vehicle.c

   1 #ifndef VEHICLE_C
   2 #define VEHICLE_C
   3
   4 #include "vehicle.h"
   5 #include "scene_rigidbody.h"
   6
   7 static int spawn_car( int argc, const char *argv[] ){
   8    v3f ra, rb, rx;
   9    v3_copy( skaterift.cam.pos, ra );
  10    v3_muladds( ra, skaterift.cam.transform[2], -10.0f, rb );
  11
  12    float t;
  13    if( spherecast_world( world_current_instance(),
  14                          ra, rb, 1.0f, &t, rx, 0 ) != -1 )
  15    {
  16       v3_lerp( ra, rb, t, gzoomer.rb.co );
  17       gzoomer.rb.co[1] += 4.0f;
  18       q_axis_angle( gzoomer.rb.q, (v3f){1.0f,0.0f,0.0f}, 0.001f );
  19       v3_zero( gzoomer.rb.v );
  20       v3_zero( gzoomer.rb.w );
  21
  22       rb_update_matrices( &gzoomer.rb );
  23       gzoomer.alive = 1;
  24
  25       vg_success( "Spawned car\n" );
  26    }
  27    else{
  28       vg_error( "Can't spawn here\n" );
  29    }
  30
  31    return 0;
  32 }
  33
  34 static void vehicle_init(void){
  35    q_identity( gzoomer.rb.q );
  36    v3_zero( gzoomer.rb.w );
  37    v3_zero( gzoomer.rb.v );
  38    v3_zero( gzoomer.rb.co );
  39    rb_setbody_sphere( &gzoomer.rb, 1.0f, 8.0f, 1.0f );
  40
  41    VG_VAR_F32( k_car_spring,        flags=VG_VAR_PERSISTENT );
  42    VG_VAR_F32( k_car_spring_damp,   flags=VG_VAR_PERSISTENT );
  43    VG_VAR_F32( k_car_spring_length, flags=VG_VAR_PERSISTENT );
  44    VG_VAR_F32( k_car_wheel_radius,  flags=VG_VAR_PERSISTENT );
  45    VG_VAR_F32( k_car_friction_lat,  flags=VG_VAR_PERSISTENT );
  46    VG_VAR_F32( k_car_friction_roll, flags=VG_VAR_PERSISTENT );
  47    VG_VAR_F32( k_car_drive_force,   flags=VG_VAR_PERSISTENT );
  48    VG_VAR_F32( k_car_air_resistance,flags=VG_VAR_PERSISTENT );
  49    VG_VAR_F32( k_car_downforce,     flags=VG_VAR_PERSISTENT );
  50
  51    VG_VAR_I32( gzoomer.inside );
  52
  53    vg_console_reg_cmd( "spawn_car", spawn_car, NULL );
  54
  55    v3_copy((v3f){ -1.0f, -0.25f, -1.5f }, gzoomer.wheels_local[0] );
  56    v3_copy((v3f){  1.0f, -0.25f, -1.5f }, gzoomer.wheels_local[1] );
  57    v3_copy((v3f){ -1.0f, -0.25f,  1.5f }, gzoomer.wheels_local[2] );
  58    v3_copy((v3f){  1.0f, -0.25f,  1.5f }, gzoomer.wheels_local[3] );
  59 }
  60
  61 static void vehicle_wheel_force( int index ){
  62    v3f pa, pb, n;
  63    m4x3_mulv( gzoomer.rb.to_world, gzoomer.wheels_local[index], pa );
  64    v3_muladds( pa, gzoomer.rb.to_world[1], -k_car_spring_length, pb );
  65
  66
  67 #if 1
  68    float t;
  69    if( spherecast_world( world_current_instance(), pa, pb,
  70                          k_car_wheel_radius, &t, n, 0 ) == -1 )
  71    { t = 1.0f;
  72    }
  73
  74 #else
  75
  76    v3f dir;
  77    v3_muls( gzoomer.rb.up, -1.0f, dir );
  78
  79    ray_hit hit;
  80    hit.dist = k_car_spring_length;
  81    ray_world( pa, dir, &hit );
  82
  83    float t = hit.dist / k_car_spring_length;
  84
  85 #endif
  86
  87    v3f pc;
  88    v3_lerp( pa, pb, t, pc );
  89
  90    m4x3f mtx;
  91    m3x3_copy( gzoomer.rb.to_world, mtx );
  92    v3_copy( pc, mtx[3] );
  93    vg_line_sphere( mtx, k_car_wheel_radius, VG__BLACK );
  94    vg_line( pa, pc, VG__WHITE );
  95    v3_copy( pc, gzoomer.wheels[index] );
  96
  97    if( t < 1.0f ){
