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common/tgaloader.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//=============================================================================
+
+#include "tgaloader.h"
+#include "tier0/dbg.h"
+
+#pragma pack(1)
+typedef struct _TargaHeader {
+	unsigned char 	id_length, colormap_type, image_type;
+	unsigned short	colormap_index, colormap_length;
+	unsigned char	colormap_size;
+	unsigned short	x_origin, y_origin, width, height;
+	unsigned char	pixel_size, attributes;
+} TargaHeader;
+#pragma pack()
+
+#define TGA_ATTRIBUTE_HFLIP		16
+#define TGA_ATTRIBUTE_VFLIP		32
+
+
+int fgetLittleShort (unsigned char **p)
+{
+	byte	b1, b2;
+
+	b1 = *((*p)++);
+	b2 = *((*p)++);
+
+	return (short)(b1 + b2*256);
+}
+
+int fgetLittleLong (unsigned char **p)
+{
+	byte	b1, b2, b3, b4;
+
+	b1 = *((*p)++);
+	b2 = *((*p)++);
+	b3 = *((*p)++);
+	b4 = *((*p)++);
+
+	return b1 + (b2<<8) + (b3<<16) + (b4<<24);
+}
+
+
+bool GetTGADimensions( int32 iBytes, char *pData, int * width, int *height )
+{
+	TargaHeader header;
+	unsigned char *p = (unsigned char *)pData;
+	if (width) *width = 0;
+	if (height) *height = 0;
+
+	header.id_length = *(p++);
+	header.colormap_type = *(p++);
+	header.image_type = *(p++);
+
+	header.colormap_index = fgetLittleShort(&p);
+	header.colormap_length = fgetLittleShort(&p);
+	header.colormap_size = *(p++);
+	header.x_origin = fgetLittleShort(&p);
+	header.y_origin = fgetLittleShort(&p);
+	header.width = fgetLittleShort(&p);
+	header.height = fgetLittleShort(&p);
+	header.pixel_size = *(p++);
+	header.attributes = *(p++);
+
+	if ( header.image_type != 2 && header.image_type != 10 ) 
+	{
+		Msg( "LoadTGA: Only type 2 and 10 targa RGB images supported\n" );
+		return false;
+	}
+
+	if ( header.colormap_type !=0 || ( header.pixel_size != 32 && header.pixel_size != 24 ) )
+	{
+		Msg("Texture_LoadTGA: Only 32 or 24 bit images supported (no colormaps)\n");
+		return false;
+	}
+
+	if (width) *width = header.width;
+	if (height) *height = header.height;
+	return true;
+}
+
+
+bool LoadTGA( int32 iBytes, char *pData, byte **rawImage, int * rawImageBytes, int * width, int *height )
+{
+	TargaHeader header;
+	unsigned char *p = (unsigned char *)pData;
+	if (width) *width = 0;
+	if (height) *height = 0;
+
+	header.id_length = *(p++);
+	header.colormap_type = *(p++);
+	header.image_type = *(p++);
+
+	header.colormap_index = fgetLittleShort(&p);
+	header.colormap_length = fgetLittleShort(&p);
+	header.colormap_size = *(p++);
+	header.x_origin = fgetLittleShort(&p);
+	header.y_origin = fgetLittleShort(&p);
+	header.width = fgetLittleShort(&p);
+	header.height = fgetLittleShort(&p);
+	header.pixel_size = *(p++);
+	header.attributes = *(p++);
+
+	if ( header.image_type != 2 && header.image_type != 10 ) 
+	{
+		Msg( "LoadTGA: Only type 2 and 10 targa RGB images supported\n" );
+		return false;
+	}
+
+	if ( header.colormap_type !=0 || ( header.pixel_size != 32 && header.pixel_size != 24 ) )
+	{
+		Msg("Texture_LoadTGA: Only 32 or 24 bit images supported (no colormaps)\n");
+		return false;
+	}
+
+	int columns = header.width;
+	int rows = header.height;
+	int numPixels = columns * rows;
+
+	if (width) *width = header.width;
+	if (height) *height = header.height;
+	if (rawImageBytes) *rawImageBytes = header.width * header.height * 4; 
+
+	*rawImage = new byte[ numPixels * 4 ];
+	byte *pixbuf = *rawImage;
+
+	if ( header.id_length != 0 )
+		p += header.id_length;  // skip TARGA image comment.
