Added SoftBody demo, contribution by Nathanael Presson. Will integrate into Bullet broadphase.
Added very basic drawTriangle for btIDebugDraw, useful for basic softbody visualization. Added btGjkEpa2, contribution by Nathanael Presson. Improved version of EPA penetration depth computation, more suitable for multi-core/SPU (less memory usage). Note: btGjkEpa2 is not enabled by default currently.
This commit is contained in:
erwin.coumans
356
src/BulletDynamics/SoftBody/btSoftBody.h
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356
src/BulletDynamics/SoftBody/btSoftBody.h
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/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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///btSoftBody implementation by Nathanael Presson
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#ifndef _312AEEF3_52DA_4ff6_B804_FCF937182E46_
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#define _312AEEF3_52DA_4ff6_B804_FCF937182E46_
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#include "LinearMath/btAlignedObjectArray.h"
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#include "LinearMath/btPoint3.h"
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#include "LinearMath/btTransform.h"
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#include "LinearMath/btIDebugDraw.h"
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#include "BulletDynamics/Dynamics/btRigidBody.h"
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//
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// btSoftBody
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//
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struct btSoftBody
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{
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//
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// Enumerations
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//
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/* eLType */
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struct eLType { enum _ {
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Structural, /* Master constraints */
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Bending, /* Secondary constraints */
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};};
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/* eAeroModel */
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struct eAeroModel { enum _ {
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V_Point, /* Vertex normals are oriented toward velocity */
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V_TwoSided, /* Vertex normals are fliped to match velocity */
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V_OneSided, /* Vertex normals are taken as it is */
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F_TwoSided, /* Face normals are fliped to match velocity */
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F_OneSided, /* Face normals are taken as it is */
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};};
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//
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// Interfaces
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//
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/* ISoftBody */
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struct ISoftBody
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{
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struct sCti
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{
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btRigidBody* m_body; /* Rigid body */
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btVector3 m_normal; /* Outward normal */
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btScalar m_offset; /* Offset from origin */
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};
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struct sMedium
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{
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btVector3 m_velocity; /* Velocity */
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btScalar m_pressure; /* Pressure */
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btScalar m_density; /* Density */
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};
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virtual void Attach(btSoftBody*)
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{}
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virtual void Detach(btSoftBody*)
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{ delete this; }
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virtual void StartCollide( const btVector3& /*minbounds*/,
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const btVector3& /*maxbounds*/)
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{}
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virtual bool CheckContact (const btVector3& /*position*/,
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sCti& /*contact*/)
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{ return(false); }
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virtual void EndCollide()
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{}
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virtual void EvaluateMedium( const btVector3& /*position*/,
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sMedium& medium)
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{ medium.m_velocity=btVector3(0,0,0);
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medium.m_pressure=0;
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medium.m_density=0; }
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};
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//
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// Internal types
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//
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typedef btAlignedObjectArray<btScalar> tScalarArray;
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typedef btAlignedObjectArray<btVector3> tVector3Array;
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/* Base type */
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struct Element
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{
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void* m_tag; // User data
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};
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/* Node */
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struct Node : Element
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{
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btVector3 m_x; // Position
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btVector3 m_q; // Previous step position
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btVector3 m_v; // Velocity
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btVector3 m_f; // Force accumulator
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btVector3 m_n; // Normal
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btScalar m_im; // 1/mass
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btScalar m_area; // Area
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int m_battach:1; // Attached
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};
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/* Link */
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struct Link : Element
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{
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Node* m_n[2]; // Node pointers
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btScalar m_rl; // Rest length
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btScalar m_kST; // Stiffness coefficient
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btScalar m_c0; // (ima+imb)*kLST
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btScalar m_c1; // rl^2
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eLType::_ m_type; // Link type
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};
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/* Face */
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struct Face : Element
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{
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Node* m_n[3]; // Node pointers
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btVector3 m_normal; // Normal
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btScalar m_ra; // Rest area
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};
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/* Contact */
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struct Contact
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{
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ISoftBody::sCti m_cti; // Contact infos
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Node* m_node; // Owner node
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btMatrix3x3 m_c0; // Impulse matrix
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btVector3 m_c1; // Relative anchor
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btScalar m_c2; // ima*dt
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btScalar m_c3; // Friction
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};
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/* Anchor */
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struct Anchor
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{
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Node* m_node; // Node pointer
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btVector3 m_local; // Anchor position in body space
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btRigidBody* m_body; // Body
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btMatrix3x3 m_c0; // Impulse matrix
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btVector3 m_c1; // Relative anchor
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btScalar m_c2; // ima*dt
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};
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/* Pose */
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struct Pose
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{
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bool m_bvolume; // Is valid
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bool m_bframe; // Is frame
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btScalar m_volume; // Rest volume
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tVector3Array m_pos; // Reference positions
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tScalarArray m_wgh; // Weights
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btVector3 m_com; // COM
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btMatrix3x3 m_trs; // Transform
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};
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/* Config */
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struct Config
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{
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eAeroModel::_ aeromodel; // Aerodynamic model (default: V_Point)
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btScalar kLST; // Linear stiffness coefficient [0,1]
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btScalar kDP; // Damping coefficient [0,1]
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btScalar kDG; // Drag coefficient [0,+inf]
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btScalar kLF; // Lift coefficient [0,+inf]
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btScalar kPR; // Pressure coefficient [-inf,+inf]
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btScalar kVC; // Volume conversation coefficient [0,+inf]
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btScalar kDF; // Dynamic friction coefficient [0,1]
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btScalar kMT; // Pose matching coefficient [0,1]
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btScalar kSOR; // SOR(w) [1,2] default 1, never use with solver!=Accurate
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btScalar kCHR; // Contacts hardness [0,1]
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btScalar kAHR; // Anchors hardness [0,1]
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btScalar timescale; // Time scale
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btScalar timestep; // Time step
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int maxsteps; // Maximum time steps
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int iterations; // Solver iterations
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bool becollide; // Enable external collisions
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bool bscollide; // Enable self collisions
