X-Git-Url: https://harrygodden.com/git/?p=vg.git;a=blobdiff_plain;f=vg_rigidbody_constraints.c;fp=vg_rigidbody_constraints.c;h=3d6b932d398bff2ef3331404faa1a64be4fe7fce;hp=0000000000000000000000000000000000000000;hb=3b14f3dcd5bf9dd3c85144f2123d667bfa4bb63f;hpb=fce86711735b15bff37de0f70716808410fcf269

diff --git a/vg_rigidbody_constraints.c b/vg_rigidbody_constraints.c
new file mode 100644
index 0000000..3d6b932
--- /dev/null
+++ b/vg_rigidbody_constraints.c
@@ -0,0 +1,497 @@
+#pragma once
+#include "vg_rigidbody.h"
+#include "vg_rigidbody_constraints.h"
+#include "vg_m.h"
+#include "vg_lines.h"
+
+/*
+ * -----------------------------------------------------------------------------
+ *                               Constraints
+ * -----------------------------------------------------------------------------
+ */
+
+void rb_debug_position_constraints( rb_constr_pos *buffer, int len )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_pos *constr = &buffer[i];
+      rigidbody *rba = constr->rba, *rbb = constr->rbb;
+
+      v3f wca, wcb;
+      m3x3_mulv( rba->to_world, constr->lca, wca );
+      m3x3_mulv( rbb->to_world, constr->lcb, wcb );
+
+      v3f p0, p1;
+      v3_add( wca, rba->co, p0 );
+      v3_add( wcb, rbb->co, p1 );
+      vg_line_point( p0, 0.0025f, 0xff000000 );
+      vg_line_point( p1, 0.0025f, 0xffffffff );
+      vg_line2( p0, p1, 0xff000000, 0xffffffff );
+   }
+}
+
+void rb_presolve_swingtwist_constraints( rb_constr_swingtwist *buf, int len )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[ i ];
+      
+      v3f vx, vy, va, vxb, axis, center;
+
+      m3x3_mulv( st->rba->to_world, st->conevx, vx );
+      m3x3_mulv( st->rbb->to_world, st->conevxb, vxb );
+      m3x3_mulv( st->rba->to_world, st->conevy, vy );
+      m3x3_mulv( st->rbb->to_world, st->coneva, va );
+      m4x3_mulv( st->rba->to_world, st->view_offset, center );
+      v3_cross( vy, vx, axis );
+
+      /* Constraint violated ? */
+      float fx = v3_dot( vx, va ),     /* projection world */
+            fy = v3_dot( vy, va ),
+            fn = v3_dot( va, axis ),
+
+            rx = st->conevx[3],        /* elipse radii */
+            ry = st->conevy[3],
+
+            lx = fx/rx,                /* projection local (fn==lz) */
+            ly = fy/ry;
+
+      st->tangent_violation = ((lx*lx + ly*ly) > fn*fn) || (fn <= 0.0f);
+      if( st->tangent_violation ){
+         /* Calculate a good position and the axis to solve on */
+         v2f closest, tangent, 
+             p = { fx/fabsf(fn), fy/fabsf(fn) };
+
+         closest_point_elipse( p, (v2f){rx,ry}, closest );
+         tangent[0] = -closest[1] / (ry*ry);
+         tangent[1] =  closest[0] / (rx*rx);
+         v2_normalize( tangent );
+
+         v3f v0, v1;
+         v3_muladds( axis, vx, closest[0], v0 );
+         v3_muladds( v0, vy, closest[1], v0 );
+         v3_normalize( v0 );
+
+         v3_muls( vx, tangent[0], v1 );
+         v3_muladds( v1, vy, tangent[1], v1 );
+
+         v3_copy( v0, st->tangent_target );
+         v3_copy( v1, st->tangent_axis );
+
+         /* calculate mass */
+         v3f aIw, bIw;
