1

bitmap/float_bm2.cpp

@@ -0,0 +1,144 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+//===========================================================================//
+
+#include <tier0/platform.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#include <stdlib.h>
+#include "bitmap/float_bm.h"
+
+
+static float ScaleValue(float f, float overbright)
+{
+	// map a value between 0..255 to the scale factor
+	int ival=f;
+	return ival*(overbright/255.0);
+}
+
+static float IScaleValue(float f, float overbright)
+{
+	f*=(1.0/overbright);
+	int ival=min(255,(int)ceil(f*255.0));
+	return ival;
+}
+
+void MaybeSetScaleVaue(FloatBitMap_t const &orig, FloatBitMap_t &newbm, int x, int y, 
+					   float newscale, float overbright)
+{
+	// clamp the given scale value to the legal range for that pixel and regnerate the rgb
+	// components.
+	float maxc=max(max(orig.Pixel(x,y,0),orig.Pixel(x,y,1)),orig.Pixel(x,y,2));
+	if (maxc==0.0)
+	{
+		// pixel is black. any scale value is fine.
+		newbm.Pixel(x,y,3)=newscale;
+		for(int c=0;c<3;c++)
+			newbm.Pixel(x,y,c)=0;
+	}
+	else
+	{
+//		float desired_floatscale=maxc;
+		float scale_we_will_get=ScaleValue(newscale,overbright);
+//		if (scale_we_will_get >= desired_floatscale )
+		{
+			newbm.Pixel(x,y,3)=newscale;
+			for(int c=0;c<3;c++)
+				newbm.Pixel(x,y,c)=orig.Pixel(x,y,c)/(scale_we_will_get);
+		}
+	}
+}
+
+
+void FloatBitMap_t::Uncompress(float overbright)
+{
+	for(int y=0;y<Height;y++)
+		for(int x=0;x<Width;x++)
+		{
+			int iactual_alpha_value=255.0*Pixel(x,y,3);
+			float actual_alpha_value=iactual_alpha_value*(1.0/255.0);
+			for(int c=0;c<3;c++)
+			{
+				int iactual_color_value=255.0*Pixel(x,y,c);
+				float actual_color_value=iactual_color_value*(1.0/255.0);
+				Pixel(x,y,c)=actual_alpha_value*actual_color_value*overbright;
+			}
+		}
+}
+
+#define GAUSSIAN_WIDTH 5
+#define SQ(x) ((x)*(x))
+
+void FloatBitMap_t::CompressTo8Bits(float overbright)
+{
+	FloatBitMap_t TmpFBM(Width,Height);
+	// first, saturate to max overbright
+	for(int y=0;y<Height;y++)
+		for(int x=0;x<Width;x++)
+			for(int c=0;c<3;c++)
+				Pixel(x,y,c)=min(overbright,Pixel(x,y,c));
+	// first pass - choose nominal scale values to convert to rgb,scale
+	for(int y=0;y<Height;y++)
+		for(int x=0;x<Width;x++)
+		{
+			// determine maximum component
+			float maxc=max(max(Pixel(x,y,0),Pixel(x,y,1)),Pixel(x,y,2));
+			if (maxc==0)
+			{
+				for(int c=0;c<4;c++)
+					TmpFBM.Pixel(x,y,c)=0;
+			}
+			else
+			{
+				float desired_floatscale=maxc;
+				float closest_iscale=IScaleValue(desired_floatscale, overbright);
+				float scale_value_we_got=ScaleValue(closest_iscale, overbright );
+				TmpFBM.Pixel(x,y,3)=closest_iscale;
+				for(int c=0;c<3;c++)
+					TmpFBM.Pixel(x,y,c)=Pixel(x,y,c)/scale_value_we_got;
+			}
+		}
+	// now, refine scale values
+#ifdef FILTER_TO_REDUCE_LERP_ARTIFACTS
+// I haven't been able to come up with a filter which eleiminates objectionable artifacts on all
+// source textures. So, I've gone to doing the lerping in the shader.
+	int pass=0;
+	while(pass<1)
+	{
+		FloatBitMap_t temp_filtered(&TmpFBM);
+		for(int y=0;y<Height;y++)
+		{
+			for(int x=0;x<Width;x++)
+			{
+				float sum_scales=0.0;
+				float sum_weights=0.0;
+				for(int yofs=-GAUSSIAN_WIDTH;yofs<=GAUSSIAN_WIDTH;yofs++)
+					for(int xofs=-GAUSSIAN_WIDTH;xofs<=GAUSSIAN_WIDTH;xofs++)
+					{
+						float r=0.456*GAUSSIAN_WIDTH;
+						r=0.26*GAUSSIAN_WIDTH;
+						float x1=xofs/r;
+						float y1=yofs/r;
+						float a=(SQ(x1)+SQ(y1))/(2.0*SQ(r));
+						float w=exp(-a);
+						sum_scales+=w*TmpFBM.PixelClamped(x+xofs,y+yofs,3);
+						sum_weights+=w;
+					}
+				int new_trial_scale=sum_scales*(1.0/sum_weights);
+				MaybeSetScaleVaue(*this,temp_filtered,x,y,new_trial_scale,overbright);
+			}
+		}
+		pass++;
+		memcpy(TmpFBM.RGBAData,temp_filtered.RGBAData,Width*Height*4*sizeof(float));
+	}
+#endif
+
+	memcpy(RGBAData,TmpFBM.RGBAData,Width*Height*4*sizeof(float));
+	// now, map scale to real value
+	for(int y=0;y<Height;y++)
+		for(int x=0;x<Width;x++)
+			Pixel(x,y,3)*=(1.0/255.0);
+}