diff --git a/tools/quake3/q3map2/image.c b/tools/quake3/q3map2/image.c
index 7ce08aa..6d12a67 100644
--- a/tools/quake3/q3map2/image.c
+++ b/tools/quake3/q3map2/image.c
@@ -177,10 +177,12 @@ static void LoadPNGBuffer( byte *buffer, int size, byte **pixels, int *width, in
 	pb.size = size;
 	pb.offset = 0;
 	png_set_read_fn( png, &pb, PNGReadData );
+#if 0
 	png->io_ptr = &pb; /* hack! */
+#endif
 	
 	/* set error longjmp */
-	if( setjmp( png->jmpbuf ) )
+	if( setjmp( png_jmpbuf(png) ) )
 	{
 		Sys_Printf( "WARNING: An error occurred reading PNG image\n" );
 		png_destroy_read_struct( &png, &info, &end );
diff --git a/tools/quake3/q3map2/light.c b/tools/quake3/q3map2/light.c
index 5d5dfc5..693ee09 100644
--- a/tools/quake3/q3map2/light.c
+++ b/tools/quake3/q3map2/light.c
@@ -2755,6 +2755,11 @@ int LightMain( int argc, char **argv )
 			Sys_Printf( "Filling lightmap colors from surrounding pixels to improve JPEG compression\n" );
 		}
 		/* unhandled args */
+		else if( !strcmp( argv[ i ], "-exporthdr" ) )
+		{
+			exporthdr = qtrue;
+			Sys_Printf( "Exporting hdr lightmaps\n" );
+		}
 		else
 		{
 			Sys_Printf( "WARNING: Unknown argument \"%s\"\n", argv[ i ] );
diff --git a/tools/quake3/q3map2/light_bounce.c b/tools/quake3/q3map2/light_bounce.c
index 0e59dde..a051f24 100644
--- a/tools/quake3/q3map2/light_bounce.c
+++ b/tools/quake3/q3map2/light_bounce.c
@@ -389,14 +389,19 @@ static void RadSample( int lightmapNum, bspDrawSurface_t *ds, rawLightmap_t *lm,
 	/* create the color gradient */
 	//%	VectorSubtract( maxs, mins, delta );
 	
-	/* new: color gradient will always be 0-1.0, expressed as the range of light relative to overall light */
-	//%	gradient[ 0 ] = maxs[ 0 ] > 0.0f ? (maxs[ 0 ] - mins[ 0 ]) / maxs[ 0 ] : 0.0f;
-	//%	gradient[ 1 ] = maxs[ 1 ] > 0.0f ? (maxs[ 1 ] - mins[ 1 ]) / maxs[ 1 ] : 0.0f;
-	//%	gradient[ 2 ] = maxs[ 2 ] > 0.0f ? (maxs[ 2 ] - mins[ 2 ]) / maxs[ 2 ] : 0.0f;
-	
-	/* newer: another contrast function */
-	for( i = 0; i < 3; i++ )
-		gradient[ i ] = (maxs[ i ] - mins[ i ]) * maxs[ i ];
+	if (exporthdr)
+	{
+		/* new: color gradient will always be 0-1.0, expressed as the range of light relative to overall light */
+		gradient[ 0 ] = maxs[ 0 ] > 0.0f ? (maxs[ 0 ] - mins[ 0 ]) / maxs[ 0 ] : 0.0f;
+		gradient[ 1 ] = maxs[ 1 ] > 0.0f ? (maxs[ 1 ] - mins[ 1 ]) / maxs[ 1 ] : 0.0f;
+		gradient[ 2 ] = maxs[ 2 ] > 0.0f ? (maxs[ 2 ] - mins[ 2 ]) / maxs[ 2 ] : 0.0f;
+	}
+	else
+	{
+		/* newer: another contrast function */
+		for( i = 0; i < 3; i++ )
+			gradient[ i ] = (maxs[ i ] - mins[ i ]) * maxs[ i ];
+	}
 }
 
 
diff --git a/tools/quake3/q3map2/light_ydnar.c b/tools/quake3/q3map2/light_ydnar.c
index f291e7a..91547be 100644
--- a/tools/quake3/q3map2/light_ydnar.c
+++ b/tools/quake3/q3map2/light_ydnar.c
@@ -128,6 +128,51 @@ void ColorToBytes( const float *color, byte *colorBytes, float scale )
 }
 
