Fleshed out some more of the library

CMakeLists.txt

@@ -3,3 +3,4 @@ PROJECT(TexC)
 
 ADD_SUBDIRECTORY(BPTCEncoder)
 ADD_SUBDIRECTORY(IO)
+ADD_SUBDIRECTORY(Core)

Core/CMakeLists.txt

@@ -1,15 +1,21 @@
 
 SET( SOURCES
 	"src/TexComp.cpp"
+	"src/CompressedImage.cpp"
 )
 
 SET( HEADERS
 	"include/TexComp.h"
+	"include/CompressedImage.h"
 )
 
+INCLUDE_DIRECTORIES( ${TexC_BINARY_DIR}/IO/include )
+INCLUDE_DIRECTORIES( ${TexC_SOURCE_DIR}/IO/include )
 INCLUDE_DIRECTORIES( ${TexC_SOURCE_DIR}/Core/include )
 
 ADD_LIBRARY( TexCompCore
 	${HEADERS}
 	${SOURCES}
 )
+
+TARGET_LINK_LIBRARIES( TexCompCore TexCompIO )

Core/include/CompressedImage.h

@@ -0,0 +1,34 @@
+#ifndef _COMPRESSED_IMAGE_H_
+#define _COMPRESSED_IMAGE_H_
+
+enum ECompressionFormat {
+  eCompressionFormat_DXT1,
+  eCompressionFormat_DXT5,
+  eCompressionFormat_BPTC,
+
+  kNumCompressionFormats
+};
+
+class CompressedImage {
+
+ private:
+  unsigned char *m_Data;
+  unsigned int m_DataSz;
+  unsigned int m_Width;
+  unsigned int m_Height;
+  ECompressionFormat m_Format;
+
+  void InitData(const unsigned char *withData);
+ public:
+  CompressedImage(
+    const unsigned int width, 
+    const unsigned int height, 
+    const ECompressionFormat format, 
+    const unsigned char *data
+  );
+
+  CompressedImage( const CompressedImage &other );
+  ~CompressedImage();
+};
+
+#endif // _COMPRESSED_IMAGE_H_

Core/include/TexComp.h

@@ -1,4 +1,27 @@
 #ifndef _TEX_COMP_H_
 #define _TEX_COMP_H_
 
+#include "ImageFile.h"
+#include "CompressedImage.h"
+
+struct SCompressionSettings {
+  SCompressionSettings(); // defaults
+  ECompressionFormat format; 
+  bool bUseSIMD;
+  int iNumThreads;
+};
+
+extern void CompressImage(
+  const ImageFile &, 
+  CompressedImage &, 
+  const SCompressionSettings &settings
+);
+
+typedef void (* CompressionFunc)(
+  const unsigned char *inData,
+  unsigned char *outData,
+  unsigned int width,
+  unsigned int height
+);
+
 #endif //_TEX_COMP_H_

Core/src/CompressedImage.cpp

@@ -0,0 +1,50 @@
+#include "CompressedImage.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+CompressedImage::CompressedImage( const CompressedImage &other )
+  : m_Width(other.m_Width)
+  , m_Height(other.m_Height)
+  , m_Format(other.m_Format)
+  , m_Data(0)
+{
+  InitData(other.m_Data);
+}
+
+CompressedImage::CompressedImage(
+  const unsigned int width,				 
+  const unsigned int height,
+  const ECompressionFormat format,
+  const unsigned char *data
+) 
+: m_Width(width)
+, m_Height(height)
+, m_Format(format)
+, m_Data(0)
+{
+  InitData(data);
+}
+
+void CompressedImage::InitData(const unsigned char *withData) {
+  unsigned int dataSz = 0;
+  int uncompDataSz = m_Width * m_Height * 4;
+
+  switch(m_Format) {
+    case eCompressionFormat_DXT1: dataSz = uncompDataSz / 8; break;
+    case eCompressionFormat_DXT5: dataSz = uncompDataSz / 4; break;
+    case eCompressionFormat_BPTC: dataSz = uncompDataSz / 4; break;
+  }
+  
+  if(dataSz > 0) {
+    m_Data = new unsigned char[dataSz];
+    memcpy(m_Data, withData, dataSz);
+  }
+}
+
+CompressedImage::~CompressedImage() {
+  if(m_Data) {
+    delete [] m_Data;
+    m_Data = NULL;
+  }
+}

