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