 
+/*
+ColorToRGBE()
+Tr3B: standard conversion from float pixels to rgbe pixels
+*/
+
+void ColorToRGBE(const float *color, unsigned char rgbe[4])
+{
+	vec3_t          sample;
+	float			maxComponent;
+	int				e;
+
+	VectorCopy(color, sample);
+
+	maxComponent = sample[0];
+	if(sample[1] > maxComponent)
+		maxComponent = sample[1];
+	if(sample[2] > maxComponent)
+		maxComponent = sample[2];
+
+	if(maxComponent < 1e-32)
+	{
+		rgbe[0] = 0;
+		rgbe[1] = 0;
+		rgbe[2] = 0;
+		rgbe[3] = 0;
+	}
+	else
+	{
+#if 1
+		maxComponent = frexp(maxComponent, &e) * 255.0 / maxComponent;
+		rgbe[0] = (unsigned char) (sample[0] * maxComponent);
+		rgbe[1] = (unsigned char) (sample[1] * maxComponent);
+		rgbe[2] = (unsigned char) (sample[2] * maxComponent);
+		rgbe[3] = (unsigned char) (e + 128);
+#else
+		e = ceil(log2(maxComponent));
+		VectorScale(sample, 1.0 / exp2(e), sample);
+
+		rgbe[0] = (unsigned char) (sample[0] * 255);
+		rgbe[1] = (unsigned char) (sample[1] * 255);
+		rgbe[2] = (unsigned char) (sample[2] * 255);
+		rgbe[3] = (unsigned char) (e + 128);
+#endif
+	}
+}
 
 /* -------------------------------------------------------------------------------
 
diff --git a/tools/quake3/q3map2/lightmaps_ydnar.c b/tools/quake3/q3map2/lightmaps_ydnar.c
index 5c53405..b23ad6a 100644
--- a/tools/quake3/q3map2/lightmaps_ydnar.c
+++ b/tools/quake3/q3map2/lightmaps_ydnar.c
@@ -37,6 +37,7 @@ several games based on the Quake III Arena engine, in the form of "Q3Map2."
 #include "q3map2.h"
 
 
+#define USE_HDR_LIGHTMAPS
 
 
 /* -------------------------------------------------------------------------------
@@ -105,9 +106,66 @@ void WriteTGA24( char *filename, byte *data, int width, int height, qboolean fli
 	free( buffer );
 }
 
