labs/physics.c

   1 #include "vg/vg_engine.h"
   2 #include "vg/vg_opt.h"
   3 #include "vg/vg_audio.h"
   4 #include "vg/vg_camera.h"
   5 #include "vg/vg_rigidbody.h"
   6 #include "vg/vg_rigidbody_collision.h"
   7 #include "vg/vg_rigidbody_view.h"
   8 #include "vg/vg_profiler.h"
   9 #include "vg/vg_bvh.h"
  10 #include "vg/vg_input.h"
  11
  12 #define SHAPE_MAX 256
  13 static rigidbody shapes[SHAPE_MAX];
  14 static rb_capsule shapes_inf[SHAPE_MAX];
  15 static v4f  shapes_colour[SHAPE_MAX];
  16 static boxf shapes_bbx[SHAPE_MAX];
  17
  18 static boxf floor_box = {{-6.999,-2.001,-6.999},{6.999,-0.999,6.999}};
  19
  20 static rigidbody racket;
  21
  22 static f32 k_iterations = 8.0f,
  23            k_view_x = 0.0f,
  24            k_view_y = 0.2f,
  25            k_view_z = 10.0f,
  26            k_shapes = 32.0f,
  27            k_racket_d  = 8.0f;
  28
  29 static rb_capsule racket_ca = { .h = 4.3f, .r = 0.6f },
  30                   racket_cb = { .h = 5.5f, .r = 0.9f };
  31 static m4x3f racket_a_mdl, racket_b_mdl;
  32 static m3x3f racket_I;
  33
  34 static v3f k_racket_init_w;
  35 static i32 k_demo = 0;
  36 static i32 k_gyro = 0;
  37 static i32 k_prof_normalize = 0;
  38 static i32 k_bbx = 1;
  39 static i32 k_spacial = 0;
  40
  41 static struct vg_profile prof_refit   = { .name = "Refit" },
  42                          prof_broad = { .name = "Broad phase",
  43                                         .mode = k_profile_mode_accum },
  44                          prof_narrow = { .name = "Narrow phase",
  45                                          .mode = k_profile_mode_accum },
  46                          prof_solve   = { .name = "Solver" };
  47
  48 static void shape_bvh_expand_bound( void *user, boxf bound, u32 item_index ){
  49    box_concat( bound, shapes_bbx[item_index] );
  50 }
  51
  52 static f32 shape_bvh_centroid( void *user, u32 item_index, int axis ){
  53    f32 x = shapes_bbx[item_index][0][axis] + shapes_bbx[item_index][1][axis];
  54    return x*0.5f;
  55 }
  56
  57 static void shape_bvh_closest( void *user, u32 item_index,
  58                                v3f point, v3f closest ){
  59    closest_point_aabb( point, shapes_bbx[item_index], closest );
  60 }
  61
  62 static void shape_bvh_swap( void *user, u32 ia, u32 ib ){
  63    rigidbody temp = shapes[ib];
  64    shapes[ib] = shapes[ia];
  65    shapes[ia] = temp;
  66
  67    rb_capsule cb = shapes_inf[ib];
  68    shapes_inf[ib] = shapes_inf[ia];
  69    shapes_inf[ia] = cb;
  70
  71    v4f colourb;
  72    v4_copy( shapes_colour[ib], colourb );
  73    v4_copy( shapes_colour[ia], shapes_colour[ib] );
  74    v4_copy( colourb, shapes_colour[ia] );
  75
  76    boxf boxb;
  77    box_copy( shapes_bbx[ib], boxb );
  78    box_copy( shapes_bbx[ia], shapes_bbx[ib] );
  79    box_copy( boxb, shapes_bbx[ia] );
  80 }
  81
  82 static bh_system shape_bvh = {
  83    .expand_bound = shape_bvh_expand_bound,
  84    .item_centroid = shape_bvh_centroid,
  85    .item_closest = shape_bvh_closest,
  86    .item_swap = shape_bvh_swap
  87 };
  88
  89 static bh_tree *shape_bvh_tree = NULL;
  90
  91 int main( int argc, char *argv[] ){
  92    vg_mem.use_libc_malloc = 0;
  93    vg_set_mem_quota( 80*1024*1024 );
