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Diffstat (limited to 'src/physac.h')
| -rw-r--r-- | src/physac.h | 776 |
1 files changed, 754 insertions, 22 deletions
diff --git a/src/physac.h b/src/physac.h index b2ae2766..dd4c4126 100644 --- a/src/physac.h +++ b/src/physac.h @@ -1,8 +1,53 @@ /********************************************************************************************** * -* [physac] raylib physics module - Basic functions to apply physics to 2D objects +* physac 1.0 - 2D Physics library for raylib (https://github.com/raysan5/raylib) * -* Copyright (c) 2016 Victor Fisac and Ramon Santamaria +* // TODO: Description... +* +* CONFIGURATION: +* +* #define PHYSAC_IMPLEMENTATION +* Generates the implementation of the library into the included file. +* If not defined, the library is in header only mode and can be included in other headers +* or source files without problems. But only ONE file should hold the implementation. +* +* #define PHYSAC_STATIC (defined by default) +* The generated implementation will stay private inside implementation file and all +* internal symbols and functions will only be visible inside that file. +* +* #define PHYSAC_NO_THREADS +* The generated implementation won't include pthread library and user must create a secondary thread to call PhysicsThread(). +* It is so important that the thread where PhysicsThread() is called must not have v-sync or any other CPU limitation. +* +* #define PHYSAC_STANDALONE +* Avoid raylib.h header inclusion in this file. Data types defined on raylib are defined +* internally in the library and input management and drawing functions must be provided by +* the user (check library implementation for further details). +* +* #define PHYSAC_MALLOC() +* #define PHYSAC_FREE() +* You can define your own malloc/free implementation replacing stdlib.h malloc()/free() functions. +* Otherwise it will include stdlib.h and use the C standard library malloc()/free() function. +* +* LIMITATIONS: +* +* - There is a limit of 256 physic objects. +* - Physics behaviour can be unexpected using bounciness or friction values out of 0.0f - 1.0f range. +* - The module is limited to 2D axis oriented physics. +* - Physics colliders must be rectangle or circle shapes (there is not a custom polygon collider type). +* +* VERSIONS: +* +* 1.0 (14-Jun-2016) New module defines and fixed some delta time calculation bugs. +* 0.9 (09-Jun-2016) Module names review and converted to header-only. +* 0.8 (23-Mar-2016) Complete module redesign, steps-based for better physics resolution. +* 0.3 (13-Feb-2016) Reviewed to add PhysicObjects pool. +* 0.2 (03-Jan-2016) Improved physics calculations. +* 0.1 (30-Dec-2015) Initial release. +* +* LICENSE: zlib/libpng +* +* Copyright (c) 2016 Victor Fisac (main developer) and Ramon Santamaria * * This software is provided "as-is", without any express or implied warranty. In no event * will the authors be held liable for any damages arising from the use of this software. @@ -24,6 +69,21 @@ #ifndef PHYSAC_H #define PHYSAC_H +#if !defined(RAYGUI_STANDALONE) + #include "raylib.h" +#endif + +#define PHYSAC_STATIC +#ifdef PHYSAC_STATIC + #define PHYSACDEF static // Functions just visible to module including this file +#else + #ifdef __cplusplus + #define PHYSACDEF extern "C" // Functions visible from other files (no name mangling of functions in C++) + #else + #define PHYSACDEF extern // Functions visible from other files + #endif +#endif + //---------------------------------------------------------------------------------- // Defines and Macros //---------------------------------------------------------------------------------- @@ -33,12 +93,28 @@ // Types and Structures Definition // NOTE: Below types are required for PHYSAC_STANDALONE usage //---------------------------------------------------------------------------------- +#if defined(PHYSAC_STANDALONE) + #ifndef __cplusplus + // Boolean type + #ifndef true + typedef enum { false, true } bool; + #endif + #endif + + // Vector2 type + typedef struct Vector2 { + float x; + float y; + } Vector2; -// Vector2 type -typedef struct Vector2 { - float x; - float y; -} Vector2; + // Rectangle type + typedef struct Rectangle { + int x; + int y; + int width; + int height; + } Rectangle; +#endif typedef enum { COLLIDER_CIRCLE, COLLIDER_RECTANGLE } ColliderType; @@ -66,35 +142,691 @@ typedef struct Collider { int radius; // Used for COLLIDER_CIRCLE } Collider; -typedef struct PhysicObjectData { +typedef struct PhysicBodyData { unsigned int id; Transform transform; Rigidbody rigidbody; Collider collider; bool enabled; -} PhysicObjectData, *PhysicObject; +} PhysicBodyData, *PhysicBody; + +//---------------------------------------------------------------------------------- +// Module Functions Declaration +//---------------------------------------------------------------------------------- +PHYSACDEF void InitPhysics(Vector2 gravity); // Initializes pointers array (just pointers, fixed size) +PHYSACDEF void* PhysicsThread(void *arg); // Physics calculations thread function +PHYSACDEF void ClosePhysics(); // Unitialize all physic objects and empty the objects pool + +PHYSACDEF PhysicBody CreatePhysicBody(Vector2 position, float rotation, Vector2 scale); // Create a new physic body dinamically, initialize it and add to pool +PHYSACDEF void DestroyPhysicBody(PhysicBody pbody); // Destroy a specific physic body and take it out of the list + +PHYSACDEF void ApplyForce(PhysicBody pbody, Vector2 force); // Apply directional force to a physic body +PHYSACDEF void ApplyForceAtPosition(Vector2 position, float force, float radius); // Apply radial force to all physic objects in range + +PHYSACDEF Rectangle TransformToRectangle(Transform transform); // Convert Transform data type to Rectangle (position and scale) -#ifdef __cplusplus -extern "C" { // Prevents name mangling of functions +#endif // PHYSAC_H + + +/*********************************************************************************** +* +* PHYSAC IMPLEMENTATION +* +************************************************************************************/ + +#if defined(PHYSAC_IMPLEMENTATION) + +// Check if custom malloc/free functions defined, if not, using standard ones +#if !defined(PHYSAC_MALLOC) + #include <stdlib.h> // Required for: malloc(), free() + + #define PHYSAC_MALLOC(size) malloc(size) + #define PHYSAC_FREE(ptr) free(ptr) +#endif + +#include <math.h> // Required for: cos(), sin(), abs(), fminf() +#include <stdint.h> // Required for typedef unsigned long long int uint64_t, used by hi-res timer + +#ifndef PHYSAC_NO_THREADS + #include <pthread.h> // Required for: pthread_create() +#endif + +#if defined(PLATFORM_DESKTOP) + // Functions required to query time on Windows + int __stdcall QueryPerformanceCounter(unsigned long long int *lpPerformanceCount); + int __stdcall QueryPerformanceFrequency(unsigned long long int *lpFrequency); +#elif defined(PLATFORM_ANDROID) || defined(PLATFORM_RPI) + #include <sys/time.h> // Required for: timespec + #include <time.h> // Required for: clock_gettime() #endif //---------------------------------------------------------------------------------- -// Module Functions Declaration +// Defines and Macros +//---------------------------------------------------------------------------------- +#define MAX_PHYSIC_BODIES 256 // Maximum available physic bodies slots in bodies pool +#define PHYSICS_TIMESTEP 0.016666 // Physics fixed time step (1/fps) +#define PHYSICS_ACCURACY 0.0001f // Velocity subtract operations round filter (friction) +#define PHYSICS_ERRORPERCENT 0.001f // Collision resolve position fix + +//---------------------------------------------------------------------------------- +// Types and Structures Definition +// NOTE: Below types are required for PHYSAC_STANDALONE usage +//---------------------------------------------------------------------------------- +// ... + //---------------------------------------------------------------------------------- -void