274 lines
7.5 KiB
C++
274 lines
7.5 KiB
C++
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#include "../precompiled.h"
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#pragma hdrstop
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const float idMath::PI = 3.14159265358979323846f;
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const float idMath::TWO_PI = 2.0f * PI;
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const float idMath::HALF_PI = 0.5f * PI;
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const float idMath::ONEFOURTH_PI = 0.25f * PI;
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const float idMath::E = 2.71828182845904523536f;
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const float idMath::SQRT_TWO = 1.41421356237309504880f;
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const float idMath::SQRT_THREE = 1.73205080756887729352f;
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// RAVEN BEGIN
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const float idMath::THREEFOURTHS_PI = 0.75f * PI;
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// RAVEN END
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const float idMath::SQRT_1OVER2 = 0.70710678118654752440f;
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const float idMath::SQRT_1OVER3 = 0.57735026918962576450f;
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const float idMath::M_DEG2RAD = PI / 180.0f;
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const float idMath::M_RAD2DEG = 180.0f / PI;
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const float idMath::M_SEC2MS = 1000.0f;
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const float idMath::M_MS2SEC = 0.001f;
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const float idMath::INFINITY = 1e30f;
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// RAVEN BEGIN
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// jscott: renamed to prevent name clash
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const float idMath::FLOAT_EPSILON = 1.192092896e-07f;
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// ddynerman: added, from limits.h
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const int idMath::INT_MIN = (-2147483647 - 1);
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const int idMath::INT_MAX = 2147483647;
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// RAVEN END
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bool idMath::initialized = false;
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#ifdef _FAST_MATH
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dword idMath::iSqrt[SQRT_TABLE_SIZE]; // inverse square root lookup table
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#endif
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#ifdef ID_WIN_X86_SSE
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const float idMath::SSE_FLOAT_ZERO = 0.0f;
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const float idMath::SSE_FLOAT_255 = 255.0f;
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#endif
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/*
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===============
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idMath::Init
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===============
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*/
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void idMath::Init( void ) {
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#ifdef _FAST_MATH
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union _flint fi, fo;
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for ( int i = 0; i < SQRT_TABLE_SIZE; i++ ) {
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fi.i = ((EXP_BIAS-1) << EXP_POS) | (i << LOOKUP_POS);
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fo.f = (float)( 1.0 / sqrt( fi.f ) );
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iSqrt[i] = ((dword)(((fo.i + (1<<(SEED_POS-2))) >> SEED_POS) & 0xFF))<<SEED_POS;
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}
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iSqrt[SQRT_TABLE_SIZE / 2] = ((dword)(0xFF))<<(SEED_POS);
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#endif
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initialized = true;
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}
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/*
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================
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idMath::FloatToBits
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================
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*/
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int idMath::FloatToBits( float f, int exponentBits, int mantissaBits ) {
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int i, sign, exponent, mantissa, value;
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assert( exponentBits >= 2 && exponentBits <= 8 );
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assert( mantissaBits >= 2 && mantissaBits <= 23 );
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int maxBits = ( ( ( 1 << ( exponentBits - 1 ) ) - 1 ) << mantissaBits ) | ( ( 1 << mantissaBits ) - 1 );
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int minBits = ( ( ( 1 << exponentBits ) - 2 ) << mantissaBits ) | 1;
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float max = BitsToFloat( maxBits, exponentBits, mantissaBits );
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float min = BitsToFloat( minBits, exponentBits, mantissaBits );
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if ( f >= 0.0f ) {
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if ( f >= max ) {
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return maxBits;
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} else if ( f <= min ) {
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return minBits;
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}
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} else {
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if ( f <= -max ) {
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return ( maxBits | ( 1 << ( exponentBits + mantissaBits ) ) );
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} else if ( f >= -min ) {
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return ( minBits | ( 1 << ( exponentBits + mantissaBits ) ) );
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}
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}
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exponentBits--;
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i = *reinterpret_cast<int *>(&f);
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sign = ( i >> IEEE_FLT_SIGN_BIT ) & 1;
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exponent = ( ( i >> IEEE_FLT_MANTISSA_BITS ) & ( ( 1 << IEEE_FLT_EXPONENT_BITS ) - 1 ) ) - IEEE_FLT_EXPONENT_BIAS;
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mantissa = i & ( ( 1 << IEEE_FLT_MANTISSA_BITS ) - 1 );
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value = sign << ( 1 + exponentBits + mantissaBits );
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value |= ( ( INTSIGNBITSET( exponent ) << exponentBits ) | ( abs( exponent ) & ( ( 1 << exponentBits ) - 1 ) ) ) << mantissaBits;
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value |= mantissa >> ( IEEE_FLT_MANTISSA_BITS - mantissaBits );
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return value;
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}
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/*
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================
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idMath::BitsToFloat
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================
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*/
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float idMath::BitsToFloat( int i, int exponentBits, int mantissaBits ) {
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static int exponentSign[2] = { 1, -1 };
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int sign, exponent, mantissa, value;
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assert( exponentBits >= 2 && exponentBits <= 8 );
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assert( mantissaBits >= 2 && mantissaBits <= 23 );
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exponentBits--;
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sign = i >> ( 1 + exponentBits + mantissaBits );
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exponent = ( ( i >> mantissaBits ) & ( ( 1 << exponentBits ) - 1 ) ) * exponentSign[( i >> ( exponentBits + mantissaBits ) ) & 1];
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mantissa = ( i & ( ( 1 << mantissaBits ) - 1 ) ) << ( IEEE_FLT_MANTISSA_BITS - mantissaBits );
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value = sign << IEEE_FLT_SIGN_BIT | ( exponent + IEEE_FLT_EXPONENT_BIAS ) << IEEE_FLT_MANTISSA_BITS | mantissa;
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return *reinterpret_cast<float *>(&value);
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}
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// RAVEN BEGIN
