[VM] 3D audio panning (riperiperi#243)

* [VM[ 3D audio panning

Calculates panning for entity sounds and adds avatars to sound entities on sound events.

* Fix crashing when rendering a city with no roads.

Author: LazyDuchess

TSOClient/tso.client/Rendering/City/CityGeometry.cs

@@ -468,11 +468,14 @@ public void RegenMeshVerts(GraphicsDevice gd, Rectangle? range)
 
             RoadIndices?.Dispose();
             RoadVertices?.Dispose();
-            RoadIndices = new IndexBuffer(gd, IndexElementSize.ThirtyTwoBits, roadIndices.Count, BufferUsage.None);
-            RoadIndices.SetData(roadIndices.ToArray());
-            RoadVertices = new VertexBuffer(gd, typeof(TLayerVertex), roadVertices.Count, BufferUsage.None);
-            RoadVertices.SetData(roadVertices.ToArray());
-            RoadPrims = roadIndices.Count / 3;
+            if (roadVertices.Count > 0)
+            {
+                RoadIndices = new IndexBuffer(gd, IndexElementSize.ThirtyTwoBits, roadIndices.Count, BufferUsage.None);
+                RoadIndices.SetData(roadIndices.ToArray());
+                RoadVertices = new VertexBuffer(gd, typeof(TLayerVertex), roadVertices.Count, BufferUsage.None);
+                RoadVertices.SetData(roadVertices.ToArray());
+                RoadPrims = roadIndices.Count / 3;
+            }
         }
 
         private int O(int x, int y, int minx, int maxx)

TSOClient/tso.simantics/Entities/VMAvatar.cs

@@ -490,6 +490,7 @@ private void HandleTimePropsEvent(TimePropertyListItem tp)
                         Zoom = true,
                     };
                     owner.SoundThreads.Add(entry);
+                    owner.Thread.Context.VM.SoundEntities.Add(this);
                     owner.TickSounds();
                 }
             }

TSOClient/tso.simantics/Entities/VMEntity.cs

@@ -369,7 +369,6 @@ public void TickSounds()
                     float pan = (SoundThreads[i].Pan) ? Math.Max(-1.0f, Math.Min(1.0f, scrPos.X / worldSpace.WorldPxWidth)) : 0;
                     pan = pan * pan * ((pan > 0)?1:-1);
 
-
                     float volume = 1f;
 
                     var rcs = worldState.Cameras.ActiveCamera as CameraController3D;
@@ -382,6 +381,29 @@ public void TickSounds()
                         volume = 1.5f - delta.Length() / 40f;
                         volume *= (10 / ((rcs.Zoom3D * rcs.Zoom3D) + 10));
                         volume *= worldState.PreciseZoom;
+
+                        //Calculate 3D sound
+                        if (SoundThreads[i].Pan)
+                        {
+                            //Calculate camera vectors and heading relative to sound source
+                            var sourcePos = new Vector3(vp.X, vp.Z, vp.Y);
+
+                            var lookAt = rcs.Camera.Target - rcs.Camera.Position;
+                            lookAt.Normalize();
+
+                            var lookUp = Vector3.Up;
+
+                            var lookSide = Vector3.Cross(lookAt, lookUp);
+                            lookSide.Normalize();
+
+                            var heading = sourcePos - rcs.Camera.Position;
+                            heading.Normalize();
+
+                            pan = Vector3.Dot(lookSide, heading);
+
+                            //Tweak exponent so that sounds don't go off one ear too soon
+                            pan = (float)Math.Pow(Math.Abs(pan), 2.25f) * Math.Sign(pan);
+                        }
                     }
                     else
                     {