From 3bf9df6b2785fa6d951086978a3e66f49427166a Mon Sep 17 00:00:00 2001
From: FluorescentCIAAfricanAmerican <0934gj3049fk@protonmail.com>
Date: Wed, 22 Apr 2020 12:56:21 -0400
Subject: 1

---
 bitmap/float_cube.cpp | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 bitmap/float_cube.cpp

(limited to 'bitmap/float_cube.cpp')

diff --git a/bitmap/float_cube.cpp b/bitmap/float_cube.cpp
new file mode 100644
index 0000000..df7726a
--- /dev/null
+++ b/bitmap/float_cube.cpp
@@ -0,0 +1,119 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+#include <tier0/platform.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#include <stdlib.h>
+#include "bitmap/float_bm.h"
+#include <filesystem.h>
+#include <mathlib/vector.h>
+
+static Vector face_xvector[6]={								// direction of x pixels on face
+	Vector(-1,0,0),											// back
+	Vector(1,0,0),											// down
+	Vector(1,0,0),											// front
+	Vector(0,1,0),											// left
+	Vector(0,-1,0),											// right
+	Vector(1,0,0)											// up
+};
+
+static Vector face_yvector[6]={								// direction of y pixels on face
+	Vector(0,0,-1),											// back
+	Vector(0,1,0),											// down
+	Vector(0,0,-1),											// front
+	Vector(0,0,-1),											// left
+	Vector(0,0,-1),											// right
+	Vector(0,-1,0)											// up
+};
+
+
+static Vector face_zvector[6]={
+	Vector(1,1,1),											// back
+	Vector(-1,-1,-1),										// down
+	Vector(-1,-1,1),										// front
+	Vector(1,-1,1),											// left
+	Vector(-1,1,1),											// right
+	Vector(-1,1,1)											// up
+};
+
+
+static char const *namepts[6]={"%sbk.pfm","%sdn.pfm","%sft.pfm","%slf.pfm","%srt.pfm","%sup.pfm"};
+
+FloatCubeMap_t::FloatCubeMap_t(char const *basename)
+{
+	for(int f=0;f<6;f++)
+	{
+		char fnamebuf[512];
+		sprintf(fnamebuf,namepts[f],basename);
+		face_maps[f].LoadFromPFM(fnamebuf);
+	}
+}
+
+void FloatCubeMap_t::WritePFMs(char const *basename)
+{
+	for(int f=0;f<6;f++)
+	{
+		char fnamebuf[512];
+		sprintf(fnamebuf,namepts[f],basename);
+		face_maps[f].WritePFM(fnamebuf);
+	}
+}
+
+Vector FloatCubeMap_t::PixelDirection(int face, int x, int y)
+{
+	FloatBitMap_t const &bm=face_maps[face];
+	float xc=x*1.0/(bm.Width-1);
+	float yc=y*1.0/(bm.Height-1);
+	Vector dir=2*xc*face_xvector[face]+
+			2*yc*face_yvector[face]+face_zvector[face];
+	VectorNormalize(dir);
+	return dir;
+}
+
+Vector FloatCubeMap_t::FaceNormal(int face)
+{
+	float xc=0.5;
+	float yc=0.5;
+	Vector dir=2*xc*face_xvector[face]+
+			2*yc*face_yvector[face]+face_zvector[face];
+	VectorNormalize(dir);
+	return dir;
+}
+
+void FloatCubeMap_t::Resample( FloatCubeMap_t &out, float flPhongExponent )
+{
+	// terribly slow brute force algorithm just so I can try it out
+	for(int dface=0;dface<6;dface++)
+	{
+		for(int dy=0;dy<out.face_maps[dface].Height;dy++)
+			for(int dx=0;dx<out.face_maps[dface].Width;dx++)
+			{
+				float sum_weights=0;
+				float sum_rgb[3]={0,0,0};
+				for(int sface=0;sface<6;sface++)
+				{
+					// easy 15% optimization - check if faces point away from each other
+					if (DotProduct(FaceNormal(sface),FaceNormal(sface))>-0.9)
+					{
+						Vector ddir=out.PixelDirection(dface,dx,dy);
+						for(int sy=0;sy<face_maps[sface].Height;sy++)
+							for(int sx=0;sx<face_maps[sface].Width;sx++)
+							{
+								float dp=DotProduct(ddir,PixelDirection(sface,sx,sy));
+								if (dp>0.0)
+								{
+									dp=pow( dp, flPhongExponent );
+									sum_weights += dp;
+									for(int c=0;c<3;c++)
+										sum_rgb[c] += dp*face_maps[sface].Pixel( sx, sy, c );
+								}
+							}
+					}
+				}
+				for(int c=0;c<3;c++)
+					out.face_maps[dface].Pixel( dx, dy, c )=sum_rgb[c]*(1.0/sum_weights);
+			}
+	}
+}
+
+						
-- 
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