Fixing spring simulations and some write ups

1 files changed, 4 insertions, 6 deletions

diff --git a/2d/softbody/softbody_1/damped.cpp b/2d/softbody/softbody_1/damped.cpp
index 0525e25..efba99a 100644
--- a/2d/softbody/softbody_1/damped.cpp
+++ b/2d/softbody/softbody_1/damped.cpp
@@ -40,10 +40,8 @@ namespace Damped {
 
         // Update variables
 		float32 force = 0.f;
-		float32 acceleration = 0.f;
 		float32 velocity = 0.f;
         float32 position = 0.f;
-        
 
         void load(Renderer2d* renderer, DampedSpringWeight* inWieight, float32 length, float32 loopRadius, float32 initialDisplacement, float32 inK, float32 inC);
         void update(float32 dtSeconds);
@@ -163,9 +161,9 @@ namespace Damped {
 		float32 C = k;
 		
 		float32 discriminant = B * B - (4 * A * C);
-		acceleration = 0;
 		velocity = 0;
-		position = initialDisplacement;
+		position = -initialDisplacement;
+        force = -c * velocity - k * position;
 
         if (discriminant < epsilon && discriminant > -epsilon) {
 			// Real repeated root (~ zero): Critically damped motion
@@ -221,8 +219,8 @@ namespace Damped {
     }
 
     void DampedSpring::update(float32 dtSeconds) {
-		force = -weight->mass * acceleration - c * velocity - k * position;
-		acceleration = (force * dtSeconds) / weight->mass;
+		force = -c * velocity - k * position;
+		float32 acceleration = force / weight->mass;
 		velocity = velocity + acceleration * dtSeconds;
 		float32 lastPosition = position;
 		position = position + velocity * dtSeconds;