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physac module redesign (2/3)

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physac module base almost finished. All collisions are now resolved
properly and some force functions was added.

COLLIDER_CAPSULE removed for now because in 2D everything is composed by
rectangle and circle colliders...

The last step is move physics update loop into another thread and update
it in a fixed time step based on fps.
This commit is contained in:
victorfisac 2016-03-16 12:45:01 +01:00
parent d728494099
commit 7128ef686d
2 changed files with 378 additions and 139 deletions
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508
src/physac.c
View file

@ -36,10 +36,9 @@
// Defines and Macros
//----------------------------------------------------------------------------------
#define MAX_PHYSIC_OBJECTS 256
#define PHYSICS_GRAVITY -9.81f/2
#define PHYSICS_STEPS 450
#define PHYSICS_ACCURACY 0.0001f // Velocity subtract operations round filter (friction)
#define PHYSICS_ERRORPERCENT 0.001f // Collision resolve position fix
#define PHYSICS_ACCURACY 0.0001f // Velocity subtract operations round filter (friction)
#define PHYSICS_ERRORPERCENT 0.001f // Collision resolve position fix
//----------------------------------------------------------------------------------
// Types and Structures Definition
@ -52,53 +51,70 @@
//----------------------------------------------------------------------------------
static PhysicObject *physicObjects[MAX_PHYSIC_OBJECTS]; // Physic objects pool
static int physicObjectsCount; // Counts current enabled physic objects
static Vector2 gravityForce; // Gravity force
//----------------------------------------------------------------------------------
// Module specific Functions Declaration
//----------------------------------------------------------------------------------
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)
void InitPhysics()
void InitPhysics(Vector2 gravity)
{
// Initialize physics variables
physicObjectsCount = 0;
gravityForce = gravity;
}
// Update physic objects, calculating physic behaviours and collisions detection
void UpdatePhysics()
{
// Reset all physic objects is grounded state
for(int i = 0; i < physicObjectsCount; i++)
for (int i = 0; i < physicObjectsCount; i++)
{
if(physicObjects[i]->rigidbody.enabled) physicObjects[i]->rigidbody.isGrounded = false;
if (physicObjects[i]->rigidbody.enabled) physicObjects[i]->rigidbody.isGrounded = false;
}
for(int steps = 0; steps < PHYSICS_STEPS; steps++)
for (int steps = 0; steps < PHYSICS_STEPS; steps++)
{
for(int i = 0; i < physicObjectsCount; i++)
for (int i = 0; i < physicObjectsCount; i++)
{
if(physicObjects[i]->enabled)
if (physicObjects[i]->enabled)
{
// Update physic behaviour
if(physicObjects[i]->rigidbody.enabled)
if (physicObjects[i]->rigidbody.enabled)
{
// Apply friction to acceleration in X axis
if (physicObjects[i]->rigidbody.acceleration.x > PHYSICS_ACCURACY) physicObjects[i]->rigidbody.acceleration.x -= physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else if (physicObjects[i]->rigidbody.acceleration.x < PHYSICS_ACCURACY) physicObjects[i]->rigidbody.acceleration.x += physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else physicObjects[i]->rigidbody.acceleration.x = 0.0f;
// Apply friction to acceleration in Y axis
if (physicObjects[i]->rigidbody.acceleration.y > PHYSICS_ACCURACY) physicObjects[i]->rigidbody.acceleration.y -= physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else if (physicObjects[i]->rigidbody.acceleration.y < PHYSICS_ACCURACY) physicObjects[i]->rigidbody.acceleration.y += physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else physicObjects[i]->rigidbody.acceleration.y = 0.0f;
