JurassicParkTrespasser/jp2_pc/Source/Lib/Renderer/Primitives/P5/FastBumpEx.hpp
2018-01-01 23:07:24 +01:00

84 lines
2.6 KiB
C++

/***********************************************************************************************
*
* Copyright © DreamWorks Interactive. 1996
*
* Contents:
* Assembly functions for fast bumpmapping.
*
* Notes:
*
* To Do:
*
***********************************************************************************************
*
* $Log:: /JP2_PC/source/Lib/Renderer/Primitives/P5/FastBumpEx.hpp $
*
* 5 1/19/98 7:30p Pkeet
* Added support for 16 bit bumpmaps by adding lower colour resolution and a smaller size for
* 'CBumpAnglePair.'
*
* 4 9/01/97 8:03p Rwyatt
*
* 3 9/24/96 2:56p Pkeet
* Removed the overloaded '+' operator assembly function.
*
* 2 9/11/96 11:35a Pkeet
* Added explicit references (dword ptr's) to assembly operations involving the angle pair
* format.
*
* 1 9/06/96 2:50p Pkeet
* Initial implementation.
*
**********************************************************************************************/
#ifndef HEADER_LIB_RENDERER_PRIMITIVES_P5_FASTBUMPEX_HPP
#define HEADER_LIB_RENDERER_PRIMITIVES_P5_FASTBUMPEX_HPP
// Make sure this file is being included from 'FastBump.hpp'.
#ifndef HEADER_LIB_RENDERER_PRIMITIVES_FASTBUMP_HPP
#error The header file 'FastBump.hpp' has not been included!
#endif
//*********************************************************************************************
//
inline uint8 u1GetIntensityFromBumpmap
(
CBumpAnglePair bangp, // The angle pair of a bumpmap's pixel.
uint32 u4_light_theta, // The theta component only of the light source relative
// to the polygon.
uint8* u1a_subtable // Pointer into the angle to intensity lookup table (this
// pointer should be set to represent the light source's
// phi value relative to the polygon.
)
//
// Returns the intensity value given a bumpmap pixel and lighting source values.
//
//**************************************
{
uint8 u1_intensity; // Storage for the intensity return value.
Assert(u1a_subtable);
__asm
{
#if iBUMPMAP_RESOLUTION == 16
movzx eax, word ptr [bangp] // Load the bumpmap pixel.
#else
mov eax, dword ptr [bangp] // Load the bumpmap pixel.
#endif // iBUMPMAP_RESOLUTION == 16
mov ebx, u1a_subtable // Load the pointer to the angle to intensity
// lookup table.
sub eax, u4_light_theta // Find differences in theta.
and eax, iMASK_ANGLETABLE_LOOKUP // Mask out everything but the theta-phi index.
mov al, byte ptr[eax + ebx] // Copy intensity value from the lookup table.
mov u1_intensity, al // Move the intensity value to the return value.
};
// Return the intensity value.
return u1_intensity;
}
#endif