Core/src/TexComp.cpp

@@ -1 +1,55 @@
 #include "TexComp.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+SCompressionSettings:: SCompressionSettings()
+  : format(eCompressionFormat_BPTC)
+  , bUseSIMD(false)
+  , iNumThreads(1)
+{}
+
+static CompressionFunc ChooseFuncFromSettings(const SCompressionSettings &s) {
+  return NULL;
+}
+
+static void ReportError(const char *msg) {
+  fprintf(stderr, "TexComp -- %s\n", msg);
+}
+
+void CompressImage(
+  const ImageFile &img, 
+  CompressedImage &outImg, 
+  const SCompressionSettings &settings
+) { 
+  
+  const unsigned int dataSz = img.GetWidth() * img.GetHeight() * 4;
+
+  // Allocate data based on the compression method
+  int cmpDataSz = 0;
+  switch(settings.format) {
+    case eCompressionFormat_DXT1: cmpDataSz = dataSz / 8;
+    case eCompressionFormat_DXT5: cmpDataSz = dataSz / 4;
+    case eCompressionFormat_BPTC: cmpDataSz = dataSz / 4;
+  }
+
+  if(cmpDataSz == 0) {
+    ReportError("Unknown compression format");
+    return;
+  }
+
+  unsigned char *cmpData = new unsigned char[cmpDataSz];
+
+  CompressionFunc f = ChooseFuncFromSettings(settings);
+  if(f) {
+    (*f)(img.GetPixels(), cmpData, img.GetWidth(), img.GetHeight());
+    outImg = CompressedImage(img.GetWidth(), img.GetHeight(), settings.format, cmpData);
+  }
+  else {
+    ReportError("Could not find adequate compression function for specified settings");
+    // return
+  }
+
+  // Cleanup
+  delete [] cmpData;
+} 

IO/CMakeLists.txt

@@ -12,7 +12,6 @@ FIND_PACKAGE( PNG )
 IF( PNG_FOUND )
 	INCLUDE_DIRECTORIES( ${PNG_INCLUDE_DIR} )
 
-
 	SET( SOURCES ${SOURCES} "src/ImageLoaderPNG.cpp" )
 	SET( HEADERS ${HEADERS} "src/ImageLoaderPNG.h" )
 ENDIF()

IO/config/ImageLoader.h.in

@@ -62,16 +62,19 @@ class ImageLoader {
   virtual bool ReadData() = 0;
 
   int GetRedChannelPrecision() const { return m_RedChannelPrecision; }
-  unsigned char * GetRedPixelData() const { return m_RedData; }
+  const unsigned char * GetRedPixelData() const { return m_RedData; }
 
   int GetGreenChannelPrecision() const { return m_GreenChannelPrecision; }
-  unsigned char * GetGreenPixelData() const { return m_GreenData; }
+  const unsigned char * GetGreenPixelData() const { return m_GreenData; }
 
   int GetBlueChannelPrecision() const { return m_BlueChannelPrecision; }
-  unsigned char * GetBluePixelData() const { return m_BlueData; }
+  const unsigned char * GetBluePixelData() const { return m_BlueData; }
 
   int GetAlphaChannelPrecision() const { return m_AlphaChannelPrecision; }
-  unsigned char * GetAlphaPixelData() const { return m_AlphaData; }
+  const unsigned char * GetAlphaPixelData() const { return m_AlphaData; }
+
+  int GetWidth() const { return m_Width; }
+  int GetHeight() const { return m_Height; }
 };
 
 #cmakedefine PNG_FOUND

IO/src/ImageFile.cpp

@@ -1,6 +1,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <limits.h>
 #include <assert.h>
 