  94    vg_enter( argc, argv, "Voyager Game Engine" );
  95    return 0;
  96 }
  97
  98 void vg_launch_opt(void){
  99    const char *arg;
 100 }
 101
 102 void vg_preload(void)
 103 {
 104    vg_audio.dsp_enabled = 0;
 105 }
 106
 107 static void init_random(void)
 108 {
 109    for( u32 i=0; i<(u32)k_shapes; i ++ ){
 110       f32 h  = vg_randf64( &vg.rand ) * 2.0f + 1.3f,
 111           r  = vg_randf64( &vg.rand ) * 0.5f + 0.125f,
 112           pv = vg_capsule_volume( r, h ),
 113           k_density = 8.0f,
 114           pm = pv * k_density;
 115
 116       shapes_inf[i].r = r;
 117       shapes_inf[i].h = h;
 118
 119       m3x3f pI;
 120       vg_capsule_inertia( r, h, pm, pI );
 121       m3x3_inv( pI, shapes[i].iI );
 122       shapes[i].inv_mass = 1.0f / pm;
 123
 124       v3f dir;
 125       vg_rand_dir( &vg.rand, dir );
 126       q_axis_angle( shapes[i].q, dir, vg_randf64(&vg.rand)*VG_TAUf );
 127       vg_rand_sphere( &vg.rand, shapes[i].co );
 128       v3_muladds( (v3f){0,4,0}, shapes[i].co, 4.0f, shapes[i].co );
 129       v3_zero( shapes[i].v );
 130       v3_zero( shapes[i].w );
 131       shapes_colour[i][0] = vg_randf64(&vg.rand);
 132       shapes_colour[i][1] = vg_randf64(&vg.rand);
 133       shapes_colour[i][2] = vg_randf64(&vg.rand);
 134       shapes_colour[i][3] = 1.0f;
 135       rb_update_matrices( &shapes[i] );
 136    }
 137 }
 138
 139 static void init_racket(void){
 140    f32 ma = vg_capsule_volume( racket_ca.r, racket_ca.h ) * k_racket_d,
 141        mb = vg_capsule_volume( racket_cb.r, racket_cb.h ) * k_racket_d,
 142        mt = ma+mb;
 143    m3x3f aI, bI;
 144
 145    /* tensor for A */
 146    vg_capsule_inertia( racket_ca.r, racket_ca.h, ma, aI );
 147    m4x3_identity( racket_a_mdl );
 148    racket_a_mdl[3][1] = -racket_ca.h*0.5f*(mb/mt);
 149    vg_translate_inertia( aI, ma, racket_a_mdl[3] );
 150
 151    /* tensor for B */
 152    vg_capsule_inertia( racket_cb.r, racket_cb.h, mb, bI );
 153
 154    v4f q;
 155    q_axis_angle( q, (v4f){1,0,0}, VG_TAUf*0.25f );
 156
 157    m4x3_identity( racket_b_mdl );
 158    q_m3x3( q, racket_b_mdl );
 159    vg_rotate_inertia( bI, racket_b_mdl );
 160    racket_b_mdl[3][1] = racket_ca.h*0.5f*(ma/mt);
 161    vg_translate_inertia( bI, mb, racket_b_mdl[3] );
 162
 163    m3x3_add( aI, bI, racket_I );
 164    m3x3_inv( racket_I, racket.iI );
 165    racket.inv_mass = 1.0f/(mb+ma);
 166 }
 167
 168 static void reset_racket(void){
 169    q_identity( racket.q );
 170    v3_zero( racket.co );
 171    v3_copy( k_racket_init_w, racket.w );
 172    v3_zero( racket.v );
 173    rb_update_matrices( &racket );
 174 }
 175
 176 void vg_load(void)
 177 {
 178    vg_bake_shaders();
 179    init_random();
 180    shape_bvh_tree = bh_create( NULL, &shape_bvh, NULL, SHAPE_MAX, 1 );
 181    init_racket();
 182    reset_racket();
 183 }
 184
 185 void vg_pre_update(void)
 186 {
 187    vg_console.cheats =  1;
 188    vg_lines.render = 1;
 189 }
 190
 191 static void demo0_refit(void){
 192    if( k_spacial == 0 ) return;
 193
 194    for( u32 i=0; i<(u32)k_shapes; i ++ ){
 195       f32 h = shapes_inf[i].h,
 196           r = shapes_inf[i].r;
 197
 198       rigidbody *rb = &shapes[i];
 199