InitPhysics(Vector2 gravity); // Initializes pointers array (just pointers, fixed size) -void UpdatePhysics(); // Update physic objects, calculating physic behaviours and collisions detection -void ClosePhysics(); // Unitialize all physic objects and empty the objects pool +// Global Variables Definition +//---------------------------------------------------------------------------------- +static bool physicsThreadEnabled = false; // Physics calculations thread exit control +static uint64_t baseTime; // Base time measure for hi-res timer +static double currentTime, previousTime; // Used to track timmings +static PhysicBody physicBodies[MAX_PHYSIC_BODIES]; // Physic bodies pool +static int physicBodiesCount; // Counts current enabled physic bodies +static Vector2 gravityForce; // Gravity force + +//---------------------------------------------------------------------------------- +// Module specific Functions Declaration +//---------------------------------------------------------------------------------- +static void UpdatePhysics(double deltaTime); // Update physic objects, calculating physic behaviours and collisions detection +static void InitTimer(void); // Initialize hi-resolution timer +static double GetCurrentTime(void); // Time measure returned are microseconds +static float Vector2DotProduct(Vector2 v1, Vector2 v2); // Returns the dot product of two Vector2 +static float Vector2Length(Vector2 v); // Returns the length of a Vector2 + +//---------------------------------------------------------------------------------- +// Module Functions Definition +//---------------------------------------------------------------------------------- + +// Initializes pointers array (just pointers, fixed size) +PHYSACDEF void InitPhysics(Vector2 gravity) +{ + // Initialize physics variables + physicBodiesCount = 0; + gravityForce = gravity; + + #ifndef PHYSAC_NO_THREADS // NOTE: if defined, user will need to create a thread for PhysicsThread function manually + // Create physics thread + pthread_t tid; + pthread_create(&tid, NULL, &PhysicsThread, NULL); + #endif +} + +// Unitialize all physic objects and empty the objects pool +PHYSACDEF void ClosePhysics() +{ + // Exit physics thread loop + physicsThreadEnabled = false; + + // Free all dynamic memory allocations + for (int i = 0; i < physicBodiesCount; i++) PHYSAC_FREE(physicBodies[i]); + + // Reset enabled physic objects count + physicBodiesCount = 0; +} + +// Create a new physic body dinamically, initialize it and add to pool +PHYSACDEF PhysicBody CreatePhysicBody(Vector2 position, float rotation, Vector2 scale) +{ + // Allocate dynamic memory + PhysicBody obj = (PhysicBody)PHYSAC_MALLOC(sizeof(PhysicBodyData)); + + // Initialize physic body values with generic values + obj->id = physicBodiesCount; + obj->enabled = true; + + obj->transform = (Transform){ (Vector2){ position.x - scale.x/2, position.y - scale.y/2 }, rotation, scale }; + + obj->rigidbody.enabled = false; + obj->rigidbody.mass = 1.0f; + obj->rigidbody.acceleration = (Vector2){ 0.0f, 0.0f }; + obj->rigidbody.velocity = (Vector2){ 0.0f, 0.0f }; + obj->rigidbody.applyGravity = false; + obj->rigidbody.isGrounded = false; + obj->rigidbody.friction = 0.0f; + obj->rigidbody.bounciness = 0.0f; + + obj->collider.enabled = true; + obj->collider.type = COLLIDER_RECTANGLE; + obj->collider.bounds = TransformToRectangle(obj->transform); + obj->collider.radius = 0.0f; + + // Add new physic body to the pointers array + physicBodies[physicBodiesCount] = obj; + + // Increase enabled physic bodies count + physicBodiesCount++; + + return obj; +} + +// Destroy a specific physic body and take it out of the list +PHYSACDEF void DestroyPhysicBody(PhysicBody pbody) +{ + // Free dynamic memory allocation + PHYSAC_FREE(physicBodies[pbody->id]); + + // Remove *obj from the pointers array + for (int i = pbody->id; i < physicBodiesCount; i++) + { + // Resort all the following pointers of the array + if ((i + 1) < physicBodiesCount) + { + physicBodies[i] = physicBodies[i + 1]; + physicBodies[i]->id = physicBodies[i + 1]->id; + } + else PHYSAC_FREE(physicBodies[i]); + } + + // Decrease enabled physic bodies count + physicBodiesCount--; +} + +// Apply directional force to a physic body +PHYSACDEF void ApplyForce(PhysicBody pbody, Vector2 force) +{ + if (pbody->rigidbody.enabled) + { + pbody->rigidbody.velocity.x += force.x/pbody->rigidbody.mass; + pbody->rigidbody.velocity.y += force.y/pbody->rigidbody.mass; + } +} + +// Apply radial force to all physic objects in range +PHYSACDEF void ApplyForceAtPosition(Vector2 position, float force, float radius) +{ + for (int i = 0; i < physicBodiesCount; i++) + { + if (physicBodies[i]->rigidbody.enabled) + { + // Calculate direction and distance between force and physic body position + Vector2 distance = (Vector2){ physicBodies[i]->transform.position.x - position.x, physicBodies[i]->transform.position.y - position.y }; + + if (physicBodies[i]->collider.type == COLLIDER_RECTANGLE) + { + distance.x += physicBodies[i]->transform.scale.x/2; + distance.y += physicBodies[i]->transform.scale.y/2; + } + + float distanceLength = Vector2Length(distance); + + // Check if physic body is in force range + if (distanceLength <= radius) + { + // Normalize force direction + distance.x /= distanceLength; + distance.y /= -distanceLength; + + // Calculate final force + Vector2 finalForce = { distance.x*force, distance.y*force }; + + // Apply force to the physic body + ApplyForce(physicBodies[i], finalForce); + } + } + } +} + +// Convert Transform data type to Rectangle (position and scale) +PHYSACDEF Rectangle TransformToRectangle(Transform transform) +{ + return (Rectangle){transform.position.x, transform.position.y, transform.scale.x, transform.scale.y}; +} -PhysicObject CreatePhysicObject(Vector2 position, float rotation, Vector2 scale); // Create a new physic object dinamically, initialize it and add to pool -void DestroyPhysicObject(PhysicObject pObj); // Destroy a specific physic object and take it out of the list +// Physics calculations thread function +PHYSACDEF void* PhysicsThread(void *arg) +{ + // Initialize thread loop state + physicsThreadEnabled = true; + + // Initialize hi-resolution timer + InitTimer(); + + // Physics update loop + while (physicsThreadEnabled) + { + currentTime = GetCurrentTime(); + double deltaTime = (double)(currentTime - previousTime); + previousTime = currentTime; -void ApplyForce(PhysicObject pObj, Vector2 force); // Apply directional force to a physic object -void ApplyForceAtPosition(Vector2 position, float force, float radius); // Apply radial force to all physic objects in range + // Delta time value needs to be inverse multiplied by physics time step value (1/target fps) + UpdatePhysics(deltaTime/PHYSICS_TIMESTEP); + } + + return NULL; +} + +//---------------------------------------------------------------------------------- +// Module specific Functions Definition +//---------------------------------------------------------------------------------- +// Initialize hi-resolution timer +static void InitTimer(void) +{ +#if defined(PLATFORM_ANDROID) || defined(PLATFORM_RPI) + struct timespec now; -Rectangle TransformToRectangle(Transform transform); // Convert Transform data type to Rectangle (position and scale) + if (clock_gettime(CLOCK_MONOTONIC, &now) == 0) // Success + { + baseTime = (uint64_t)now.tv_sec*1000000000LLU + (uint64_t)now.tv_nsec; + } +#endif -#ifdef __cplusplus + previousTime = GetCurrentTime(); // Get time as double } + +// Time measure returned are microseconds +static double GetCurrentTime(void) +{ + double time; + +#if defined(PLATFORM_DESKTOP) + unsigned long long int clockFrequency, currentTime; + + QueryPerformanceFrequency(&clockFrequency); + QueryPerformanceCounter(¤tTime); + + time = (double)((double)currentTime/(double)clockFrequency); #endif -#endif // PHYSAC_H +#if defined(PLATFORM_ANDROID) || defined(PLATFORM_RPI) + struct timespec ts; + clock_gettime(CLOCK_MONOTONIC, &ts); + uint64_t