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

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <math.h>
   5 #include <assert.h>
   6 #include "screen.h"
   7 #include "demo.h"
   8 #include "3dgfx.h"
   9 #include "gfxutil.h"
  10 #include "util.h"
  11 #include "metasurf.h"
  12
  13 struct mesh {
  14         int prim;
  15         struct g3d_vertex *varr;
  16         int16_t *iarr;
  17         int vcount, icount;
  18 };
  19
  20 struct metaball {
  21         float energy;
  22         float pos[3];
  23 };
  24
  25 static int init(void);
  26 static void destroy(void);
  27 static void start(long trans_time);
  28 static void draw(void);
  29 static void draw_mesh(struct mesh *mesh);
  30 static void zsort(struct mesh *m);
  31
  32 static void calc_voxel_field(void);
  33
  34 static struct screen scr = {
  35         "metaballs",
  36         init,
  37         destroy,
  38         start, 0,
  39         draw
  40 };
  41
  42 static float cam_theta, cam_phi = 25;
  43 static float cam_dist = 10;
  44 static struct mesh mmesh;
  45
  46 static struct metasurface *msurf;
  47
  48 #define VOL_SZ  32
  49 #define VOL_SCALE       10.0f
  50 #define VOX_DIST        (VOL_SCALE / VOL_SZ)
  51 #define VOL_HALF_SCALE  (VOL_SCALE * 0.5f)
  52
  53 #define NUM_MBALLS      3
  54 static struct metaball mball[NUM_MBALLS];
  55
  56 static int dbg;
  57
  58 struct screen *metaballs_screen(void)
  59 {
  60         return &scr;
  61 }
  62
  63 static int init(void)
  64 {
  65         mball[0].energy = 1.2;
  66         mball[1].energy = 0.8;
  67         mball[2].energy = 1.0;
  68
  69         if(!(msurf = msurf_create())) {
  70                 fprintf(stderr, "failed to initialize metasurf\n");
  71                 return -1;
  72         }
  73         msurf_set_resolution(msurf, VOL_SZ, VOL_SZ, VOL_SZ);
  74         msurf_set_bounds(msurf, -VOL_HALF_SCALE, -VOL_HALF_SCALE, -VOL_HALF_SCALE,
  75                         VOL_HALF_SCALE, VOL_HALF_SCALE, VOL_HALF_SCALE);
  76         msurf_set_threshold(msurf, 1.7);
  77         msurf_set_inside(msurf, MSURF_GREATER);
  78
  79         mmesh.prim = G3D_TRIANGLES;
  80         mmesh.varr = 0;
  81         mmesh.iarr = 0;
  82         mmesh.vcount = mmesh.icount = 0;
  83
  84         return 0;
  85 }
  86
  87 static void destroy(void)
  88 {
  89         msurf_free(msurf);
  90 }
  91
  92 static void start(long trans_time)
  93 {
  94         g3d_matrix_mode(G3D_PROJECTION);
  95         g3d_load_identity();
  96         g3d_perspective(50.0, 1.3333333, 0.5, 100.0);
  97
  98         g3d_enable(G3D_CULL_FACE);
  99         g3d_enable(G3D_LIGHTING);
 100         g3d_enable(G3D_LIGHT0);
 101
 102         g3d_polygon_mode(G3D_GOURAUD);
 103 }
 104
 105 static void update(void)
 106 {
 107         static int prev_mx, prev_my;
 108         static unsigned int prev_bmask;
 109
 110         if(mouse_bmask) {
 111                 if((mouse_bmask ^ prev_bmask) == 0) {
 112                         int dx = mouse_x - prev_mx;
 113                         int dy = mouse_y - prev_my;
 114
 115                         if(dx || dy) {
 116                                 if(mouse_bmask & 1) {
 117                                         cam_theta += dx * 1.0;
 118                                         cam_phi += dy * 1.0;
 119
 120                                         if(cam_phi < -90) cam_phi = -90;
 121                                         if(cam_phi > 90) cam_phi = 90;
 122                                 }
 123                                 if(mouse_bmask & 4) {
 124                                         cam_dist += dy * 0.5;
 125
 126                                         if(cam_dist < 0) cam_dist = 0;
 127                                 }
 128                         }
 129                 }
 130         }
 131         prev_mx = mouse_x;
 132         prev_my = mouse_y;
 133         prev_bmask = mouse_bmask;
 134
 135         {
 136                 int i, j;
 137                 float tsec = time_msec / 1000.0f;
 138                 static float phase[] = {0.0, M_PI / 3.0, M_PI * 0.8};
 139                 static float speed[] = {0.8, 1.4, 1.0};