 200       v3f p0, p1;
 201       v3_muladds( rb->to_world[3], rb->to_world[1], -h*0.5f+r, p0 );
 202       v3_muladds( rb->to_world[3], rb->to_world[1],  h*0.5f-r, p1 );
 203
 204       v3f *bbx = shapes_bbx[i];
 205       v3_minv( p0, p1, bbx[0] );
 206       v3_maxv( p0, p1, bbx[1] );
 207       v3_muladds( bbx[0], (v3f){-1,-1,-1}, r, bbx[0] );
 208       v3_muladds( bbx[1], (v3f){ 1, 1, 1}, r, bbx[1] );
 209    }
 210
 211    if( k_spacial == 1 ) return;
 212
 213    if( k_spacial == 2 )
 214       bh_rebuild( shape_bvh_tree, (u32)k_shapes );
 215 }
 216
 217 static void demo0(void){
 218    vg_profile_begin( &prof_refit );
 219    demo0_refit();
 220    vg_profile_end( &prof_refit );
 221
 222    static rigidbody _null,
 223                     _mover;
 224    rb_solver_reset();
 225
 226    f32 t = vg.time * 0.1f * VG_TAUf;
 227    v3f sphere_pos = { sinf(t)*2.0f, -1, cosf(t)*2.0f };
 228    _mover.v[0] = (sinf(t+vg.time_fixed_delta)-sinf(t))*2.0f;
 229    _mover.v[2] = (cosf(t+vg.time_fixed_delta)-cosf(t))*2.0f;
 230
 231    for( u32 i=0; i<(u32)k_shapes; i ++ ){
 232       rigidbody *rbi = &shapes[i];
 233       rb_capsule *infi = &shapes_inf[i];
 234       v3f *bbxi = shapes_bbx[i];
 235
 236       if( rb_global_has_space() ){
 237          rb_ct *buf = rb_global_buffer();
 238          m4x3f mtx;
 239          m4x3_identity( mtx );
 240          u32 l = rb_capsule__box( rbi->to_world, infi,
 241                                   mtx, mtx, floor_box, buf );
 242
 243          for( u32 k=0; k<l; k ++ ){
 244             buf[k].rba = rbi;
 245             buf[k].rbb = &_null;
 246          }
 247
 248          rb_contact_count += l;
 249       }
 250       else break;
 251
 252       if( rb_global_has_space() ){
 253          rb_ct *buf = rb_global_buffer();
 254          u32 l = rb_capsule__sphere( rbi->to_world, infi, sphere_pos, 1, buf );
 255
 256          for( u32 k=0; k<l; k ++ ){
 257             buf[k].rba = rbi;
 258             buf[k].rbb = &_mover;
 259          }
 260
 261          rb_contact_count += l;
 262       }
 263
 264       if( k_spacial == 2 ){
 265          bh_iter it;
 266          bh_iter_init_box( 0, &it, bbxi );
 267          i32 idx;
 268
 269          while(1){
 270             vg_profile_begin( &prof_broad );
 271             if( !bh_next( shape_bvh_tree, &it, &idx ) ){
 272                vg_profile_end( &prof_broad );
 273                break;
 274             }
 275             vg_profile_end( &prof_broad );
 276
 277             if( idx <= i ) continue;
 278
 279             vg_profile_begin( &prof_narrow );
 280
 281             rigidbody *rbj = &shapes[idx];
 282             v3f *bbxj = shapes_bbx[idx];
 283             rb_capsule *infj = &shapes_inf[idx];
 284
 285             if( rb_global_has_space() ){
 286                rb_ct *buf = rb_global_buffer();
 287                u32 l = rb_capsule__capsule( rbi->to_world, infi,
 288                                             rbj->to_world, infj, buf );
 289
 290                for( u32 k=0; k<l; k ++ ){
 291                   buf[k].rba = rbi;
 292                   buf[k].rbb = rbj;
 293                }
 294
 295                rb_contact_count += l;
 296             }
 297
