mirrors/raylib
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix physac's fixed time step

Browse Source
This commit is contained in:
Pablo Marcos Oltra 2018-09-23 13:55:39 +02:00
parent 589152b658
commit 35634f37c8
2 changed files with 37 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
examples/physac/physics_restitution.c
View File

@ -51,6 +51,9 @@ int main()
circleC->restitution = 1;
SetTargetFPS(60);
// Restitution demo needs a very tiny physics time step for a proper simulation
SetPhysicsTimeStep(1.0/60.0/100 * 1000);
//--------------------------------------------------------------------------------------
// Main game loop

71
src/physac.h
View File

@ -96,8 +96,6 @@
#define PHYSAC_MAX_VERTICES 24
#define PHYSAC_CIRCLE_VERTICES 24
#define PHYSAC_DESIRED_DELTATIME 1.0/60.0
#define PHYSAC_MAX_TIMESTEP 0.02
#define PHYSAC_COLLISION_ITERATIONS 100
#define PHYSAC_PENETRATION_ALLOWANCE 0.05f
#define PHYSAC_PENETRATION_CORRECTION 0.4f
@ -197,6 +195,7 @@ extern "C" { // Prevents name mangling of fun
//----------------------------------------------------------------------------------
PHYSACDEF void InitPhysics(void); // Initializes physics values, pointers and creates physics loop thread
PHYSACDEF void RunPhysicsStep(void); // Run physics step, to be used if PHYSICS_NO_THREADS is set in your main loop
PHYSACDEF void SetPhysicsTimeStep(double delta); // Sets physics fixed time step in milliseconds. 1.666666 by default
PHYSACDEF bool IsPhysicsEnabled(void); // Returns true if physics thread is currently enabled
PHYSACDEF void SetPhysicsGravity(float x, float y); // Sets physics global gravity force
PHYSACDEF PhysicsBody CreatePhysicsBodyCircle(Vector2 pos, float radius, float density); // Creates a new circle physics body with generic parameters
@ -279,16 +278,15 @@ static pthread_t physicsThreadId; // Physics thread id
#endif
static unsigned int usedMemory = 0; // Total allocated dynamic memory
static bool physicsThreadEnabled = false; // Physics thread enabled state
static double baseTime = 0.0; // Offset time for MONOTONIC clock
static double startTime = 0.0; // Start time in milliseconds
static double deltaTime = 0.0; // Delta time used for physics steps
static double deltaTime = 1.0/60.0/10.0 * 1000; // Delta time used for physics steps, in milliseconds
static double currentTime = 0.0; // Current time in milliseconds
static uint64_t frequency = 0; // Hi-res clock frequency
static double accumulator = 0.0; // Physics time step delta time accumulator
static unsigned int stepsCount = 0; // Total physics steps processed
static Vector2 gravityForce = { 0.0f, 9.81f/1000 }; // Physics world gravity force
static Vector2 gravityForce = { 0.0f, 9.81f }; // Physics world gravity force
static PhysicsBody bodies[PHYSAC_MAX_BODIES]; // Physics bodies pointers array
static unsigned int physicsBodiesCount = 0; // Physics world current bodies counter
static PhysicsManifold contacts[PHYSAC_MAX_MANIFOLDS]; // Physics bodies pointers array
@ -322,13 +320,12 @@ static bool BiasGreaterThan(float valueA, float valueB);
static Vector2 TriangleBarycenter(Vector2 v1, Vector2 v2, Vector2 v3); // Returns the barycenter of a triangle given by 3 points
static void InitTimer(void); // Initializes hi-resolution MONOTONIC timer
static uint64_t GetTimeCount(void); // Get hi-res MONOTONIC time measure in seconds
static double GetCurrentTime(void); // // Get hi-res MONOTONIC time measure in seconds
static uint64_t GetTimeCount(void); // Get hi-res MONOTONIC time measure in mseconds
static double GetCurrentTime(void); // Get current time measure in milliseconds
static int GetRandomNumber(int min, int max); // Returns a random number between min and max (both included)
// Math functions
static void MathClamp(double *value, double min, double max); // Clamp a value in a range
static Vector2 MathCross(float value, Vector2 vector); // Returns the cross product of a vector and a value
static float MathCrossVector2(Vector2 v1, Vector2 v2); // Returns the cross product of two vectors
static float MathLenSqr(Vector2 vector); // Returns the len square root of a vector
@ -363,6 +360,8 @@ PHYSACDEF void InitPhysics(void)
#if defined(PHYSAC_DEBUG)
printf("[PHYSAC] physics module initialized successfully\n");
#endif
accumulator = 0.0;
}
// Returns true if physics thread is currently enabled
@ -917,6 +916,18 @@ PHYSACDEF void ClosePhysics(void)