+         m3x3_mulv( st->rba->iIw, st->tangent_axis, aIw );
+         m3x3_mulv( st->rbb->iIw, st->tangent_axis, bIw );
+         st->tangent_mass = 1.0f / (v3_dot( st->tangent_axis, aIw ) +
+                                    v3_dot( st->tangent_axis, bIw ));
+
+         float angle = v3_dot( va, st->tangent_target );
+      }
+
+      v3f refaxis;
+      v3_cross( vy, va, refaxis );  /* our default rotation */
+      v3_normalize( refaxis );
+
+      float angle = v3_dot( refaxis, vxb );
+      st->axis_violation = fabsf(angle) < st->conet;
+
+      if( st->axis_violation ){
+         v3f dir_test;
+         v3_cross( refaxis, vxb, dir_test );
+
+         if( v3_dot(dir_test, va) < 0.0f )
+            st->axis_violation = -st->axis_violation;
+
+         float newang = (float)st->axis_violation * acosf(st->conet-0.0001f);
+
+         v3f refaxis_up;
+         v3_cross( va, refaxis, refaxis_up );
+         v3_muls( refaxis_up, sinf(newang), st->axis_target );
+         v3_muladds( st->axis_target, refaxis, -cosf(newang), st->axis_target );
+
+         /* calculate mass */
+         v3_copy( va, st->axis );
+         v3f aIw, bIw;
+         m3x3_mulv( st->rba->iIw, st->axis, aIw );
+         m3x3_mulv( st->rbb->iIw, st->axis, bIw );
+         st->axis_mass = 1.0f / (v3_dot( st->axis, aIw ) +
+                                 v3_dot( st->axis, bIw ));
+      }
+   }
+}
+
+void rb_debug_swingtwist_constraints( rb_constr_swingtwist *buf, int len )
+{
+   float size = 0.12f;
+
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[ i ];
+      
+      v3f vx, vxb, vy, va, axis, center;
+
+      m3x3_mulv( st->rba->to_world, st->conevx, vx );
+      m3x3_mulv( st->rbb->to_world, st->conevxb, vxb );
+      m3x3_mulv( st->rba->to_world, st->conevy, vy );
+      m3x3_mulv( st->rbb->to_world, st->coneva, va );
+      m4x3_mulv( st->rba->to_world, st->view_offset, center );
+      v3_cross( vy, vx, axis );
+
+      float rx = st->conevx[3],        /* elipse radii */
+            ry = st->conevy[3];
+
+      v3f p0, p1;
+      v3_muladds( center, va, size, p1 );
+      vg_line( center, p1, 0xffffffff );
+      vg_line_point( p1, 0.00025f, 0xffffffff );
+
+      if( st->tangent_violation ){
+         v3_muladds( center, st->tangent_target, size, p0 );
+
+         vg_line( center, p0, 0xff00ff00 );
+         vg_line_point( p0, 0.00025f, 0xff00ff00 );
+         vg_line( p1, p0, 0xff000000 );
+      }
+      
+      for( int x=0; x<32; x++ ){
+         float t0 = ((float)x * (1.0f/32.0f)) * VG_TAUf,
+               t1 = (((float)x+1.0f) * (1.0f/32.0f)) * VG_TAUf,
+               c0 = cosf( t0 ),
+               s0 = sinf( t0 ),
+               c1 = cosf( t1 ),
+               s1 = sinf( t1 );
+
+         v3f v0, v1;
+         v3_muladds( axis, vx, c0*rx, v0 );
+         v3_muladds( v0,   vy, s0*ry, v0 );
+         v3_muladds( axis, vx, c1*rx, v1 );
+         v3_muladds( v1,   vy, s1*ry, v1 );
+
+         v3_normalize( v0 );
+         v3_normalize( v1 );
+
+         v3_muladds( center, v0, size, p0 );
+         v3_muladds( center, v1, size, p1 );
+
+         u32 col0r = fabsf(c0) * 255.0f,
