Add some warnings about using non-GL_TEXTURE_2D textures which are un…

…supported by ImGui.

Thanks to d3cod3 for reporting this: d3cod3/Mosaic#17

src/BaseEngine.cpp

@@ -30,6 +30,6 @@ namespace ofxImGui
 
 		glBindTexture(GL_TEXTURE_2D, last_texture);
 
-		return new_texture;
+		return new_texture; // And who will clean up the garbage ? Seemingly nobody...
 	};
 }

src/BaseEngine.h

@@ -25,6 +25,8 @@ namespace ofxImGui
 
         virtual bool updateFontsTexture() = 0;
 
+		// This is here to keep a compatibility layer with old codebases.
+		// Not recommended to use, Upload with OF and use the GL_TEXTURE_2D's textureID directly.
 		virtual GLuint loadTextureImage2D(unsigned char * pixels, int width, int height);
 
 	protected:

src/Gui.cpp

@@ -5,6 +5,8 @@
 
 
 
+// Todo: Texture/Pixel loading functions: Stop using ofDisableArbTex and use appropriate textureSettings instead.
+
 namespace ofxImGui
 {
 	//--------------------------------------------------------------

src/ImHelpers.h

@@ -128,6 +128,10 @@ namespace ofxImGui
 
 static ImTextureID GetImTextureID(const ofTexture& texture)
 {
+	if (texture.getTextureData().textureTarget == GL_TEXTURE_RECTANGLE)
+	{
+		ofLogWarning("Warning, ImGui only supports drawing textures of type GL_TEXTURE_RECTANGLE.");
+	}
     return (ImTextureID)(uintptr_t)texture.texData.textureID;
 }