Evaluate the editor expression on the fly, not immediately after addi…

…ng a layer. This way the editor texture expression will not snap to that layer and can be changed (and react to changes) at runtime

radiantcore/shaders/CShader.cpp

@@ -79,10 +79,24 @@ TexturePtr CShader::getEditorImage()
 {
     if (!_editorTexture)
     {
+        auto editorTex = _template->getEditorTexture();
+
+        if (!editorTex)
+        {
+            // If there is no editor expression defined, use the an image from a layer, but no Bump or speculars
+            for (const auto& layer : _layers)
+            {
+                if (layer->getType() != IShaderLayer::BUMP && layer->getType() != IShaderLayer::SPECULAR &&
+                    std::dynamic_pointer_cast<MapExpression>(layer->getMapExpression()))
+                {
+                    editorTex = std::static_pointer_cast<MapExpression>(layer->getMapExpression());
+                    break;
+                }
+            }
+        }
+
         // Pass the call to the GLTextureManager to realise this image
-        _editorTexture = GetTextureManager().getBinding(
-            _template->getEditorTexture()
-        );
+        _editorTexture = GetTextureManager().getBinding(editorTex);
     }
 
     return _editorTexture;
@@ -590,9 +604,27 @@ void CShader::subscribeToTemplateChanges()
     _templateChanged = _template->sig_TemplateChanged().connect([this]()
     {
         _sigMaterialModified.emit();
+
+        // Check if the editor image needs an update
+        updateEditorImage();
     });
 }
 
+void CShader::updateEditorImage()
+{
+    // In case the editor tex is pointing to the fallback "shader not found"
+    // check if we have some possible replacements
+    if (!_editorTexture) return;
+
+    if (isEditorImageNoTex() || !_template->getEditorTexture())
+    {
+        // The editor image is "shader not found", but we might have layers and/or an qer_editorImage defined
+        // In case we don't have an editor texture expression, remove it from the slot
+        // we will update it again as soon as it will be requested
+        _editorTexture.reset();
+    }
+}
+
 void CShader::refreshImageMaps()
 {
     if (_template->getEditorTexture())

radiantcore/shaders/CShader.h

@@ -162,6 +162,7 @@ class CShader final :
 private:
     void ensureTemplateCopy();
     void subscribeToTemplateChanges();
+    void updateEditorImage();
 };
 typedef std::shared_ptr<CShader> CShaderPtr;
 

radiantcore/shaders/ShaderTemplate.cpp

@@ -1321,13 +1321,6 @@ void ShaderTemplate::addLayer(const Doom3ShaderLayer::Ptr& layer)
 {
 	// Add the layer
 	_layers.emplace_back(layer);
-
-	// If there is no editor texture yet, use the bindable texture, but no Bump or speculars
-	if (!_editorTex && layer->getType() != IShaderLayer::BUMP && 
-        layer->getType() != IShaderLayer::SPECULAR && std::dynamic_pointer_cast<MapExpression>(layer->getMapExpression()))
-	{
-		_editorTex = std::static_pointer_cast<MapExpression>(layer->getMapExpression());
-	}
 }
 
 void ShaderTemplate::addLayer(IShaderLayer::Type type, const MapExpressionPtr& mapExpr)