+             col0g = fabsf(s0) * 255.0f,
+             col1r = fabsf(c1) * 255.0f,
+             col1g = fabsf(s1) * 255.0f,
+             col   = st->tangent_violation? 0xff0000ff: 0xff000000,
+             col0  = col | (col0r<<16) | (col0g << 8),
+             col1  = col | (col1r<<16) | (col1g << 8);
+
+         vg_line2( center, p0, VG__NONE, col0 );
+         vg_line2( p0, p1, col0, col1 );
+      }
+
+      /* Draw twist */
+      v3_muladds( center, va, size, p0 );
+      v3_muladds( p0, vxb, size, p1 );
+
+      vg_line( p0, p1, 0xff0000ff );
+
+      if( st->axis_violation ){
+         v3_muladds( p0, st->axis_target, size*1.25f, p1 );
+         vg_line( p0, p1, 0xffffff00 );
+         vg_line_point( p1, 0.0025f, 0xffffff80 );
+      }
+
+      v3f refaxis;
+      v3_cross( vy, va, refaxis );  /* our default rotation */
+      v3_normalize( refaxis );
+      v3f refaxis_up;
+      v3_cross( va, refaxis, refaxis_up );
+      float newang = acosf(st->conet-0.0001f);
+
+      v3_muladds( p0, refaxis_up, sinf(newang)*size, p1 );
+      v3_muladds( p1, refaxis, -cosf(newang)*size, p1 );
+      vg_line( p0, p1, 0xff000000 );
+
+      v3_muladds( p0, refaxis_up, sinf(-newang)*size, p1 );
+      v3_muladds( p1, refaxis, -cosf(-newang)*size, p1 );
+      vg_line( p0, p1, 0xff404040 );
+   }
+}
+
+void rb_solve_position_constraints( rb_constr_pos *buf, int len )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_pos *constr = &buf[i];
+      rigidbody *rba = constr->rba, *rbb = constr->rbb;
+
+      v3f wa, wb;
+      m3x3_mulv( rba->to_world, constr->lca, wa );
+      m3x3_mulv( rbb->to_world, constr->lcb, wb );
+
+      m3x3f ssra, ssrat, ssrb, ssrbt;
+      
+      m3x3_skew_symetric( ssrat, wa );
+      m3x3_skew_symetric( ssrbt, wb );
+      m3x3_transpose( ssrat, ssra );
+      m3x3_transpose( ssrbt, ssrb );
+
+      v3f b, b_wa, b_wb, b_a, b_b;
+      m3x3_mulv( ssra, rba->w, b_wa );
+      m3x3_mulv( ssrb, rbb->w, b_wb );
+      v3_add( rba->v, b_wa, b );
+      v3_sub( b, rbb->v, b );
+      v3_sub( b, b_wb, b );
+      v3_muls( b, -1.0f, b );
+
+      m3x3f invMa, invMb;
+      m3x3_diagonal( invMa, rba->inv_mass );
+      m3x3_diagonal( invMb, rbb->inv_mass );
+
+      m3x3f ia, ib;
+      m3x3_mul( ssra, rba->iIw, ia );
+      m3x3_mul( ia, ssrat, ia );
+      m3x3_mul( ssrb, rbb->iIw, ib );
+      m3x3_mul( ib, ssrbt, ib );
+
+      m3x3f cma, cmb;
+      m3x3_add( invMa, ia, cma );
+      m3x3_add( invMb, ib, cmb );
+
+      m3x3f A;
+      m3x3_add( cma, cmb, A );
+
+      /* Solve Ax = b ( A^-1*b = x ) */
+      v3f impulse;
+      m3x3f invA;
+      m3x3_inv( A, invA );
+      m3x3_mulv( invA, b, impulse );
+
+      v3f delta_va, delta_wa, delta_vb, delta_wb;
+      m3x3f iwa, iwb;
+      m3x3_mul( rba->iIw, ssrat, iwa );
+      m3x3_mul( rbb->iIw, ssrbt, iwb );
+
+      m3x3_mulv( invMa, impulse, delta_va );
+      m3x3_mulv( invMb, impulse, delta_vb );
+      m3x3_mulv( iwa, impulse, delta_wa );
+      m3x3_mulv( iwb, impulse, delta_wb );
+
+      v3_add( rba->v, delta_va, rba->v );
+      v3_add( rba->w, delta_wa, rba->w );
+      v3_sub( rbb->v, delta_vb, rbb->v );
