vehicle.h

   1 #ifndef VEHICLE_H
   2 #define VEHICLE_H
   3
   4 #define VG_GAME
   5 #include "vg/vg.h"
   6 #include "rigidbody.h"
   7 #include "world.h"
   8 #include "player_physics.h"
   9
  10 VG_STATIC float k_car_spring = 1.0f,
  11                 k_car_spring_damp = 0.001f,
  12                 k_car_spring_length = 0.5f,
  13                 k_car_wheel_radius = 0.2f,
  14                 k_car_friction_lat = 0.6f,
  15                 k_car_friction_roll = 0.01f,
  16                 k_car_drive_force = 1.0f,
  17                 k_car_air_resistance = 0.1f,
  18                 k_car_downforce      = 0.5f;
  19
  20 VG_STATIC struct gvehicle
  21 {
  22    int alive, inside;
  23    rigidbody rb;
  24
  25    v3f wheels[4];
  26
  27    float tangent_mass[4][2],
  28          normal_forces[4],
  29          tangent_forces[4][2];
  30
  31    float steer, drive;
  32    v3f steerv;
  33
  34    v3f   tangent_vectors[4][2];
  35    v3f   wheels_local[4];
  36 }
  37 gzoomer =
  38 {
  39    .rb = { .type = k_rb_shape_sphere, .inf.sphere.radius = 1.0f }
  40 };
  41
  42 VG_STATIC int spawn_car( int argc, const char *argv[] )
  43 {
  44    v3f ra, rb, rx;
  45    v3_copy( main_camera.pos, ra );
  46    v3_muladds( ra, main_camera.transform[2], -10.0f, rb );
  47
  48    float t;
  49    if( spherecast_world( ra, rb, gzoomer.rb.inf.sphere.radius, &t, rx ) != -1 )
  50    {
  51       v3_lerp( ra, rb, t, gzoomer.rb.co );
  52       gzoomer.rb.co[1] += 4.0f;
  53       q_axis_angle( gzoomer.rb.q, (v3f){1.0f,0.0f,0.0f}, 0.001f );
  54       v3_zero( gzoomer.rb.v );
  55       v3_zero( gzoomer.rb.w );
  56
  57       rb_update_transform( &gzoomer.rb );
  58       gzoomer.alive = 1;
  59
  60       vg_success( "Spawned car\n" );
  61    }
  62    else
  63    {
  64       vg_error( "Can't spawn here\n" );
  65    }
  66
  67    return 0;
  68 }
  69
  70 VG_STATIC void vehicle_init(void)
  71 {
  72    q_identity( gzoomer.rb.q );
  73    rb_init( &gzoomer.rb );
  74
  75    VG_VAR_F32_PERSISTENT( k_car_spring );
  76    VG_VAR_F32_PERSISTENT( k_car_spring_damp );
  77    VG_VAR_F32_PERSISTENT( k_car_spring_length );
  78    VG_VAR_F32_PERSISTENT( k_car_wheel_radius );
  79    VG_VAR_F32_PERSISTENT( k_car_friction_lat );
  80    VG_VAR_F32_PERSISTENT( k_car_friction_roll );
  81    VG_VAR_F32_PERSISTENT( k_car_drive_force );
  82    VG_VAR_F32_PERSISTENT( k_car_air_resistance );
  83    VG_VAR_F32_PERSISTENT( k_car_downforce );
  84
  85    VG_VAR_I32( gzoomer.inside );
  86
  87         vg_function_push( (struct vg_cmd){
  88                 .name = "spawn_car",
  89                 .function = spawn_car
  90         });
  91
  92    v3_copy((v3f){ -1.0f, -0.25f, -1.5f }, gzoomer.wheels_local[0] );
  93    v3_copy((v3f){  1.0f, -0.25f, -1.5f }, gzoomer.wheels_local[1] );
  94    v3_copy((v3f){ -1.0f, -0.25f,  1.5f }, gzoomer.wheels_local[2] );
  95    v3_copy((v3f){  1.0f, -0.25f,  1.5f }, gzoomer.wheels_local[3] );
  96 }
  97
  98 VG_STATIC void vehicle_wheel_force( int index )
  99 {
 100    v3f pa, pb, n;
 101    m4x3_mulv( gzoomer.rb.to_world, gzoomer.wheels_local[index], pa );
 102    v3_muladds( pa, gzoomer.rb.up, -k_car_spring_length, pb );
 103
 104
 105 #if 1
 106    float t;
 107    if( spherecast_world( pa, pb, k_car_wheel_radius, &t, n ) == -1 )
 108       t = 1.0f;
 109
 110 #else
 111
 112    v3f dir;
 113    v3_muls( gzoomer.rb.up, -1.0f, dir );
 114
 115    ray_hit hit;
 116    hit.dist = k_car_spring_length;
 117    ray_world( pa, dir, &hit );
 118
 119    float t = hit.dist / k_car_spring_length;
 120
 121 #endif
 122
 123    v3f pc;
