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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
|
/*
* fly.c $Revision: 1.2 $
*/
#include "stdio.h"
#include "math.h"
#include "skyfly.h"
#if defined(_WIN32)
#pragma warning (disable:4244) /* disable bogus conversion warnings */
#pragma warning (disable:4305) /* VC++ 5.0 version of above warning. */
#endif
#define cosf(a) cos((float)a)
#define sinf(a) sin((float)a)
#define sqrtf(a) sqrt((float)a)
#define expf(a) exp((float)a)
typedef struct paper_plane_struct {
float Pturn_rate;
float PX, PY, PZ, PZv;
float Pazimuth;
float Proll;
int Pcount, Pdirection;
} paper_plane;
static paper_plane flock[NUM_PLANES];
static float X, Y, Z, Azimuth, Speed;
static int Keyboard_mode;
extern float *A;
extern int Wxorg, Wyorg;
static float terrain_height(float x, float y);
int Xgetbutton(int b);
int Xgetvaluator(int v);
void init_positions(void)
{
int i;
X = GRID_RANGE / 2.;
Y = GRID_RANGE / 2.;
Z = 1.5;
/*
* randomly position the planes near center of world
* take MAX of height above terrain and 0, so planes
* don't fall into canyon. Canyon has negative elevation
*/
for (i = 0; i < NUM_PLANES; i++) {
flock[i].PX = (float) IRND(20) + GRID_RANGE / 2 - 10;
flock[i].PY = (float) IRND(20) + GRID_RANGE / 2 - 10;
flock[i].PZ = MAX(terrain_height(flock[i].PX, flock[i].PY),0.) +
2.*(float)i/NUM_PLANES+.3;
flock[i].Pazimuth = ((float)IRND(256) / 128.) * M_PI;
}
Speed = 0.1f;
Azimuth = M_PI / 2.;
#if 0
// if (Init_pos) {
// X = Init_x;
// Y = Init_y;
// Z = Init_z;
// Azimuth = Init_azimuth;
// Keyboard_mode = 1;
// }
#endif
}
int _frame = 0;
void fly(perfobj_t *viewer_pos)
{
float terrain_z, xpos, ypos, xcntr, ycntr;
float delta_speed = .003;
/* if (++_frame == 1000) {
_frame = 0;
init_positions();
}*/
xcntr = Wxsize / 2;
ycntr = Wysize / 2;
if (Xgetbutton(RKEY))
init_positions();
if (Xgetbutton(SPACEKEY)) {
Keyboard_mode = !Keyboard_mode;
}
if (Keyboard_mode) {
/*
* step-at-a-time debugging mode
*/
if (Keyboard_mode && Xgetbutton(LEFTARROWKEY)) {
Azimuth -= 0.025;
}
if (Keyboard_mode && Xgetbutton(RIGHTARROWKEY)) {
Azimuth += 0.025;
}
if (Keyboard_mode && Xgetbutton(UPARROWKEY)) {
X += cosf(-Azimuth + M_PI / 2.) * 0.025;
Y += sinf(-Azimuth + M_PI / 2.) * 0.025;
}
if (Keyboard_mode && Xgetbutton(DOWNARROWKEY)) {
X -= cosf(-Azimuth + M_PI / 2.) * 0.025;
Y -= sinf(-Azimuth + M_PI / 2.) * 0.025;
}
if (Keyboard_mode && Xgetbutton(PAGEUPKEY)) {
Z += 0.025;
}
if (Keyboard_mode && Xgetbutton(PAGEDOWNKEY)) {
Z -= 0.025;
}
} else {
/*
* simple, mouse-driven flight model
*/
if (Xgetbutton(LEFTMOUSE) && Speed < .3)
Speed += delta_speed;
if (Xgetbutton(RIGHTMOUSE) && Speed > -.3)
Speed -= delta_speed;
if (Xgetbutton(MIDDLEMOUSE))
Speed = Speed*.8;
xpos = (Xgetvaluator(MOUSEX)-xcntr) / ((float)Wxsize*14.);
ypos = (Xgetvaluator(MOUSEY)-ycntr) / ((float)Wysize*.5);
/*
* move in direction of view
*/
Azimuth += xpos;
X += cosf(-Azimuth + M_PI / 2.) * Speed;