 298             vg_profile_end( &prof_narrow );
 299          }
 300       }
 301       else {
 302          if( i == ((u32)k_shapes)-1 ){
 303             break;
 304          }
 305          for( u32 j=i+1; j<(u32)k_shapes; j ++ ){
 306             rigidbody *rbj = &shapes[j];
 307             v3f *bbxj = shapes_bbx[j];
 308             rb_capsule *infj = &shapes_inf[j];
 309
 310             if( k_spacial == 1 ){
 311                vg_profile_begin( &prof_broad );
 312                if( !box_overlap( bbxi, bbxj ) ){
 313                   vg_profile_end( &prof_broad );
 314                   continue;
 315                }
 316             }
 317
 318             vg_profile_begin( &prof_narrow );
 319             if( rb_global_has_space() ){
 320                rb_ct *buf = rb_global_buffer();
 321                u32 l = rb_capsule__capsule( rbi->to_world, infi,
 322                                             rbj->to_world, infj, buf );
 323
 324                for( u32 k=0; k<l; k ++ ){
 325                   buf[k].rba = rbi;
 326                   buf[k].rbb = rbj;
 327                }
 328
 329                rb_contact_count += l;
 330             }
 331             vg_profile_end( &prof_narrow );
 332          }
 333       }
 334    }
 335
 336    vg_profile_increment( &prof_broad );
 337    vg_profile_increment( &prof_narrow );
 338
 339    vg_profile_begin( &prof_solve );
 340    rb_presolve_contacts( rb_contact_buffer,
 341                          vg.time_fixed_delta, rb_contact_count );
 342    for( u32 i=0; i<(u32)k_iterations; i ++ )
 343       rb_solve_contacts( rb_contact_buffer, rb_contact_count );
 344
 345    for( u32 i=0; i<(u32)k_shapes; i ++ ){
 346       rigidbody *rbi = &shapes[i];
 347       if( k_gyro ){
 348          m3x3f I;
 349          m3x3_inv( rbi->iI, I );
 350          rb_solve_gyroscopic( rbi, I, vg.time_fixed_delta );
 351       }
 352       rb_iter( rbi );
 353       rb_update_matrices( rbi );
 354    }
 355    vg_profile_end( &prof_solve );
 356 }
 357
 358 static void demo1(void){
 359    vg_profile_begin( &prof_refit );
 360    vg_profile_end( &prof_refit );
 361
 362    vg_profile_increment( &prof_broad );
 363    vg_profile_increment( &prof_narrow );
 364
 365    vg_profile_begin( &prof_solve );
 366
 367    v3_muladds( racket.v, (v3f){0,9.8f,0}, vg.time_fixed_delta, racket.v );
 368    if( k_gyro ) rb_solve_gyroscopic( &racket, racket_I, vg.time_fixed_delta );
 369    rb_iter( &racket );
 370    rb_update_matrices( &racket );
 371
 372    vg_profile_end( &prof_solve );
 373 }
 374
 375 void vg_fixed_update(void)
 376 {
 377    if( k_demo == 0 ) demo0();
 378    else if( k_demo == 1 ) demo1();
 379 }
 380
 381 void vg_post_update(void)
 382 {
 383    if( vg_getkey( SDLK_8 ) )
 384       init_random();
 385 }
 386
 387 void vg_framebuffer_resize( int w, int h )
 388 {
 389 }
 390
 391 static void draw_origin_axis(void){
 392    vg_line( (v3f){ 0.0f, 0.0f, 0.0f }, (v3f){ 1.0f, 0.0f, 0.0f }, 0xffff0000 );
 393    vg_line( (v3f){ 0.0f, 0.0f, 0.0f }, (v3f){ 0.0f, 1.0f, 0.0f }, 0xff00ff00 );
 394    vg_line( (v3f){ 0.0f, 0.0f, 0.0f }, (v3f){ 0.0f, 0.0f, 1.0f }, 0xff0000ff );
 395 }
 396
 397 static void render0(void){
 398    f32 t = vg.time * 0.1f * VG_TAUf;
