Don't serialize texture if is a render target

src/Materials/Node/Blocks/Dual/currentScreenBlock.ts

@@ -282,7 +282,7 @@ export class CurrentScreenBlock extends NodeMaterialBlock {
 
         serializationObject.convertToGammaSpace = this.convertToGammaSpace;
         serializationObject.convertToLinearSpace = this.convertToLinearSpace;
-        if (this.texture) {
+        if (this.texture && !this.texture.isRenderTarget) {
             serializationObject.texture = this.texture.serialize();
         }
 

src/Materials/Node/Blocks/Dual/reflectionTextureBaseBlock.ts

@@ -440,7 +440,7 @@ export abstract class ReflectionTextureBaseBlock extends NodeMaterialBlock {
     public serialize(): any {
         let serializationObject = super.serialize();
 
-        if (this.texture) {
+        if (this.texture && !this.texture.isRenderTarget) {
             serializationObject.texture = this.texture.serialize();
         }
 

src/Materials/Node/Blocks/PBR/refractionBlock.ts

@@ -324,7 +324,7 @@ export class RefractionBlock extends NodeMaterialBlock {
     public serialize(): any {
         let serializationObject = super.serialize();
 
-        if (this.texture) {
+        if (this.texture && !this.texture.isRenderTarget) {
             serializationObject.texture = this.texture.serialize();
         }
 

src/Materials/Node/Blocks/Particle/particleTextureBlock.ts

@@ -200,7 +200,7 @@ export class ParticleTextureBlock extends NodeMaterialBlock {
 
         serializationObject.convertToGammaSpace = this.convertToGammaSpace;
         serializationObject.convertToLinearSpace = this.convertToLinearSpace;
-        if (this.texture) {
+        if (this.texture && !this.texture.isRenderTarget) {
             serializationObject.texture = this.texture.serialize();
         }