#if !defined(PHYSAC_NO_THREADS)
pthread_join(physicsThreadId, NULL);
#endif
// Unitialize physics manifolds dynamic memory allocations
for (int i = physicsManifoldsCount - 1; i >= 0; i--) DestroyPhysicsManifold(contacts[i]);
// Unitialize physics bodies dynamic memory allocations
for (int i = physicsBodiesCount - 1; i >= 0; i--) DestroyPhysicsBody(bodies[i]);
#if defined(PHYSAC_DEBUG)
if (physicsBodiesCount > 0 || usedMemory != 0) printf("[PHYSAC] physics module closed with %i still allocated bodies [MEMORY: %i bytes]\n", physicsBodiesCount, usedMemory);
else if (physicsManifoldsCount > 0 || usedMemory != 0) printf("[PHYSAC] physics module closed with %i still allocated manifolds [MEMORY: %i bytes]\n", physicsManifoldsCount, usedMemory);
else printf("[PHYSAC] physics module closed successfully\n");
#endif
}
//----------------------------------------------------------------------------------
@ -1011,7 +1022,6 @@ static void *PhysicsLoop(void *arg)
// Initialize physics loop thread values
physicsThreadEnabled = true;
accumulator = 0;
// Physics update loop
while (physicsThreadEnabled)
@ -1019,18 +1029,6 @@ static void *PhysicsLoop(void *arg)
RunPhysicsStep();
}
// Unitialize physics manifolds dynamic memory allocations
for (int i = physicsManifoldsCount - 1; i >= 0; i--) DestroyPhysicsManifold(contacts[i]);
// Unitialize physics bodies dynamic memory allocations
for (int i = physicsBodiesCount - 1; i >= 0; i--) DestroyPhysicsBody(bodies[i]);
#if defined(PHYSAC_DEBUG)
if (physicsBodiesCount > 0 || usedMemory != 0) printf("[PHYSAC] physics module closed with %i still allocated bodies [MEMORY: %i bytes]\n", physicsBodiesCount, usedMemory);
else if (physicsManifoldsCount > 0 || usedMemory != 0) printf("[PHYSAC] physics module closed with %i still allocated manifolds [MEMORY: %i bytes]\n", physicsManifoldsCount, usedMemory);
else printf("[PHYSAC] physics module closed successfully\n");
#endif
return NULL;
}
@ -1147,17 +1145,18 @@ PHYSACDEF void RunPhysicsStep(void)
currentTime = GetCurrentTime();
// Calculate current delta time
deltaTime = currentTime - startTime;
const double delta = currentTime - startTime;
// Store the time elapsed since the last frame began
accumulator += deltaTime;
// Clamp accumulator to max time step to avoid bad performance
MathClamp(&accumulator, 0.0, PHYSAC_MAX_TIMESTEP);
accumulator += delta;
// Fixed time stepping loop
while (accumulator >= PHYSAC_DESIRED_DELTATIME)
while (accumulator >= deltaTime)
{
#ifdef PHYSAC_DEBUG
//printf("currentTime %f, startTime %f, accumulator-pre %f, accumulator-post %f, delta %f, deltaTime %f\n",
// currentTime, startTime, accumulator, accumulator-deltaTime, delta, deltaTime);
#endif
PhysicsStep();
accumulator -= deltaTime;
}
@ -1166,6 +1165,11 @@ PHYSACDEF void RunPhysicsStep(void)
startTime = currentTime;
}
PHYSACDEF void SetPhysicsTimeStep(double delta)
{
deltaTime = delta;
}
// Finds a valid index for a new manifold initialization
static int FindAvailableManifoldIndex()
{
@ -1557,8 +1561,8 @@ static void IntegratePhysicsForces(PhysicsBody body)
if (body->useGravity)
{
body->velocity.x += gravityForce.x*(deltaTime/2.0);
body->velocity.y += gravityForce.y*(deltaTime/2.0);
body->velocity.x += gravityForce.x*(deltaTime/1000/2.0);
body->velocity.y += gravityForce.y*(deltaTime/1000/2.0);
}
if (!body->freezeOrient) body->angularVelocity += body->torque*body->inverseInertia*(deltaTime/2.0);
@ -1592,7 +1596,7 @@ static void InitializePhysicsManifolds(PhysicsManifold manifold)
// Determine if we should perform a resting collision or not;
// The idea is if the only thing moving this object is gravity, then the collision should be performed without any restitution
if (MathLenSqr(radiusV) < (MathLenSqr((Vector2){ gravityForce.x*deltaTime, gravityForce.y*deltaTime }) + PHYSAC_EPSILON)) manifold->restitution = 0;
if (MathLenSqr(radiusV) < (MathLenSqr((Vector2){ gravityForce.x*deltaTime/1000, gravityForce.y*deltaTime/1000 }) + PHYSAC_EPSILON)) manifold->restitution = 0;
}
}
@ -1953,13 +1957,6 @@ static int GetRandomNumber(int min, int max)
return (rand()%(abs(max - min) + 1) + min);
}
// Clamp a value in a range
static inline void MathClamp(double *value, double min, double max)
{
if (*value < min) *value = min;
else if (*value > max) *value = max;
}
// Returns the cross product of a vector and a value
static inline Vector2 MathCross(float value, Vector2 vector)
{