 399    m4x3f mdl;
 400    m4x3_identity( mdl );
 401    vg_rb_view_box( mdl, floor_box, (v4f){0.8f,0.8f,0.8f,1} );
 402
 403    mdl[3][0] = sinf(t)*2.0f;
 404    mdl[3][1] = -1;
 405    mdl[3][2] = cosf(t)*2.0f;
 406    vg_rb_view_sphere( mdl, 1, (v4f){0,1,0,1} );
 407
 408    for( u32 i=0; i<(u32)k_shapes; i ++ ){
 409       rigidbody *rbi = &shapes[i];
 410       rb_capsule *infi = &shapes_inf[i];
 411       f32 *coli = shapes_colour[i];
 412
 413       v4f q;
 414       v3f co;
 415       rb_extrapolate( rbi, co, q );
 416       q_m3x3( q, mdl );
 417       v3_copy( co, mdl[3] );
 418       vg_rb_view_capsule( mdl, infi->r, infi->h, coli );
 419    }
 420
 421    if( k_spacial && k_bbx ){
 422       for( u32 i=0; i<(u32)k_shapes; i ++ ){
 423          vg_line_boxf( shapes_bbx[i], VG__RED );
 424       }
 425
 426       if( k_spacial == 2 ){
 427          bh_debug_trace( shape_bvh_tree, 0, (v3f){0,0,0}, VG__GREEN );
 428       }
 429    }
 430 }
 431
 432 static void render1(void){
 433    m4x3f mdl, mmdl;
 434    v4f q;
 435    rb_extrapolate( &racket, mdl[3], q );
 436    q_m3x3( q, mdl );
 437
 438    m4x3_mul( mdl, racket_a_mdl, mmdl );
 439    vg_rb_view_capsule( mmdl, racket_ca.r, racket_ca.h, (v4f){1,0,0,1} );
 440
 441    m4x3_mul( mdl, racket_b_mdl, mmdl );
 442    vg_rb_view_capsule( mmdl, racket_cb.r, racket_cb.h, (v4f){0,1,0,1} );
 443 }
 444
 445 void vg_render(void)
 446 {
 447    glBindFramebuffer( GL_FRAMEBUFFER, 0 );
 448    glViewport( 0,0, vg.window_x, vg.window_y );
 449    glEnable( GL_DEPTH_TEST );
 450    glDisable( GL_BLEND );
 451
 452    glClearColor( 0.05f, 0.05f, 0.05f, 1.0f );
 453    glClear( GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT );
 454
 455    vg_camera cam = {
 456       .angles = { -k_view_x, k_view_y, 0 },
 457       .nearz = 0.01f,
 458       .farz = 500.0f,
 459       .fov = 90.0f,
 460       .pos = { sinf(k_view_x)*k_view_z*cosf(k_view_y),
 461                sinf(k_view_y)*k_view_z,
 462                cosf(k_view_x)*k_view_z*cosf(k_view_y) },
 463    };
 464
 465    vg_camera_update_transform( &cam );
 466    vg_camera_update_view( &cam );
 467    vg_camera_update_projection( &cam );
 468    vg_camera_finalize( &cam );
 469    m4x4_copy( cam.mtx.pv, vg.pv );
 470
 471    vg_rb_view_bind();
 472    if( k_demo == 0 ) render0();
 473    else if( k_demo == 1 ) render1();
 474
 475    draw_origin_axis();
 476    vg_lines_drawall();
 477
 478    glDisable(GL_DEPTH_TEST);
 479 }
 480
 481 struct ui_enum_opt spacial_mode_ui_enum[] = {
 482    { 0, "None" },
 483    { 1, "BBX" },
 484    { 2, "BVH - Full rebuild" },
 485    { 3, "BVH - Temporal fitting" }
 486 };
 487
 488 static void gui0( ui_rect panel ){
 489    ui_slider( panel, "Shapes", 2, vg_list_size(shapes), &k_shapes, "%.0f" );
 490
 491    if( ui_button( panel, "randomize" ) == k_ui_button_click ){
 492       init_random();
 493    }
 494 }
 495
 496 static void gui1( ui_rect panel ){
 497    ui_rect l, r;
 498    ui_standard_widget( panel, l, 1 );
 499    ui_split_ratio( l, k_ui_axis_v, 0.5f, 4, l, r );
 500    ui_slider( l, "aH", 1.0f, 10.0f, &racket_ca.h, "%.1f" );
 501    ui_slider( r, "aR", 0.1f, 10.0f, &racket_ca.r, "%.1f" );
 502
 503    ui_standard_widget( panel, l, 1 );