 140                 static float scale[][3] = {{1, 2, 0.8}, {0.5, 1.6, 0.6}, {1.5, 0.7, 0.5}};
 141                 static float offset[][3] = {{0, 0, 0}, {0.25, 0, 0}, {-0.2, 0.15, 0.2}};
 142
 143                 for(i=0; i<NUM_MBALLS; i++) {
 144                         float t = (tsec + phase[i]) * speed[i];
 145
 146                         for(j=0; j<3; j++) {
 147                                 float x = sin(t + j * M_PI / 2.0);
 148                                 mball[i].pos[j] = offset[i][j] + x * scale[i][j];
 149                         }
 150                 }
 151         }
 152
 153         calc_voxel_field();
 154         msurf_polygonize(msurf);
 155
 156         mmesh.vcount = msurf_vertex_count(msurf);
 157         mmesh.varr = msurf_vertices(msurf);
 158 }
 159
 160 static void draw(void)
 161 {
 162         update();
 163
 164         memset(fb_pixels, 0, fb_width * fb_height * 2);
 165
 166         g3d_matrix_mode(G3D_MODELVIEW);
 167         g3d_load_identity();
 168         g3d_translate(0, 0, -cam_dist);
 169         g3d_rotate(cam_phi, 1, 0, 0);
 170         g3d_rotate(cam_theta, 0, 1, 0);
 171
 172         g3d_light_pos(0, -10, 10, 20);
 173
 174         zsort(&mmesh);
 175
 176         g3d_mtl_diffuse(0.6, 0.6, 0.6);
 177
 178         draw_mesh(&mmesh);
 179
 180         swap_buffers(fb_pixels);
 181 }
 182
 183 static void draw_mesh(struct mesh *mesh)
 184 {
 185         if(mesh->iarr) {
 186                 g3d_draw_indexed(mesh->prim, mesh->varr, mesh->vcount, mesh->iarr, mesh->icount);
 187         } else {
 188                 g3d_draw(mesh->prim, mesh->varr, mesh->vcount);
 189         }
 190 }
 191
 192 static struct {
 193         struct g3d_vertex *varr;
 194         const float *xform;
 195 } zsort_cls;
 196
 197 static int zsort_cmp(const void *aptr, const void *bptr)
 198 {
 199         const float *m = zsort_cls.xform;
 200
 201         const struct g3d_vertex *va = (const struct g3d_vertex*)aptr;
 202         const struct g3d_vertex *vb = (const struct g3d_vertex*)bptr;
 203
 204         float za = m[2] * va->x + m[6] * va->y + m[10] * va->z + m[14];
 205         float zb = m[2] * vb->x + m[6] * vb->y + m[10] * vb->z + m[14];
 206
 207         ++va;
 208         ++vb;
 209
 210         za += m[2] * va->x + m[6] * va->y + m[10] * va->z + m[14];
 211         zb += m[2] * vb->x + m[6] * vb->y + m[10] * vb->z + m[14];
 212
 213         return za - zb;
 214 }
 215
 216 static void zsort(struct mesh *m)
 217 {
 218         int nfaces = m->vcount / m->prim;
 219
 220         zsort_cls.varr = m->varr;
 221         zsort_cls.xform = g3d_get_matrix(G3D_MODELVIEW, 0);
 222
 223         qsort(m->varr, nfaces, m->prim * sizeof *m->varr, zsort_cmp);
 224 }
 225
 226 static void calc_voxel_field(void)
 227 {
 228         int i, j, k, b;
 229         float *voxptr;
 230
 231         if(!(voxptr = msurf_voxels(msurf))) {
 232                 fprintf(stderr, "failed to allocate voxel field\n");
 233                 abort();
 234         }
 235
 236         for(i=0; i<VOL_SZ; i++) {
 237                 float z = -VOL_HALF_SCALE + i * VOX_DIST;
 238
 239                 for(j=0; j<VOL_SZ; j++) {
 240                         float y = -VOL_HALF_SCALE + j * VOX_DIST;
 241
 242                         for(k=0; k<VOL_SZ; k++) {
 243                                 float x = -VOL_HALF_SCALE + k * VOX_DIST;
 244
 245                                 float val = 0.0f;
 246                                 for(b=0; b<NUM_MBALLS; b++) {
 247                                         float dx = mball[b].pos[0] - x;
 248                                         float dy = mball[b].pos[1] - y;
 249                                         float dz = mball[b].pos[2] - z;
 250
 251                                         float lensq = dx * dx + dy * dy + dz * dz;
 252
 253                                         val += lensq == 0.0f ? 1024.0f : mball[b].energy / lensq;
 254                                 }
 255
 256                                 *voxptr++ = val;
 257                         }
 258                 }
 259         }
 260         ++dbg;
 261 }