vg_rigidbody.h

   1 #pragma once
   2 /*
   3  * Copyright (C) 2021-2024 Mt.ZERO Software - All Rights Reserved
   4  *
   5  * Rigidbody main file, related:
   6  *  vg_rigidbody_collision.h
   7  *  vg_rigidbody_constraints.h
   8  */
   9
  10 #define k_friction         0.4f
  11 #define k_damp_linear      0.1f               /* scale velocity 1/(1+x) */
  12 #define k_damp_angular     0.1f               /* scale angular  1/(1+x) */
  13 #define k_penetration_slop 0.01f
  14 #define k_rb_inertia_scale 4.0f
  15 #define k_phys_baumgarte   0.2f
  16 #define k_gravity          9.6f
  17 #define k_rb_density       8.0f
  18
  19 enum rb_shape {
  20    k_rb_shape_none    = 0,
  21    k_rb_shape_box     = 1,
  22    k_rb_shape_sphere  = 2,
  23    k_rb_shape_capsule = 3,
  24 };
  25
  26 typedef struct rigidbody rigidbody;
  27 typedef struct rb_capsule rb_capsule;
  28
  29 struct rb_capsule
  30 {
  31    f32 h, r;
  32 };
  33
  34 struct rigidbody
  35 {
  36    v3f co, v, w;
  37    v4f q;
  38
  39    f32 inv_mass;
  40
  41    m3x3f iI, iIw; /* inertia model and inverse world tensor */
  42    m4x3f to_world, to_local;
  43 };
  44
  45 /*
  46  * Initialize rigidbody inverse mass and inertia tensor with some common shapes
  47  */
  48 void rb_setbody_capsule( rigidbody *rb, f32 r, f32 h,
  49                          f32 density, f32 inertia_scale );
  50 void rb_setbody_box( rigidbody *rb, boxf box, f32 density, f32 inertia_scale );
  51 void rb_setbody_sphere( rigidbody *rb, f32 r, f32 density, f32 inertia_scale );
  52
  53 /*
  54  * Update ALL matrices and tensors on rigidbody
  55  */
  56 void rb_update_matrices( rigidbody *rb );
  57
  58 /*
  59  * Extrapolate rigidbody into a transform based on vg accumulator.
  60  * Useful for rendering
  61  */
  62 void rb_extrapolate( rigidbody *rb, v3f co, v4f q );
  63 void rb_iter( rigidbody *rb );
  64 void rb_solve_gyroscopic( rigidbody *rb, m3x3f I, f32 h );
  65
  66 /*
  67  * Creates relative contact velocity vector
  68  */
  69 void rb_rcv( rigidbody *rba, rigidbody *rbb, v3f ra, v3f rb, v3f rv );
  70
  71 /*
  72  * Apply impulse to object
  73  */
  74 void rb_linear_impulse( rigidbody *rb, v3f delta, v3f impulse );
  75
  76 /*
  77  * Effectors
  78  */
  79 void rb_effect_simple_bouyency( rigidbody *ra, v4f plane, f32 amt, f32 drag );
  80 void rb_effect_spring_target_vector( rigidbody *rba, v3f ra, v3f rt,
  81                                      f32 spring, f32 dampening, f32 timestep );