 #include "ImageFile.h"
@@ -9,6 +10,101 @@
 #  include "ImageLoaderPNG.h"
 #endif
 
+//////////////////////////////////////////////////////////////////////////////////////////
+//
+// Static helper functions
+//
+//////////////////////////////////////////////////////////////////////////////////////////
+
+static inline void ReportError(const char *msg) {
+  fprintf(stderr, "ImageFile -- %s\n", msg);
+}
+
+template <typename T>
+static inline T abs(const T &a) {
+  return a > 0? a : -a;
+}
+
+template <typename T>
+static inline T min(const T &a, const T &b) {
+  return (a < b)? a : b;
+}
+
+static unsigned int GetChannelForPixel(
+  const ImageLoader *loader, 
+  unsigned int x, unsigned int y,
+  int ch
+) {
+  unsigned int prec;
+  const unsigned char *data;
+
+  switch(ch) {
+  case 0:
+    prec = loader->GetRedChannelPrecision();
+    data = loader->GetRedPixelData();
+    break;
+
+  case 1:
+    prec = loader->GetGreenChannelPrecision();
+    data = loader->GetGreenPixelData();
+    break;
+
+  case 2:
+    prec = loader->GetBlueChannelPrecision();
+    data = loader->GetBluePixelData();
+    break;
+
+  case 3:
+    prec = loader->GetAlphaChannelPrecision();
+    data = loader->GetAlphaPixelData();
+    break;
+
+  default:
+    ReportError("Unspecified channel");
+    return INT_MAX;
+  }
+
+  if(0 == prec)
+    return 0;
+
+  assert(x < loader->GetWidth());
+  assert(y < loader->GetHeight());
+
+  int pixelIdx = y * loader->GetWidth() + x;
+  const unsigned int val = data[pixelIdx];
+  
+  if(prec < 8) {
+    unsigned int ret = 0;
+    for(unsigned int precLeft = 8; precLeft > 0; precLeft -= min(prec, abs(prec - precLeft))) {
+      
+      if(prec > precLeft) {
+	const int toShift = prec - precLeft;
+	ret = ret << precLeft;
+	ret |= val >> toShift;
+      }
+      else {
+	ret = ret << prec;
+	ret |= val;
+      }
+
+    }
+
+    return ret;
+  }
+  else if(prec > 8) {
+    const int toShift = prec - 8;
+    return val >> toShift;
+  }
+
+  return val;
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////
+//
+// ImageFile implementation
+//
+//////////////////////////////////////////////////////////////////////////////////////////
+
 ImageFile::ImageFile(const char *filename) : 
   m_PixelData(0),
   m_FileFormat(  DetectFileFormat(filename) )
@@ -80,7 +176,77 @@ bool ImageFile::LoadImage(const unsigned char *rawImageData) {
       break;
   }
 
+  m_Width = loader->GetWidth();
+  m_Height = loader->GetHeight();
+
+  // Create RGBA buffer 
+  const unsigned int dataSz = 4 * m_Width * m_Height;
+  m_PixelData = new unsigned char[dataSz];
+
+  // Populate buffer in block stream order... make 
+  // sure that width and height are aligned to multiples of four.
+  const unsigned int aw = ((m_Width + 3) >> 2) << 2;
+  const unsigned int ah = ((m_Height + 3) >> 2) << 2;
+
+  int byteIdx = 0;
+  for(int i = 0; i < ah; i+=4) {
+    for(int j = 0; j < aw; j+= 4) {
+
+      // For each block, visit the pixels in sequential order
+      for(int y = i; y < i+4; y++) {
+	for(int x = j; x < j+4; x++) {
+
+	  if(y >= m_Height || x >= m_Width) {
+	    m_PixelData[byteIdx++] = 0; // r
+	    m_PixelData[byteIdx++] = 0; // g
+	    m_PixelData[byteIdx++] = 0; // b
+	    m_PixelData[byteIdx++] = 0; // a
+	    continue;
+	  }
+
+	  unsigned int redVal = GetChannelForPixel(loader, x, y, 0);
+	  if(redVal == INT_MAX)
 	    return false;
+
+	  unsigned int greenVal = redVal;
+	  unsigned int blueVal = redVal;
+
+	  if(loader->GetGreenChannelPrecision() > 0) {
+	    greenVal = GetChannelForPixel(loader, x, y, 1);
+	    if(greenVal == INT_MAX)
+	      return false;
+	  }
+
+	  if(loader->GetBlueChannelPrecision() > 0) {
+	    blueVal = GetChannelForPixel(loader, x, y, 2);
+	    if(blueVal == INT_MAX)
+	      return false;
+	  }
+
+	  unsigned int alphaVal = 0xFF;
+	  if(loader->GetAlphaChannelPrecision() > 0) {
+	    alphaVal = GetChannelForPixel(loader, x, y, 3);
+	    if(alphaVal == INT_MAX)
+	      return false;
+	  }
+
+	  // Red channel
+	  m_PixelData[byteIdx++] = redVal & 0xFF;
+
+	  // Green channel
+	  m_PixelData[byteIdx++] = greenVal & 0xFF;
+
+	  // Blue channel
+	  m_PixelData[byteIdx++] = blueVal & 0xFF;
+
+	  // Alpha channel
+	  m_PixelData[byteIdx++] = alphaVal & 0xFF;
+	}
+      }
+    }
+  }
+
+  return true;
 }
 
 #ifdef _MSC_VER