Y += sinf(-Azimuth + M_PI / 2.) * Speed;
Z -= ypos * Speed;
}
/*
* keep from getting too close to terrain
*/
terrain_z = terrain_height(X, Y);
if (Z < terrain_z +.4)
Z = terrain_z +.4;
X = MAX(X, 1.);
X = MIN(X, GRID_RANGE);
Y = MAX(Y, 1.);
Y = MIN(Y, GRID_RANGE);
Z = MIN(Z, 20.);
*((float *) viewer_pos->vdata + 0) = X;
*((float *) viewer_pos->vdata + 1) = Y;
*((float *) viewer_pos->vdata + 2) = Z;
*((float *) viewer_pos->vdata + 3) = Azimuth;
}
void fly_paper_planes(perfobj_t *paper_plane_pos)
{
int i;
float speed = .08;
float terrain_z;
/*
* slow planes down in cyclops mode since
* frame rate is doubled
*/
for (i = 0; i < NUM_PLANES; i++) {
/*
* If plane is not turning, one chance in 50 of
* starting a turn
*/
if (flock[i].Pcount == 0 && IRND(50) == 1) {
/* initiate a roll */
/* roll for a random period */
flock[i].Pcount = IRND(100);
/* random turn rate */
flock[i].Pturn_rate = IRND(100) / 10000.;
flock[i].Pdirection = IRND(3) - 1;
}
if (flock[i].Pcount > 0) {
/* continue rolling */
flock[i].Proll += flock[i].Pdirection * flock[i].Pturn_rate;
flock[i].Pcount--;
} else
/* damp amount of roll when turn complete */
flock[i].Proll *=.95;
/* turn as a function of roll */
flock[i].Pazimuth -= flock[i].Proll *.05;
/* follow terrain elevation */
terrain_z=terrain_height(flock[i].PX,flock[i].PY);
/* use a "spring-mass-damp" system of terrain follow */
flock[i].PZv = flock[i].PZv -
.01 * (flock[i].PZ - (MAX(terrain_z,0.) +
2.*(float)i/NUM_PLANES+.3)) - flock[i].PZv *.04;
/* U-turn if fly off world!! */
if (flock[i].PX < 1 || flock[i].PX > GRID_RANGE - 2 || flock[i].PY < 1 || flock[i].PY > GRID_RANGE - 2)
flock[i].Pazimuth += M_PI;
/* move planes */
flock[i].PX += cosf(flock[i].Pazimuth) * speed;
flock[i].PY += sinf(flock[i].Pazimuth) * speed;
flock[i].PZ += flock[i].PZv;
}
for (i = 0; i < NUM_PLANES; i++) {
*((float *) paper_plane_pos[i].vdata + 0) = flock[i].PX;
*((float *) paper_plane_pos[i].vdata + 1) = flock[i].PY;
*((float *) paper_plane_pos[i].vdata + 2) = flock[i].PZ;
*((float *) paper_plane_pos[i].vdata + 3) = flock[i].Pazimuth * RAD_TO_DEG;
*((float *) paper_plane_pos[i].vdata + 4) = flock[i].PZv * (-500.);
*((float *) paper_plane_pos[i].vdata + 5) = flock[i].Proll *RAD_TO_DEG;
}
}
/* compute height above terrain */
static float terrain_height(float x, float y)
{
float dx, dy;
float z00, z01, z10, z11;
float dzx1, dzx2, z1, z2;
int xi, yi;
x /= XYScale;
y /= XYScale;
xi = MIN((int)x, GridDim-2);
yi = MIN((int)y, GridDim-2);
dx = x - xi;
dy = y - yi;
/*
View looking straight down onto terrain
<--dx-->
z00----z1-------z10 (terrain elevations)
| | |
^ | Z at(x,y) |
| | | |
dy | | |
| | | |
| | | |
V z00----z2-------z10
(xi,yi)
Z= height returned
*/
z00 = A[xi * GridDim + yi];
z10 = A[(xi + 1) * GridDim + yi];
z01 = A[xi * GridDim + yi + 1];
z11 = A[(xi + 1) * GridDim + yi + 1];
dzx1 = z10 - z00;
dzx2 = z11 - z01;
z1 = z00 + dzx1 * dx;
z2 = z01 + dzx2 * dx;
return (ScaleZ*((1.0 - dy) * z1 + dy * z2));
}
|