temp = (uint64_t)ts.tv_sec*1000000000LLU + (uint64_t)ts.tv_nsec; + + time = (double)(temp - baseTime)*1e-9; +#endif + + return time; +} + +// Returns the dot product of two Vector2 +static float Vector2DotProduct(Vector2 v1, Vector2 v2) +{ + float result; + + result = v1.x*v2.x + v1.y*v2.y; + + return result; +} + +static float Vector2Length(Vector2 v) +{ + float result; + + result = sqrt(v.x*v.x + v.y*v.y); + + return result; +} + +// Update physic objects, calculating physic behaviours and collisions detection +static void UpdatePhysics(double deltaTime) +{ + for (int i = 0; i < physicBodiesCount; i++) + { + if (physicBodies[i]->enabled) + { + // Update physic behaviour + if (physicBodies[i]->rigidbody.enabled) + { + // Apply friction to acceleration in X axis + if (physicBodies[i]->rigidbody.acceleration.x > PHYSICS_ACCURACY) physicBodies[i]->rigidbody.acceleration.x -= physicBodies[i]->rigidbody.friction*deltaTime; + else if (physicBodies[i]->rigidbody.acceleration.x < PHYSICS_ACCURACY) physicBodies[i]->rigidbody.acceleration.x += physicBodies[i]->rigidbody.friction*deltaTime; + else physicBodies[i]->rigidbody.acceleration.x = 0.0f; + + // Apply friction to acceleration in Y axis + if (physicBodies[i]->rigidbody.acceleration.y > PHYSICS_ACCURACY) physicBodies[i]->rigidbody.acceleration.y -= physicBodies[i]->rigidbody.friction*deltaTime; + else if (physicBodies[i]->rigidbody.acceleration.y < PHYSICS_ACCURACY) physicBodies[i]->rigidbody.acceleration.y += physicBodies[i]->rigidbody.friction*deltaTime; + else physicBodies[i]->rigidbody.acceleration.y = 0.0f; + + // Apply friction to velocity in X axis + if (physicBodies[i]->rigidbody.velocity.x > PHYSICS_ACCURACY) physicBodies[i]->rigidbody.velocity.x -= physicBodies[i]->rigidbody.friction*deltaTime; + else if (physicBodies[i]->rigidbody.velocity.x < PHYSICS_ACCURACY) physicBodies[i]->rigidbody.velocity.x += physicBodies[i]->rigidbody.friction*deltaTime; + else physicBodies[i]->rigidbody.velocity.x = 0.0f; + + // Apply friction to velocity in Y axis + if (physicBodies[i]->rigidbody.velocity.y > PHYSICS_ACCURACY) physicBodies[i]->rigidbody.velocity.y -= physicBodies[i]->rigidbody.friction*deltaTime; + else if (physicBodies[i]->rigidbody.velocity.y < PHYSICS_ACCURACY) physicBodies[i]->rigidbody.velocity.y += physicBodies[i]->rigidbody.friction*deltaTime; + else physicBodies[i]->rigidbody.velocity.y = 0.0f; + + // Apply gravity to velocity + if (physicBodies[i]->rigidbody.applyGravity) + { + physicBodies[i]->rigidbody.velocity.x += gravityForce.x*deltaTime; + physicBodies[i]->rigidbody.velocity.y += gravityForce.y*deltaTime; + } + + // Apply acceleration to velocity + physicBodies[i]->rigidbody.velocity.x += physicBodies[i]->rigidbody.acceleration.x*deltaTime; + physicBodies[i]->rigidbody.velocity.y += physicBodies[i]->rigidbody.acceleration.y*deltaTime; + + // Apply velocity to position + physicBodies[i]->transform.position.x += physicBodies[i]->rigidbody.velocity.x*deltaTime; + physicBodies[i]->transform.position.y -= physicBodies[i]->rigidbody.velocity.y*deltaTime; + } + + // Update collision detection + if (physicBodies[i]->collider.enabled) + { + // Update collider bounds + physicBodies[i]->collider.bounds = TransformToRectangle(physicBodies[i]->transform); + + // Check collision with other colliders + for (int k = 0; k < physicBodiesCount; k++) + { + if (physicBodies[k]->collider.enabled && i != k) + { + // Resolve physic collision + // NOTE: collision resolve is generic for all directions and conditions (no axis separated cases behaviours) + // and it is separated in rigidbody attributes resolve (velocity changes by impulse) and position correction (position overlap) + + // 1. Calculate collision normal + // ------------------------------------------------------------------------------------------------------------------------------------- + + // Define collision contact normal, direction and penetration depth + Vector2 contactNormal = { 0.0f, 0.0f }; + Vector2 direction = { 0.0f, 0.0f }; + float penetrationDepth = 0.0f; + + switch (physicBodies[i]->collider.type) + { + case COLLIDER_RECTANGLE: + { + switch (physicBodies[k]->collider.type) + { + case COLLIDER_RECTANGLE: + { + // Check if colliders are overlapped + if (CheckCollisionRecs(physicBodies[i]->collider.bounds, physicBodies[k]->collider.bounds)) + { + // Calculate direction vector from i to k + direction.x = (physicBodies[k]->transform.position.x + physicBodies[k]->transform.scale.x/2) - (physicBodies[i]->transform.position.x + physicBodies[i]->transform.scale.x/2); + direction.y = (physicBodies[k]->transform.position.y + physicBodies[k]->transform.scale.y/2) - (physicBodies[i]->transform.position.y + physicBodies[i]->transform.scale.y/2); + + // Define overlapping and penetration attributes + Vector2 overlap; + + // Calculate overlap on X axis + overlap.x = (physicBodies[i]->transform.scale.x + physicBodies[k]->transform.scale.x)/2 - abs(direction.x); + + // SAT test on X axis + if (overlap.x > 0.0f) + { + // Calculate overlap on Y axis + overlap.y = (physicBodies[i]->transform.scale.y + physicBodies[k]->transform.scale.y)/2 - abs(direction.y); + + // SAT test on Y axis + if (overlap.y > 0.0f) + { + // Find out which axis is axis of least penetration + if (overlap.y > overlap.x) + { + // Point towards k knowing that direction points from i to k + if (direction.x < 0.0f) contactNormal = (Vector2){ -1.0f, 0.0f }; + else contactNormal = (Vector2){ 1.0f, 0.0f }; + + // Update penetration depth for position correction + penetrationDepth = overlap.x; + } + else + { + // Point towards k knowing that direction points from i to k + if (direction.y < 0.0f) contactNormal = (Vector2){ 0.0f, 1.0f }; + else contactNormal = (Vector2){ 0.0f, -1.0f }; + + // Update penetration depth for position correction + penetrationDepth = overlap.y; + } + } + } + } + } break; + case COLLIDER_CIRCLE: + { + if (CheckCollisionCircleRec(physicBodies[k]->transform.position, physicBodies[k]->collider.radius, physicBodies[i]->collider.bounds)) + { + // Calculate direction vector between circles + direction.x = physicBodies[k]->transform.position.x - physicBodies[i]->transform.position.x + physicBodies[i]->transform.scale.x/2; + direction.y = physicBodies[k]->transform.position.y - physicBodies[i]->transform.position.y + physicBodies[i]->transform.scale.y/2; + + // Calculate closest point on rectangle to circle + Vector2 closestPoint = { 0.0f, 0.0f }; + if (direction.x > 0.0f) closestPoint.x = physicBodies[i]->collider.bounds.x + physicBodies[i]->collider.bounds.width; + else closestPoint.x = physicBodies[i]->collider.bounds.x; + + if (direction.y > 0.0f) closestPoint.y = physicBodies[i]->collider.bounds.y + physicBodies[i]->collider.bounds.height; + else closestPoint.y = physicBodies[i]->collider.bounds.y; + + // Check if the closest point is inside the circle + if (CheckCollisionPointCircle(closestPoint, physicBodies[k]->transform.position, physicBodies[k]->collider.radius)) + { + // Recalculate direction based on closest point position + direction.x = physicBodies[k]->transform.position.x - closestPoint.x; + direction.y = physicBodies[k]->transform.position.y - closestPoint.y; + float distance = Vector2Length(direction); + + // Calculate final contact normal + contactNormal.x = direction.x/distance; + contactNormal.y = -direction.y/distance; + + // Calculate penetration depth + penetrationDepth = physicBodies[k]->collider.radius - distance; + } + else + { + if (abs(direction.y) < abs(direction.x)) + { + // Calculate final contact normal + if (direction.y > 0.0f) + { + contactNormal = (Vector2){ 0.0f, -1.0f }; + penetrationDepth = fabs(physicBodies[i]->collider.bounds.y - physicBodies[k]->transform.position.y - physicBodies[k]->collider.radius); + } + else + { + contactNormal = (Vector2){ 0.0f, 1.0f }; + penetrationDepth = fabs(physicBodies[i]->collider.bounds.y - physicBodies[k]->transform.position.y + physicBodies[k]->collider.radius); + } + } + else + { + // Calculate