r_main.c

Nxdoom真的满好用的

// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: r_main.c,v 1.2 2003/09/08 22:34:31 jasonk Exp $
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log: r_main.c,v $
// Revision 1.2  2003/09/08 22:34:31  jasonk
// Updated files because this fucker won't build for no fucking good reason.
//
// Revision 1.1.1.1  2003/09/04 21:08:13  jasonk
// Initial import
//
// Revision 1.1  2000/12/08 21:07:54  jeffw
// nxdoom initial entry -- No nxdoom/Makefile so it won't build automatically
//
//
// DESCRIPTION:
//	Rendering main loop and setup functions,
//	 utility functions (BSP, geometry, trigonometry).
//	See tables.c, too.
//
//-----------------------------------------------------------------------------


static const char rcsid[] = "$Id: r_main.c,v 1.2 2003/09/08 22:34:31 jasonk Exp $";



#include <stdlib.h>
#include <math.h>


#include "doomdef.h"
#include "d_net.h"

#include "m_bbox.h"

#include "r_local.h"
#include "r_sky.h"





// Fineangles in the SCREENWIDTH wide window.
#define FIELDOFVIEW		2048	



int			viewangleoffset;

// increment every time a check is made
int			validcount = 1;		


lighttable_t*		fixedcolormap;
extern lighttable_t**	walllights;

int			centerx;
int			centery;

fixed_t			centerxfrac;
fixed_t			centeryfrac;
fixed_t			projection;

// just for profiling purposes
int			framecount;	

int			sscount;
int			linecount;
int			loopcount;

fixed_t			viewx;
fixed_t			viewy;
fixed_t			viewz;

angle_t			viewangle;

fixed_t			viewcos;
fixed_t			viewsin;

player_t*		viewplayer;

// 0 = high, 1 = low
int			detailshift;	

//
// precalculated math tables
//
angle_t			clipangle;

// The viewangletox[viewangle + FINEANGLES/4] lookup
// maps the visible view angles to screen X coordinates,
// flattening the arc to a flat projection plane.
// There will be many angles mapped to the same X. 
int			viewangletox[FINEANGLES/2];

// The xtoviewangleangle[] table maps a screen pixel
// to the lowest viewangle that maps back to x ranges
// from clipangle to -clipangle.
angle_t			xtoviewangle[SCREENWIDTH+1];


// UNUSED.
// The finetangentgent[angle+FINEANGLES/4] table
// holds the fixed_t tangent values for view angles,
// ranging from MININT to 0 to MAXINT.
// fixed_t		finetangent[FINEANGLES/2];

// fixed_t		finesine[5*FINEANGLES/4];
fixed_t*		finecosine = &finesine[FINEANGLES/4];


lighttable_t*		scalelight[LIGHTLEVELS][MAXLIGHTSCALE];
lighttable_t*		scalelightfixed[MAXLIGHTSCALE];
lighttable_t*		zlight[LIGHTLEVELS][MAXLIGHTZ];

// bumped light from gun blasts
int			extralight;			



void (*colfunc) (void);
void (*basecolfunc) (void);
void (*fuzzcolfunc) (void);
void (*transcolfunc) (void);
void (*spanfunc) (void);



//
// R_AddPointToBox
// Expand a given bbox
// so that it encloses a given point.
//
void
R_AddPointToBox
( int		x,
  int		y,
  fixed_t*	box )
{
    if (x< box[BOXLEFT])
	box[BOXLEFT] = x;
    if (x> box[BOXRIGHT])
	box[BOXRIGHT] = x;
    if (y< box[BOXBOTTOM])
	box[BOXBOTTOM] = y;
    if (y> box[BOXTOP])
	box[BOXTOP] = y;
}


//
// R_PointOnSide
// Traverse BSP (sub) tree,
//  check point against partition plane.
// Returns side 0 (front) or 1 (back).
//
int
R_PointOnSide
( fixed_t	x,
  fixed_t	y,
  node_t*	node )
{
    fixed_t	dx;
    fixed_t	dy;
    fixed_t	left;
    fixed_t	right;
	
    if (!node->dx)
    {
	if (x <= node->x)
	    return node->dy > 0;
	
	return node->dy < 0;
    }
    if (!node->dy)
    {
	if (y <= node->y)
	    return node->dx < 0;
	
	return node->dx > 0;
    }
	
    dx = (x - node->x);
    dy = (y - node->y);
	