 504    ui_split_ratio( l, k_ui_axis_v, 0.5f, 4, l, r );
 505    ui_slider( l, "bH", 1.0f, 10.0f, &racket_cb.h, "%.1f" );
 506    ui_slider( r, "bR", 0.1f, 10.0f, &racket_cb.r, "%.1f" );
 507
 508    for( u32 i=0; i<3; i ++ ){
 509       ui_rect v0,v1,v2;
 510       ui_standard_widget( panel, v0, 1 );
 511       ui_split_ratio( v0, k_ui_axis_v, 2.0f/3.0f, 4, v0, v2 );
 512       ui_split_ratio( v0, k_ui_axis_v, 1.0f/2.0f, 4, v0, v1 );
 513
 514       char buf[16];
 515       snprintf( buf, sizeof(buf), "%.3f", racket_I[i][0] );
 516       ui_text( v0, buf, 1, k_ui_align_middle_center, 0 );
 517       snprintf( buf, sizeof(buf), "%.3f", racket_I[i][1] );
 518       ui_text( v1, buf, 1, k_ui_align_middle_center, 0 );
 519       snprintf( buf, sizeof(buf), "%.3f", racket_I[i][2] );
 520       ui_text( v2, buf, 1, k_ui_align_middle_center, 0 );
 521    }
 522
 523    init_racket();
 524
 525    ui_info( panel, "init conditions" );
 526    ui_rect v0,v1,v2;
 527    ui_standard_widget( panel, v0, 1 );
 528    ui_split_ratio( v0, k_ui_axis_v, 2.0f/3.0f, 4, v0, v2 );
 529    ui_split_ratio( v0, k_ui_axis_v, 1.0f/2.0f, 4, v0, v1 );
 530    ui_slider( v0, "X", 0.01f, 30.0f, k_racket_init_w+0, "%.1f" );
 531    ui_slider( v1, "Y", 0.01f, 30.0f, k_racket_init_w+1, "%.1f" );
 532    ui_slider( v2, "Z", 0.01f, 30.0f, k_racket_init_w+2, "%.1f" );
 533
 534    if( ui_button( panel, "init" ) == k_ui_button_click ){
 535       reset_racket();
 536    }
 537 }
 538
 539 void vg_gui(void)
 540 {
 541    vg_ui.wants_mouse = 1;
 542    ui_rect panel = { vg.window_x-300, 0, 300, vg.window_y };
 543    ui_rect_pad( panel, (ui_px[2]){ 8, 8 } );
 544
 545    ui_rect box;
 546    ui_split( panel, k_ui_axis_h, VG_PROFILE_SAMPLE_COUNT*2 +4, 8, box, panel );
 547    vg_profile_drawn( (struct vg_profile *[]){ &prof_refit,
 548                                               &prof_broad,
 549                                               &prof_narrow,
 550                                               &prof_solve }, 4,
 551                      vg.time_fixed_delta*1000.0, box, 0, k_prof_normalize );
 552
 553    ui_split( panel, k_ui_axis_h, 14*2+8, 4, box, panel );
 554    ui_checkbox( panel, "Normalize", &k_prof_normalize );
 555
 556    ui_slider( panel, "Iterations", 1.0f, 20.0f, &k_iterations, "%.0f" );
 557    ui_enum( panel, "Spacial Type", spacial_mode_ui_enum,
 558             vg_list_size(spacial_mode_ui_enum), &k_spacial );
 559
 560    static f32 rate = 60.0f;
 561    ui_slider( panel, "Fixed timestep", 10, 200, &rate, "%.1f" );
 562    vg.time_fixed_delta = 1.0f/rate;
 563
 564    ui_checkbox( panel, "Show BBX", &k_bbx );
 565    ui_checkbox( panel, "Gyroscopic Term", &k_gyro );
 566
 567    ui_tabs( panel, panel,
 568             (const char *[]){ "collision", "racket" }, 2, &k_demo );
 569
 570    if( k_demo == 0 ) gui0( panel );
 571    else if( k_demo == 1 ) gui1( panel );
 572
 573    ui_rect viewport = { 0,0, vg.window_x-300, vg.window_y };
 574
 575    if( ui_inside_rect( viewport, vg_ui.mouse ) && ui_clicking(UI_MOUSE_LEFT) ){
 576       k_view_x += -((f32)vg.mouse_delta[0] / (f32)vg.window_x) * VG_TAUf,
 577       k_view_y +=  ((f32)vg.mouse_delta[1] / (f32)vg.window_y) * VG_PIf;
 578    }
 579 }