1 files changed, 92 insertions, 21 deletions

diff --git a/2d/softbody/softbody_2/SpringRectangle.h b/2d/softbody/softbody_2/SpringRectangle.h
index 47f4aff..848db23 100644
--- a/2d/softbody/softbody_2/SpringRectangle.h
+++ b/2d/softbody/softbody_2/SpringRectangle.h
@@ -3,7 +3,11 @@
 #include "../../../shared_cpp/mathlib.h"
 
 struct SoftbodyUpdateVertexData {
-	Vector2 position;
+	Vector2 position;  // Position is in world coordinates, for math's sake.
+    Vector2 displacement;
+	Vector2 initialVelocity;
+	Vector2 initialDisplacement;
+	bool isHovered = false;
 
 	SoftbodyUpdateVertexData* left;
 	SoftbodyUpdateVertexData* right;
@@ -11,24 +15,35 @@ struct SoftbodyUpdateVertexData {
 	SoftbodyUpdateVertexData* bottom;
 };
 
-struct SoftbodyRectangle {
-	float32 width = 100;
-	float32 height = 100;
-
-	Vector2 position = Vector2(300, 400);
+EM_BOOL onMouseMove(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
+EM_BOOL onMouseDown(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
+EM_BOOL onMouseUp(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
 
-	// Represents the density of springs that will be in the rectangle.
+struct SoftbodyRectangle {
+	float32 width = 200;
+	float32 height = 200;
+	Vector2 position;
 	int32 springDensity = 10;
+	float32 springConstant = 4.f; // in N /m
+	float32 jointMassKg = 10;
+	float32 angularVelocity = 0.f;
+
+	// Runtime data
 	float32 totalTimeSeconds = 0.f;
 	SoftbodyUpdateVertexData* updateData = NULL;
+	bool hasLastPositionChanged = false;
+	Vector2 lastMousePosition;
+    SoftbodyUpdateVertexData* draggedVertex = NULL;
 
+	// Render data
 	Mesh2d mesh;
 	Mesh2d pointsMesh;
-
 	Vertex2d* vertices = NULL;
 	Vertex2d* pointsVertices = NULL;
 
 	void load(Renderer2d* renderer) {
+		position = Vector2(800 / 2 - width / 2, 600 / 2 - height / 2);
+		angularVelocity = sqrtf(springConstant / jointMassKg);
 	    int32 numVertices = springDensity * springDensity; // Each subdivision is a square.
 		int32 numIndices = 6 * ((springDensity - 1) * (springDensity - 1));
 	    vertices = new Vertex2d[numVertices];
@@ -39,12 +54,16 @@ struct SoftbodyRectangle {
 		int32 vIdx = 0;
 		int32 iIdx = 0;
 		float32 inverseDensity = 1.f / springDensity;
-		float32 halfInv = inverseDensity - (inverseDensity / 2.f);
+		float32 halfInv = inverseDensity / 2.f;
 		for (int32 y = 0; y < springDensity; y++) {  // Rows
 			for (int32 x = 0; x < springDensity; x++) { // Columns
-			    Vector2 position = Vector2(x * inverseDensity - halfInv, y * inverseDensity- halfInv);
-				vertices[vIdx] = { position, Vector4(1, 0, 0, 1) };
-			    updateData[vIdx].position = position;
+			    Vector2 vpos = Vector2(x * inverseDensity - halfInv, y * inverseDensity- halfInv);
+				vpos.x = vpos.x * width + position.x;
+				vpos.y = vpos.y * height + position.y;
+				vertices[vIdx] = { vpos, Vector4(1, 0, 0, 1) };
+			    updateData[vIdx].position = vpos;
+				updateData[vIdx].initialVelocity = Vector2(randomFloatBetween(0, 1.0) * 0.1, randomFloatBetween(0, 1.0) * 0.1);
+				updateData[vIdx].initialDisplacement = Vector2(randomFloatBetween(0, 1.0) * 0.1, randomFloatBetween(0, 1.0) * 0.1);
 
 				if (x != 0) updateData[vIdx].left = &updateData[vIdx - 1];
 				if (x != springDensity - 1) updateData[vIdx].right = &updateData[vIdx + 1];
@@ -65,32 +84,57 @@ struct SoftbodyRectangle {
 		}
 