+      v3_sub( rbb->w, delta_wb, rbb->w );
+   }
+}
+
+void rb_solve_swingtwist_constraints( rb_constr_swingtwist *buf, int len )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[ i ];
+
+      if( !st->axis_violation )
+         continue;
+
+      float rv = v3_dot( st->axis, st->rbb->w ) - 
+                 v3_dot( st->axis, st->rba->w );
+
+      if( rv * (float)st->axis_violation > 0.0f )
+         continue;
+
+      v3f impulse, wa, wb;
+      v3_muls( st->axis, rv*st->axis_mass, impulse );
+      m3x3_mulv( st->rba->iIw, impulse, wa );
+      v3_add( st->rba->w, wa, st->rba->w );
+
+      v3_muls( impulse, -1.0f, impulse );
+      m3x3_mulv( st->rbb->iIw, impulse, wb );
+      v3_add( st->rbb->w, wb, st->rbb->w );
+
+      float rv2 = v3_dot( st->axis, st->rbb->w ) - 
+                  v3_dot( st->axis, st->rba->w );
+   }
+
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[ i ];
+
+      if( !st->tangent_violation )
+         continue;
+
+      float rv = v3_dot( st->tangent_axis, st->rbb->w ) - 
+                 v3_dot( st->tangent_axis, st->rba->w );
+
+      if( rv > 0.0f )
+         continue;
+
+      v3f impulse, wa, wb;
+      v3_muls( st->tangent_axis, rv*st->tangent_mass, impulse );
+      m3x3_mulv( st->rba->iIw, impulse, wa );
+      v3_add( st->rba->w, wa, st->rba->w );
+
+      v3_muls( impulse, -1.0f, impulse );
+      m3x3_mulv( st->rbb->iIw, impulse, wb );
+      v3_add( st->rbb->w, wb, st->rbb->w );
+
+      float rv2 = v3_dot( st->tangent_axis, st->rbb->w ) - 
+                  v3_dot( st->tangent_axis, st->rba->w );
+   }
+}
+
+/* debugging */
+void rb_postsolve_swingtwist_constraints( rb_constr_swingtwist *buf, u32 len )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[ i ];
+
+      if( !st->axis_violation ){
+         st->conv_axis = 0.0f;
+         continue;
+      }
+
+      f32 rv = v3_dot( st->axis, st->rbb->w ) - 
+               v3_dot( st->axis, st->rba->w );
+
+      if( rv * (f32)st->axis_violation > 0.0f )
+         st->conv_axis = 0.0f;
+      else
+         st->conv_axis = rv;
+   }
+
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[ i ];
+
+      if( !st->tangent_violation ){
+         st->conv_tangent = 0.0f;
+         continue;
+      }
+
+      f32 rv = v3_dot( st->tangent_axis, st->rbb->w ) - 
+               v3_dot( st->tangent_axis, st->rba->w );
+
+      if( rv > 0.0f )
+         st->conv_tangent = 0.0f;
+      else
+         st->conv_tangent = rv;
+   }
+}
+
+void rb_solve_constr_angle( rigidbody *rba, rigidbody *rbb, v3f ra, v3f rb )
+{
+   m3x3f ssra, ssrb, ssrat, ssrbt;
+   m3x3f cma, cmb;
+
+   m3x3_skew_symetric( ssrat, ra );
+   m3x3_skew_symetric( ssrbt, rb );
+   m3x3_transpose( ssrat, ssra );
+   m3x3_transpose( ssrbt, ssrb );
+
+   m3x3_mul( ssra, rba->iIw, cma );
+   m3x3_mul( cma, ssrat, cma );
+   m3x3_mul( ssrb, rbb->iIw, cmb );
+   m3x3_mul( cmb, ssrbt, cmb );
+
+   m3x3f A, invA;
+   m3x3_add( cma, cmb, A );
+   m3x3_inv( A, invA );
+
+   v3f b_wa, b_wb, b;
+   m3x3_mulv( ssra, rba->w, b_wa );
+   m3x3_mulv( ssrb, rbb->w, b_wb );
+   v3_add( b_wa, b_wb, b );
+   v3_negate( b, b );