  98       /* spring force */
  99       float Fv = (1.0f-t) * k_car_spring*vg.time_fixed_delta;
 100
 101       v3f delta;
 102       v3_sub( pa, gzoomer.rb.co, delta );
 103
 104       v3f rv;
 105       v3_cross( gzoomer.rb.w, delta, rv );
 106       v3_add( gzoomer.rb.v, rv, rv );
 107
 108       Fv += v3_dot(rv, gzoomer.rb.to_world[1])
 109                * -k_car_spring_damp*vg.time_fixed_delta;
 110
 111       /* scale by normal incident */
 112       Fv *= v3_dot( n, gzoomer.rb.to_world[1] );
 113
 114       v3f F;
 115       v3_muls( gzoomer.rb.to_world[1], Fv, F );
 116       rb_linear_impulse( &gzoomer.rb, delta, F );
 117
 118       /* friction vectors
 119        * -------------------------------------------------------------*/
 120       v3f tx, ty;
 121
 122       if( index <= 1 )
 123          v3_cross( gzoomer.steerv, n, tx );
 124       else
 125          v3_cross( n, gzoomer.rb.to_world[2], tx );
 126       v3_cross( tx, n, ty );
 127
 128       v3_copy( tx, gzoomer.tangent_vectors[ index ][0] );
 129       v3_copy( ty, gzoomer.tangent_vectors[ index ][1] );
 130
 131       gzoomer.normal_forces[ index ] = Fv;
 132       gzoomer.tangent_forces[ index ][0] = 0.0f;
 133       gzoomer.tangent_forces[ index ][1] = 0.0f;
 134
 135       /* orient inverse inertia tensors */
 136       v3f raW;
 137       m3x3_mulv( gzoomer.rb.to_world, gzoomer.wheels_local[index], raW );
 138
 139       v3f raCtx, raCtxI, raCty, raCtyI;
 140       v3_cross( tx, raW, raCtx );
 141       v3_cross( ty, raW, raCty );
 142       m3x3_mulv( gzoomer.rb.iIw, raCtx, raCtxI );
 143       m3x3_mulv( gzoomer.rb.iIw, raCty, raCtyI );
 144
 145       gzoomer.tangent_mass[index][0] = gzoomer.rb.inv_mass;
 146       gzoomer.tangent_mass[index][0] += v3_dot( raCtx, raCtxI );
 147       gzoomer.tangent_mass[index][0] = 1.0f/gzoomer.tangent_mass[index][0];
 148
 149       gzoomer.tangent_mass[index][1] = gzoomer.rb.inv_mass;
 150       gzoomer.tangent_mass[index][1] += v3_dot( raCty, raCtyI );
 151       gzoomer.tangent_mass[index][1] = 1.0f/gzoomer.tangent_mass[index][1];
 152
 153       /* apply drive force */
 154       if( index >= 2 ){
 155          v3_muls( ty, -gzoomer.drive * k_car_drive_force
 156                                      * vg.time_fixed_delta, F );
 157          rb_linear_impulse( &gzoomer.rb, raW, F );
 158       }
 159    }
 160    else{
 161       gzoomer.normal_forces[ index ] = 0.0f;
 162       gzoomer.tangent_forces[ index ][0] = 0.0f;
 163       gzoomer.tangent_forces[ index ][1] = 0.0f;
 164    }
 165 }
 166
 167 static void vehicle_solve_friction(void){
 168    rigidbody *rb = &gzoomer.rb;
 169    for( int i=0; i<4; i++ ){
 170       v3f raW;
 171       m3x3_mulv( rb->to_world, gzoomer.wheels_local[i], raW );
 172
 173       v3f rv;
 174       v3_cross( rb->w, raW, rv );
 175       v3_add( rb->v, rv, rv );
 176
 177       float     fx = k_car_friction_lat * gzoomer.normal_forces[i],
 178                 fy = k_car_friction_roll * gzoomer.normal_forces[i],
 179                vtx = v3_dot( rv, gzoomer.tangent_vectors[i][0] ),
 180                vty = v3_dot( rv, gzoomer.tangent_vectors[i][1] ),
 181            lambdax = gzoomer.tangent_mass[i][0] * -vtx,
