88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
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/*
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* Copyright (c) 1993-1995 Argonaut Technologies Limited. All rights reserved.
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*
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* $Id: lightmac.h 1.1 1997/07/11 16:15:30 jon Exp JON $
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* $Locker: JON $
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*
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* Macros for building the lighting functions
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*/
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/*
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* Clamp a component to (0,1], scale and offset
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*/
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#define CLAMP_SCALE(c) do { \
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if ((c) >= BR_SCALAR(1.0)) \
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(c) = BR_SCALAR(256.0) - BR_SCALAR_EPSILON; \
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else if ((c) <= BR_SCALAR(0.0)) \
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(c) = BR_SCALAR(0.0); \
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else \
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(c) = BR_MUL(BR_SCALAR(256.0), (c)); \
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} while(0);
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/*
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* Find dot product of reflected vector and eye
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*
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* uses dirn_norm, n, and rend.eye_l
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*
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* produces dot
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*/
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#define SPECULAR_DOT() do { \
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br_vector3 r; \
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br_scalar rd; \
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\
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rd = BR_CONST_MUL(BrVector3Dot(&dirn_norm,n),2); \
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BrVector3Scale(&r,n,rd); \
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BrVector3Sub(&r,&r,&dirn_norm); \
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\
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dot = BrVector3Dot(&rend.eye_l,&r); \
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} while(0)
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/*
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* Given the dot-product of eye & reflected vector, returns specular component of lighting eqn.
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*/
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#define SPECULAR_POWER(l) BR_MULDIV(dot,l,self->state.surface.power-BR_MUL(self->state.surface.power,dot)+dot)
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/*
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* Given dist, calculates dirn_norm & dist
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*/
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#define CALCULATE_DIRN_NORM() do { \
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br_scalar s; \
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dist = BrVector3Length(&dirn); \
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if(dist <= 2 * BR_SCALAR_EPSILON) \
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return; \
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s = BR_RCP(dist); \
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BrVector3Scale(&dirn_norm,&dirn,s); \
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} while(0)
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/*
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* Given dist, calculates attn
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*/
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#define CALCULATE_ATTENUATION() do { \
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br_scalar dist2; \
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if(dist >= BR_SCALAR(180.0)) \
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dist2 = BR_SCALAR(32767.0); \
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else \
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dist2 = BR_MUL(dist,dist); \
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\
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attn = BR_RCP(alp->s->attenuation_c \
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+ BR_MUL(dist,alp->s->attenuation_l) \
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+ BR_MUL(dist2,alp->s->attenuation_q)); \
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} while(0)
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#define DIFFUSE_DOT() do { \
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dot = BrVector3Dot(n,&dirn_norm); \
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if(dot <= BR_SCALAR(0.0)) \
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return; \
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} while(0)
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#define SPOT_DOT() do { \
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dot_spot = BrVector3Dot(&dirn_norm,&alp->direction); \
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if(dot_spot < alp->s->spot_outer) \
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return; \
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} while(0)
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#define SPOT_FALLOFF(v) ((dot_spot < alp->s->spot_inner)?\
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BR_MULDIV((v),alp->s->spot_outer - dot_spot, alp->s->spot_outer - alp->s->spot_inner) : (v))
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