_info->height; y++)
   {
     q = QueueAuthenticPixels(image, 0, y, dds_info->width, 1,exception);
@@ -2222,15 +2264,43 @@ static MagickBooleanType ReadUncompressedRGBA(Image *image, DDSInfo *dds_info,
       return MagickFalse;
     
     for (x = 0; x < (ssize_t) dds_info->width; x++)
-    {
-      SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
-      SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
-      SetPixelRed(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
-      SetPixelAlpha(image,ScaleCharToQuantum((unsigned char)
-        ReadBlobByte(image)),q);
+    {
+      if (dds_info->pixelformat.rgb_bitcount == 16)
+        {
+           color=ReadBlobShort(image);
+           if (alphaBits == 1)
+             {
+               SetPixelAlpha(image,(color & (1 << 15)) ? QuantumRange : 0,q);
+               SetPixelRed(image,ScaleCharToQuantum((unsigned char)
+                 ((((unsigned short)(color << 1) >> 11)/31.0)*255)),q);
+               SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
+                 ((((unsigned short)(color << 6) >> 11)/31.0)*255)),q);
+               SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
+                 ((((unsigned short)(color << 11) >> 11)/31.0)*255)),q);
+             }
+          else
+            {
+               SetPixelAlpha(image,ScaleCharToQuantum((unsigned char)
+                 (((color >> 12)/15.0)*255)),q);
+               SetPixelRed(image,ScaleCharToQuantum((unsigned char)
+                 ((((unsigned short)(color << 4) >> 12)/15.0)*255)),q);
+               SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
+                 ((((unsigned short)(color << 8) >> 12)/15.0)*255)),q);
+               SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
+                 ((((unsigned short)(color << 12) >> 12)/15.0)*255)),q);
+            }
+        }
+      else
+        {
+          SetPixelBlue(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+          SetPixelGreen(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+          SetPixelRed(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+          SetPixelAlpha(image,ScaleCharToQuantum((unsigned char)
+            ReadBlobByte(image)),q);
+        }
       q+=GetPixelChannels(image);
     }
     
-- 
2.40.0