1 files changed, 30 insertions, 16 deletions

diff --git a/2d/softbody/softbody_1/undamped.cpp b/2d/softbody/softbody_1/undamped.cpp
index ec53f50..a77e2a4 100644
--- a/2d/softbody/softbody_1/undamped.cpp
+++ b/2d/softbody/softbody_1/undamped.cpp
@@ -16,10 +16,10 @@ namespace Undamped {
     
     struct SpringWeight {
         Mesh2d shape;
-        float32 radius;
-        float32 mass = 2.f;
+        float32 radius = 2.f;
+        float32 mass = 1.f;
 
-        void load(Renderer2d* renderer, float32 inRadius, Vector4 startColor, Vector4 endColor);
+        void load(Renderer2d* renderer, float32 inMass, Vector4 startColor, Vector4 endColor);
         void update(float32 dtSeconds);
         void render(Renderer2d* renderer);
         void unload();
@@ -28,24 +28,31 @@ namespace Undamped {
     struct Spring {
         SpringWeight* weight;
 
+        // -- Rendering
         Mesh2d shape;
-
         Vertex2d* vertices = NULL;
         int32 numSegments = 0;
         int32 numVertices = 0;
+
+        // -- Spring initial variables
         float32 k = 4; // Spring Constant, in N / m
         float32 initialDisplacement = 3.f;
         float32 initialVelocity = 0.f;
-        float32 angularVelocity = 0.f; // To be calculated
+
+        // -- Spring runtime variables
+        float32 angularVelocity = 0.f;
         float32 displacement = 0.f;
         float32 timeElapsed = 0.f;
 
-        void load(Renderer2d* renderer, SpringWeight* inWieight, float32 length, float32 loopRadius);
+        void load(Renderer2d* renderer, SpringWeight* inWieight, float32 length, float32 inInitialDisplacement, float32 inK, float32 loopRadius);
         void update(float32 dtSeconds);
         void render(Renderer2d* renderer);
         void unload();
     };
 
+    UndampedInitVariables initVariables;
+    void setInitVariables(UndampedInitVariables newVariables) { initVariables = newVariables; }
+    UndampedInitVariables getInitVariables() { return initVariables; }
     WebglContext* context;
     Renderer2d renderer;
     MainLoop mainLoop;
@@ -69,8 +76,8 @@ namespace Undamped {
         
         renderer.load(context);
 
-        weight.load(&renderer, 32.f, Vector4 { 55.f, 235.f, 35.f, 255.f }, Vector4 { 235.f, 5.f, 235.f, 255.f });
-        spring.load(&renderer, &weight, 250.f, 64.f);
+        weight.load(&renderer, initVariables.mass, Vector4 { 55.f, 235.f, 35.f, 255.f }, Vector4 { 235.f, 5.f, 235.f, 255.f });
+        spring.load(&renderer, &weight, initVariables.springLength, initVariables.initialDisplacement, initVariables.k, 64.f);
 
         mainLoop.run(update);
     }
@@ -96,8 +103,9 @@ namespace Undamped {
     }
 
 
-    void SpringWeight::load(Renderer2d* renderer, float32 inRadius, Vector4 startColor, Vector4 endColor) {
-        radius = inRadius;
+    void SpringWeight::load(Renderer2d* renderer, float32 inMass, Vector4 startColor, Vector4 endColor) {
+        mass = inMass;
+        radius = mass * 16.f;
         const int32 numSegments = 96;
         const float32 radiansPerSegment = (2.f * PI) / static_cast<float>(numSegments);
         const int32 numVertices = numSegments * 3;
@@ -141,11 +149,15 @@ namespace Undamped {
         shape.unload();
     }
 
-    void Spring::load(Renderer2d* renderer, SpringWeight* inWeight, float32 length, float32 loopRadius) {
+    void Spring::load(Renderer2d* renderer, SpringWeight* inWeight, float32 length, float32 inInitialDisplacement, float32 inK, float32 loopRadius) {
         weight = inWeight;
+        initialDisplacement = inInitialDisplacement;
+        displacement = initialDisplacement;
+        k = inK;
+
         angularVelocity = sqrtf(k / weight->mass);
         timeElapsed = 0.f;
-
+        
         const int32 verticesPerSegment = 6;
         numSegments = 256;
         numVertices = numSegments * verticesPerSegment;
@@ -181,12 +193,14 @@ namespace Undamped {
 
     void Spring::update(float32 dtSeconds) {
         timeElapsed += dtSeconds;
+        float32 lastDisplacement = displacement;
         displacement = initialDisplacement * cosf(angularVelocity * timeElapsed - initialVelocity);
+        float32 dx = displacement - lastDisplacement;
 
         int32 vidx = 0;
         for (int pidx = 0; pidx < numSegments; pidx++) {
-            float32 y1Offset = displacement * (1.f - pidx / static_cast<float32>(numSegments));
-            float32 y2Offset = displacement * (1.f - (pidx + 1) / static_cast<float32>(numSegments));
+            float32 y1Offset = dx * (1.f - pidx / static_cast<float32>(numSegments));
+            float32 y2Offset = dx * (1.f - (pidx + 1) / static_cast<float32>(numSegments));
             vertices[vidx++].position.y += y1Offset;
             vertices[vidx++].position.y += y2Offset;
             vertices[vidx++].position.y += y1Offset;
@@ -194,8 +208,8 @@ namespace Undamped {
             vertices[vidx++].position.y += y2Offset;
             vertices[vidx++].position.y += y2Offset;
         }
-    
-        weight->shape.model = weight->shape.model.translateByVec2(Vector2(0, displacement));
+
+        weight->shape.model = weight->shape.model.translateByVec2(Vector2(0, dx));
     }
 
     void Spring::render(Renderer2d* renderer) {