lol

C++/Verlet Cloth/main.cpp

@@ -8,6 +8,7 @@
 const float GRAVITY = 5.81f;
 const float    DRAG = 0.99f;
 
+struct Link;
 struct Vec2f {
     float x, y;
 };
@@ -15,10 +16,14 @@ struct Vec2f {
 struct MassPoint {
     Vec2f sPosition;
     bool bLocked = false; // If true, the point will not be able to move
+    float fMass;
 
-    MassPoint(Vec2f sPos)
+    std::vector<Link*> sLinks;
+
+    MassPoint(Vec2f sPos, float fMass)
         : sPosition(sPos),
-          sLastPosition(sPos) {  }
+          sLastPosition(sPos),
+          fMass(fMass) {  }
 
     void step() {
         if (bLocked) return;
@@ -33,13 +38,47 @@ struct MassPoint {
         sLastPosition.x = sPosition.x;
         sLastPosition.y = sPosition.y;
     }
+
+    void solve() {
+
+    }
 private:
     Vec2f sLastPosition;
 };
 
+struct Link {
+    float fRestingDistance;
+    float fStiffness;
+    float fTear;
+
+    MassPoint* p0;
+    MassPoint* p1;
+
+    void solve() {
+        float diffX = p0->sPosition.x - p1->sPosition.x;
+        float diffY = p0->sPosition.y - p1->sPosition.y;
+        float d = sqrt(diffX * diffX + diffY * diffY);
+        
+        float difference = (fRestingDistance - d) / d;
+        
+        float im1 = 1 / p0->fMass;
+        float im2 = 1 / p1->fMass;
+        float scalarP1 = (im1 / (im1 + im2)) * fStiffness;
+        float scalarP2 = fStiffness - scalarP1;
+        
+        p0->sPosition.x += diffX * scalarP1 * difference;
+        p0->sPosition.y += diffY * scalarP1 * difference;
+        
+        p1->sPosition.x -= diffX * scalarP2 * difference;
+        p1->sPosition.y -= diffY * scalarP2 * difference;
+    }
+
+};
+
 class VerletCloth : public olc::PixelGameEngine {
 public:
     std::vector<MassPoint> sPoints;
+    int iConstraintAccuracy;
 
     VerletCloth() {
         sAppName = "Verlet Cloth Simulation";
@@ -47,7 +86,9 @@ public:
 
     bool OnUserCreate() override {
 
-        sPoints.push_back({{ 1.0f, 1.0f }});
+        sPoints.push_back({{ 1.0f, 1.0f }, 1.0f});
+
+        iConstraintAccuracy = 5;
         
         return true;
     }
@@ -60,6 +101,12 @@ public:
             Clear(olc::WHITE);
             m_fTimeCounter = 0.0f;
 
+            for (int x = 0; x < iConstraintAccuracy; x++) {
+                for (int i = 0; i < sPoints.size(); i++) {
+                    MassPoint pointmass = sPoints[i];
+                    pointmass.solve();
+                }
+            }
 
 
             for (auto& sPoint : sPoints){
@@ -80,6 +127,13 @@ public:
 
         return true;
     }
+
+    void DrawLink(Link& link) {
+        DrawLine(link.p0->sPosition.x, link.p0->sPosition.y,
+                 link.p1->sPosition.x, link.p1->sPosition.y,
+                 olc::RED);
+    }
+
 private:
     float m_fTimeCounter = 0.0f;
 };