+// ================================================================
+
 
 
 /*
+WriteRGBE()
+*/
+
+void WriteRGBE(char *filename, float * data, int width, int height)
+{
+	int             i, c;
+	FILE           *file;
+	unsigned char   rgbe[4];
+	float			rgb[3];
+
+	file = fopen(filename, "wb");
+	if(file == NULL)
+		Error("Unable to open %s for writing", filename);
+
+
+	// write header
+	if(fprintf(file,"#?RGBE\n") < 0)
+		Error("RGBE write error: %s", filename);
+
+	if(fprintf(file,"# Generated by ETXMap \n") < 0)
+			Error("RGBE write error: %s", filename);
+
+	if(fprintf(file, "FORMAT=32-bit_rle_rgbe\n\n") < 0)
+		Error("RGBE write error: %s", filename);
+
+	if(fprintf(file, "-Y %d +X %d\n", height, width) < 0)
+		Error("RGBE write error: %s", filename);
+
+	c = (width * height * 3);
+	for(i = 0; i < c; i += 3)
+	{
+#if 0
+		// FIXME XMap2's output is 255 times too high
+		rgb[0] = data[i + 0] / 255.0f;
+		rgb[1] = data[i + 1] / 255.0f;
+		rgb[2] = data[i + 2] / 255.0f;
+
+		ColorToRGBE(rgb, rgbe);
+		if(fwrite(rgbe, sizeof(rgbe), 1, file) < 1)
+			Error("RGBE write error: %s", filename);
+#else
+		rgb[0] = data[i + 0];
+		rgb[1] = data[i + 1];
+		rgb[2] = data[i + 2];
+
+		if(fwrite(rgb, sizeof(rgb), 1, file) < 1)
+			Error("RGBE write error: %s", filename);
+#endif
+	}
+
+	// close the file
+	fclose(file);
+}
+
+/*
 ExportLightmaps()
 exports the lightmaps as a list of numbered tga images
 */
@@ -1897,8 +1955,22 @@ static void SetupOutLightmap( rawLightmap_t *lm, outLightmap_t *olm )
 	/* allocate buffers */
 	olm->lightBits = safe_malloc( (olm->customWidth * olm->customHeight / 8) + 8 );
 	memset( olm->lightBits, 0, (olm->customWidth * olm->customHeight / 8) + 8 );
+
 	olm->bspLightBytes = safe_malloc( olm->customWidth * olm->customHeight * 3 );
 	memset( olm->bspLightBytes, 0, olm->customWidth * olm->customHeight * 3 );
+
+#if defined(USE_HDR_LIGHTMAPS)
+	if(exporthdr)
+	{
+		olm->bspLightFloats = safe_malloc(olm->customWidth * olm->customHeight * 3 * sizeof(float));
+		memset(olm->bspLightFloats, 0, olm->customWidth * olm->customHeight * 3 * sizeof(float));
+	}
+	else
+#endif
+	{
+		olm->bspLightFloats = NULL;
+	}
+
 	if( deluxemap )
 	{
 		olm->bspDirBytes = safe_malloc( olm->customWidth * olm->customHeight * 3 );
@@ -2183,6 +2255,17 @@ static void FindOutLightmaps( rawLightmap_t *lm )
 				/* store color */
 				pixel = olm->bspLightBytes + (((oy * olm->customWidth) + ox) * 3);
 				ColorToBytes( color, pixel, lm->brightness );
+#if defined(USE_HDR_LIGHTMAPS)
+				if(exporthdr)
+				{
+					float		*hdrPixel;
+
+					hdrPixel = olm->bspLightFloats + (((oy * olm->customWidth) + ox) * 3);
+
+					// FIXME gamma
+					VectorScale(color, lm->brightness <= 0.0f ? 1.0f : lm->brightness, hdrPixel);
+				}
+#endif
 				
 				/* store direction */
 				if( deluxemap )
@@ -2971,6 +3054,13 @@ void StoreSurfaceLightmaps( void )
 		{
 			free( outLightmaps[ i ].lightBits );
 			free( outLightmaps[ i ].bspLightBytes );
+#if defined(USE_HDR_LIGHTMAPS)
+			if(exporthdr)
+			{
+				free(outLightmaps[i].bspLightFloats);
+			}
+#endif
+
 		}
 		free( outLightmaps );
 		outLightmaps = NULL;
@@ -3014,6 +3104,20 @@ void StoreSurfaceLightmaps( void )
 	   store output lightmaps
 	   ----------------------------------------------------------------- */
 	
+	/* delete old conflicting external lightmaps */
+	// FIXME scan for all lightmaps
+	for(i = 0; i < (numOutLightmaps * 2); i++)
+	{
+		/* determine if file exists */
+		sprintf(filename, "%s/" EXTERNAL_LIGHTMAP, dirname, i);
+		if(FileExists(filename))
+			remove(filename);
+
+		sprintf(filename, "%s/" EXTERNAL_HDRLIGHTMAP, dirname, i);
+		if(FileExists(filename))
+			remove(filename);
+	}
+
 	/* note it */
 	Sys_Printf( "storing..." );
 	