 		mesh.load(vertices, numVertices, indices, numIndices, renderer, GL_DYNAMIC_DRAW);
-		mesh.model = Mat4x4().scale(Vector3(width, height, 0)).translateByVec2(Vector2(300, 400));
+		// mesh.model = Mat4x4().scale(Vector3(width, height, 0)).translateByVec2(position);
 
 	    pointsVertices = new Vertex2d[numVertices];
 		for (int32 v = 0; v < numVertices; v++) {
 			pointsVertices[v].position = vertices[v].position;
-			pointsVertices[v].color = Vector4(1, 1, 0, 1);
+			pointsVertices[v].color = Vector4(0, 0, 0, 1);
 		}
-		pointsMesh.model = mesh.model;
+		//pointsMesh.model = mesh.model;
 		pointsMesh.load(pointsVertices, numVertices, renderer, GL_DYNAMIC_DRAW);
 		
 		delete [] indices;
+
+		// Setup callbacks
+		emscripten_set_mousemove_callback("#gl_canvas", this, false, onMouseMove);
+		emscripten_set_mousedown_callback("#gl_canvas", this, false, onMouseDown);
+		emscripten_set_mouseup_callback("#gl_canvas", this, false, onMouseUp);
 	}
 
 	void update(float32 dtSeconds) {
 		totalTimeSeconds += dtSeconds;
+
 		for (int32 v = 0; v < pointsMesh.numVertices; v++) {
-			float32 r = rand();
-			updateData[v].position += (Vector2(cosf(r), sinf(r)) * 0.005f);
+			auto springWeight = &updateData[v];
+			
+			//springWeight->displacement.x = springWeight->initialDisplacement.x * cosf(angularVelocity * totalTimeSeconds - springWeight->initialVelocity.x);
+			//springWeight->displacement.y = springWeight->initialDisplacement.y * cosf(angularVelocity * totalTimeSeconds - springWeight->initialVelocity.y);
 
+			//Vector2 nextPosition = springWeight->position + springWeight->displacement;
+			//vertices[v].position = nextPosition;
+			//pointsVertices[v].position = nextPosition;
 
-			Vector2 nextPosition = Vector2(updateData[v].position.x, updateData[v].position.y);
-			
-			vertices[v].position = nextPosition;
-			pointsVertices[v].position = nextPosition;
+			if (springWeight == draggedVertex && hasLastPositionChanged) {
+				hasLastPositionChanged = false;
+				vertices[v].position = lastMousePosition;
+				pointsVertices[v].position = lastMousePosition;
+			}
+
+			if (!draggedVertex && hasLastPositionChanged) {
+			    if ((springWeight->position - lastMousePosition).length() < 10.f) {
+					pointsVertices[v].color = Vector4(1, 1, 0, 1);
+					springWeight->isHovered = true;
+				}
+				else {
+					pointsVertices[v].color = Vector4(0, 0, 0, 1);
+				    springWeight->isHovered = false;
+				}
+			}
 		}
 
+		if (hasLastPositionChanged) hasLastPositionChanged = false;
+
 		mesh.updateVertices(vertices);
 		pointsMesh.updateVertices(pointsVertices);
 	}
@@ -107,3 +151,30 @@ struct SoftbodyRectangle {
 		delete [] pointsVertices;
 	}
 };
+
+EM_BOOL onMouseMove(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData) {
+	SoftbodyRectangle* rectangle = (SoftbodyRectangle*)userData;
+	rectangle->hasLastPositionChanged = true;
+	rectangle->lastMousePosition = Vector2(static_cast<float32>(mouseEvent->targetX), static_cast<float32>(600 - mouseEvent->targetY));
+	return true;
+}
+
+EM_BOOL onMouseDown(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData) {
+	SoftbodyRectangle* rectangle = (SoftbodyRectangle*)userData;
+
+    for (int32 v = 0; v < rectangle->pointsMesh.numVertices; v++) {
+		auto springWeight = &rectangle->updateData[v];
+		if (springWeight->isHovered) {
+			rectangle->draggedVertex = springWeight;
+			break;
+		}
+	}
+
+	return true;
+}
+
+EM_BOOL onMouseUp(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData) {
+	SoftbodyRectangle* rectangle = (SoftbodyRectangle*)userData;
+	rectangle->draggedVertex = NULL;
+	return true;
+}