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Implemented a custom physics engine #316

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direnbharwani merged 95 commits from SHPhysics into main 2023-01-23 15:55:45 +08:00
Conversation 0 Commits 95 Files Changed 144 +77 -76
4 changed files with 77 additions and 76 deletions
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28
Assets/Scenes/PhysicsSandbox.shade
View File

@ -4,22 +4,22 @@
NumberOfChildren: 0
Components:
Transform Component:
Translate: {x: 0, y: 2.5, z: 0}
Rotate: {x: -0, y: 0, z: -0}
Scale: {x: 1, y: 1, z: 1}
Translate: {x: -1.80977702, y: 3, z: 0}
Rotate: {x: -0, y: 0, z: -0.506194055}
Scale: {x: 3.27252102, y: 0.999997199, z: 1}
IsActive: true
RigidBody Component:
Type: Dynamic
Type: Static
Auto Mass: false
Mass: 10
Drag: 1
Angular Drag: 1
Mass: .inf
Drag: 0.00999999978
Angular Drag: 0.00999999978
Use Gravity: true
Gravity Scale: 1
Interpolate: true
Sleeping Enabled: true
Freeze Position X: false
Freeze Position Y: true
Freeze Position Y: false
Freeze Position Z: false
Freeze Rotation X: false
Freeze Rotation Y: false
@ -49,9 +49,9 @@
NumberOfChildren: 0
Components:
Camera Component:
Position: {x: 3, y: 4, z: 0}
Position: {x: 0, y: 4, z: 5}
Pitch: 0
Yaw: 90
Yaw: 0
Roll: 0
Width: 1920
Height: 1080
@ -107,7 +107,7 @@
NumberOfChildren: 0
Components:
Transform Component:
Translate: {x: 0, y: 5, z: 0.834425449}
Translate: {x: -1.97624588, y: 5, z: 0}
Rotate: {x: -0, y: 0, z: -0}
Scale: {x: 1, y: 1, z: 1}
IsActive: true
@ -115,14 +115,14 @@
Type: Dynamic
Auto Mass: false
Mass: 1
Drag: 1
Angular Drag: 1
Drag: 0.00999999978
Angular Drag: 0.00999999978
Use Gravity: true
Gravity Scale: 1
Interpolate: true
Sleeping Enabled: true
Freeze Position X: false
Freeze Position Y: true
Freeze Position Y: false
Freeze Position Z: false
Freeze Rotation X: false
Freeze Rotation Y: false

2
SHADE_Engine/src/Physics/Collision/CollisionShapes/SHBoxCollisionShape.cpp
View File

@ -159,8 +159,6 @@ namespace SHADE
if (index < 0 || index >= NUM_VERTICES)
throw std::invalid_argument("Index out-of-range!");
// DirectX already puts vertex 0 - 4 on the front face for our case.
// Otherwise, it would need to be wrapped around for the correct vertex.
return GetVertices()[index];
}

