I created a simple gui, based on the sign gui:

package com.mta.utzonmod.client.gui;

import java.io.IOException;

import org.lwjgl.input.Keyboard;

import net.minecraft.client.gui.GuiButton;
import net.minecraft.client.gui.GuiScreen;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.client.resources.I18n;
import net.minecraft.util.ChatAllowedCharacters;
import net.minecraft.util.text.ITextComponent;
import net.minecraft.util.text.TextComponentString;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

@SideOnly(Side.CLIENT)
public class signInputGui extends GuiScreen {
	
	private GuiButton doneBtn;
	
	private int updateCounter;
	
	private int editLine;
	
	public String playerInput;
	
	public void initGui() {
		this.buttonList.clear();
		Keyboard.enableRepeatEvents(true);
		this.doneBtn = this.addButton(new GuiButton(0, this.width / 2 - 100, this.height / 4 + 120, I18n.format("gui.done")));	
	}
	
	public void onGuiClosed() {
		Keyboard.enableRepeatEvents(false);
	}
	
	public void updateScreen() {
		++this.updateCounter;
	}
	
	protected void actionPerformed(GuiButton button) throws IOException {
		if(button.enabled) {
			if(button.id == 0) {
				this.mc.displayGuiScreen((GuiScreen)null);
			}
		}
	}
	
	public final ITextComponent[] signText = new ITextComponent[] {new TextComponentString(""), new TextComponentString(""), new TextComponentString(""), new TextComponentString("")};
	
//	protected void keyTyped(char typedChar, int keyCode) throws IOException {
//		if(keyCode == 200) {
//			this.editLine = this.editLine - 1 & 3;
//		}
//		
//		if (keyCode == 208 || keyCode == 28 || keyCode == 156) {
//			this.editLine = this.editLine + 1 & 3;
//		}
//		
//		for (int i = 0; i < 4; ++i)
//        {
//            playerInput = ITextComponent.Serializer.componentToJson(this.signText[i]);
//        }
//		
//		if (keyCode == 14 && !playerInput.isEmpty()) {
//			playerInput = playerInput.substring(0, playerInput.length() - 1);
//		}
//		
//		if (ChatAllowedCharacters.isAllowedCharacter(typedChar) && this.fontRenderer.getStringWidth(playerInput + typedChar) <= 90) {
//			playerInput = playerInput + typedChar;
//		}
//		
//		if (keyCode == 1) {
//			this.actionPerformed(this.doneBtn);
//		}	
//	}
	
	public void drawScreen(int mouseX, int mouseY, float partialTicks) {
		this.drawDefaultBackground();
		this.drawCenteredString(this.fontRenderer, I18n.format("sign.edit"),this.width / 2, 40, 16777215);
		GlStateManager.color(1.0F,  1.0F,  1.0F, 1.0F);
		GlStateManager.pushMatrix();
		GlStateManager.translate((float)(this.width / 2), 0.0F, 50.0F);
		
        GlStateManager.scale(-93.75F, -93.75F, -93.75F);
        GlStateManager.rotate(180.0F, 0.0F, 1.0F, 0.0F);
		
		GlStateManager.popMatrix();
		super.drawScreen(mouseX, mouseY, partialTicks);
	}
}

 

But for some reason when I open the GUI, my cursor disappears completely. Am I missing a function, or where am I going wrong?

I'm not sure if this will help you, but you can at least try. I've had this problem myself too, and I'm not quite sure what fixed it, but I think it might be the way that you do the drawScreen(). Try this:

1. Backup that entire class in case I mess everything up by letting you do the next 3 steps

2. Let your class extend the GuiContainer class

3. Fix any errors that step 2 causes

4. remove this part:

public void drawScreen(int mouseX, int mouseY, float partialTicks) {
	this.drawDefaultBackground();
	this.drawCenteredString(this.fontRenderer, I18n.format("sign.edit"),this.width / 2, 40, 16777215);
	GlStateManager.color(1.0F,  1.0F,  1.0F, 1.0F);
	GlStateManager.pushMatrix();
	GlStateManager.translate((float)(this.width / 2), 0.0F, 50.0F);
	
	GlStateManager.scale(-93.75F, -93.75F, -93.75F);
	GlStateManager.rotate(180.0F, 0.0F, 1.0F, 0.0F);
	
	GlStateManager.popMatrix();
	super.drawScreen(mouseX, mouseY, partialTicks);
}

5. add this to the class:

@Override
protected void drawGuiContainerBackgroundLayer(float partialTicks, int mouseX, int mouseY) {
	//Whatever you want to draw goes here	
}

I hope this was helpful,

Lenardjee

bump

Try Mouse#setCatched(), it could work but I am not sure 

4 minutes ago, Reflxction said:

Try Mouse#setCatched(), it could work but I am not sure 

Can you give an example on where I should use it and how?

Just now, Stenbergcsgo said:

Can you give an example on where I should use it and how?

I'm not sure, I think in initGui method, but if it doesn't work there try in different methods. And try Mouse.setCatched(false), if it doesn't work try true idk