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// bdube: added block
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void idMath::ArtesianFromPolar( idVec3 &result, idVec3 view )
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{
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float s1, c1, s2, c2;
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idMath::SinCos( view[1], s1, c1 );
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idMath::SinCos( view[2], s2, c2 );
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result[0] = c1 * s2 * view[0];
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result[1] = s1 * s2 * view[0];
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result[2] = c2 * view[0];
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}
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void idMath::PolarFromArtesian( idVec3 &view, idVec3 artesian )
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{
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float length;
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view[0] = artesian.Length();
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view[1] = idMath::ATan( artesian[1], artesian[0] );
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length = sqrtf( ( artesian[0] * artesian[0] ) + ( artesian[1] * artesian[1] ) );
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view[2] = idMath::ATan( length, artesian[2] );
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}
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// ================================================================================================
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// jscott: fast and reliable random routines
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// ================================================================================================
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unsigned long rvRandom::mSeed;
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float rvRandom::flrand( float min, float max )
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{
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float result;
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mSeed = ( mSeed * 214013L ) + 2531011;
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// Note: the shift and divide cannot be combined as this breaks the routine
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result = ( float )( mSeed >> 17 ); // 0 - 32767 range
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result = ( ( result * ( max - min ) ) * ( 1.0f / 32768.0f ) ) + min;
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return( result );
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}
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float rvRandom::flrand() {
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return flrand( 0.0f, 1.0f );
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}
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float rvRandom::flrand( const idVec2& v ) {
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return flrand( v[0], v[1] );
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}
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int rvRandom::irand( int min, int max )
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{
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int result;
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max++;
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mSeed = ( mSeed * 214013L ) + 2531011;
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result = mSeed >> 17;
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result = ( ( result * ( max - min ) ) >> 15 ) + min;
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return( result );
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}
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// Try to get a seed independent of the random number system
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int rvRandom::Init( void )
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{
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mSeed *= ( unsigned long )sys->Milliseconds();
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return( mSeed );
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}
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// ================================================================================================
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// Barycentric texture coordinate functions
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// Get the *SIGNED* area of a triangle required for barycentric
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// ================================================================================================
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float idMath::BarycentricTriangleArea( const idVec3 &normal, const idVec3 &a, const idVec3 &b, const idVec3 &c )
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{
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idVec3 v1, v2;
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idVec3 cross;
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float area;
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v1 = b - a;
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v2 = c - a;
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cross = v1.Cross( v2 );
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area = 0.5f * DotProduct( cross, normal );
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return( area );
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}
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void idMath::BarycentricEvaluate( idVec2 &result, const idVec3 &point, const idVec3 &normal, const float area, const idVec3 t[3], const idVec2 tc[3] )
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{
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float b1, b2, b3;
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b1 = idMath::BarycentricTriangleArea( normal, point, t[1], t[2] ) / area;
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b2 = idMath::BarycentricTriangleArea( normal, t[0], point, t[2] ) / area;
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b3 = idMath::BarycentricTriangleArea( normal, t[0], t[1], point ) / area;
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result[0] = ( b1 * tc[0][0] ) + ( b2 * tc[1][0] ) + ( b3 * tc[2][0] );
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result[1] = ( b1 * tc[0][1] ) + ( b2 * tc[1][1] ) + ( b3 * tc[2][1] );
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}
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// abahr:
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float idMath::Lerp( const idVec2& range, float frac ) {
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return Lerp( range[0], range[1], frac );
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}
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// abahr:
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float idMath::Lerp( float start, float end, float frac ) {
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if( frac >= 1.0f ) {
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return end;
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}
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if( frac <= 0.0f ) {
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return start;
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}
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return start + (end - start) * frac;
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}
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// abahr:
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float idMath::MidPointLerp( float start, float mid, float end, float frac ) {
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if( frac < 0.5f ) {
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return Lerp( start, mid, 2.0f * frac );
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}
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return Lerp( mid, end, 2.0f * (frac - 0.5f) );
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}
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float idMath::dBToScale( float db ) {
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if( db < -60.0f ) {
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return( 0.0f );
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} else {
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return( powf( 2.0f, db * ( 1.0f / 6.0f ) ) );
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}
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}
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float idMath::ScaleToDb( float scale ) {
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if( scale <= 0.0f ) {
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return( -60.0f );
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} else {
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return( 6.0f * idMath::Log( scale ) / idMath::Log( 2 ) );
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}
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}
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// RAVEN END
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