121
SHADE_Engine/src/Physics/Collision/Narrowphase/SHSphereVsConvex.cpp
View File

@ -101,22 +101,22 @@ namespace SHADE
}
uint32_t numContacts = 0;
const float penetration = TOTAL_RADIUS - bestDistance;
// Rotate the normal into the world space
const SHVec3& BEST_NORMAL = CONVEX.GetNormal(closestFaceIndex);
const float PENETRATION = TOTAL_RADIUS - bestDistance;
// Check if center is inside polyhedron (below the face)
if (bestDistance < SHMath::EPSILON)
{
manifold.normal = -BEST_NORMAL;
SHContact newContact;
newContact.penetration = penetration;
newContact.position = SPHERE.GetCenter();
newContact.penetration = PENETRATION;
newContact.position = SPHERE.GetCenter() - BEST_NORMAL * PENETRATION;
newContact.featurePair.key = 0;
manifold.contacts[numContacts++] = newContact;
manifold.normal = BEST_NORMAL;
manifold.numContacts = numContacts;
return true;
}
@ -125,95 +125,98 @@ namespace SHADE
// We have 3 voronoi regions to check: cp -> prev, cp -> next and cp -> center
// If none of these are true, the sphere is above the face but not separating
/*
* | A
* _ _ _ _ _ _ | _ _ _
* / /
* | / | / regionA
* |/ _ _ _ _ _|/ _ _ _
* B/ regionB /C
* / / regionC
*/
const SHHalfEdgeDS::Face& CLOSEST_FACE = HALF_EDGE_STRUCTURE->GetFace(closestFaceIndex);
const int32_t NUM_VERTICES_ON_FACE = static_cast<int32_t>(CLOSEST_FACE.vertexIndices.size());
const SHVec3& CLOSEST_POINT = CONVEX.GetVertex(CLOSEST_FACE.vertexIndices[closestPointIndex]);
const SHVec3 CP_TO_CENTER = SPHERE.GetCenter() - CLOSEST_POINT;
const SHVec3 C = CONVEX.GetVertex(CLOSEST_FACE.vertexIndices[closestPointIndex]);
const SHVec3 C_TO_CENTER = SPHERE.GetCenter() - C;
// Check closest point -> prev point
const int32_t INDEX_A = (closestPointIndex + 1) % NUM_VERTICES_ON_FACE;
const int32_t INDEX_B = closestPointIndex == 0 ? NUM_VERTICES_ON_FACE - 1 : closestPointIndex - 1;
const SHVec3 POINTS[2] =
{
const int32_t PREV_POINT_INDEX = closestPointIndex == 0 ? NUM_VERTICES_ON_FACE - 1 : closestPointIndex - 1;
const SHVec3& PREV_POINT = CONVEX.GetVertex(CLOSEST_FACE.vertexIndices[PREV_POINT_INDEX]);
CONVEX.GetVertex(CLOSEST_FACE.vertexIndices[INDEX_A]) // A
, CONVEX.GetVertex(CLOSEST_FACE.vertexIndices[INDEX_B]) // B
};
const SHVec3 CP_TO_PREV = SHVec3::Normalise(PREV_POINT - CLOSEST_POINT);
// To be inside either region A or B, 2 conditions must be satisfied
// 1. Same side as tangent
// 2. Same side as normal from edge to sphere
float projection = SHVec3::Dot(CP_TO_CENTER, CP_TO_PREV);
// Check in regions A & B
for (int i = 0; i < 2; ++i)
{
const SHVec3 TANGENT = SHVec3::Normalise(POINTS[i] - C);
float projection = SHVec3::Dot(C_TO_CENTER, TANGENT);
if (projection >= 0.0f)
{
// Sphere is inside this region, check if distance from center is lesser than radius
if (penetration >= TOTAL_RADIUS)
return false;
// Check 2nd condition
// Find closest point
const SHVec3 CP = C + projection * TANGENT;
const SHVec3 CP_TO_CENTER = SHVec3::Normalise(C - CP);
SHContact newContact;
newContact.penetration = penetration;
newContact.position = SPHERE.GetCenter() - BEST_NORMAL * TOTAL_RADIUS;
newContact.featurePair.key = 0;
projection = SHVec3::Dot(C_TO_CENTER, CP_TO_CENTER);
if (projection >= 0.0f)
{
// Sphere Within region A
manifold.normal = CP_TO_CENTER;
manifold.contacts[numContacts++] = newContact;
manifold.normal = BEST_NORMAL;
SHContact newContact;
newContact.penetration = TOTAL_RADIUS - projection;
newContact.position = CP;
newContact.featurePair.key = 0;
manifold.numContacts = numContacts;
return true;
manifold.contacts[numContacts++] = newContact;
manifold.numContacts = numContacts;
return true;
}
}
}
// Check closest point -> next point
// Check region C (closest point)
{
const int32_t NEXT_POINT_INDEX = closestPointIndex + 1 % NUM_VERTICES_ON_FACE;
const SHVec3& NEXT_POINT = CONVEX.GetVertex(CLOSEST_FACE.vertexIndices[NEXT_POINT_INDEX]);
const SHVec3 CP_TO_NEXT = SHVec3::Normalise(NEXT_POINT - CLOSEST_POINT);
float projection = SHVec3::Dot(CP_TO_CENTER, CP_TO_NEXT);
if (projection >= 0.0f)
if (C_TO_CENTER.LengthSquared() < TOTAL_RADIUS * TOTAL_RADIUS)
{
// Sphere is inside this region, check if distance from center is lesser than radius
if (penetration >= TOTAL_RADIUS)
return false;
manifold.normal = SHVec3::Normalise(C_TO_CENTER);
SHContact newContact;
newContact.penetration = penetration;
newContact.position = SPHERE.GetCenter() - BEST_NORMAL * TOTAL_RADIUS;
newContact.penetration = PENETRATION;
newContact.position = C;
newContact.featurePair.key = 0;
manifold.contacts[numContacts++] = newContact;
manifold.normal = BEST_NORMAL;
manifold.numContacts = numContacts;
return true;
}
}
// Check if it hit the closest point
// Region D
if (PENETRATION <= TOTAL_RADIUS)
{
if (CP_TO_CENTER.LengthSquared() < TOTAL_RADIUS * TOTAL_RADIUS)
{
SHContact newContact;
newContact.penetration = penetration;
newContact.position = CLOSEST_POINT;
newContact.featurePair.key = 0;
manifold.normal = -BEST_NORMAL;
manifold.contacts[numContacts++] = newContact;
manifold.normal = SHVec3::Normalise(CP_TO_CENTER);
manifold.numContacts = numContacts;
return true;
}
}
// It is above the closest face
if (penetration <= TOTAL_RADIUS)
{
SHContact newContact;
newContact.penetration = penetration;
newContact.penetration = PENETRATION;
newContact.position = SPHERE.GetCenter() - BEST_NORMAL * TOTAL_RADIUS;
newContact.featurePair.key = 0;
manifold.contacts[numContacts++] = newContact;
manifold.normal = BEST_NORMAL;
manifold.numContacts = numContacts;
return true;
}

2
SHADE_Engine/src/Physics/System/Routines/SHPhysicsDebugDrawRoutine.cpp
View File

@ -81,7 +81,7 @@ namespace SHADE
{
const SHMatrix TRS = SHMatrix::Transform(contactPoint.position, SHQuaternion::Identity, SHVec3{ 0.1f });
debugDrawSystem->DrawCube(TRS, CONTACT_COLOUR);
debugDrawSystem->DrawLine(contactPoint.position, contactPoint.position + contactPoint.normal * 0.3f, CONTACT_COLOUR, true);
debugDrawSystem->DrawLine(contactPoint.position, contactPoint.position + contactPoint.normal * 0.5f, CONTACT_COLOUR, true);
}
}