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};
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//
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// Typedef's
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//
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typedef btAlignedObjectArray<Node> tNodeArray;
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typedef btAlignedObjectArray<Link> tLinkArray;
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typedef btAlignedObjectArray<Face> tFaceArray;
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typedef btAlignedObjectArray<Anchor> tAnchorArray;
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typedef btAlignedObjectArray<Contact> tContactArray;
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//
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// Fields
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//
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Config m_cfg; // Configuration
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Pose m_pose; // Pose
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ISoftBody* m_isb; // ISoftBody
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void* m_tag; // User data
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tNodeArray m_nodes; // Nodes
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tLinkArray m_links; // Links
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tFaceArray m_faces; // Faces
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tAnchorArray m_anchors; // Anchors
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tContactArray m_contacts; // Contacts
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btScalar m_timeacc; // Time accumulator
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btVector3 m_bounds[2]; // Spatial bounds
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bool m_bUpdateRtCst; // Update runtime constants
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//
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// Api
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//
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/* Create a soft body */
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static btSoftBody* Create( ISoftBody* isoftbody,
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int node_count,
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const btVector3* x=0,
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const btScalar* m=0);
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/* Delete a body */
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void Delete();
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/* Check for existing link */
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bool CheckLink( int node0,
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int node1) const;
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bool CheckLink( const btSoftBody::Node* node0,
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const btSoftBody::Node* node1) const;
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/* Check for existring face */
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bool CheckFace( int node0,
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int node1,
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int node2) const;
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/* Append link */
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void AppendLink( int node0,
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int node1,
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btScalar kST,
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btSoftBody::eLType::_ type,
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bool bcheckexist=false);
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void AppendLink( btSoftBody::Node* node0,
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btSoftBody::Node* node1,
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btScalar kST,
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btSoftBody::eLType::_ type,
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bool bcheckexist=false);
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/* Append face */
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void AppendFace( int node0,
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int node1,
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int node2);
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/* Append anchor */
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void AppendAnchor( int node,
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btRigidBody* body);
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/* Add force (or gravity) to the entire body */
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void AddForce( const btVector3& force);
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/* Add force (or gravity) to a node of the body */
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void AddForce( const btVector3& force,
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int node);
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/* Add velocity to the entire body */
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void AddVelocity( const btVector3& velocity);
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/* Add velocity to a node of the body */
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void AddVelocity( const btVector3& velocity,
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int node);
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/* Set mass */
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void SetMass( int node,
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btScalar mass);
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/* Get mass */
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btScalar GetMass( int node) const;
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/* Get total mass */
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btScalar GetTotalMass() const;
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/* Set total mass (weighted by previous masses) */
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void SetTotalMass( btScalar mass,
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bool fromfaces=false);
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/* Set total density */
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void SetTotalDensity(btScalar density);
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/* Transform */
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void Transform( const btTransform& trs);
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/* Scale */
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void Scale( const btVector3& scl);
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/* Set current state as pose */
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void SetPose( bool bvolume,
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bool bframe);
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/* Return the volume */
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btScalar GetVolume() const;
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/* Generate bending constraints based on distance in the adjency graph */
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int GenerateBendingConstraints( int distance,
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btScalar stiffness);
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/* Randomize constraints to reduce solver bias */
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void RandomizeConstraints();
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/* Ray casting */
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btScalar Raycast( const btVector3& org,
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const btVector3& dir) const;
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/* Step */
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void Step( btScalar dt);
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};
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//
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// Helpers
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//
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/* fDrawFlags */
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struct fDrawFlags { enum _ {
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Nodes = 0x0001,
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SLinks = 0x0002,
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BLinks = 0x0004,
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Faces = 0x0008,
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Tetras = 0x0010,
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Normals = 0x0020,
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Contacts = 0x0040,
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Anchors = 0x0080,
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/* presets */
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Links = SLinks+BLinks,
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Std = SLinks+Faces+Anchors,
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StdTetra = Std-Faces+Tetras,
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};};
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/* Draw body */
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void Draw( btSoftBody* psb,
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btIDebugDraw* idraw,
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int drawflags=fDrawFlags::Std);
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/* Draw body infos */
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void DrawInfos( btSoftBody* psb,
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btIDebugDraw* idraw,
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bool masses,
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bool areas,
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bool stress);
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/* Draw rigid frame */
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void DrawFrame( btSoftBody* psb,
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btIDebugDraw* idraw);
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/* Create a rope */
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btSoftBody* CreateRope( btSoftBody::ISoftBody* isoftbody,
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const btVector3& from,
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const btVector3& to,
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int res,
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int fixeds);
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/* Create a patch */
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btSoftBody* CreatePatch( btSoftBody::ISoftBody* isoftbody,
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const btVector3& corner00,
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const btVector3& corner10,
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const btVector3& corner01,
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const btVector3& corner11,
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int resx,
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int resy,
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int fixeds,
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bool gendiags);
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/* Create an ellipsoid */
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btSoftBody* CreateEllipsoid(btSoftBody::ISoftBody* isoftbody,
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const btVector3& center,
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const btVector3& radius,
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int res);
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/* Create from convex-hull */
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btSoftBody* CreateFromConvexHull( btSoftBody::ISoftBody* isoftbody,
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const btVector3* vertices,
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int nvertices);
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/* Create from trimesh */
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btSoftBody* CreateFromTriMesh( btSoftBody::ISoftBody* isoftbody,
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const btScalar* vertices,
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const int* triangles,
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int ntriangles);
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#endif
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