1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
Copyright (C) 1997-2001 Id Software, Inc.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "sw_local.h"
vec3_t r_pright, r_pup, r_ppn;
#define PARTICLE_33 0
#define PARTICLE_66 1
#define PARTICLE_OPAQUE 2
typedef struct
{
particle_t *particle;
int level;
int color;
} partparms_t;
static partparms_t partparms;
/*
** R_DrawParticle
**
** Yes, this is amazingly slow, but it's the C reference
** implementation and should be both robust and vaguely
** understandable. The only time this path should be
** executed is if we're debugging on x86 or if we're
** recompiling and deploying on a non-x86 platform.
**
** To minimize error and improve readability I went the
** function pointer route. This exacts some overhead, but
** it pays off in clean and easy to understand code.
*/
static void R_DrawParticle( void )
{
particle_t *pparticle = partparms.particle;
int level = partparms.level;
vec3_t local, transformed;
float zi;
byte *pdest;
short *pz;
int color = pparticle->color;
int i, izi, pix, count, u, v;
/*
** transform the particle
*/
VectorSubtract (pparticle->origin, r_origin, local);
transformed[0] = DotProduct(local, r_pright);
transformed[1] = DotProduct(local, r_pup);
transformed[2] = DotProduct(local, r_ppn);
if (transformed[2] < PARTICLE_Z_CLIP)
return;
/*
** project the point
*/
// FIXME: preadjust xcenter and ycenter
zi = 1.0 / transformed[2];
u = (int)(xcenter + zi * transformed[0] + 0.5);
v = (int)(ycenter - zi * transformed[1] + 0.5);
if ((v > d_vrectbottom_particle) ||
(u > d_vrectright_particle) ||
(v < d_vrecty) ||
(u < d_vrectx))
{
return;
}
/*
** compute addresses of zbuffer, framebuffer, and
** compute the Z-buffer reference value.
*/
pz = d_pzbuffer + (d_zwidth * v) + u;
pdest = d_viewbuffer + d_scantable[v] + u;
izi = (int)(zi * 0x8000);
/*
** determine the screen area covered by the particle,
** which also means clamping to a min and max
*/
pix = izi >> d_pix_shift;
if (pix < d_pix_min)
pix = d_pix_min;
else if (pix > d_pix_max)
pix = d_pix_max;
/*
** render the appropriate pixels
*/
count = pix;
switch (level) {
case PARTICLE_33 :
for ( ; count ; count--, pz += d_zwidth, pdest += r_screenwidth)
{
//FIXME--do it in blocks of 8?
for (i=0 ; i<pix ; i++)
{
if (pz[i] <= izi)
{
pz[i] = izi;
pdest[i] = vid.alphamap[color + ((int)pdest[i]<<8)];
}
}
}
break;
case PARTICLE_66 :
for ( ; count ; count--, pz += d_zwidth, pdest += r_screenwidth)
{
for (i=0 ; i<pix ; i++)
{
if (pz[i] <= izi)
{
pz[i] = izi;
pdest[i] = vid.alphamap[(color<<8) + (int)pdest[i]];
}
}
}
break;
default: //100
for ( ; count ; count--, pz += d_zwidth, pdest += r_screenwidth)
{
for (i=0 ; i<pix ; i++)
{
if (pz[i] <= izi)
{
pz[i] = izi;
pdest[i] = color;
}
}
}
break;
}
}
/*
** R_DrawParticles
**
** Responsible for drawing all of the particles in the particle list
** throughout the world. Doesn't care if we're using the C path or
** if we're using the asm path, it simply assigns a function pointer
** and goes.
*/
void R_DrawParticles (void)
{
particle_t *p;
int i;
VectorScale( vright, xscaleshrink, r_pright );
VectorScale( vup, yscaleshrink, r_pup );
VectorCopy( vpn, r_ppn );
for (p=r_newrefdef.particles, i=0 ; i<r_newrefdef.num_particles ; i++,p++)
{
if ( p->alpha > 0.66 )
partparms.level = PARTICLE_OPAQUE;
else if ( p->alpha > 0.33 )
partparms.level = PARTICLE_66;
else
partparms.level = PARTICLE_33;
partparms.particle = p;
partparms.color = p->color;
R_DrawParticle();
}
}
|