// Apply friction to velocity in X axis
if (physicObjects[i]->rigidbody.velocity.x > PHYSICS_ACCURACY) physicObjects[i]->rigidbody.velocity.x -= physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else if (physicObjects[i]->rigidbody.velocity.x < PHYSICS_ACCURACY) physicObjects[i]->rigidbody.velocity.x += physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else physicObjects[i]->rigidbody.velocity.x = 0.0f;
// Apply friction to velocity in Y axis
if (physicObjects[i]->rigidbody.velocity.y > PHYSICS_ACCURACY) physicObjects[i]->rigidbody.velocity.y -= physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else if (physicObjects[i]->rigidbody.velocity.y < PHYSICS_ACCURACY) physicObjects[i]->rigidbody.velocity.y += physicObjects[i]->rigidbody.friction/PHYSICS_STEPS;
else physicObjects[i]->rigidbody.velocity.y = 0.0f;
// Apply gravity to velocity
if (physicObjects[i]->rigidbody.applyGravity) physicObjects[i]->rigidbody.velocity.y += PHYSICS_GRAVITY/PHYSICS_STEPS;
if (physicObjects[i]->rigidbody.applyGravity)
{
physicObjects[i]->rigidbody.velocity.x += gravityForce.x/PHYSICS_STEPS;
physicObjects[i]->rigidbody.velocity.y += gravityForce.y/PHYSICS_STEPS;
}
// Apply acceleration to velocity
physicObjects[i]->rigidbody.velocity.x += physicObjects[i]->rigidbody.acceleration.x/PHYSICS_STEPS;
@ -120,142 +136,314 @@ void UpdatePhysics()
{
if (physicObjects[k]->collider.enabled && i != k)
{
// Check if colliders are overlapped
if (CheckCollisionRecs(physicObjects[i]->collider.bounds, physicObjects[k]->collider.bounds))
{
// 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 ontact normal
Vector2 contactNormal = { 0.0f, 0.0f };
// Calculate direction vector from i to k
Vector2 direction;
direction.x = (physicObjects[k]->transform.position.x + physicObjects[k]->transform.scale.x/2) - (physicObjects[i]->transform.position.x + physicObjects[i]->transform.scale.x/2);
direction.y = (physicObjects[k]->transform.position.y + physicObjects[k]->transform.scale.y/2) - (physicObjects[i]->transform.position.y + physicObjects[i]->transform.scale.y/2);
// Define overlapping and penetration attributes
Vector2 overlap;
float penetrationDepth = 0.0f;
// Calculate overlap on X axis
overlap.x = (physicObjects[i]->transform.scale.x + physicObjects[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 = (physicObjects[i]->transform.scale.y + physicObjects[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;
}
}
}
// Update rigidbody grounded state
if (physicObjects[i]->rigidbody.enabled)
{
if (contactNormal.y < 0.0f) physicObjects[i]->rigidbody.isGrounded = true;
}
// 2. Calculate collision impulse
// -------------------------------------------------------------------------------------------------------------------------------------
// Calculate relative velocity
Vector2 relVelocity = { physicObjects[k]->rigidbody.velocity.x - physicObjects[i]->rigidbody.velocity.x, physicObjects[k]->rigidbody.velocity.y - physicObjects[i]->rigidbody.velocity.y };
// Calculate relative velocity in terms of the normal direction
float velAlongNormal = Vector2DotProduct(relVelocity, contactNormal);
// 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)
// Dot not resolve if velocities are separating
if (velAlongNormal <= 0.0f)
// 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(physicObjects[i]->collider.type)
{
case COLLIDER_RECTANGLE:
{
// Calculate minimum bounciness value from both objects
float e = fminf(physicObjects[i]->rigidbody.bounciness, physicObjects[k]->rigidbody.bounciness);
