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-rw-r--r--2d/softbody/softbody_2/SpringRectangle.h171
-rwxr-xr-x2d/softbody/softbody_2/dist/output.wasmbin37728 -> 43836 bytes
2 files changed, 121 insertions, 50 deletions
diff --git a/2d/softbody/softbody_2/SpringRectangle.h b/2d/softbody/softbody_2/SpringRectangle.h
index 848db23..e2cdf60 100644
--- a/2d/softbody/softbody_2/SpringRectangle.h
+++ b/2d/softbody/softbody_2/SpringRectangle.h
@@ -2,17 +2,15 @@
#include "../../../shared_cpp/types.h"
#include "../../../shared_cpp/mathlib.h"
-struct SoftbodyUpdateVertexData {
- Vector2 position; // Position is in world coordinates, for math's sake.
- Vector2 displacement;
- Vector2 initialVelocity;
- Vector2 initialDisplacement;
+struct PointMassUpdateData {
+ int32 index = 0;
+ Vector2 restingPosition; // Position is in world coordinates
+ Vector2 currentPosition; // Position is in world coordinates
+ Vector2 velocity;
+ Vector2 force;
bool isHovered = false;
- SoftbodyUpdateVertexData* left;
- SoftbodyUpdateVertexData* right;
- SoftbodyUpdateVertexData* top;
- SoftbodyUpdateVertexData* bottom;
+ PointMassUpdateData* neighbors[4];
};
EM_BOOL onMouseMove(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
@@ -20,20 +18,23 @@ EM_BOOL onMouseDown(int eventType, const EmscriptenMouseEvent *mouseEvent, void
EM_BOOL onMouseUp(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
struct SoftbodyRectangle {
+ // User defined
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;
+ float32 k = 3.f; // in N /m
+ float32 c = 3.f;
+ float32 jointMassKg = 1.f;
+
+ // Calculated before runtime
+ Vector2 springDimensions;
// Runtime data
float32 totalTimeSeconds = 0.f;
- SoftbodyUpdateVertexData* updateData = NULL;
+ PointMassUpdateData* updateData = NULL;
bool hasLastPositionChanged = false;
Vector2 lastMousePosition;
- SoftbodyUpdateVertexData* draggedVertex = NULL;
+ PointMassUpdateData* draggedVertex = NULL;
// Render data
Mesh2d mesh;
@@ -42,12 +43,12 @@ struct SoftbodyRectangle {
Vertex2d* pointsVertices = NULL;
void load(Renderer2d* renderer) {
- position = Vector2(800 / 2 - width / 2, 600 / 2 - height / 2);
- angularVelocity = sqrtf(springConstant / jointMassKg);
+ Vector2 position = Vector2(800 / 2 - width / 2, 600 / 2 - height / 2);
+ springDimensions = Vector2(width / springDensity, height / springDensity);
int32 numVertices = springDensity * springDensity; // Each subdivision is a square.
int32 numIndices = 6 * ((springDensity - 1) * (springDensity - 1));
vertices = new Vertex2d[numVertices];
- updateData = new SoftbodyUpdateVertexData[numVertices];
+ updateData = new PointMassUpdateData[numVertices];
auto indices = new GLuint[numIndices];
// Load a square with the desired density
@@ -61,14 +62,21 @@ struct SoftbodyRectangle {
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];
- if (y != 0) updateData[vIdx].top = &updateData[vIdx - springDensity];
- if (y != springDensity - 1) updateData[vIdx].bottom = &updateData[vIdx + springDensity];
+ updateData[vIdx].index = vIdx;
+ updateData[vIdx].restingPosition = vpos;
+ updateData[vIdx].currentPosition = vpos;
+ updateData[vIdx].force = Vector2(0, 0);
+ updateData[vIdx].velocity = Vector2(0, 0);
+
+ if (x != 0) updateData[vIdx].neighbors[0] = &updateData[vIdx - 1]; // Left
+ else updateData[vIdx].neighbors[0] = NULL;
+ if (x != springDensity - 1) updateData[vIdx].neighbors[1] = &updateData[vIdx + 1]; // Right
+ else updateData[vIdx].neighbors[1] = NULL;
+ if (y != 0) updateData[vIdx].neighbors[2] = &updateData[vIdx - springDensity]; // Top
+ else updateData[vIdx].neighbors[2] = NULL;
+ if (y != springDensity - 1) updateData[vIdx].neighbors[3] = &updateData[vIdx + springDensity]; // Bottom
+ else updateData[vIdx].neighbors[3] = NULL;
if (y != springDensity - 1 && x != springDensity - 1) {
indices[iIdx++] = vIdx;
@@ -84,14 +92,12 @@ struct SoftbodyRectangle {
}
mesh.load(vertices, numVertices, indices, numIndices, renderer, GL_DYNAMIC_DRAW);
- // 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(0, 0, 0, 1);
}
- //pointsMesh.model = mesh.model;
pointsMesh.load(pointsVertices, numVertices, renderer, GL_DYNAMIC_DRAW);
delete [] indices;
@@ -102,33 +108,98 @@ struct SoftbodyRectangle {
emscripten_set_mouseup_callback("#gl_canvas", this, false, onMouseUp);
}
+ Vector2 getForceBetweenPointMasses(PointMassUpdateData* first, PointMassUpdateData* second) {
+ auto relativeVelocity = second->velocity - first->velocity;
+ auto restLength = (first->restingPosition - second->restingPosition).length();
