vg_rigidbody.h

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