git.mutantstargoat.com Git - dosdemo/blob - src/hairball.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include "demo.h"
   5 #include "3dgfx.h"
   6 #include "vmath.h"
   7 #include "screen.h"
   8 #include "util.h"
   9 #include "cfgopt.h"
  10
  11
  12 #ifdef MSDOS
  13 #include "dos/gfx.h"    /* for wait_vsync assembly macro */
  14 #else
  15 void wait_vsync(void);
  16 #endif
  17
  18 #define NSPAWNPOS       128
  19 #define SPAWN_RATE      16.0f
  20 #define GRAV            (-6.0f)
  21 #define HAIR_LENGTH 32
  22
  23 struct particle {
  24         vec3_t pos;
  25         vec3_t vel;
  26         int r, g, b, a;
  27         int life;
  28
  29         struct particle *next;
  30 };
  31
  32 struct hairball {
  33         vec3_t pos;
  34         quat_t rot;
  35         float xform[16];
  36
  37         struct particle *plist[NSPAWNPOS];
  38 };
  39
  40 static int init(void);
  41 static void destroy(void);
  42 static void start(long trans_time);
  43 static void draw(void);
  44 static void update_hairball(struct hairball *hb, float dt);
  45 static void draw_hairball(struct hairball *hb);
  46
  47 static struct particle *palloc(void);
  48 void pfree(struct particle *p);
  49
  50
  51 static struct screen scr = {
  52         "hairball",
  53         init,
  54         destroy,
  55         start, 0,
  56         draw
  57 };
  58
  59 static long start_time;
  60
  61 static vec3_t *spawnpos, *spawndir;
  62
  63 static struct hairball hball;
  64
  65 struct screen *hairball_screen(void)
  66 {
  67         return &scr;
  68 }
  69
  70 static int init(void)
  71 {
  72         int i;
  73
  74         hball.xform[0] = hball.xform[5] = hball.xform[10] = hball.xform[15] = 1.0f;
  75         hball.rot.w = 1.0f;
  76
  77         if(!(spawnpos = malloc(NSPAWNPOS * sizeof *spawnpos)) ||
  78                         !(spawndir = malloc(NSPAWNPOS * sizeof *spawndir))) {
  79                 fprintf(stderr, "failed to allocate spawnpos/dir array\n");
  80                 return -1;
  81         }
  82
  83         for(i=0; i<NSPAWNPOS; i++) {
  84                 spawnpos[i] = spawndir[i] = sphrand(1.0f);
  85         }
  86
  87         return 0;
  88 }
  89
  90 static void destroy(void)
  91 {
  92 }
  93
  94 static void start(long trans_time)
  95 {
  96         g3d_matrix_mode(G3D_PROJECTION);
  97         g3d_load_identity();
  98         g3d_perspective(50.0, 1.33333, 0.5, 100.0);
  99
 100         start_time = time_msec;
 101 }
 102
 103 static void update(void)
 104 {
 105         static float prev_mx, prev_my;
 106         static long prev_msec;
 107         int mouse_dx, mouse_dy;
 108         long msec = time_msec - start_time;
 109         float dt = (msec - prev_msec) / 1000.0f;
 110         prev_msec = msec;
 111
 112         mouse_dx = mouse_x - prev_mx;
 113         mouse_dy = mouse_y - prev_my;
 114         prev_mx = mouse_x;
 115         prev_my = mouse_y;
 116
 117         if(mouse_bmask) {
 118                 hball.pos.x += mouse_dx * 0.05;
 119                 hball.pos.y -= mouse_dy * 0.05;
 120         }
 121
 122         //hball.rot = quat_rotate(hball.rot, dt * 2.0f, 0, 1, 0);
 123
 124         quat_to_mat(hball.xform, hball.rot);
 125         hball.xform[12] = hball.pos.x;
 126         hball.xform[13] = hball.pos.y;
 127         hball.xform[14] = hball.pos.z;
 128
 129         update_hairball(&hball, dt);
 130 }
 131
 132 static void draw(void)
 133 {
 134         unsigned long msec;
 135         static unsigned long last_swap;
 136
 137         update();
 138
 139         memset(fb_pixels, 0, fb_width * fb_height * 2);
 140
 141         g3d_matrix_mode(G3D_MODELVIEW);
 142         g3d_load_identity();
 143         g3d_translate(0, 0, -8);
 144
 145         draw_hairball(&hball);
