- v3f ground, norm;
- v3_copy( pos, ground );
-
- if( bvh_scene_sample( &world.geo, ground, norm ) )
- {
- v3f angle;
- v3_copy( player.v, angle );
- v3_normalize( angle );
- float resistance = v3_dot( norm, angle );
-
- if( resistance < 0.25f )
- {
- v3_copy( ground, pos );
- return 1;
- }
- }
-
- return 0;
-}
-
-static float stable_force( float current, float diff )
-{
- float new = current + diff;
-
- if( new * current < 0.0f )
- return 0.0f;
-
- return new;
-}
-
-static void player_physics_ground(void)
-{
- /*
- * Getting surface collision points,
- * the contact manifold is a triangle for simplicity.
- */
- v3f contact_front, contact_back, fwd, fwd1, contact_norm, vup, vside,
- axis;
-
- float klength = 0.65f;
- m3x3_mulv( player.to_world, (v3f){ 0.0f, 0.0f,-1.0f}, fwd );
- m4x3_mulv( player.to_world, (v3f){ 0.15f,0.0f,-klength}, contact_norm );
- m4x3_mulv( player.to_world, (v3f){-0.15f,0.0f,-klength}, contact_front );
- m4x3_mulv( player.to_world, (v3f){ 0.00f,0.0f, klength}, contact_back );
- m3x3_mulv( player.to_world, (v3f){ 0.0f, 1.0f, 0.0f}, vup );
- m3x3_mulv( player.to_world, (v3f){ 1.0f, 0.0f, 0.0f}, vside );
-
- v3f cn0, cn1, cn2;
-
- int contact_count =
- sample_if_resistant( contact_front ) +
- sample_if_resistant( contact_back ) +
- sample_if_resistant( contact_norm );
-
- if( contact_count < 3 )
- {
- player_start_air();
- return;
- }
-
- v3f norm;
- v3f v0, v1;
- v3_sub( contact_norm, contact_front, v0 );
- v3_sub( contact_back, contact_front, v1 );
- v3_cross( v1, v0, norm );
- v3_normalize( norm );
-
- vg_line( contact_norm, contact_front, 0xff00ff00 );
- vg_line( contact_back, contact_front, 0xff0000ff );
-
- /* Surface alignment */
- float angle = v3_dot( vup, norm );
- v3_cross( vup, norm, axis );
-
- if( angle < 0.999f )
- {
- v4f correction;
- q_axis_angle( correction, axis, acosf(angle) );
- q_mul( correction, player.rot, player.rot );
- }
-
- float resistance = v3_dot( norm, player.v );
-
- if( resistance >= 0.0f )
- {
- player_start_air();
- return;
- }
- else
- {
- v3_muladds( player.v, norm, -resistance, player.v );
- }
-
- /* This is where velocity integration used to be */
-
- float slip = 0.0f;
-
- player.co[1] = (contact_front[1]+contact_back[1])*0.5f;
-
- v3f vel;
- m3x3_mulv( player.to_local, player.v, vel );
-
- /* Calculate local forces */
-
- slip = fabsf(-vel[0] / vel[2]) * vg_signf(vel[0]);
- if( fabsf( slip ) > 1.2f )
- slip = vg_signf( slip ) * 1.2f;
- player.slip = slip;
- player.reverse = -vg_signf(vel[2]);
-
- float substep = ktimestep * 0.2f;
- for( int i=0; i<5; i++ )
- {
- vel[2] = stable_force( vel[2], vg_signf( vel[2] ) * -0.02f*substep );
- vel[0] = stable_force( vel[0], vg_signf( vel[0] ) * -7.0f *substep );
- }
-
- m3x3_mulv( player.to_world, vel, player.v );
-
- if( vg_get_button( "yawl" ) )
- player.iY += 3.6f * ktimestep;
- if( vg_get_button( "yawr" ) )
- player.iY -= 3.6f * ktimestep;
-
- float steer = vg_get_axis( "horizontal" );
- player.iY -= vg_signf(steer)*powf(steer,2.0f) * 1.5f * ktimestep;
-
- /* Too much lean and it starts to look like a snowboard here */
- v2_lerp( player.board_xy, (v2f){ slip*0.25f, 0.0f },
- ktimestep*5.0f, player.board_xy);
-}
-
-static void draw_cross(v3f pos,u32 colour)
-{
- v3f p0, p1;
- v3_add( (v3f){ 1.0f,0.0f,0.0f}, pos, p0 );
- v3_add( (v3f){-1.0f,0.0f,0.0f}, pos, p1 );
- vg_line( p0, p1, colour );
- v3_add( (v3f){0.0f, 1.0f,0.0f}, pos, p0 );
- v3_add( (v3f){0.0f,-1.0f,0.0f}, pos, p1 );
- vg_line( p0, p1, colour );
- v3_add( (v3f){0.0f,0.0f, 1.0f}, pos, p0 );
- v3_add( (v3f){0.0f,0.0f,-1.0f}, pos, p1 );
- vg_line( p0, p1, colour );