+
+   v3f impulse;
+   m3x3_mulv( invA, b, impulse );
+
+   v3f delta_wa, delta_wb;
+   m3x3f iwa, iwb;
+   m3x3_mul( rba->iIw, ssrat, iwa );
+   m3x3_mul( rbb->iIw, ssrbt, iwb );
+   m3x3_mulv( iwa, impulse, delta_wa );
+   m3x3_mulv( iwb, impulse, delta_wb );
+   v3_add( rba->w, delta_wa, rba->w );
+   v3_sub( rbb->w, delta_wb, rbb->w );
+}
+
+void rb_correct_position_constraints( rb_constr_pos *buf, int len, f32 amt )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_pos *constr = &buf[i];
+      rigidbody *rba = constr->rba, *rbb = constr->rbb;
+
+      v3f p0, p1, d;
+      m3x3_mulv( rba->to_world, constr->lca, p0 );
+      m3x3_mulv( rbb->to_world, constr->lcb, p1 );
+      v3_add( rba->co, p0, p0 );
+      v3_add( rbb->co, p1, p1 );
+      v3_sub( p1, p0, d );
+
+#if 1
+      v3_muladds( rbb->co, d, -1.0f * amt, rbb->co );
+      rb_update_matrices( rbb );
+#else
+      f32 mt = 1.0f/(rba->inv_mass+rbb->inv_mass),
+          a  = mt * (k_phys_baumgarte/k_rb_delta);
+
+      v3_muladds( rba->v, d, a* rba->inv_mass, rba->v );
+      v3_muladds( rbb->v, d, a*-rbb->inv_mass, rbb->v );
+#endif
+   }
+}
+
+void rb_correct_swingtwist_constraints( rb_constr_swingtwist *buf, 
+                                        int len, float amt )
+{
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[i];
+
+      if( !st->tangent_violation )
+         continue;
+
+      v3f va;
+      m3x3_mulv( st->rbb->to_world, st->coneva, va );
+
+      f32 angle = v3_dot( va, st->tangent_target );
+
+      if( fabsf(angle) < 0.9999f ){
+         v3f axis;
+         v3_cross( va, st->tangent_target, axis );
+#if 1
+         angle = acosf(angle) * amt;
+         v4f correction;
+         q_axis_angle( correction, axis, angle );
+         q_mul( correction, st->rbb->q, st->rbb->q );
+         q_normalize( st->rbb->q );
+         rb_update_matrices( st->rbb );
+#else
+         f32 mt = 1.0f/(st->rba->inv_mass+st->rbb->inv_mass),
+             wa = mt * acosf(angle) * (k_phys_baumgarte/k_rb_delta);
+         //v3_muladds( st->rba->w, axis, wa*-st->rba->inv_mass, st->rba->w );
+         v3_muladds( st->rbb->w, axis, wa* st->rbb->inv_mass, st->rbb->w );
+#endif
+      }
+   }
+
+   for( int i=0; i<len; i++ ){
+      rb_constr_swingtwist *st = &buf[i];
+
+      if( !st->axis_violation )
+         continue;
+
+      v3f vxb;
+      m3x3_mulv( st->rbb->to_world, st->conevxb, vxb );
+
+      f32 angle = v3_dot( vxb, st->axis_target );
+
+      if( fabsf(angle) < 0.9999f ){
+         v3f axis;
+         v3_cross( vxb, st->axis_target, axis );
+
+#if 1
+         angle = acosf(angle) * amt;
+         v4f correction;
+         q_axis_angle( correction, axis, angle );
+         q_mul( correction, st->rbb->q, st->rbb->q );
+         q_normalize( st->rbb->q );
+         rb_update_matrices( st->rbb );
+#else
+         f32 mt = 1.0f/(st->rba->inv_mass+st->rbb->inv_mass),
+             wa = mt * acosf(angle) * (k_phys_baumgarte/k_rb_delta);
+         //v3_muladds( st->rba->w, axis, wa*-0.5f, st->rba->w );
+         v3_muladds( st->rbb->w, axis, wa* st->rbb->inv_mass, st->rbb->w );
+#endif
+      }
+   }
+}