 146
 147         msec = get_msec();
 148         if(msec - last_swap < 16) {
 149                 wait_vsync();
 150         }
 151         if(!opt.vsync) {
 152                 wait_vsync();
 153         }
 154         swap_buffers(fb_pixels);
 155         last_swap = get_msec();
 156 }
 157
 158 static void update_hairball(struct hairball *hb, float dt)
 159 {
 160         int i, j, spawn_count;
 161         struct particle pdummy, *prev, *p;
 162         static float spawn_acc;
 163
 164         /* update particles */
 165         for(i=0; i<NSPAWNPOS; i++) {
 166                 pdummy.next = hb->plist[i];
 167                 prev = &pdummy;
 168                 while(prev && prev->next) {
 169                         p = prev->next;
 170                         if(--p->life <= 0) {
 171                                 prev->next = p->next;
 172                                 pfree(p);
 173                                 prev = prev->next;
 174                                 continue;
 175                         }
 176
 177                         p->pos.x += p->vel.x * dt;
 178                         p->pos.y += p->vel.y * dt;
 179                         p->pos.z += p->vel.z * dt;
 180                         p->vel.y += GRAV * dt;
 181
 182                         p->r = p->g = p->b = (p->life << 8) / HAIR_LENGTH - 1;
 183
 184                         prev = p;
 185                 }
 186
 187                 hb->plist[i] = pdummy.next;
 188         }
 189
 190         /* spawn new particles */
 191         spawn_acc += dt;
 192         if(spawn_acc >= (1.0f / SPAWN_RATE)) {
 193                 for(i=0; i<NSPAWNPOS; i++) {
 194                         struct particle *p = palloc();
 195                         float *mat = hb->xform;
 196                         vec3_t pos = spawnpos[i];
 197
 198                         p->pos.x = mat[0] * pos.x + mat[4] * pos.y + mat[8] * pos.z + mat[12];
 199                         p->pos.y = mat[1] * pos.x + mat[5] * pos.y + mat[9] * pos.z + mat[13];
 200                         p->pos.z = mat[2] * pos.x + mat[6] * pos.y + mat[10] * pos.z + mat[14];
 201
 202                         p->vel = spawndir[i];
 203                         p->life = HAIR_LENGTH;
 204
 205                         p->next = hb->plist[i];
 206                         hb->plist[i] = p;
 207                 }
 208                 spawn_acc -= 1.0f / SPAWN_RATE;
 209         }
 210 }
 211
 212 static void draw_hairball(struct hairball *hb)
 213 {
 214         int i, j, col;
 215         struct particle *p;
 216         vec3_t prevpos;
 217
 218         g3d_begin(G3D_LINES);
 219         for(i=0; i<NSPAWNPOS; i++) {
 220                 p = hb->plist[i];
 221                 prevpos.x = hb->xform[0] * spawnpos[i].x + hb->xform[4] * spawnpos[i].y + hb->xform[8] * spawnpos[i].z + hb->xform[12];
 222                 prevpos.y = hb->xform[1] * spawnpos[i].x + hb->xform[5] * spawnpos[i].y + hb->xform[9] * spawnpos[i].z + hb->xform[13];
 223                 prevpos.z = hb->xform[2] * spawnpos[i].x + hb->xform[6] * spawnpos[i].y + hb->xform[10] * spawnpos[i].z + hb->xform[14];
 224
 225                 j = 0;
 226                 while(p) {
 227                         g3d_color3b(p->r, p->g, p->b);
 228                         g3d_vertex(prevpos.x, prevpos.y, prevpos.z);
 229                         g3d_vertex(p->pos.x, p->pos.y, p->pos.z);
 230                         prevpos = p->pos;
 231                         p = p->next;
 232                 }
 233         }
 234         g3d_end();
 235 }
 236
 237
 238 static struct particle *palloc(void)
 239 {
 240         return malloc(sizeof(struct particle));
 241 }
 242
 243 void pfree(struct particle *p)
 244 {
 245         free(p);
 246 }