// Calculate impulse scalar value
float j = -(1.0f + e) * velAlongNormal;
j /= 1.0f/physicObjects[i]->rigidbody.mass + 1.0f/physicObjects[k]->rigidbody.mass;
// Calculate final impulse vector
Vector2 impulse = { j*contactNormal.x, j*contactNormal.y };
// Calculate collision mass ration
float massSum = physicObjects[i]->rigidbody.mass + physicObjects[k]->rigidbody.mass;
float ratio = 0.0f;
// Apply impulse to current rigidbodies velocities if they are enabled
if (physicObjects[i]->rigidbody.enabled)
switch(physicObjects[k]->collider.type)
{
// Calculate inverted mass ration
ratio = physicObjects[i]->rigidbody.mass/massSum;
// Apply impulse direction to velocity
physicObjects[i]->rigidbody.velocity.x -= impulse.x*ratio;
physicObjects[i]->rigidbody.velocity.y -= impulse.y*ratio;
case COLLIDER_RECTANGLE:
{
// Check if colliders are overlapped
if (CheckCollisionRecs(physicObjects[i]->collider.bounds, physicObjects[k]->collider.bounds))
{
// Calculate direction vector from i to k
direction.x = (physicObjects[k]->transform.position.x + physicObjects[k]->transform.scale.x/2) - (physicObjects[i]->transform.position.x + physicObjects[i]->transform.scale.x/2);
direction.y = (physicObjects[k]->transform.position.y + physicObjects[k]->transform.scale.y/2) - (physicObjects[i]->transform.position.y + physicObjects[i]->transform.scale.y/2);
// Define overlapping and penetration attributes
Vector2 overlap;
// Calculate overlap on X axis
overlap.x = (physicObjects[i]->transform.scale.x + physicObjects[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 = (physicObjects[i]->transform.scale.y + physicObjects[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(physicObjects[k]->transform.position, physicObjects[k]->collider.radius, physicObjects[i]->collider.bounds))
{
// Calculate direction vector between circles
direction.x = physicObjects[k]->transform.position.x - physicObjects[i]->transform.position.x + physicObjects[i]->transform.scale.x/2;
direction.y = physicObjects[k]->transform.position.y - physicObjects[i]->transform.position.y + physicObjects[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 = physicObjects[i]->collider.bounds.x + physicObjects[i]->collider.bounds.width;
else closestPoint.x = physicObjects[i]->collider.bounds.x;
if (direction.y > 0.0f) closestPoint.y = physicObjects[i]->collider.bounds.y + physicObjects[i]->collider.bounds.height;
else closestPoint.y = physicObjects[i]->collider.bounds.y;
// Check if the closest point is inside the circle
if (CheckCollisionPointCircle(closestPoint, physicObjects[k]->transform.position, physicObjects[k]->collider.radius))
{
// Recalculate direction based on closest point position
direction.x = physicObjects[k]->transform.position.x - closestPoint.x;
direction.y = physicObjects[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 = physicObjects[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(physicObjects[i]->collider.bounds.y - physicObjects[k]->transform.position.y - physicObjects[k]->collider.radius);
}
else
{
contactNormal = (Vector2){ 0.0f, 1.0f };
penetrationDepth = fabs(physicObjects[i]->collider.bounds.y - physicObjects[k]->transform.position.y + physicObjects[k]->collider.radius);
}
}
else
{
// Calculate final contact normal
if (direction.x > 0.0f)
{
contactNormal = (Vector2){ 1.0f, 0.0f };
penetrationDepth = fabs(physicObjects[k]->transform.position.x + physicObjects[k]->collider.radius - physicObjects[i]->collider.bounds.x);
}
else
{
contactNormal = (Vector2){ -1.0f, 0.0f };
penetrationDepth = fabs(physicObjects[i]->collider.bounds.x + physicObjects[i]->collider.bounds.width - physicObjects[k]->transform.position.x - physicObjects[k]->collider.radius);