@@ -3070,6 +3174,15 @@ void StoreSurfaceLightmaps( void )
 			sprintf( filename, "%s/" EXTERNAL_LIGHTMAP, dirname, numExtLightmaps );
 			Sys_FPrintf( SYS_VRB, "\nwriting %s", filename );
 			WriteTGA24( filename, olm->bspLightBytes, olm->customWidth, olm->customHeight, qtrue );
+
+#if defined(USE_HDR_LIGHTMAPS)
+			if(exporthdr)
+			{
+				sprintf(filename, "%s/" EXTERNAL_HDRLIGHTMAP, dirname, numExtLightmaps);
+				Sys_FPrintf(SYS_VRB, "\nwriting %s", filename);
+				WriteRGBE(filename, olm->bspLightFloats, olm->customWidth, olm->customHeight);
+			}
+#endif
 			numExtLightmaps++;
 			
 			/* write deluxemap */
@@ -3084,6 +3197,20 @@ void StoreSurfaceLightmaps( void )
 					olm->extLightmapNum++;
 			}
 		}
+
+#if defined(USE_HDR_LIGHTMAPS)
+		/* HDR lightmaps are always exported */
+		if (exporthdr && !externalLightmaps && olm->lightmapNum >= 0)
+		{
+			/* make a directory for the lightmaps */
+			Q_mkdir( dirname );
+
+			sprintf(filename, "%s/" EXTERNAL_HDRLIGHTMAP, dirname, olm->lightmapNum);
+			Sys_FPrintf(SYS_VRB, "\nwriting %s", filename);
+			WriteRGBE(filename, olm->bspLightFloats, olm->customWidth, olm->customHeight);
+		}
+#endif		
+
 	}
 	
 	if( numExtLightmaps > 0 )
@@ -3093,12 +3220,15 @@ void StoreSurfaceLightmaps( void )
 	for( i = numExtLightmaps; i; i++ )
 	{
 		/* determine if file exists */
-		sprintf( filename, "%s/" EXTERNAL_LIGHTMAP, dirname, i );
-		if( !FileExists( filename ) )
+		sprintf(filename, "%s/" EXTERNAL_HDRLIGHTMAP, dirname, i);
+		if(FileExists(filename))
+			remove(filename);
+ 		
+		sprintf(filename, "%s/" EXTERNAL_LIGHTMAP, dirname, i);
+		if(FileExists(filename))
+			remove( filename );
+		else
 			break;
-		
-		/* delete it */
-		remove( filename );
 	}
 	
 	/* -----------------------------------------------------------------
diff --git a/tools/quake3/q3map2/q3map2.h b/tools/quake3/q3map2/q3map2.h
index e912d15..03a5bd1 100644
--- a/tools/quake3/q3map2/q3map2.h
+++ b/tools/quake3/q3map2/q3map2.h
@@ -306,6 +306,7 @@ abstracted bsp file
 ------------------------------------------------------------------------------- */
 
 #define EXTERNAL_LIGHTMAP		"lm_%04d.tga"
+#define EXTERNAL_HDRLIGHTMAP		"lm_%04d.hdr"
 
 #define MAX_LIGHTMAPS			4			/* RBSP */
 #define MAX_LIGHT_STYLES		64
@@ -1427,6 +1428,7 @@ typedef struct outLightmap_s
 	shaderInfo_t		*shaders[ MAX_LIGHTMAP_SHADERS ];
 	byte				*lightBits;
 	byte				*bspLightBytes;
+	float				*bspLightFloats;
 	byte				*bspDirBytes;
 }
 outLightmap_t;
@@ -2220,6 +2222,8 @@ Q_EXTERN qboolean			deluxemap Q_ASSIGN( qfalse );
 Q_EXTERN qboolean			debugDeluxemap Q_ASSIGN( qfalse );
 Q_EXTERN int				deluxemode Q_ASSIGN( 0 );	/* deluxemap format (0 - modelspace, 1 - tangentspace with renormalization, 2 - tangentspace without renormalization) */
 
+Q_EXTERN qboolean			exporthdr Q_ASSIGN( qfalse );
+
 Q_EXTERN qboolean			fast Q_ASSIGN( qfalse );
 Q_EXTERN qboolean			faster Q_ASSIGN( qfalse );
 Q_EXTERN qboolean			fastgrid Q_ASSIGN( qfalse );