Decently working demo for rigidbody 1

3 files changed, 12 insertions, 9 deletions

diff --git a/2d/rigidbody/rigidbody_1/dist/output.wasm b/2d/rigidbody/rigidbody_1/dist/output.wasm
index 5ceed51..f6625a9 100755
--- a/2d/rigidbody/rigidbody_1/dist/output.wasm
+++ b/2d/rigidbody/rigidbody_1/dist/output.wasm
diff --git a/2d/rigidbody/rigidbody_1/main.cpp b/2d/rigidbody/rigidbody_1/main.cpp
index b3ed359..88c322c 100644
--- a/2d/rigidbody/rigidbody_1/main.cpp
+++ b/2d/rigidbody/rigidbody_1/main.cpp
@@ -60,14 +60,15 @@ struct Rigidbody {
             }
             
             float32 impulseDtSeconds = nextTimeAppliedSeconds - i.timeAppliedSeconds;
-            force += i.force * impulseDtSeconds;
+            Vector2 forceToApply = i.force * (impulseDtSeconds / i.timeOfApplicationSeconds);
+            force += forceToApply * impulseDtSeconds;
             
 
             i.timeAppliedSeconds = nextTimeAppliedSeconds;
         }
 
         Vector2 acceleration = force / mass;
-        velocity += (acceleration * impulseDtSeconds);
+        velocity += (acceleration * deltaTimeSeconds);
         position += (velocity * deltaTimeSeconds);
 
         // Cleanup any impulses that have expired in the mean time
@@ -207,7 +208,7 @@ int main() {
 void load() {
     renderer.load(&context);
 
-	rectangle.load(&renderer, Vector4 { 55.f, 235.f, 35.f, 255.f }, 32.f, 32.f);
+	rectangle.load(&renderer, Vector4 { 55.f, 235.f, 35.f, 255.f }, 100.f, 75.f);
 	rectangle.body.position = Vector2 { context.width / 3.f, context.height / 3.f };
 	rectangle.body.velocity = Vector2 { 100.f, 250.f };
 
@@ -300,8 +301,8 @@ EM_BOOL onMouseMove(int eventType, const EmscriptenMouseEvent *mouseEvent, void
 		return true;
 	}
 
-	pointer.force.x = static_cast<float32>(mouseEvent->movementX) * 2000.f;
-	pointer.force.y = static_cast<float32>(-mouseEvent->movementY) * 2000.f;
+	pointer.force.x = static_cast<float32>(mouseEvent->movementX) * 100000.f;
+	pointer.force.y = static_cast<float32>(-mouseEvent->movementY) * 100000.f;
 
 	pointer.body.position.x = static_cast<float32>(mouseEvent->targetX);
 	pointer.body.position.y = static_cast<float32>(600.f - mouseEvent->targetY);
diff --git a/2d/rigidbody/rigidbody_1/snippet3.cpp b/2d/rigidbody/rigidbody_1/snippet3.cpp
index a43c884..4727a9a 100644
--- a/2d/rigidbody/rigidbody_1/snippet3.cpp
+++ b/2d/rigidbody/rigidbody_1/snippet3.cpp
@@ -17,24 +17,26 @@ struct Rigidbody {
     void update(float32 deltaTimeSeconds) {
         applyGravity(deltaTimeSeconds);
 
-        // Add up all of the forces acting at this moment
         Vector2 force;
         for (int32 idx = 0; idx < numImpulses; idx++) {
             Impulse& i = activeImpulses[idx];
 
             float32 nextTimeAppliedSeconds = i.timeAppliedSeconds + deltaTimeSeconds;
             if (nextTimeAppliedSeconds >= i.timeOfApplicationSeconds) {
-                nextTimeAppliedSeconds = i.timeOfApplicationSeconds;
+                nextTimeAppliedSeconds = i.timeOfApplicationSeconds; // Do the remainder of the time
                 i.isDead = true;
             }
             
+            // We apply the force spread out over timeOfApplicationSeconds, so we need
+            // to calculate the fractional amount of force that was applied in this frame.
             float32 impulseDtSeconds = nextTimeAppliedSeconds - i.timeAppliedSeconds;
-            force += i.force * impulseDtSeconds;
+            Vector2 forceToApply = i.force * (impulseDtSeconds / i.timeOfApplicationSeconds);
+            force += forceToApply * impulseDtSeconds;
             i.timeAppliedSeconds = nextTimeAppliedSeconds;
         }
 
         Vector2 acceleration = force / mass;
-        velocity += (acceleration * impulseDtSeconds);
+        velocity += (acceleration * deltaTimeSeconds);
         position += (velocity * deltaTimeSeconds);
 
         // Cleanup any impulses that have expired in the mean time