}
}
}
}
} break;
}
if (physicObjects[k]->rigidbody.enabled)
} break;
case COLLIDER_CIRCLE:
{
switch(physicObjects[k]->collider.type)
{
// Calculate inverted mass ration
ratio = physicObjects[k]->rigidbody.mass/massSum;
// Apply impulse direction to velocity
physicObjects[k]->rigidbody.velocity.x += impulse.x*ratio;
physicObjects[k]->rigidbody.velocity.y += impulse.y*ratio;
case COLLIDER_RECTANGLE:
{
if (CheckCollisionCircleRec(physicObjects[i]->transform.position, physicObjects[i]->collider.radius, physicObjects[k]->collider.bounds))
{
// Calculate direction vector between circles
direction.x = physicObjects[k]->transform.position.x + physicObjects[i]->transform.scale.x/2 - physicObjects[i]->transform.position.x;
direction.y = physicObjects[k]->transform.position.y + physicObjects[i]->transform.scale.y/2 - physicObjects[i]->transform.position.y;
// Calculate closest point on rectangle to circle
Vector2 closestPoint = { 0.0f, 0.0f };
if (direction.x > 0.0f) closestPoint.x = physicObjects[k]->collider.bounds.x + physicObjects[k]->collider.bounds.width;
else closestPoint.x = physicObjects[k]->collider.bounds.x;
if (direction.y > 0.0f) closestPoint.y = physicObjects[k]->collider.bounds.y + physicObjects[k]->collider.bounds.height;
else closestPoint.y = physicObjects[k]->collider.bounds.y;
// Check if the closest point is inside the circle
if (CheckCollisionPointCircle(closestPoint, physicObjects[i]->transform.position, physicObjects[i]->collider.radius))
{
// Recalculate direction based on closest point position
direction.x = physicObjects[i]->transform.position.x - closestPoint.x;
direction.y = physicObjects[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 = physicObjects[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(physicObjects[k]->collider.bounds.y - physicObjects[i]->transform.position.y - physicObjects[i]->collider.radius);
}
else
{
contactNormal = (Vector2){ 0.0f, 1.0f };
penetrationDepth = fabs(physicObjects[k]->collider.bounds.y - physicObjects[i]->transform.position.y + physicObjects[i]->collider.radius);
}
}
else
{
// Calculate final contact normal and penetration depth
if (direction.x > 0.0f)
{
contactNormal = (Vector2){ 1.0f, 0.0f };
penetrationDepth = fabs(physicObjects[i]->transform.position.x + physicObjects[i]->collider.radius - physicObjects[k]->collider.bounds.x);
}
else
{
contactNormal = (Vector2){ -1.0f, 0.0f };
penetrationDepth = fabs(physicObjects[k]->collider.bounds.x + physicObjects[k]->collider.bounds.width - physicObjects[i]->transform.position.x - physicObjects[i]->collider.radius);
}
}
}
}
} break;
case COLLIDER_CIRCLE:
{
// Check if colliders are overlapped
if (CheckCollisionCircles(physicObjects[i]->transform.position, physicObjects[i]->collider.radius, physicObjects[k]->transform.position, physicObjects[k]->collider.radius))
{
// Calculate direction vector between circles
direction.x = physicObjects[k]->transform.position.x - physicObjects[i]->transform.position.x;
direction.y = physicObjects[k]->transform.position.y - physicObjects[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 (physicObjects[i]->rigidbody.enabled)
{
if (contactNormal.y < 0.0f) physicObjects[i]->rigidbody.isGrounded = true;
}
// 2. Calculate collision impulse
// -------------------------------------------------------------------------------------------------------------------------------------
// Calculate relative velocity
Vector2 relVelocity = { 0.0f, 0.0f };
relVelocity.x = physicObjects[k]->rigidbody.velocity.x - physicObjects[i]->rigidbody.velocity.x;
