I’m in the process of converting a heap of .js scripts to C#, and have been running into a bunch of syntax issues when trying to directly pass a value into a struct.
Here’s the line of JavaScript code that I’m trying to convert (decreasing a health bar GUI):
// - Adjust maximum pixel inset based on it
healthGUI.pixelInset.xMax = healthGUI.pixelInset.xMin + healthGUIWidth * healthFraction;
In C#, I get the following error:
Assets/Scripts/PlayerBehaviour.cs(118,27): error CS1612: Cannot modify a value type return value of `UnityEngine.GUITexture.pixelInset’. Consider storing the value in a temporary variable
I’m at an absolute loss as to how to create a temporary variable in order to set the xMax value to the above formula.
As an aside, I kludged through a solution for a similar issue when trying to pass a value to a Color struct. I would be grateful if someone could take a look at the conversion and confirm and/or laugh at whether I am on the right path:
Original JavaScript:
// Start off by fading out GUI by setting alpha channel to 'clear'
guiTexture.color.a = 0;
C# ‘fix’ to get rid of “storing in temporary variable” error:
// Start off by fading out GUI by setting alpha channel to 'clear'
Color tempTextureClear = new Color(0,0,0,0);
guiTexture.color += tempTextureClear;
This really stems to how the languages handle structs in the context of property getters/setters. Since pixelInsert is a getter/setter, when you access it a copy of the Rect is returned, not the original Rect itself. C# handles this strictly so modifying the copy is meaningless so it throws an error. UnityScript hacks it by changing the code to create a new instance, modify it, then reassigns it through the setter which to me is scary (especially if no setter is defined).
EDIT: Perhaps one quick tweak to MightMao’s code would be:
pos.xMax = pos.xMin + healthGUIWidth * healthFraction;
if only to avoid hitting the pixelInsert getter a second time.
MightyMao and FizixMan, you are both legends! Thank you for your code tips and explanations.
Coming from a non-programming background and learning C# for the first time, UnityScript just seems a lot more straightforward and noob-friendly (like in this example, using only one line vs. having to break it down into a separate variable in C#), but I’ve heard that C# is easier to debug in the long run. Plus, it feels like I’m learning more about programming, no matter how hair-pulling it can get at times…
I’ve noticed you guys have been actively posting help a lot - is there a rep/give candy system? You guys sure deserve it.
C# might have a higher learning curve, but at least once you learn it you got your foot in the door to developing against the entire .NET framework (ASP.NET, Silverlight, C#.NET, WPF, Winforms, etc.)
No problem about the help, I’m just bored. Plus I talk out of my ass more often than not. >.> There are other posters here which are legends.
I guess C# has a wider application, but all I really want to do is make games… but hey, you never know. Maybe Silverlight will actually take off and become the de facto gaming platform sometime in the distant future.
Silverlight 5 was just recently announced with an actual hardware accelerated 3D API so likely we’ll see more gaming in its future (especially if the Windows Series Phone 7 Series Phone Name OS Thing takes off). I might be biased being a Silverlight developer myself, but there’s nothing else like it in the web-application world – I’d never go back to Flash/Java/JavaFX/JavaScript if I had the option – so I hope it never goes away!
Though I doubt it’d become the de facto gaming platform – that’s not its true purpose (right tool for the right job); I’d rather see the focus continue to be on LOB apps. (perhaps if only because that’s what I currently use it for >.>)
