1 files changed, 103 insertions, 0 deletions
diff --git a/utils/dist2alpha/dist2alpha.cpp b/utils/dist2alpha/dist2alpha.cpp
new file mode 100644
index 0000000..a6e6f90
--- /dev/null
+++ b/utils/dist2alpha/dist2alpha.cpp
@@ -0,0 +1,103 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+#include "tier0/platform.h"
+#include "tier0/progressbar.h"
+#include "bitmap/float_bm.h"
+#include "mathlib/mathlib.h"
+#include "tier2/tier2.h"
+#include "tier0/memdbgon.h"
+
+#define SQ(x) ((x)*(x))
+
+int main( int argc, char ** argv )
+{
+	InitCommandLineProgram( argc, argv );
+
+	int nCurArg = 1;
+	float flSpread = 1.0;
+
+	bool bCodeChannel[4];
+	bCodeChannel[0] = false;
+	bCodeChannel[1] = false;
+	bCodeChannel[2] = false;
+	bCodeChannel[3] = true;
+
+	while (( nCurArg < argc ) && ( argv[nCurArg][0] == '-' ) )
+	{
+		switch( argv[nCurArg][1] )
+		{
+			case 's':										// spread
+			{
+				flSpread = atof( argv[++nCurArg] );
+			}
+			break;
+
+			case '4':										// encode all 4 channels
+			{
+				bCodeChannel[0] = true;
+				bCodeChannel[1] = true;
+				bCodeChannel[2] = true;
+			}
+			break;
+
+				
+			default:
+				printf("unrecogized option %s\n", argv[nCurArg] );
+				exit(1);
+		}
+		nCurArg++;
+		
+	}
+	argc -= ( nCurArg - 1 );
+	argv += ( nCurArg - 1 );
+
+	if ( argc != 5 )
+	{
+		printf( "format is dist2alpha src_bm.tga dest_bm.tga dest_width dest_height\n" );
+		exit( 1 );
+	}
+	FloatBitMap_t hires_image( argv[1] );
+	int out_w = atoi( argv[3] );
+	int out_h = atoi( argv[4] );
+	FloatBitMap_t lores( out_w, out_h );
+
+	float max_rad = 2.0 * flSpread * max( hires_image.Width * ( 1.0 / out_w ), hires_image.Height * ( 1.0 / out_h ));
+	int irad = ceil( max_rad );
+	for( int comp = 0;comp < 4;comp ++ )
+	{
+		for( int y = 0;y < out_h;y ++ )
+			for( int x = 0;x < out_w;x ++ )
+			{
+				int orig_x = FLerp( 0, hires_image.Width - 1, 0, out_w - 1, x );
+				int orig_y = FLerp( 0, hires_image.Height - 1, 0, out_h - 1, y );
+				if ( bCodeChannel[ comp ] )
+				{
+					float closest_dist = 100000;
+					int inside_test = ( hires_image.Pixel( orig_x, orig_y, comp ) >.9 );
+					for( int oy =- irad;oy <= irad;oy ++ )
+						for( int ox =- irad;ox <= irad;ox ++ )
+						{
+							int x1 = orig_x + ox;
+							int y1 = orig_y + oy;
+							if ( ( x1 >= 0 ) && ( x1 < hires_image.Width ) && ( y1 >= 0 ) && ( y1 < hires_image.Height ) &&
+								 ( inside_test != ( hires_image.Pixel( orig_x + ox, orig_y + oy, comp ) >.9 )) )
+							{
+								float d2 = sqrt( (float ) ( SQ( ox ) + SQ( oy )) );
+								if ( d2 < closest_dist )
+									closest_dist = d2;
+							}
+						}
+					// done
+					float dnum = min( 0.5f, FLerp( 0, .5, 0, max_rad, closest_dist ));
+					if ( !inside_test )
+						dnum =- dnum;
+					lores.Pixel( x, y, comp ) = 0.5 + dnum;
+				}
+				else
+					lores.Pixel( x, y, comp ) = hires_image.Pixel( orig_x, orig_y, comp );
+			}
+	}
+
+	lores.WriteTGAFile( argv[2] );
+	return 0;
+
+}