windows-nt/Source/XPSP1/NT/multimedia/directx/dxg/ref8/rast/refrasti.hpp

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2020-09-26 03:20:57 -05:00
///////////////////////////////////////////////////////////////////////////////
// Copyright (C) Microsoft Corporation, 2000.
//
// refrasti.hpp
//
// Direct3D Reference Device - Main Internal Header File
//
///////////////////////////////////////////////////////////////////////////////
#ifndef _REFRASTI_HPP
#define _REFRASTI_HPP
///////////////////////////////////////////////////////////////////////////////
// //
// Texture Mapping Utility Functions //
// //
///////////////////////////////////////////////////////////////////////////////
//
// various approximations and tricks to speed up the texture map coverage
// computations
//
// Integer value of first exponent bit in a float. Provides a scaling factor
// for exponent values extracted directly from float representation.
#define FLOAT_EXPSCALE ((FLOAT)0x00800000)
#define FLOAT_OOEXPSCALE ((FLOAT)(1.0 / (double)FLOAT_EXPSCALE))
// Integer representation of 1.0f.
#define INT32_FLOAT_ONE 0x3f800000
static inline FLOAT
RR_LOG2(FLOAT f)
{
return (FLOAT)(AS_INT32(f) - INT32_FLOAT_ONE) * FLOAT_OOEXPSCALE;
}
static inline FLOAT
RR_ALOG2(FLOAT f)
{
INT32 i = (INT32)(f * FLOAT_EXPSCALE) + INT32_FLOAT_ONE;
return AS_FLOAT((long int)i);
}
static inline FLOAT
RR_ABSF(FLOAT f)
{
UINT32 i = AS_UINT32(f) & 0x7fffffff;
return AS_FLOAT((unsigned long int)i);
}
static inline FLOAT
RR_SQRT(FLOAT f)
{
INT32 i = (AS_INT32(f) >> 1) + (INT32_FLOAT_ONE >> 1);
return AS_FLOAT((long int)i);
}
//
// Steve Gabriel's version of an octagonal approximation euclidian distance -
// return is approximating sqrt(fX*fX + fY*fY)
//
static inline FLOAT
RR_LENGTH(FLOAT fX, FLOAT fY)
{
fX = RR_ABSF(fX);
fY = RR_ABSF(fY);
return ((11.0f/32.0f)*(fX + fY) + (21.0f/32.0f)*max(fX, fY));
}
// compute level of detail (texel->pixel coverage)
void
ComputeSimpleLevelOfDetail(
const RDTextureCoord& TCoord, // inputs
FLOAT& fLOD ); // outputs
void
ComputeCubeMapLevelOfDetail(
const RDTextureCoord& TCoord, // inputs
FLOAT& fLOD ); // outputs
void
ComputeAnisotropicLevelOfDetail(
const RDTextureCoord& TCoord, FLOAT fMaxAniso, // inputs
FLOAT& fLOD, FLOAT& fRatio, FLOAT fDelta[] ); // outputs
// color interpolation utilities
void LerpColor(RDColor& Color,
const RDColor& Color0, const RDColor& Color1, UINT8 uT);
void BiLerpColor( RDColor& OutColor,
const RDColor& Color00, const RDColor& Color01,
const RDColor& Color10, const RDColor& Color11,
UINT8 uA, UINT8 uB);
void BiLerpColor3D( RDColor& OutColor,
const RDColor& Color000, const RDColor& Color010,
const RDColor& Color100, const RDColor& Color110,
const RDColor& Color001, const RDColor& Color011,
const RDColor& Color101, const RDColor& Color111,
UINT8 uA, UINT8 uB, UINT8 uC);
///////////////////////////////////////////////////////////////////////////////
#endif // _REFRASTI_HPP