 182            lambday = gzoomer.tangent_mass[i][1] * -vty;
 183
 184       float tempx = gzoomer.tangent_forces[i][0],
 185             tempy = gzoomer.tangent_forces[i][1];
 186       gzoomer.tangent_forces[i][0] = vg_clampf( tempx + lambdax, -fx, fx );
 187       gzoomer.tangent_forces[i][1] = vg_clampf( tempy + lambday, -fy, fy );
 188       lambdax = gzoomer.tangent_forces[i][0] - tempx;
 189       lambday = gzoomer.tangent_forces[i][1] - tempy;
 190
 191       v3f impulsex, impulsey;
 192       v3_muls( gzoomer.tangent_vectors[i][0], lambdax, impulsex );
 193       v3_muls( gzoomer.tangent_vectors[i][1], lambday, impulsey );
 194       rb_linear_impulse( rb, raW, impulsex );
 195       rb_linear_impulse( rb, raW, impulsey );
 196    }
 197 }
 198
 199 static void vehicle_update_fixed(void)
 200 {
 201    if( !gzoomer.alive )
 202       return;
 203
 204    rigidbody *rb = &gzoomer.rb;
 205
 206    v3_muls( rb->to_world[2], -cosf(gzoomer.steer), gzoomer.steerv );
 207    v3_muladds( gzoomer.steerv, rb->to_world[0],
 208                sinf(gzoomer.steer), gzoomer.steerv );
 209
 210    /* apply air resistance */
 211    v3f Fair, Fdown;
 212
 213    v3_muls( rb->v, -k_car_air_resistance, Fair );
 214    v3_muls( rb->to_world[1], -fabsf(v3_dot( rb->v, rb->to_world[2] )) *
 215                                  k_car_downforce, Fdown );
 216
 217    v3_muladds( rb->v, Fair,  vg.time_fixed_delta, rb->v );
 218    v3_muladds( rb->v, Fdown, vg.time_fixed_delta, rb->v );
 219
 220    for( int i=0; i<4; i++ )
 221       vehicle_wheel_force( i );
 222
 223    rigidbody _null = {0};
 224    _null.inv_mass = 0.0f;
 225    m3x3_zero( _null.iI );
 226
 227    rb_ct manifold[64];
 228    int len = rb_sphere__scene( rb->to_world, 1.0f, NULL,
 229                                world_current_instance()->geo_bh,
 230                                manifold, 0 );
 231    for( int j=0; j<len; j++ ){
 232       manifold[j].rba = rb;
 233       manifold[j].rbb = &_null;
 234    }
 235    rb_manifold_filter_coplanar( manifold, len, 0.05f );
 236
 237    if( len > 1 ){
 238       rb_manifold_filter_backface( manifold, len );
 239       rb_manifold_filter_joint_edges( manifold, len, 0.05f );
 240       rb_manifold_filter_pairs( manifold, len, 0.05f );
 241    }
 242    len = rb_manifold_apply_filtered( manifold, len );
 243
 244    rb_presolve_contacts( manifold, vg.time_fixed_delta, len );
 245    for( int i=0; i<8; i++ ){
 246       rb_solve_contacts( manifold, len );
 247       vehicle_solve_friction();
 248    }
 249
 250    rb_iter( rb );
 251    rb_update_matrices( rb );
 252 }
 253
 254 static void vehicle_update_post(void){
 255    if( !gzoomer.alive )
 256       return;
 257
 258    vg_line_sphere( gzoomer.rb.to_world, 1.0f, VG__WHITE );
 259
 260    /* draw friction vectors */
 261    v3f p0, px, py;
 262
 263    for( int i=0; i<4; i++ ){
 264       v3_copy( gzoomer.wheels[i], p0 );
 265       v3_muladds( p0, gzoomer.tangent_vectors[i][0], 0.5f, px );
 266       v3_muladds( p0, gzoomer.tangent_vectors[i][1], 0.5f, py );
 267
 268       vg_line( p0, px, VG__RED );
 269       vg_line( p0, py, VG__GREEN );
 270    }
 271 }
 272
 273 #endif /* VEHICLE_H */