relVelocity.y = physicObjects[k]->rigidbody.velocity.y - physicObjects[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(physicObjects[i]->rigidbody.bounciness, physicObjects[k]->rigidbody.bounciness);
// Calculate impulse scalar value
float j = -(1.0f + e)*velAlongNormal;
j /= 1.0f/physicObjects[i]->rigidbody.mass + 1.0f/physicObjects[k]->rigidbody.mass;
// Calculate final impulse vector
Vector2 impulse = { j*contactNormal.x, j*contactNormal.y };
// Calculate collision mass ration
float massSum = physicObjects[i]->rigidbody.mass + physicObjects[k]->rigidbody.mass;
float ratio = 0.0f;
// Apply impulse to current rigidbodies velocities if they are enabled
if (physicObjects[i]->rigidbody.enabled)
{
// Calculate inverted mass ration
ratio = physicObjects[i]->rigidbody.mass/massSum;
// 3. Correct colliders overlaping (transform position)
// ---------------------------------------------------------------------------------------------------------------------------------
// Apply impulse direction to velocity
physicObjects[i]->rigidbody.velocity.x -= impulse.x*ratio*(1.0f+physicObjects[i]->rigidbody.bounciness);
physicObjects[i]->rigidbody.velocity.y -= impulse.y*ratio*(1.0f+physicObjects[i]->rigidbody.bounciness);
}
if (physicObjects[k]->rigidbody.enabled)
{
// Calculate inverted mass ration
ratio = physicObjects[k]->rigidbody.mass/massSum;
// Calculate transform position penetration correction
Vector2 posCorrection;
posCorrection.x = penetrationDepth/((1.0f/physicObjects[i]->rigidbody.mass) + (1.0f/physicObjects[k]->rigidbody.mass))*PHYSICS_ERRORPERCENT*contactNormal.x;
posCorrection.y = penetrationDepth/((1.0f/physicObjects[i]->rigidbody.mass) + (1.0f/physicObjects[k]->rigidbody.mass))*PHYSICS_ERRORPERCENT*contactNormal.y;
// Apply impulse direction to velocity
physicObjects[k]->rigidbody.velocity.x += impulse.x*ratio*(1.0f+physicObjects[i]->rigidbody.bounciness);
physicObjects[k]->rigidbody.velocity.y += impulse.y*ratio*(1.0f+physicObjects[i]->rigidbody.bounciness);
}
// 3. Correct colliders overlaping (transform position)
// ---------------------------------------------------------------------------------------------------------------------------------
// Calculate transform position penetration correction
Vector2 posCorrection;
posCorrection.x = penetrationDepth/((1.0f/physicObjects[i]->rigidbody.mass) + (1.0f/physicObjects[k]->rigidbody.mass))*PHYSICS_ERRORPERCENT*contactNormal.x;
posCorrection.y = penetrationDepth/((1.0f/physicObjects[i]->rigidbody.mass) + (1.0f/physicObjects[k]->rigidbody.mass))*PHYSICS_ERRORPERCENT*contactNormal.y;
// Fix transform positions
if (physicObjects[i]->rigidbody.enabled)
{
// Fix physic objects transform position
physicObjects[i]->transform.position.x -= 1.0f/physicObjects[i]->rigidbody.mass*posCorrection.x;
physicObjects[i]->transform.position.y += 1.0f/physicObjects[i]->rigidbody.mass*posCorrection.y;
// Fix transform positions
if (physicObjects[i]->rigidbody.enabled)
{
// Update collider bounds
physicObjects[i]->collider.bounds = TransformToRectangle(physicObjects[i]->transform);
if (physicObjects[k]->rigidbody.enabled)
{
// Fix physic objects transform position
physicObjects[i]->transform.position.x -= 1.0f/physicObjects[i]->rigidbody.mass*posCorrection.x;
physicObjects[i]->transform.position.y += 1.0f/physicObjects[i]->rigidbody.mass*posCorrection.y;
physicObjects[k]->transform.position.x += 1.0f/physicObjects[k]->rigidbody.mass*posCorrection.x;
physicObjects[k]->transform.position.y -= 1.0f/physicObjects[k]->rigidbody.mass*posCorrection.y;
// Update collider bounds
physicObjects[i]->collider.bounds = TransformToRectangle(physicObjects[i]->transform);
