r_main.c

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    int			angleb;
    int			sinea;
    int			sineb;
    fixed_t		num;
    int			den;

    // UNUSED
#if 0
{
    fixed_t		dist;
    fixed_t		z;
    fixed_t		sinv;
    fixed_t		cosv;
	
    sinv = finesine[(visangle-rw_normalangle)>>ANGLETOFINESHIFT];	
    dist = FixedDiv (rw_distance, sinv);
    cosv = finecosine[(viewangle-visangle)>>ANGLETOFINESHIFT];
    z = abs(FixedMul (dist, cosv));
    scale = FixedDiv(projection, z);
    return scale;
}
#endif

    anglea = ANG90 + (visangle-viewangle);
    angleb = ANG90 + (visangle-rw_normalangle);

    // both sines are allways positive
    sinea = finesine[anglea>>ANGLETOFINESHIFT];	
    sineb = finesine[angleb>>ANGLETOFINESHIFT];
    num = FixedMul(projection,sineb)<<detailshift;
    den = FixedMul(rw_distance,sinea);

    if (den > num>>16)
    {
	scale = FixedDiv (num, den);

	if (scale > 64*FRACUNIT)
	    scale = 64*FRACUNIT;
	else if (scale < 256)
	    scale = 256;
    }
    else
	scale = 64*FRACUNIT;
	
    return scale;
}



//
// R_InitTables
//
void R_InitTables (void)
{
    // UNUSED: now getting from tables.c
#if 0
    int		i;
    float	a;
    float	fv;
    int		t;
    
    // viewangle tangent table
    for (i=0 ; i<FINEANGLES/2 ; i++)
    {
	a = (i-FINEANGLES/4+0.5)*PI*2/FINEANGLES;
	fv = FRACUNIT*tan (a);
	t = fv;
	finetangent[i] = t;
    }
    
    // finesine table
    for (i=0 ; i<5*FINEANGLES/4 ; i++)
    {
	// OPTIMIZE: mirror...
	a = (i+0.5)*PI*2/FINEANGLES;
	t = FRACUNIT*sin (a);
	finesine[i] = t;
    }
#endif

}



//
// R_InitTextureMapping
//
void R_InitTextureMapping (void)
{
    int			i;
    int			x;
    int			t;
    fixed_t		focallength;
    
    // Use tangent table to generate viewangletox:
    //  viewangletox will give the next greatest x
    //  after the view angle.
    //
    // Calc focallength
    //  so FIELDOFVIEW angles covers SCREENWIDTH.
    focallength = FixedDiv (centerxfrac,
			    finetangent[FINEANGLES/4+FIELDOFVIEW/2] );
	
    for (i=0 ; i<FINEANGLES/2 ; i++)
    {
	if (finetangent[i] > FRACUNIT*2)
	    t = -1;
	else if (finetangent[i] < -FRACUNIT*2)
	    t = viewwidth+1;
	else
	{
	    t = FixedMul (finetangent[i], focallength);
	    t = (centerxfrac - t+FRACUNIT-1)>>FRACBITS;

	    if (t < -1)
		t = -1;
	    else if (t>viewwidth+1)
		t = viewwidth+1;
	}
	viewangletox[i] = t;
    }
    
    // Scan viewangletox[] to generate xtoviewangle[]:
    //  xtoviewangle will give the smallest view angle
    //  that maps to x.	
    for (x=0;x<=viewwidth;x++)
    {
	i = 0;
	while (viewangletox[i]>x)
	    i++;
	xtoviewangle[x] = (i<<ANGLETOFINESHIFT)-ANG90;
    }
    
    // Take out the fencepost cases from viewangletox.
    for (i=0 ; i<FINEANGLES/2 ; i++)
    {
	t = FixedMul (finetangent[i], focallength);
	t = centerx - t;
	
	if (viewangletox[i] == -1)
	    viewangletox[i] = 0;
	else if (viewangletox[i] == viewwidth+1)
	    viewangletox[i]  = viewwidth;
    }
	
    clipangle = xtoviewangle[0];
}



//
// R_InitLightTables
// Only inits the zlight table,
//  because the scalelight table changes with view size.
//
#define DISTMAP		2

void R_InitLightTables (void)
{
    int		i;
    int		j;
    int		level;
    int		startmap; 	
    int		scale;
    
