Use bounds to choose projection targets

Source/ConformalDecals/ModuleConformalDecal.cs

@@ -142,6 +142,7 @@ namespace ConformalDecals {
 
         private Material _decalMaterial;
         private Material _previewMaterial;
+        private BoxCollider _boundsCollider;
         
         internal bool _shouldRender;
 
@@ -320,6 +321,8 @@ namespace ConformalDecals {
             var boundsBehaviour = decalBoundsTransform.gameObject.AddComponent<DecalBoundsBehaviour>();
             boundsBehaviour.decalRenderer = this;
 
+            _boundsCollider = decalBoundsTransform.GetComponent<BoxCollider>();
+
             UpdateMaterials();
 
             if (HighLogic.LoadedSceneIsGame) {
@@ -481,7 +484,7 @@ namespace ConformalDecals {
 
                 // update projection
                 foreach (var target in _targets) {
-                    target.Project(_orthoMatrix, decalProjectorTransform, useBaseNormal);
+                    target.Project(_orthoMatrix, decalProjectorTransform, _boundsCollider.bounds, useBaseNormal);
                 }
             }
             else {

Source/ConformalDecals/ProjectionTarget.cs

@@ -20,9 +20,10 @@ namespace ConformalDecals {
             _decalMPB = new MaterialPropertyBlock();
         }
 
-        public void Project(Matrix4x4 orthoMatrix, Transform projector, bool useBaseNormal) {
-            _projectionEnabled = true;
+        public void Project(Matrix4x4 orthoMatrix, Transform projector, Bounds projectorBounds, bool useBaseNormal) {
 
+            if (projectorBounds.Intersects(_targetRenderer.bounds)) {
+                _projectionEnabled = true;
                 var targetMaterial = _targetRenderer.sharedMaterial;
                 var projectorToTargetMatrix = target.worldToLocalMatrix * projector.localToWorldMatrix;
 
@@ -46,6 +47,10 @@ namespace ConformalDecals {
                     _decalMPB.SetTexture(DecalPropertyIDs._BumpMap, DecalConfig.BlankNormal);
                 }
             }
+            else {
+                _projectionEnabled = false;
+            }
+        }
 
         public bool Render(Material decalMaterial, MaterialPropertyBlock partMPB, Camera camera) {
             if (_projectionEnabled) {