if (physicObjects[k]->rigidbody.enabled)
{
// Fix physic objects transform position
physicObjects[k]->transform.position.x += 1.0f/physicObjects[k]->rigidbody.mass*posCorrection.x;
physicObjects[k]->transform.position.y -= 1.0f/physicObjects[k]->rigidbody.mass*posCorrection.y;
// Update collider bounds
physicObjects[k]->collider.bounds = TransformToRectangle(physicObjects[k]->transform);
}
physicObjects[k]->collider.bounds = TransformToRectangle(physicObjects[k]->transform);
}
}
}
@ -298,7 +486,7 @@ PhysicObject *CreatePhysicObject(Vector2 position, float rotation, Vector2 scale
obj->rigidbody.friction = 0.0f;
obj->rigidbody.bounciness = 0.0f;
obj->collider.enabled = false;
obj->collider.enabled = true;
obj->collider.type = COLLIDER_RECTANGLE;
obj->collider.bounds = TransformToRectangle(obj->transform);
obj->collider.radius = 0.0f;
@ -334,6 +522,45 @@ void DestroyPhysicObject(PhysicObject *pObj)
physicObjectsCount--;
}
// Apply directional force to a physic object
void ApplyForce(PhysicObject *pObj, Vector2 force)
{
if (pObj->rigidbody.enabled)
{
pObj->rigidbody.velocity.x += force.x/pObj->rigidbody.mass;
pObj->rigidbody.velocity.y += force.y/pObj->rigidbody.mass;
}
}
// Apply radial force to all physic objects in range
void ApplyForceAtPosition(Vector2 position, float force, float radius)
{
for(int i = 0; i < physicObjectsCount; i++)
{
// Calculate direction and distance between force and physic object pposition
Vector2 distance = (Vector2){ physicObjects[i]->transform.position.x - position.x, physicObjects[i]->transform.position.y - position.y };
if(physicObjects[i]->collider.type == COLLIDER_RECTANGLE)
{
distance.x += physicObjects[i]->transform.scale.x/2;
distance.y += physicObjects[i]->transform.scale.y/2;
}
float distanceLength = Vector2Length(distance);
// Check if physic object is in force range
if(distanceLength <= radius)
{
// Normalize force direction
distance.x /= distanceLength;
distance.y /= -distanceLength;
// Apply force to the physic object
ApplyForce(physicObjects[i], (Vector2){ distance.x*force, distance.y*force });
}
}
}
// Convert Transform data type to Rectangle (position and scale)
Rectangle TransformToRectangle(Transform transform)
{
@ -369,3 +596,12 @@ static float Vector2DotProduct(Vector2 v1, Vector2 v2)
return result;
}
static float Vector2Length(Vector2 v)
{
float result;
result = sqrt(v.x*v.x + v.y*v.y);
return result;
}

9
src/physac.h
View file

@ -40,7 +40,7 @@ typedef struct Vector2 {
float y;
} Vector2;
typedef enum { COLLIDER_CIRCLE, COLLIDER_RECTANGLE, COLLIDER_CAPSULE } ColliderType;
typedef enum { COLLIDER_CIRCLE, COLLIDER_RECTANGLE } ColliderType;
typedef struct Transform {
Vector2 position;
@ -56,7 +56,7 @@ typedef struct Rigidbody {
bool applyGravity;
bool isGrounded;
float friction; // Normalized value
float bounciness; // Normalized value
float bounciness;
} Rigidbody;
typedef struct Collider {
@ -81,13 +81,16 @@ extern "C" { // Prevents name mangling of functions
//----------------------------------------------------------------------------------
// Module Functions Declaration
//----------------------------------------------------------------------------------
void InitPhysics(); // Initializes pointers array (just pointers, fixed size)
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
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
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
Rectangle TransformToRectangle(Transform transform); // Convert Transform data type to Rectangle (position and scale)
void DrawPhysicObjectInfo(PhysicObject *pObj, Vector2 position, int fontSize); // Draw physic object information at screen position