102 lines
3.1 KiB
C++
102 lines
3.1 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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// Copyright (C) Microsoft Corporation, 2000.
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//
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// refrasti.hpp
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//
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// Direct3D Reference Device - Main Internal Header File
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//
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///////////////////////////////////////////////////////////////////////////////
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#ifndef _REFRASTI_HPP
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#define _REFRASTI_HPP
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///////////////////////////////////////////////////////////////////////////////
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// //
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// Texture Mapping Utility Functions //
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// //
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///////////////////////////////////////////////////////////////////////////////
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//
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// various approximations and tricks to speed up the texture map coverage
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// computations
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//
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// Integer value of first exponent bit in a float. Provides a scaling factor
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// for exponent values extracted directly from float representation.
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#define FLOAT_EXPSCALE ((FLOAT)0x00800000)
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#define FLOAT_OOEXPSCALE ((FLOAT)(1.0 / (double)FLOAT_EXPSCALE))
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// Integer representation of 1.0f.
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#define INT32_FLOAT_ONE 0x3f800000
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static inline FLOAT
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RR_LOG2(FLOAT f)
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{
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return (FLOAT)(AS_INT32(f) - INT32_FLOAT_ONE) * FLOAT_OOEXPSCALE;
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}
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static inline FLOAT
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RR_ALOG2(FLOAT f)
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{
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INT32 i = (INT32)(f * FLOAT_EXPSCALE) + INT32_FLOAT_ONE;
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return AS_FLOAT((long int)i);
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}
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static inline FLOAT
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RR_ABSF(FLOAT f)
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{
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UINT32 i = AS_UINT32(f) & 0x7fffffff;
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return AS_FLOAT((unsigned long int)i);
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}
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static inline FLOAT
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RR_SQRT(FLOAT f)
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{
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INT32 i = (AS_INT32(f) >> 1) + (INT32_FLOAT_ONE >> 1);
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return AS_FLOAT((long int)i);
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}
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//
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// Steve Gabriel's version of an octagonal approximation euclidian distance -
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// return is approximating sqrt(fX*fX + fY*fY)
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//
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static inline FLOAT
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RR_LENGTH(FLOAT fX, FLOAT fY)
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{
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fX = RR_ABSF(fX);
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fY = RR_ABSF(fY);
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return ((11.0f/32.0f)*(fX + fY) + (21.0f/32.0f)*max(fX, fY));
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}
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// compute level of detail (texel->pixel coverage)
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void
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ComputeSimpleLevelOfDetail(
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const RDTextureCoord& TCoord, // inputs
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FLOAT& fLOD ); // outputs
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void
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ComputeCubeMapLevelOfDetail(
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const RDTextureCoord& TCoord, // inputs
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FLOAT& fLOD ); // outputs
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void
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ComputeAnisotropicLevelOfDetail(
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const RDTextureCoord& TCoord, FLOAT fMaxAniso, // inputs
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FLOAT& fLOD, FLOAT& fRatio, FLOAT fDelta[] ); // outputs
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// color interpolation utilities
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void LerpColor(RDColor& Color,
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const RDColor& Color0, const RDColor& Color1, UINT8 uT);
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void BiLerpColor( RDColor& OutColor,
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const RDColor& Color00, const RDColor& Color01,
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const RDColor& Color10, const RDColor& Color11,
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UINT8 uA, UINT8 uB);
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void BiLerpColor3D( RDColor& OutColor,
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const RDColor& Color000, const RDColor& Color010,
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const RDColor& Color100, const RDColor& Color110,
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const RDColor& Color001, const RDColor& Color011,
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const RDColor& Color101, const RDColor& Color111,
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UINT8 uA, UINT8 uB, UINT8 uC);
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///////////////////////////////////////////////////////////////////////////////
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#endif // _REFRASTI_HPP
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