170 lines
No EOL
10 KiB
Text
170 lines
No EOL
10 KiB
Text
/**********************************************************************************************
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*
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* Physac v1.1 - 2D Physics library for videogames
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*
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* DESCRIPTION:
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*
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* Physac is a small 2D physics engine written in pure C. The engine uses a fixed time-step thread loop
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* to simluate physics. A physics step contains the following phases: get collision information,
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* apply dynamics, collision solving and position correction. It uses a very simple struct for physic
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* bodies with a position vector to be used in any 3D rendering API.
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*
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* CONFIGURATION:
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*
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* #define PHYSAC_IMPLEMENTATION
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* Generates the implementation of the library into the included file.
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* If not defined, the library is in header only mode and can be included in other headers
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* or source files without problems. But only ONE file should hold the implementation.
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*
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* #define PHYSAC_STATIC (defined by default)
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* The generated implementation will stay private inside implementation file and all
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* internal symbols and functions will only be visible inside that file.
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*
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* #define PHYSAC_DEBUG
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* Show debug traces log messages about physic bodies creation/destruction, physic system errors,
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* some calculations results and NULL reference exceptions
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*
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* #define PHYSAC_DEFINE_VECTOR2_TYPE
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* Forces library to define struct Vector2 data type (float x; float y)
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*
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* #define PHYSAC_AVOID_TIMMING_SYSTEM
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* Disables internal timming system, used by UpdatePhysics() to launch timmed physic steps,
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* it allows just running UpdatePhysics() automatically on a separate thread at a desired time step.
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* In case physics steps update needs to be controlled by user with a custom timming mechanism,
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* just define this flag and the internal timming mechanism will be avoided, in that case,
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* timming libraries are neither required by the module.
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*
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* #define PHYSAC_MALLOC()
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* #define PHYSAC_CALLOC()
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* #define PHYSAC_FREE()
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* You can define your own malloc/free implementation replacing stdlib.h malloc()/free() functions.
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* Otherwise it will include stdlib.h and use the C standard library malloc()/free() function.
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*
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* COMPILATION:
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*
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* Use the following code to compile with GCC:
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* gcc -o $(NAME_PART).exe $(FILE_NAME) -s -static -lraylib -lopengl32 -lgdi32 -lwinmm -std=c99
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*
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* VERSIONS HISTORY:
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* 1.1 (20-Jan-2021) @raysan5: Library general revision
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* Removed threading system (up to the user)
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* Support MSVC C++ compilation using CLITERAL()
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* Review DEBUG mechanism for TRACELOG() and all TRACELOG() messages
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* Review internal variables/functions naming for consistency
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* Allow option to avoid internal timming system, to allow app manage the steps
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* 1.0 (12-Jun-2017) First release of the library
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*
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*
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* LICENSE: zlib/libpng
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*
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* Copyright (c) 2016-2021 Victor Fisac (@victorfisac) and Ramon Santamaria (@raysan5)
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*
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* This software is provided "as-is", without any express or implied warranty. In no event
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* will the authors be held liable for any damages arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose, including commercial
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* applications, and to alter it and redistribute it freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not claim that you
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* wrote the original software. If you use this software in a product, an acknowledgment
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* in the product documentation would be appreciated but is not required.
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*
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* 2. Altered source versions must be plainly marked as such, and must not be misrepresented
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* as being the original software.
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*
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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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**********************************************************************************************/
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// Allow custom memory allocators
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//----------------------------------------------------------------------------------
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// Defines and Macros
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//----------------------------------------------------------------------------------
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//----------------------------------------------------------------------------------
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// Data Types Structure Definition
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//----------------------------------------------------------------------------------
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typedef enum PhysicsShapeType { PHYSICS_CIRCLE = 0, PHYSICS_POLYGON } PhysicsShapeType;
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// Previously defined to be used in PhysicsShape struct as circular dependencies
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typedef struct PhysicsBodyData *PhysicsBody;
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// Matrix2x2 type (used for polygon shape rotation matrix)
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typedef struct Matrix2x2 {
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float m00;
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float m01;
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float m10;
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float m11;
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} Matrix2x2;
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typedef struct PhysicsVertexData {
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unsigned int vertexCount; // Vertex count (positions and normals)
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Vector2 positions[24 /* Maximum number of vertex for polygons shapes*/]; // Vertex positions vectors
