1 files changed, 79 insertions, 0 deletions
diff --git a/unittests/mathlib_test/mathlib_test.cpp b/unittests/mathlib_test/mathlib_test.cpp
new file mode 100644
index 0000000..c3c1191
--- /dev/null
+++ b/unittests/mathlib_test/mathlib_test.cpp
@@ -0,0 +1,79 @@
+//========= Copyright Valve Corporation, All rights reserved. ============//
+#include "tier0/platform.h"
+#include "mathlib/mathlib.h"
+#include "mathlib/spherical_geometry.h"
+#include "tier2/tier2.h"
+#include "mathlib/halton.h"
+#include "bitmap/float_bm.h"
+#include "tier0/memdbgon.h"
+
+void main(int argc,char **argv)
+{
+	InitCommandLineProgram( argc, argv );
+
+	// 1/8th of the sphere
+	float a1=UnitSphereTriangleArea( Vector( 1, 0, 0 ), Vector( 0, 0, -1 ), Vector( 0, 1, 0 ) );
+	printf( "right spherical triangle projected percentage=%2.4f\n", a1 / ( 4 * M_PI ));
+
+	// a small one
+	Vector v1 = Vector( 1, 0, 0 );
+	Vector v2 = v1 + Vector( 0, 0.2, 0 );
+	Vector v3 = v1 + Vector( 0, 0, 0.2 );
+	v2.NormalizeInPlace();
+	v3.NormalizeInPlace();
+	float a2=UnitSphereTriangleArea( v1, v2, v3 );
+	printf( "small spherical triangle projected percentage=%2.5f\n", a2 / ( 4* M_PI ) );
+
+	// now, create a cubemap and sum the area of each of its cells
+	FloatCubeMap_t envMap( 10, 10 );
+	float flAreaSum = 0.;
+	for( int nFace = 0 ; nFace < 6; nFace ++ )
+	{
+		for( int nY = 0 ; nY < 9; nY++ )
+			for( int nX = 0 ; nX < 9; nX++ )
+			{
+				Vector v00 = envMap.PixelDirection( nFace, nX, nY );
+				Vector v01 = envMap.PixelDirection( nFace, nX, nY + 1  );
+				Vector v10 = envMap.PixelDirection( nFace, nX + 1, nY );
+				Vector v11 = envMap.PixelDirection( nFace, nX + 1 , nY + 1 );
+				v00.NormalizeInPlace();
+				v01.NormalizeInPlace();
+				v10.NormalizeInPlace();
+				v11.NormalizeInPlace();
+				flAreaSum += UnitSphereTriangleArea( v00, v01, v10 );
+				flAreaSum += UnitSphereTriangleArea( v10, v11, v01 );
+			}
+	}
+	printf( "sum of areas of cubemap cells = %2.2f\n", flAreaSum / ( 4.0 * M_PI ) );
+	
+#if 0  // visual spherical harmonics as (confusing) point sets
+	// spherical harmonics
+	DirectionalSampler_t sampler;
+	for(int i = 0 ; i < 50000; i++ )
+	{
+		Vector dir=sampler.NextValue();
+		float SH = SphericalHarmonic( 4, 3, dir );
+		float r=0;
+		float g=1; //0.5+0.5*DotProduct( dir, Vector( 0, 0, 1 ) );
+		float b=0;
+		if ( SH < 0 )
+		{
+			SH = -SH;
+			r=g;
+			g=0;
+		}
+		r *= SH;
+		g *= SH;
+		b *= SH;
+		float rad= SH * 4.0; //4.0; //SH *= 8.0;
+		printf( "2\n" );
+		printf( "%f %f %f %f %f %f\n",
+				dir.x * rad, dir.y * rad, dir.z * rad, r, g, b );
+		rad += 0.03;
+		printf( "%f %f %f %f %f %f\n",
+				dir.x * rad, dir.y * rad, dir.z * rad, r, g, b );
+	}
+#endif
+
+}
+