    // Calculate the light levels to use
    //  for each level / distance combination.
    for (i=0 ; i< LIGHTLEVELS ; i++)
    {
	startmap = ((LIGHTLEVELS-1-i)*2)*NUMCOLORMAPS/LIGHTLEVELS;
	for (j=0 ; j<MAXLIGHTZ ; j++)
	{
	    scale = FixedDiv ((SCREENWIDTH/2*FRACUNIT), (j+1)<<LIGHTZSHIFT);
	    scale >>= LIGHTSCALESHIFT;
	    level = startmap - scale/DISTMAP;
	    
	    if (level < 0)
		level = 0;

	    if (level >= NUMCOLORMAPS)
		level = NUMCOLORMAPS-1;

	    zlight[i][j] = colormaps + level*256;
	}
    }
}



//
// R_SetViewSize
// Do not really change anything here,
//  because it might be in the middle of a refresh.
// The change will take effect next refresh.
//
boolean		setsizeneeded;
int		setblocks;
int		setdetail;


void
R_SetViewSize
( int		blocks,
  int		detail )
{
    setsizeneeded = true;
    setblocks = blocks;
    setdetail = detail;
}


void WriteDebug(char *);

//
// R_ExecuteSetViewSize
//
void R_ExecuteSetViewSize (void)
   {
    fixed_t	cosadj;
    fixed_t	dy;
    int		i;
    int		j;
    int		level;
    int		startmap; 	

    setsizeneeded = false;

    if (setblocks == 11)
       {
        scaledviewwidth = SCREENWIDTH;
        viewheight = SCREENHEIGHT;
       }
    else
       {
        scaledviewwidth = (setblocks*SCREENWIDTH)/10;
        viewheight = ((setblocks*(SCREENHEIGHT-SBARHEIGHT))/10)&~7;
       }
    
    detailshift = setdetail;
    viewwidth = scaledviewwidth>>detailshift;
	
    centery = viewheight/2;
    centerx = viewwidth/2;
    centerxfrac = centerx<<FRACBITS;
    centeryfrac = centery<<FRACBITS;
    projection = centerxfrac;

    if (!detailshift)
    {
	colfunc = basecolfunc = R_DrawColumn;
	fuzzcolfunc = R_DrawFuzzColumn;
	transcolfunc = R_DrawTranslatedColumn;
	spanfunc = R_DrawSpan;
    }
    else
    {
	colfunc = basecolfunc = R_DrawColumnLow;
	fuzzcolfunc = R_DrawFuzzColumn;
	transcolfunc = R_DrawTranslatedColumn;
	spanfunc = R_DrawSpanLow;
    }

    R_InitBuffer (scaledviewwidth, viewheight);
	
    R_InitTextureMapping ();
    
    // psprite scales
//    pspritescale = FRACUNIT*viewwidth/SCREENWIDTH;
//    pspriteiscale = FRACUNIT*SCREENWIDTH/viewwidth;

    //pspritescale = FRACUNIT*viewwidth/320;
    //pspriteiscale = FRACUNIT*320/viewheight;
    if (setblocks != 10)
       {
        pspritescale = FRACUNIT*viewheight/200;
        pspriteiscale = FRACUNIT*200/viewheight;
       }
    else
       {
        pspritescale = FRACUNIT*(viewheight+32)/200;
        pspriteiscale = FRACUNIT*200/(viewheight+32);
       }
    
    // thing clipping
    for (i=0 ; i<viewwidth ; i++)
	screenheightarray[i] = viewheight;
    