 124    v3_lerp( pa, pb, t, pc );
 125
 126    m4x3f mtx;
 127    m3x3_copy( gzoomer.rb.to_world, mtx );
 128    v3_copy( pc, mtx[3] );
 129    debug_sphere( mtx, k_car_wheel_radius, VG__BLACK );
 130    vg_line( pa, pc, VG__WHITE );
 131    v3_copy( pc, gzoomer.wheels[index] );
 132
 133    if( t < 1.0f )
 134    {
 135       /* spring force */
 136       float Fv = (1.0f-t) * k_car_spring*k_rb_delta;
 137
 138       v3f delta;
 139       v3_sub( pa, gzoomer.rb.co, delta );
 140
 141       v3f rv;
 142       v3_cross( gzoomer.rb.w, delta, rv );
 143       v3_add( gzoomer.rb.v, rv, rv );
 144
 145       Fv += v3_dot( rv, gzoomer.rb.up ) * -k_car_spring_damp*k_rb_delta;
 146
 147       /* scale by normal incident */
 148       Fv *= v3_dot( n, gzoomer.rb.up );
 149
 150       v3f F;
 151       v3_muls( gzoomer.rb.up, Fv, F );
 152
 153       rb_linear_impulse( &gzoomer.rb, delta, F );
 154
 155       /* friction vectors
 156        * -------------------------------------------------------------*/
 157       v3f tx, ty;
 158
 159       if( index <= 1 )
 160          v3_cross( gzoomer.steerv, n, tx );
 161       else
 162          v3_cross( gzoomer.rb.forward, n, tx );
 163       v3_cross( tx, n, ty );
 164
 165       v3_copy( tx, gzoomer.tangent_vectors[ index ][0] );
 166       v3_copy( ty, gzoomer.tangent_vectors[ index ][1] );
 167
 168       gzoomer.normal_forces[ index ] = Fv;
 169       gzoomer.tangent_forces[ index ][0] = 0.0f;
 170       gzoomer.tangent_forces[ index ][1] = 0.0f;
 171
 172       /* orient inverse inertia tensors */
 173       v3f raW;
 174       m3x3_mulv( gzoomer.rb.to_world, gzoomer.wheels_local[index], raW );
 175
 176       v3f raCtx, raCtxI, raCty, raCtyI;
 177       v3_cross( tx, raW, raCtx );
 178       v3_cross( ty, raW, raCty );
 179       m3x3_mulv( gzoomer.rb.iIw, raCtx, raCtxI );
 180       m3x3_mulv( gzoomer.rb.iIw, raCty, raCtyI );
 181
 182       gzoomer.tangent_mass[index][0] = gzoomer.rb.inv_mass;
 183       gzoomer.tangent_mass[index][0] += v3_dot( raCtx, raCtxI );
 184       gzoomer.tangent_mass[index][0] = 1.0f/gzoomer.tangent_mass[index][0];
 185
 186       gzoomer.tangent_mass[index][1] = gzoomer.rb.inv_mass;
 187       gzoomer.tangent_mass[index][1] += v3_dot( raCty, raCtyI );
 188       gzoomer.tangent_mass[index][1] = 1.0f/gzoomer.tangent_mass[index][1];
 189
 190       /* apply drive force */
 191       if( index >= 2 )
 192       {
 193          v3_muls( ty, gzoomer.drive * k_car_drive_force * k_rb_delta, F );
 194          rb_linear_impulse( &gzoomer.rb, raW, F );
 195       }
 196    }
 197    else
 198    {
 199       gzoomer.normal_forces[ index ] = 0.0f;
 200       gzoomer.tangent_forces[ index ][0] = 0.0f;
 201       gzoomer.tangent_forces[ index ][1] = 0.0f;
 202    }
 203 }
 204
 205 VG_STATIC void vehicle_solve_friction(void)
 206 {
 207    for( int i=0; i<4; i++ )
 208    {
 209       v3f raW;
 210       m3x3_mulv( gzoomer.rb.to_world, gzoomer.wheels_local[i], raW );
 211
 212       v3f rv;
 213       v3_cross( gzoomer.rb.w, raW, rv );
 214       v3_add( gzoomer.rb.v, rv, rv );
 215
 216       float     fx = k_car_friction_lat * gzoomer.normal_forces[i],
 217                 fy = k_car_friction_roll * gzoomer.normal_forces[i],
 218                vtx = v3_dot( rv, gzoomer.tangent_vectors[i][0] ),
 219                vty = v3_dot( rv, gzoomer.tangent_vectors[i][1] ),
 220            lambdax = gzoomer.tangent_mass[i][0] * -vtx,
 221            lambday = gzoomer.tangent_mass[i][1] * -vty;
 222
 223       float tempx = gzoomer.tangent_forces[i][0],
 224             tempy = gzoomer.tangent_forces[i][1];