final contact normal + if (direction.x > 0.0f) + { + contactNormal = (Vector2){ 1.0f, 0.0f }; + penetrationDepth = fabs(physicBodies[k]->transform.position.x + physicBodies[k]->collider.radius - physicBodies[i]->collider.bounds.x); + } + else + { + contactNormal = (Vector2){ -1.0f, 0.0f }; + penetrationDepth = fabs(physicBodies[i]->collider.bounds.x + physicBodies[i]->collider.bounds.width - physicBodies[k]->transform.position.x - physicBodies[k]->collider.radius); + } + } + } + } + } break; + } + } break; + case COLLIDER_CIRCLE: + { + switch (physicBodies[k]->collider.type) + { + case COLLIDER_RECTANGLE: + { + if (CheckCollisionCircleRec(physicBodies[i]->transform.position, physicBodies[i]->collider.radius, physicBodies[k]->collider.bounds)) + { + // Calculate direction vector between circles + direction.x = physicBodies[k]->transform.position.x + physicBodies[i]->transform.scale.x/2 - physicBodies[i]->transform.position.x; + direction.y = physicBodies[k]->transform.position.y + physicBodies[i]->transform.scale.y/2 - physicBodies[i]->transform.position.y; + + // Calculate closest point on rectangle to circle + Vector2 closestPoint = { 0.0f, 0.0f }; + if (direction.x > 0.0f) closestPoint.x = physicBodies[k]->collider.bounds.x + physicBodies[k]->collider.bounds.width; + else closestPoint.x = physicBodies[k]->collider.bounds.x; + + if (direction.y > 0.0f) closestPoint.y = physicBodies[k]->collider.bounds.y + physicBodies[k]->collider.bounds.height; + else closestPoint.y = physicBodies[k]->collider.bounds.y; + + // Check if the closest point is inside the circle + if (CheckCollisionPointCircle(closestPoint, physicBodies[i]->transform.position, physicBodies[i]->collider.radius)) + { + // Recalculate direction based on closest point position + direction.x = physicBodies[i]->transform.position.x - closestPoint.x; + direction.y = physicBodies[i]->transform.position.y - closestPoint.y; + float distance = Vector2Length(direction); + + // Calculate final contact normal + contactNormal.x = direction.x/distance; + contactNormal.y = -direction.y/distance; + + // Calculate penetration depth + penetrationDepth = physicBodies[k]->collider.radius - distance; + } + else + { + if (abs(direction.y) < abs(direction.x)) + { + // Calculate final contact normal + if (direction.y > 0.0f) + { + contactNormal = (Vector2){ 0.0f, -1.0f }; + penetrationDepth = fabs(physicBodies[k]->collider.bounds.y - physicBodies[i]->transform.position.y - physicBodies[i]->collider.radius); + } + else + { + contactNormal = (Vector2){ 0.0f, 1.0f }; + penetrationDepth = fabs(physicBodies[k]->collider.bounds.y - physicBodies[i]->transform.position.y + physicBodies[i]->collider.radius); + } + } + else + { + // Calculate final contact normal and penetration depth + if (direction.x > 0.0f) + { + contactNormal = (Vector2){ 1.0f, 0.0f }; + penetrationDepth = fabs(physicBodies[i]->transform.position.x + physicBodies[i]->collider.radius - physicBodies[k]->collider.bounds.x); + } + else + { + contactNormal = (Vector2){ -1.0f, 0.0f }; + penetrationDepth = fabs(physicBodies[k]->collider.bounds.x + physicBodies[k]->collider.bounds.width - physicBodies[i]->transform.position.x - physicBodies[i]->collider.radius); + } + } + } + } + } break; + case COLLIDER_CIRCLE: + { + // Check if colliders are overlapped + if (CheckCollisionCircles(physicBodies[i]->transform.position, physicBodies[i]->collider.radius, physicBodies[k]->transform.position, physicBodies[k]->collider.radius)) + { + // Calculate direction vector between circles + direction.x = physicBodies[k]->transform.position.x - physicBodies[i]->transform.position.x; + direction.y = physicBodies[k]->transform.position.y - physicBodies[i]->transform.position.y; + + // Calculate distance between circles + float distance = Vector2Length(direction); + + // Check if circles are not completely overlapped + if (distance != 0.0f) + { + // Calculate contact normal direction (Y axis needs to be flipped) + contactNormal.x = direction.x/distance; + contactNormal.y = -direction.y/distance; + } + else contactNormal = (Vector2){ 1.0f, 0.0f }; // Choose random (but consistent) values + } + } break; + default: break; + } + } break; + default: break; + } + + // Update rigidbody grounded state + if (physicBodies[i]->rigidbody.enabled) physicBodies[i]->rigidbody.isGrounded = (contactNormal.y < 0.0f); + + // 2. Calculate collision impulse + // ------------------------------------------------------------------------------------------------------------------------------------- + + // Calculate relative velocity + Vector2 relVelocity = { 0.0f, 0.0f }; + relVelocity.x = physicBodies[k]->rigidbody.velocity.x - physicBodies[i]->rigidbody.velocity.x; + relVelocity.y = physicBodies[k]->rigidbody.velocity.y - physicBodies[i]->rigidbody.velocity.y; + + // Calculate relative velocity in terms of the normal direction + float velAlongNormal = Vector2DotProduct(relVelocity, contactNormal); + + // Dot not resolve if velocities are separating + if (velAlongNormal <= 0.0f) + { + // Calculate minimum bounciness value from both objects + float e = fminf(physicBodies[i]->rigidbody.bounciness, physicBodies[k]->rigidbody.bounciness); + + // Calculate impulse scalar value + float j = -(1.0f + e)*velAlongNormal; + j /= 1.0f/physicBodies[i]->rigidbody.mass + 1.0f/physicBodies[k]->rigidbody.mass; + + // Calculate final impulse vector + Vector2 impulse = { j*contactNormal.x, j*contactNormal.y }; + + // Calculate collision mass ration + float massSum = physicBodies[i]->rigidbody.mass + physicBodies[k]->rigidbody.mass; + float ratio = 0.0f; + + // Apply impulse to current rigidbodies velocities if they are enabled + if (physicBodies[i]->rigidbody.enabled) + { + // Calculate inverted mass ration + ratio = physicBodies[i]->rigidbody.mass/massSum; + + // Apply impulse direction to velocity + physicBodies[i]->rigidbody.velocity.x -= impulse.x*ratio*(1.0f+physicBodies[i]->rigidbody.bounciness); + physicBodies[i]->rigidbody.velocity.y -= impulse.y*ratio*(1.0f+physicBodies[i]->rigidbody.bounciness); + } + + if (physicBodies[k]->rigidbody.enabled) + { + // Calculate inverted mass ration + ratio = physicBodies[k]->rigidbody.mass/massSum; + + // Apply impulse direction to velocity + physicBodies[k]->rigidbody.velocity.x += impulse.x*ratio*(1.0f+physicBodies[i]->rigidbody.bounciness); + physicBodies[k]->rigidbody.velocity.y += impulse.y*ratio*(1.0f+physicBodies[i]->rigidbody.bounciness); + } + + // 3. Correct colliders overlaping (transform position) + // --------------------------------------------------------------------------------------------------------------------------------- + + // Calculate transform position penetration correction + Vector2 posCorrection; + posCorrection.x = penetrationDepth/((1.0f/physicBodies[i]->rigidbody.mass) + (1.0f/physicBodies[k]->rigidbody.mass))*PHYSICS_ERRORPERCENT*contactNormal.x; + posCorrection.y = penetrationDepth/((1.0f/physicBodies[i]->rigidbody.mass) + (1.0f/physicBodies[k]->rigidbody.mass))*PHYSICS_ERRORPERCENT*contactNormal.y; + + // Fix transform positions + if (physicBodies[i]->rigidbody.enabled) + { + // Fix physic objects transform position + physicBodies[i]->transform.position.x -= 1.0f/physicBodies[i]->rigidbody.mass*posCorrection.x; + physicBodies[i]->transform.position.y += 1.0f/physicBodies[i]->rigidbody.mass*posCorrection.y; + + // Update collider bounds + physicBodies[i]->collider.bounds = TransformToRectangle(physicBodies[i]->transform); + + if (physicBodies[k]->rigidbody.enabled) + { + // Fix physic objects transform position + physicBodies[k]->transform.position.x += 1.0f/physicBodies[k]->rigidbody.mass*posCorrection.x; + physicBodies[k]->transform.position.y -= 1.0f/physicBodies[k]->rigidbody.mass*posCorrection.y; + + // Update collider bounds + physicBodies[k]->collider.bounds = TransformToRectangle(physicBodies[k]->transform); + } + } + } + } + } + } + } + } +} + +#endif // PHYSAC_IMPLEMENTATION
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