    // planes
    for (i=0 ; i<viewheight ; i++)
    {
	dy = ((i-viewheight/2)<<FRACBITS)+FRACUNIT/2;
	dy = abs(dy);
	yslope[i] = FixedDiv ( (viewwidth<<detailshift)/2*FRACUNIT, dy);
    }
	
    for (i=0 ; i<viewwidth ; i++)
    {
	cosadj = abs(finecosine[xtoviewangle[i]>>ANGLETOFINESHIFT]);
	distscale[i] = FixedDiv (FRACUNIT,cosadj);
    }
    
    // Calculate the light levels to use
    //  for each level / scale combination.
    for (i=0 ; i< LIGHTLEVELS ; i++)
    {
	startmap = ((LIGHTLEVELS-1-i)*2)*NUMCOLORMAPS/LIGHTLEVELS;
	for (j=0 ; j<MAXLIGHTSCALE ; j++)
	{
	    level = startmap - j*SCREENWIDTH/(viewwidth<<detailshift)/DISTMAP;
	    
	    if (level < 0)
		level = 0;

	    if (level >= NUMCOLORMAPS)
		level = NUMCOLORMAPS-1;

	    scalelight[i][j] = colormaps + level*256;
	}
    }
    R_DrawViewBorder();
}



//
// R_Init
//
extern int	detailLevel;
extern int	screenblocks;



void R_Init (void)
   {
    R_InitData ();
    //WriteDebug("\nR_InitData");
    R_InitPointToAngle();
    //WriteDebug("\nR_InitPointToAngle");
    R_InitTables ();
    // viewwidth / viewheight / detailLevel are set by the defaults
    //WriteDebug("\nR_InitTables");

    R_SetViewSize (screenblocks, detailLevel);
    R_InitPlanes ();
    //WriteDebug("\nR_InitPlanes");
    R_InitLightTables ();
    //WriteDebug("\nR_InitLightTables");
    R_InitSkyMap ();
    //WriteDebug("\nR_InitSkyMap");
    R_InitTranslationTables ();
    //WriteDebug("\nR_InitTranslationsTables");
    R_InitFuzzTable();

    framecount = 0;
   }


//
// R_PointInSubsector
//
subsector_t*
R_PointInSubsector
( fixed_t	x,
  fixed_t	y )
{
    node_t*	node;
    int		side;
    int		nodenum;

    // single subsector is a special case
    if (!numnodes)				
	return subsectors;
		
    nodenum = numnodes-1;

    while (! (nodenum & NF_SUBSECTOR) )
    {
	node = &nodes[nodenum];
	side = R_PointOnSide (x, y, node);
	nodenum = node->children[side];
    }
	
    return &subsectors[nodenum & ~NF_SUBSECTOR];
}



//
// R_SetupFrame
//
void R_SetupFrame (player_t* player)
   {		
    int  i;
    
    viewplayer = player;
    viewx = player->mo->x;
    viewy = player->mo->y;
    viewangle = player->mo->angle + viewangleoffset;
    extralight = player->extralight;

    viewz = player->viewz;
    
    viewsin = finesine[viewangle>>ANGLETOFINESHIFT];
    viewcos = finecosine[viewangle>>ANGLETOFINESHIFT];
	
    sscount = 0;
	
    if (player->fixedcolormap)
       {
        fixedcolormap = colormaps + player->fixedcolormap*256*sizeof(lighttable_t);
        walllights = scalelightfixed;
        for (i = 0; i < MAXLIGHTSCALE; i++)
           scalelightfixed[i] = fixedcolormap;
       }
    else
       fixedcolormap = 0;
	
    framecount++;
    validcount++;
   }

//
// R_RenderView
//
void R_RenderPlayerView (player_t* player)
   {	
    R_SetupFrame(player);

    // Clear buffers.
    R_ClearClipSegs();
    R_ClearDrawSegs();
    R_ClearPlanes();
    R_ClearSprites();
    
    // check for new console commands.
    NetUpdate ();

    // The head node is the last node output.
    R_RenderBSPNode (numnodes-1);
    
    // Check for new console commands.
    NetUpdate ();
    
    R_DrawPlanes ();
    
    // Check for new console commands.
    NetUpdate ();
    
    R_DrawMasked ();

    // Check for new console commands.
    NetUpdate ();				
}