+ auto relativePosition = second->currentPosition - first->currentPosition;
+ auto currentLength = relativePosition.length();
+ auto positionDir = relativePosition.normalize();
+ auto dotProduct = positionDir.dot(relativeVelocity);
+ float32 springForce = k * (currentLength - restLength);
+ float32 dampingForce = c * dotProduct;
+ float32 totalForce = springForce + dampingForce;
+
+ return positionDir * totalForce;
+ }
+
void update(float32 dtSeconds) {
totalTimeSeconds += dtSeconds;
for (int32 v = 0; v < pointsMesh.numVertices; v++) {
- 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;
-
- if (springWeight == draggedVertex && hasLastPositionChanged) {
- hasLastPositionChanged = false;
- vertices[v].position = lastMousePosition;
- pointsVertices[v].position = lastMousePosition;
+ auto pointMass = &updateData[v];
+
+ if (draggedVertex != NULL) {
+ if (pointMass == draggedVertex && hasLastPositionChanged) {
+ hasLastPositionChanged = false;
+ Vector2 displacement = lastMousePosition - pointMass->restingPosition;
+
+ // We need to limit the new position based off of the triangle
+ if (displacement.x > springDimensions.x) {
+ displacement.x = springDimensions.x;
+ }
+ else if (displacement.x < -springDimensions.x) {
+ displacement.x = -springDimensions.x;
+ }
+
+ if (displacement.y > springDimensions.y) {
+ displacement.y = springDimensions.y;
+ }
+ else if (displacement.y < -springDimensions.y) {
+ displacement.y = -springDimensions.y;
+ }
+
+ pointMass->currentPosition = pointMass->restingPosition + displacement;
+ vertices[v].position = pointMass->currentPosition;
+ pointsVertices[v].position = pointMass->currentPosition;
+ }
}
+ else {
+ // Add the forces from it's neighbors
+ for (int32 n = 0; n < 4; n++) {
+ auto neighbor = pointMass->neighbors[n];
+ if (neighbor == NULL) continue;
- if (!draggedVertex && hasLastPositionChanged) {
- if ((springWeight->position - lastMousePosition).length() < 10.f) {
- pointsVertices[v].color = Vector4(1, 1, 0, 1);
- springWeight->isHovered = true;
+ pointMass->force += getForceBetweenPointMasses(pointMass, neighbor);
+ }
+
+ pointMass->velocity = pointMass->velocity + (pointMass->force / jointMassKg) * dtSeconds;
+ pointMass->currentPosition = pointMass->currentPosition + (pointMass->velocity * dtSeconds);
+
+ const float32 COLLISION_DISTANCE = 4.f;
+ for (int32 n = 0; n < pointsMesh.numVertices; n++) {
+ if (n == v) continue;
+ auto neighbor = &updateData[n];
+
+ if ((neighbor->currentPosition - pointMass->currentPosition).length() < COLLISION_DISTANCE) {
+ auto positionNormal = (neighbor->currentPosition - pointMass->currentPosition).normalize();
+ pointMass->currentPosition = neighbor->currentPosition - positionNormal * COLLISION_DISTANCE;
+ float32 dotProduct = pointMass->velocity.dot(positionNormal);
+ pointMass->velocity = pointMass->velocity - positionNormal * (2 * dotProduct);
+ }
}
- else {
- pointsVertices[v].color = Vector4(0, 0, 0, 1);
- springWeight->isHovered = false;
+
+ vertices[v].position = pointMass->currentPosition;
+ pointsVertices[v].position = pointMass->currentPosition;
+
+ // Hovering highlights behavior
+ if (hasLastPositionChanged) {
+ if ((pointMass->currentPosition - lastMousePosition).length() < 10.f) {
+ pointsVertices[v].color = Vector4(1, 1, 0, 1);
+ pointMass->isHovered = true;
+
+ for (int32 n = 0; n < 4; n++) {
+ if (pointMass->neighbors[n])
+ pointsVertices[pointMass->neighbors[n]->index].color = Vector4(0, 0, 1, 1);
+ }
+ }
+ else if (pointMass->isHovered) {
+ pointsVertices[v].color = Vector4(0, 0, 0, 1);
+ for (int32 n = 0; n < 4; n++) {
+ if (pointMass->neighbors[n] && !pointMass->neighbors[n]->isHovered)
+ pointsVertices[pointMass->neighbors[n]->index].color = Vector4(0, 0, 0, 1);
+ }
+ pointMass->isHovered = false;
+ }
}
}
}
@@ -163,9 +234,9 @@ EM_BOOL onMouseDown(int eventType, const EmscriptenMouseEvent *mouseEvent, void
SoftbodyRectangle* rectangle = (SoftbodyRectangle*)userData;
for (int32 v = 0; v < rectangle->pointsMesh.numVertices; v++) {
- auto springWeight = &rectangle->updateData[v];
- if (springWeight->isHovered) {
- rectangle->draggedVertex = springWeight;
+ auto pointMass = &rectangle->updateData[v];
+ if (pointMass->isHovered) {
+ rectangle->draggedVertex = pointMass;
break;
}
}
diff --git a/2d/softbody/softbody_2/dist/output.wasm b/2d/softbody/softbody_2/dist/output.wasm
index cd26200..85d82ce 100755
--- a/2d/softbody/softbody_2/dist/output.wasm
+++ b/2d/softbody/softbody_2/dist/output.wasm
Binary files differ
generated by cgit v1.2.1 (git 2.18.0) at 2024-11-22 12:36:31 +0000