    // Try to quickly decide by looking at sign bits.
    if ( (node->dy ^ node->dx ^ dx ^ dy)&0x80000000 )
    {
	if  ( (node->dy ^ dx) & 0x80000000 )
	{
	    // (left is negative)
	    return 1;
	}
	return 0;
    }

    left = FixedMul ( node->dy>>FRACBITS , dx );
    right = FixedMul ( dy , node->dx>>FRACBITS );
	
    if (right < left)
    {
	// front side
	return 0;
    }
    // back side
    return 1;			
}


int
R_PointOnSegSide
( fixed_t	x,
  fixed_t	y,
  seg_t*	line )
{
    fixed_t	lx;
    fixed_t	ly;
    fixed_t	ldx;
    fixed_t	ldy;
    fixed_t	dx;
    fixed_t	dy;
    fixed_t	left;
    fixed_t	right;
	
    lx = line->v1->x;
    ly = line->v1->y;
	
    ldx = line->v2->x - lx;
    ldy = line->v2->y - ly;
	
    if (!ldx)
    {
	if (x <= lx)
	    return ldy > 0;
	
	return ldy < 0;
    }
    if (!ldy)
    {
	if (y <= ly)
	    return ldx < 0;
	
	return ldx > 0;
    }
	
    dx = (x - lx);
    dy = (y - ly);
	
    // Try to quickly decide by looking at sign bits.
    if ( (ldy ^ ldx ^ dx ^ dy)&0x80000000 )
    {
	if  ( (ldy ^ dx) & 0x80000000 )
	{
	    // (left is negative)
	    return 1;
	}
	return 0;
    }

    left = FixedMul ( ldy>>FRACBITS , dx );
    right = FixedMul ( dy , ldx>>FRACBITS );
	
    if (right < left)
    {
	// front side
	return 0;
    }
    // back side
    return 1;			
}


//
// R_PointToAngle
// To get a global angle from cartesian coordinates,
//  the coordinates are flipped until they are in
//  the first octant of the coordinate system, then
//  the y (<=x) is scaled and divided by x to get a
//  tangent (slope) value which is looked up in the
//  tantoangle[] table.

//




angle_t
R_PointToAngle
( fixed_t	x,
  fixed_t	y )
{	
    x -= viewx;
    y -= viewy;
    
    if ( (!x) && (!y) )
	return 0;

    if (x>= 0)
    {
	// x >=0
	if (y>= 0)
	{
	    // y>= 0

	    if (x>y)
	    {
		// octant 0
		return tantoangle[ SlopeDiv(y,x)];
	    }
	    else
	    {
		// octant 1
		return ANG90-1-tantoangle[ SlopeDiv(x,y)];
	    }
	}
	else
	{
	    // y<0
	    y = -y;

	    if (x>y)
	    {
		// octant 8
		return -tantoangle[SlopeDiv(y,x)];
	    }
	    else
	    {
		// octant 7
		return ANG270+tantoangle[ SlopeDiv(x,y)];
	    }
	}
    }
    else
    {
	// x<0
	x = -x;

	if (y>= 0)
	{
	    // y>= 0
	    if (x>y)
	    {
		// octant 3
		return ANG180-1-tantoangle[ SlopeDiv(y,x)];
	    }
	    else
	    {
		// octant 2
		return ANG90+ tantoangle[ SlopeDiv(x,y)];
	    }
	}
	else
	{
	    // y<0
	    y = -y;

	    if (x>y)
	    {
		// octant 4
		return ANG180+tantoangle[ SlopeDiv(y,x)];
	    }
	    else
	    {
		 // octant 5
		return ANG270-1-tantoangle[ SlopeDiv(x,y)];
	    }
	}
    }
    return 0;
}


angle_t
R_PointToAngle2
( fixed_t	x1,
  fixed_t	y1,
  fixed_t	x2,
  fixed_t	y2 )
{	
    viewx = x1;
    viewy = y1;
    
    return R_PointToAngle (x2, y2);
}


fixed_t
R_PointToDist
( fixed_t	x,
  fixed_t	y )
{
    int		angle;
    fixed_t	dx;
    fixed_t	dy;
    fixed_t	temp;
    fixed_t	dist;
	
    dx = abs(x - viewx);
    dy = abs(y - viewy);
	
    if (dy>dx)
    {
	temp = dx;
	dx = dy;
	dy = temp;
    }
	
    angle = (tantoangle[ FixedDiv(dy,dx)>>DBITS ]+ANG90) >> ANGLETOFINESHIFT;

    // use as cosine
    dist = FixedDiv (dx, finesine[angle] );	
	
    return dist;
}




//
// R_InitPointToAngle
//
void R_InitPointToAngle (void)
{
    // UNUSED - now getting from tables.c
#if 0
    int	i;
    long	t;
    float	f;
//
// slope (tangent) to angle lookup
//
    for (i=0 ; i<=SLOPERANGE ; i++)
    {
	f = atan( (float)i/SLOPERANGE )/(3.141592657*2);
	t = 0xffffffff*f;
	tantoangle[i] = t;
    }
#endif
}