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 #include "mesh.h"
  11
  12
  13 #ifdef MSDOS
  14 #include "dos/gfx.h"    /* for wait_vsync assembly macro */
  15 #else
  16 void wait_vsync(void);
  17 #endif
  18
  19 #define NSPAWNPOS       64
  20 #define SPAWN_RATE      16.0f
  21 //#define GRAV          (-6.0f)
  22 #define GRAV            0.0f
  23 #define HAIR_LENGTH 20
  24
  25 struct particle {
  26         vec3_t pos;
  27         vec3_t vel;
  28         int r, g, b, a;
  29         int life;
  30
  31         struct particle *next;
  32 };
  33
  34 struct hairball {
  35         vec3_t pos;
  36         quat_t rot;
  37         float xform[16];
  38
  39         struct particle *plist[NSPAWNPOS];
  40 };
  41
  42 static int init(void);
  43 static void destroy(void);
  44 static void start(long trans_time);
  45 static void draw(void);
  46 static void update_hairball(struct hairball *hb, float dt);
  47 static void draw_hairball(struct hairball *hb);
  48
  49 static struct particle *palloc(void);
  50 void pfree(struct particle *p);
  51
  52
  53 static struct screen scr = {
  54         "hairball",
  55         init,
  56         destroy,
  57         start, 0,
  58         draw
  59 };
  60
  61 static long start_time;
  62
  63 static float cam_theta, cam_phi = 15;
  64 static float cam_dist = 8;
  65
  66 static vec3_t *spawnpos, *spawndir;
  67 static struct hairball hball;
  68 static struct g3d_mesh sphmesh;
  69
  70 struct screen *hairball_screen(void)
  71 {
  72         return &scr;
  73 }
  74
  75 static int init(void)
  76 {
  77         int i;
  78
  79         gen_sphere_mesh(&sphmesh, 1.0f, 12, 6);
  80
  81         hball.xform[0] = hball.xform[5] = hball.xform[10] = hball.xform[15] = 1.0f;
  82         hball.rot.w = 1.0f;
  83
  84         if(!(spawnpos = malloc(NSPAWNPOS * sizeof *spawnpos)) ||
  85                         !(spawndir = malloc(NSPAWNPOS * sizeof *spawndir))) {
  86                 fprintf(stderr, "failed to allocate spawnpos/dir array\n");
  87                 return -1;
  88         }
  89
  90         for(i=0; i<NSPAWNPOS; i++) {
  91                 spawnpos[i] = spawndir[i] = sphrand(1.0f);
  92         }
  93
  94         return 0;
  95 }
  96
  97 static void destroy(void)
  98 {
  99 }
 100
 101 static void start(long trans_time)
 102 {
 103         g3d_matrix_mode(G3D_PROJECTION);
 104         g3d_load_identity();
 105         g3d_perspective(50.0, 1.33333, 0.5, 100.0);
 106
 107         start_time = time_msec;
 108 }
 109
 110 static void update(void)
 111 {
 112         static float prev_mx, prev_my;
 113         static long prev_msec;
 114         int mouse_dx, mouse_dy;
 115         long msec = time_msec - start_time;
 116         float dt = (msec - prev_msec) / 1000.0f;
 117         prev_msec = msec;
 118
 119         mouse_dx = mouse_x - prev_mx;
 120         mouse_dy = mouse_y - prev_my;
 121         prev_mx = mouse_x;
 122         prev_my = mouse_y;
 123
 124
 125         if(opt.sball) {
 126                 memcpy(hball.xform, sball_matrix, 16 * sizeof(float));
 127         } else {
 128                 if(mouse_bmask & MOUSE_BN_MIDDLE) {
 129                         hball.pos.x += mouse_dx * 0.05;
 130                         hball.pos.y -= mouse_dy * 0.05;
 131                 }
 132
 133                 quat_to_mat(hball.xform, hball.rot);
 134                 hball.xform[12] = hball.pos.x;
 135                 hball.xform[13] = hball.pos.y;
 136                 hball.xform[14] = hball.pos.z;
 137         }
 138
 139         update_hairball(&hball, dt);
 140
 141         mouse_orbit_update(&cam_theta, &cam_phi, &cam_dist);
 142 }
 143
 144 static void draw(void)
 145 {
 146         unsigned long msec;
 147         static unsigned long last_swap;
 148
 149         update();
 150
 151         memset(fb_pixels, 0, fb_width * fb_height * 2);
 152
 153         g3d_matrix_mode(G3D_MODELVIEW);
 154         g3d_load_identity();
 155         g3d_translate(0, 0, -cam_dist);
 156         g3d_rotate(cam_phi, 1, 0, 0);
 157         g3d_rotate(cam_theta, 0, 1, 0);
 158
 159         draw_hairball(&hball);
 160
 161         msec = get_msec();
 162         if(msec - last_swap < 16) {
 163                 wait_vsync();
 164         }
 165         if(!opt.vsync) {
 166                 wait_vsync();
 167         }
 168         swap_buffers(fb_pixels);
 169         last_swap = get_msec();
 170 }
 171
