I have written the following class, its a custom keybinding class that I use to zoom the players camera in. Thought Id share, to help promote figuring out cool things that may be useful to people. Not sure how good it is, please critique it if you can see anything to critique.

 

 

public class KeyZoomIn extends KeyBinding
{
public KeyZoomIn()
{
  super("key.keyZoomIn", Keyboard.KEY_Z, "key.categories.yourmod");
}

Minecraft mc;
double zoom = 1; //default zoom is 1

@SubscribeEvent
public void keyDown(InputEvent.KeyInputEvent event)
{
Keyboard.enableRepeatEvents(true);
if(Keyboard.isRepeatEvent()){
  if (isPressed())  { 
 double currentZoom = zoom+= 0.02;	//seems to be fairly smooth and not too slow  
  this.cameraZoom(currentZoom);
  System.out.println(currentZoom);
}} 

else if (!isPressed() && zoom >=1)  { 
zoom = 1; //default zoom is 1
  this.cameraZoom(zoom);
}
}

public void cameraZoom(double zoomValue){

EntityRenderer entRenderer = Minecraft.getMinecraft().entityRenderer;
try {
	entRenderer.getClass().getField("cameraZoom").set(entRenderer, zoomValue);
	System.out.println();
} catch (IllegalArgumentException e) {
	e.printStackTrace();
} catch (IllegalAccessException e) {
	e.printStackTrace();
} catch (NoSuchFieldException e) {
	e.printStackTrace();
} catch (SecurityException e) {
	e.printStackTrace();
}
}
}

There is better way with FOVUpdateEvent(it could be slightly wrong name), you can use it for zooming.

It's good you're exploring reflection. I don't use reflection often, but I'm surprised if your code works as posted. Don't you need to use getDeclaredField() instead of getField() if you're trying to access a private field? Also, I thought you'd need to set it to accessible before you got or set the value...

Haha nope the code works as posted you need to register the keybinding using

 

in client proxy

public void registerKeyBindings()
  {
    MinecraftForge.EVENT_BUS.register(this);
    KeyZoomIn key1 = new KeyZoomIn();
    ClientRegistry.registerKeyBinding(key1);
    FMLCommonHandler.instance().bus().register(key1);
}

 

and overright that same method in common proxy and correctly pass it to your main mod file but other than that it works just fine. Not sure why like I said it was my first attempt using reflections

When I try it I get field not accessible errors. I'm really not sure how your reflection code is working. Is the field private for you? I'm not strong on reflection but I really, really though you have to set a public field to accessible before you can set it...

hmm it works correctly for me, the field is private for me. This is the first time im using reflection, and for some reason it works just fine, no errors on my end that I can see

This is the class with the imports - it works as is for me i use Eclipse as an IDE and my forge version is

 

forge\1.7.10-10.13.2.1230\forgeSrc-1.7.10-10.13.2.1230.jar

import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.EntityRenderer;
import net.minecraft.client.settings.KeyBinding;
import net.minecraft.entity.player.EntityPlayer;

import org.lwjgl.input.Keyboard;

import cpw.mods.fml.common.eventhandler.SubscribeEvent;
import cpw.mods.fml.common.gameevent.InputEvent;

public class KeyZoomIn extends KeyBinding
{
public KeyZoomIn()
{
  super("key.keyZoomIn", Keyboard.KEY_Z, "key.categories.custommod");
}

Minecraft mc;
double zoom;

@SubscribeEvent
public void keyDown(InputEvent.KeyInputEvent event)
{
Keyboard.enableRepeatEvents(true);
if(Keyboard.isRepeatEvent()){
  if (isPressed())  { 
 double currentZoom = zoom += 0.005;	  
  this.cameraZoom(currentZoom);
 System.out.println(currentZoom);
}} else if (!isPressed() && zoom !=1)  { 
zoom = 1;
  this.cameraZoom(zoom);
}
}

public void cameraZoom(double zoomValue){

EntityRenderer entRenderer = Minecraft.getMinecraft().entityRenderer;
try {
	entRenderer.getClass().getDeclaredField("cameraZoom").set(entRenderer, zoomValue);
} catch (IllegalArgumentException e) {
	e.printStackTrace();
} catch (IllegalAccessException e) {
	e.printStackTrace();
} catch (NoSuchFieldException e) {
	e.printStackTrace();
} catch (SecurityException e) {
	e.printStackTrace();
}
}
}
[code]

in Client Proxy

public void registerKeyBindings()
  {
MinecraftForge.EVENT_BUS.register(this);
    KeyZoomIn key2 = new KeyZoomIn();
    ClientRegistry.registerKeyBinding(key2);
    FMLCommonHandler.instance().bus().register(key2);
}

 

in common proxy

/* Overriden in ClientProxy*/
public void registerKeyBindings() {}


/*preInit() is called from PokeWorlds.java, and is responsible for registering all
 * 	Items and Entities. You should register the following here: creative tabs, items, 
 *  entities, blocks, tile entities, and mobs.
 *  
 */
public void preInit(){
registerKeyBindings();
}