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Vector2 normals[24 /* Maximum number of vertex for polygons shapes*/]; // Vertex normals vectors
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} PhysicsVertexData;
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typedef struct PhysicsShape {
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PhysicsShapeType type; // Shape type (circle or polygon)
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PhysicsBody body; // Shape physics body data pointer
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PhysicsVertexData vertexData; // Shape vertices data (used for polygon shapes)
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float radius; // Shape radius (used for circle shapes)
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Matrix2x2 transform; // Vertices transform matrix 2x2
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} PhysicsShape;
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typedef struct PhysicsBodyData {
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unsigned int id; // Unique identifier
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bool enabled; // Enabled dynamics state (collisions are calculated anyway)
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Vector2 position; // Physics body shape pivot
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Vector2 velocity; // Current linear velocity applied to position
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Vector2 force; // Current linear force (reset to 0 every step)
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float angularVelocity; // Current angular velocity applied to orient
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float torque; // Current angular force (reset to 0 every step)
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float orient; // Rotation in radians
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float inertia; // Moment of inertia
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float inverseInertia; // Inverse value of inertia
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float mass; // Physics body mass
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float inverseMass; // Inverse value of mass
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float staticFriction; // Friction when the body has not movement (0 to 1)
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float dynamicFriction; // Friction when the body has movement (0 to 1)
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float restitution; // Restitution coefficient of the body (0 to 1)
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bool useGravity; // Apply gravity force to dynamics
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bool isGrounded; // Physics grounded on other body state
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bool freezeOrient; // Physics rotation constraint
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PhysicsShape shape; // Physics body shape information (type, radius, vertices, transform)
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} PhysicsBodyData;
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typedef struct PhysicsManifoldData {
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unsigned int id; // Unique identifier
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PhysicsBody bodyA; // Manifold first physics body reference
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PhysicsBody bodyB; // Manifold second physics body reference
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float penetration; // Depth of penetration from collision
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Vector2 normal; // Normal direction vector from 'a' to 'b'
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Vector2 contacts[2]; // Points of contact during collision
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unsigned int contactsCount; // Current collision number of contacts
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float restitution; // Mixed restitution during collision
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float dynamicFriction; // Mixed dynamic friction during collision
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float staticFriction; // Mixed static friction during collision
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} PhysicsManifoldData, *PhysicsManifold;
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//----------------------------------------------------------------------------------
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// Module Functions Declaration
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//----------------------------------------------------------------------------------
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// Physics system management
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extern /* Functions visible from other files*/ void InitPhysics(void); // Initializes physics system
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extern /* Functions visible from other files*/ void UpdatePhysics(void); // Update physics system
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extern /* Functions visible from other files*/ void ResetPhysics(void); // Reset physics system (global variables)
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extern /* Functions visible from other files*/ void ClosePhysics(void); // Close physics system and unload used memory
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extern /* Functions visible from other files*/ void SetPhysicsTimeStep(double delta); // Sets physics fixed time step in milliseconds. 1.666666 by default
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extern /* Functions visible from other files*/ void SetPhysicsGravity(float x, float y); // Sets physics global gravity force
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// Physic body creation/destroy
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extern /* Functions visible from other files*/ PhysicsBody CreatePhysicsBodyCircle(Vector2 pos, float radius, float density); // Creates a new circle physics body with generic parameters
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extern /* Functions visible from other files*/ PhysicsBody CreatePhysicsBodyRectangle(Vector2 pos, float width, float height, float density); // Creates a new rectangle physics body with generic parameters
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extern /* Functions visible from other files*/ PhysicsBody CreatePhysicsBodyPolygon(Vector2 pos, float radius, int sides, float density); // Creates a new polygon physics body with generic parameters
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extern /* Functions visible from other files*/ void DestroyPhysicsBody(PhysicsBody body); // Destroy a physics body
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// Physic body forces
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extern /* Functions visible from other files*/ void PhysicsAddForce(PhysicsBody body, Vector2 force); // Adds a force to a physics body
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extern /* Functions visible from other files*/ void PhysicsAddTorque(PhysicsBody body, float amount); // Adds an angular force to a physics body
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extern /* Functions visible from other files*/ void PhysicsShatter(PhysicsBody body, Vector2 position, float force); // Shatters a polygon shape physics body to little physics bodies with explosion force
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extern /* Functions visible from other files*/ void SetPhysicsBodyRotation(PhysicsBody body, float radians); // Sets physics body shape transform based on radians parameter
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// Query physics info
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extern /* Functions visible from other files*/ PhysicsBody GetPhysicsBody(int index); // Returns a physics body of the bodies pool at a specific index
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extern /* Functions visible from other files*/ int GetPhysicsBodiesCount(void); // Returns the current amount of created physics bodies
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extern /* Functions visible from other files*/ int GetPhysicsShapeType(int index); // Returns the physics body shape type (PHYSICS_CIRCLE or PHYSICS_POLYGON)
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extern /* Functions visible from other files*/ int GetPhysicsShapeVerticesCount(int index); // Returns the amount of vertices of a physics body shape
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extern /* Functions visible from other files*/ Vector2 GetPhysicsShapeVertex(PhysicsBody body, int vertex); // Returns transformed position of a body shape (body position + vertex transformed position)
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/***********************************************************************************
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*
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* PHYSAC IMPLEMENTATION
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*
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************************************************************************************/ |