 172 static void update_hairball(struct hairball *hb, float dt)
 173 {
 174         int i, j, spawn_count;
 175         struct particle pdummy, *prev, *p;
 176         static float spawn_acc;
 177
 178         /* update particles */
 179         for(i=0; i<NSPAWNPOS; i++) {
 180                 pdummy.next = hb->plist[i];
 181                 prev = &pdummy;
 182                 while(prev && prev->next) {
 183                         p = prev->next;
 184                         if(--p->life <= 0) {
 185                                 prev->next = p->next;
 186                                 pfree(p);
 187                                 prev = prev->next;
 188                                 continue;
 189                         }
 190
 191                         p->pos.x += p->vel.x * dt;
 192                         p->pos.y += p->vel.y * dt;
 193                         p->pos.z += p->vel.z * dt;
 194                         p->vel.y += GRAV * dt;
 195
 196                         p->r = p->g = p->b = (p->life << 8) / HAIR_LENGTH - 1;
 197
 198                         prev = p;
 199                 }
 200
 201                 hb->plist[i] = pdummy.next;
 202         }
 203
 204         /* spawn new particles */
 205         spawn_acc += dt;
 206         if(spawn_acc >= (1.0f / SPAWN_RATE)) {
 207                 for(i=0; i<NSPAWNPOS; i++) {
 208                         struct particle *p = palloc();
 209                         float *mat = hb->xform;
 210                         vec3_t pos = spawnpos[i];
 211
 212                         p->pos.x = mat[0] * pos.x + mat[4] * pos.y + mat[8] * pos.z + mat[12];
 213                         p->pos.y = mat[1] * pos.x + mat[5] * pos.y + mat[9] * pos.z + mat[13];
 214                         p->pos.z = mat[2] * pos.x + mat[6] * pos.y + mat[10] * pos.z + mat[14];
 215
 216                         p->vel = spawndir[i];
 217                         p->life = HAIR_LENGTH;
 218
 219                         p->next = hb->plist[i];
 220                         hb->plist[i] = p;
 221                 }
 222                 spawn_acc -= 1.0f / SPAWN_RATE;
 223         }
 224 }
 225
 226 static void draw_hairball(struct hairball *hb)
 227 {
 228         int i, col;
 229         struct particle *p;
 230         vec3_t prevpos;
 231         vec3_t start[NSPAWNPOS];
 232
 233         for(i=0; i<NSPAWNPOS; i++) {
 234                 start[i].x = hb->xform[0] * spawnpos[i].x + hb->xform[4] * spawnpos[i].y + hb->xform[8] * spawnpos[i].z + hb->xform[12];
 235                 start[i].y = hb->xform[1] * spawnpos[i].x + hb->xform[5] * spawnpos[i].y + hb->xform[9] * spawnpos[i].z + hb->xform[13];
 236                 start[i].z = hb->xform[2] * spawnpos[i].x + hb->xform[6] * spawnpos[i].y + hb->xform[10] * spawnpos[i].z + hb->xform[14];
 237         }
 238
 239         g3d_begin(G3D_LINES);
 240         for(i=0; i<NSPAWNPOS; i++) {
 241                 if(start[i].z >= hb->pos.z) continue;
 242                 p = hb->plist[i];
 243                 prevpos = start[i];
 244                 while(p) {
 245                         g3d_color3b(p->r, p->g, p->b);
 246                         g3d_vertex(prevpos.x, prevpos.y, prevpos.z);
 247                         g3d_vertex(p->pos.x, p->pos.y, p->pos.z);
 248                         prevpos = p->pos;
 249                         p = p->next;
 250                 }
 251         }
 252         g3d_end();
 253
 254
 255         g3d_push_matrix();
 256         g3d_mult_matrix(hb->xform);
 257         zsort_mesh(&sphmesh);
 258         draw_mesh(&sphmesh);
 259         g3d_pop_matrix();
 260
 261         g3d_begin(G3D_LINES);
 262         for(i=0; i<NSPAWNPOS; i++) {
 263                 if(start[i].z < hb->pos.z) continue;
 264                 p = hb->plist[i];
 265                 prevpos = start[i];
 266                 while(p) {
 267                         g3d_color3b(p->r, p->g, p->b);
 268                         g3d_vertex(prevpos.x, prevpos.y, prevpos.z);
 269                         g3d_vertex(p->pos.x, p->pos.y, p->pos.z);
 270                         prevpos = p->pos;
 271                         p = p->next;
 272                 }
 273         }
 274         g3d_end();
 275
 276 }
 277
 278
 279 static struct particle *palloc(void)
 280 {
 281         return malloc(sizeof(struct particle));
 282 }
 283
 284 void pfree(struct particle *p)
 285 {
 286         free(p);
 287 }