+
+	if ( header.image_type == 2 ) {  // Uncompressed, RGB images
+		for(int row = rows - 1; row >=0; row-- ) 
+		{
+			if ( header.attributes & TGA_ATTRIBUTE_VFLIP )
+				pixbuf = *rawImage + (rows-row-1)*columns*4;
+			else
+				pixbuf = *rawImage + row*columns*4;				
+
+			for(int column=0; column < columns; column++) 
+			{
+				unsigned char red,green,blue,alphabyte;
+				switch ( header.pixel_size )
+				{
+					case 24:
+
+						blue = *(p++);
+						green = *(p++);
+						red = *(p++);
+						*pixbuf++ = red;
+						*pixbuf++ = green;
+						*pixbuf++ = blue;
+						*pixbuf++ = 255;
+						break;
+					case 32:
+						blue = *(p++);
+						green = *(p++);
+						red = *(p++);
+						alphabyte = *(p++);
+						*pixbuf++ = red;
+						*pixbuf++ = green;
+						*pixbuf++ = blue;
+						*pixbuf++ = alphabyte;
+						break;
+				}
+			}
+		}
+	}
+	else if ( header.image_type == 10 ) 
+	{   
+		// Runlength encoded RGB images
+		unsigned char red,green,blue,alphabyte,packetHeader,packetSize,j;
+		for( int row = rows - 1; row >= 0; row--) 
+		{
+			if ( header.attributes & TGA_ATTRIBUTE_VFLIP )
+				pixbuf = *rawImage + (rows-row-1)*columns*4;
+			else
+				pixbuf = *rawImage + row*columns*4;
+
+			for( int column=0; column < columns; ) {
+				packetHeader=*(p++);
+				packetSize = 1 + (packetHeader & 0x7f);
+				if (packetHeader & 0x80) {        // run-length packet
+					switch ( header.pixel_size ) 
+					{
+					case 24:
+						blue = *(p++);
+						green = *(p++);
+						red = *(p++);
+						alphabyte = 255;
+						break;
+					case 32:
+					default:
+						blue = *(p++);
+						green = *(p++);
+						red = *(p++);
+						alphabyte = *(p++);
+						break;
+					}
+
+					for(j=0;j<packetSize;j++) 
+					{
+						*pixbuf++=red;
+						*pixbuf++=green;
+						*pixbuf++=blue;
+						*pixbuf++=alphabyte;
+						column++;
+						if (column==columns) { // run spans across rows
+							column=0;
+							if (row>0)
+								row--;
+							else
+								goto breakOut;
+							pixbuf = *rawImage + row*columns*4;
+						}
+					}
+				}
+				else 
+				{                            // non run-length packet
+					for(j=0;j<packetSize;j++) {
+						switch (header.pixel_size) {
+							case 24:
+								blue = *(p++);
+								green = *(p++);
+								red = *(p++);
+								*pixbuf++ = red;
+								*pixbuf++ = green;
+								*pixbuf++ = blue;
+								*pixbuf++ = 255;
+								break;
+							case 32:
+								blue = *(p++);
+								green = *(p++);
+								red = *(p++);
+								alphabyte = *(p++);
+								*pixbuf++ = red;
+								*pixbuf++ = green;
+								*pixbuf++ = blue;
+								*pixbuf++ = alphabyte;
+								break;
+						}
+						column++;
+						if (column==columns) 
+						{ // pixel packet run spans across rows
+							column=0;
+							if (row>0)
+								row--;
+							else
+								goto breakOut;
+							pixbuf = *rawImage + row*columns*4;
+						}						
+					}
+				}
+			}
+breakOut:;
+		}
+	}
+
+	return true;
+}
+
+void WriteTGA( const char *pchFileName, void *rgba, int wide, int tall )
+{
+	_TargaHeader header;
+	memset( &header, 0x0, sizeof(header) );
+	header.width = wide;
+	header.height = tall;
+	header.image_type = 2;
+	header.pixel_size = 32;
+	
+	FILE *fp = fopen( pchFileName, "w+" );
+	fwrite( &header, 1, sizeof(header), fp );
+	fwrite( rgba, 1, wide*tall*4, fp );
+	fclose(fp);
+	
+}
+
+