 225       gzoomer.tangent_forces[i][0] = vg_clampf( tempx + lambdax, -fx, fx );
 226       gzoomer.tangent_forces[i][1] = vg_clampf( tempy + lambday, -fy, fy );
 227       lambdax = gzoomer.tangent_forces[i][0] - tempx;
 228       lambday = gzoomer.tangent_forces[i][1] - tempy;
 229
 230       v3f impulsex, impulsey;
 231       v3_muls( gzoomer.tangent_vectors[i][0], lambdax, impulsex );
 232       v3_muls( gzoomer.tangent_vectors[i][1], lambday, impulsey );
 233       rb_linear_impulse( &gzoomer.rb, raW, impulsex );
 234       rb_linear_impulse( &gzoomer.rb, raW, impulsey );
 235    }
 236 }
 237
 238 VG_STATIC void vehicle_update_fixed(void)
 239 {
 240    if( !gzoomer.alive )
 241       return;
 242
 243    gzoomer.steer = vg_lerpf( gzoomer.steer,
 244                              player.input_walkh->axis.value * 0.4f,
 245                              k_rb_delta * 8.0f );
 246
 247    gzoomer.drive = player.input_walkv->axis.value * k_car_drive_force;
 248    v3_muls( gzoomer.rb.forward, cosf(gzoomer.steer), gzoomer.steerv );
 249    v3_muladds( gzoomer.steerv, gzoomer.rb.right,
 250                sinf(gzoomer.steer), gzoomer.steerv );
 251
 252    /* apply air resistance */
 253    v3f Fair, Fdown;
 254
 255    v3_muls( gzoomer.rb.v, -k_car_air_resistance, Fair );
 256    v3_muls( gzoomer.rb.up, -fabsf(v3_dot( gzoomer.rb.v, gzoomer.rb.forward )) *
 257                                  k_car_downforce, Fdown );
 258
 259    v3_muladds( gzoomer.rb.v, Fair,  k_rb_delta, gzoomer.rb.v );
 260    v3_muladds( gzoomer.rb.v, Fdown, k_rb_delta, gzoomer.rb.v );
 261
 262    for( int i=0; i<4; i++ )
 263       vehicle_wheel_force( i );
 264
 265    rb_ct manifold[64];
 266
 267    int len = rb_sphere_scene( &gzoomer.rb, &world.rb_geo, manifold );
 268    rb_manifold_filter_coplanar( manifold, len, 0.05f );
 269
 270    if( len > 1 )
 271    {
 272       rb_manifold_filter_backface( manifold, len );
 273       rb_manifold_filter_joint_edges( manifold, len, 0.05f );
 274       rb_manifold_filter_pairs( manifold, len, 0.05f );
 275    }
 276    len = rb_manifold_apply_filtered( manifold, len );
 277
 278    rb_presolve_contacts( manifold, len );
 279    for( int i=0; i<8; i++ )
 280    {
 281       rb_solve_contacts( manifold, len );
 282       vehicle_solve_friction();
 283    }
 284
 285    rb_iter( &gzoomer.rb );
 286    rb_update_transform( &gzoomer.rb );
 287 }
 288
 289 VG_STATIC void vehicle_update_post(void)
 290 {
 291    if( !gzoomer.alive )
 292       return;
 293
 294    rb_debug( &gzoomer.rb, VG__WHITE );
 295    vg_line( player.phys.rb.co, gzoomer.rb.co, VG__WHITE );
 296
 297    /* draw friction vectors */
 298    v3f p0, px, py;
 299
 300    for( int i=0; i<4; i++ )
 301    {
 302       v3_copy( gzoomer.wheels[i], p0 );
 303       v3_muladds( p0, gzoomer.tangent_vectors[i][0], 0.5f, px );
 304       v3_muladds( p0, gzoomer.tangent_vectors[i][1], 0.5f, py );
 305
 306       vg_line( p0, px, VG__RED );
 307       vg_line( p0, py, VG__GREEN );
 308    }
 309 }
 310
 311 VG_STATIC void vehicle_camera(void)
 312 {
 313    float yaw = atan2f( gzoomer.rb.forward[0], -gzoomer.rb.forward[2] ),
 314        pitch = atan2f
 315                (
 316                    -gzoomer.rb.forward[1],
 317                    sqrtf
 318                    (
 319                      gzoomer.rb.forward[0]*gzoomer.rb.forward[0] +
 320                      gzoomer.rb.forward[2]*gzoomer.rb.forward[2]
 321                    )
 322                );
 323
 324
 325    main_camera.angles[0] = yaw;
 326    main_camera.angles[1] = pitch;
 327    v3_copy( gzoomer.rb.co, main_camera.pos );
 328 }
 329
 330 #endif /* VEHICLE_H */