Making a minimap

[bkvaluemeal]

I'm trying to understand how minimap mods actually work. I found the open source MapWriter and have browsed the source code for other popular minimaps, but what I can't seem to figure out is how they actually get the colors for the map. I've tried something like how the map item works (getting the color of the block I'm standing on and drawing a rectangle on screen with that integer), but nothing happened. Could someone explain this to me please?

 

This is what I've got so far, and you can see where I'd like to add the minimap. The zone your in (top left) will change based on a text file stored locally or on the server. When your armor's durability is less than 75%, a manikin type thing will appear in the bottom right.

 

[/img]

[bkvaluemeal]

At first I tried this:

 

IBlockState state = MC.theWorld.getBlockState(MC.thePlayer.getPosition());
int color = state.getBlock().getMapColor(state).colorValue;
drawRect(0, 0, 100, 100, color);

 

That didn't work. So then I found a thread talking about getting the textures from the jar like so:

 

MC.getTextureManager().bindTexture(new ResourceLocation("textures/blocks/grass_side.png"));
drawModalRectWithCustomSizedTexture(0, 0, 0, 0, 64, 64, 64, 64);

 

This does work, and I could get the RGB values like this:

 

static int[] loadTexture(String block)
{
try
{
	final ResourceLocation resourceLocation = new ResourceLocation("textures/blocks/" + block + ".png");
	final IResourceManager resourceManager = Minecraft.getMinecraft().getResourceManager();
	final IResource resource = resourceManager.getResource(resourceLocation);
	final InputStream in = resource.getInputStream();
	final BufferedImage image = ImageIO.read(in);
	return image.getRGB(0, 0, image.getWidth(), image.getHeight(), null, 0, image.getWidth());
}
catch (Exception e)
{

}
return null;
}

 

My thought now is to cache all the block colors found in Minecraft, but what do I do about custom blocks added by a mod? Is it possible to iterate through the textures in their jar?

[bkvaluemeal]

Cool, that works too.

 

IBlockState state = MC.theWorld.getBlockState(MC.thePlayer.getPosition());
int color = 0xFF000000 | state.getBlock().getMapColor(state).colorValue;
drawRect(50, 50, 100, 100, color);

 

Although, it's not the level of detail I was looking for. It swaps between black and the actual color for whatever reason. Xaero's map mod doesn't work like this, right?

[bkvaluemeal]

Well, no, but what I'm saying is that Xaero's map, for instance, looks nothing like the item you can craft in game. It is much more detailed. I don't think the getMapColor() function has the ability to yield that level of detail. So, how do they do it?

 

I'll play around with the getMapColor() function and see what I get. I'll post that when I'm done.

[Draco18s]

GetMapColor() returns a predefined color (one of 16, IIRC although there are some duplicates).  The more advanced maps go "this color is useless" and examine the block's actual texture and make a "best guess" average color for the block.

[bkvaluemeal]

Right, my question is how do they get that texture? The default Minecraft blocks are easy enough, but how do you grab the textures of custom blocks?

 

Edit:

Let me clarify, I can use the loadTexture() function I mentioned before only if I know where the resource location is, correct? I will assume I don't know that. Some modder may decide not to follow convention. I can't seem to find a way to pull a texture from an arbitrary block.

[bkvaluemeal]

This works, but I get tons of errors. What is the right way to do this? I really don't even want to use the getMapColor() function because it flickers between black and green. I don't know why.

 

public class MiniMapHandler
{
private static final Minecraft MC = Minecraft.getMinecraft();
private static final BufferedImage MAP = new BufferedImage(75, 75, BufferedImage.TYPE_INT_RGB);
private static DynamicTexture TEXTURE = new DynamicTexture(MAP);

@SubscribeEvent
public void onTick(PlayerTickEvent event)
{
	// (Y, X) They're swapped. Don't feel like retyping.
	BlockPos zero_zero = MC.thePlayer.getPosition();
	BlockPos one_zero = MC.thePlayer.getPosition().north();
	BlockPos n_one_zero = MC.thePlayer.getPosition().south();
	BlockPos zero_one = MC.thePlayer.getPosition().east();
	BlockPos zero_n_one = MC.thePlayer.getPosition().west();

	IBlockState state_zero_zero = MC.theWorld.getBlockState(zero_zero);
	IBlockState state_one_zero = MC.theWorld.getBlockState(one_zero);
	IBlockState state_n_one_zero = MC.theWorld.getBlockState(n_one_zero);
	IBlockState state_zero_one = MC.theWorld.getBlockState(zero_one);
	IBlockState state_zero_n_one = MC.theWorld.getBlockState(zero_n_one);

	int color_zero_zero = state_zero_zero.getBlock().getMapColor(state_zero_zero).colorValue;
	int color_one_zero = state_one_zero.getBlock().getMapColor(state_one_zero).colorValue;
	int color_n_one_zero = state_n_one_zero.getBlock().getMapColor(state_n_one_zero).colorValue;
	int color_zero_one = state_zero_one.getBlock().getMapColor(state_zero_one).colorValue;
	int color_zero_n_one = state_zero_n_one.getBlock().getMapColor(state_zero_n_one).colorValue;

	MAP.setRGB(37, 37, color_zero_zero);
	MAP.setRGB(37, 38, color_one_zero);
	MAP.setRGB(37, 36, color_n_one_zero);
	MAP.setRGB(38, 37, color_zero_one);
	MAP.setRGB(36, 37, color_zero_n_one);

	TEXTURE = new DynamicTexture(MAP);
}

public static ResourceLocation getTexture()
{
	return MC.getTextureManager().getDynamicTextureLocation("minimap", TEXTURE);
}
}

 

Inside onRenderGui(RenderGameOverlayEvent event):

MC.getTextureManager().bindTexture(MiniMapHandler.getTexture());
drawModalRectWithCustomSizedTexture(MC.displayWidth / 2 - 78, 13, 0, 0, 75, 75, 75, 75);

[Elix_x]

Take a look at Journey Map.

Although, it is not open source, you can always decompile the jar with programs like jd gui.

[bkvaluemeal]

I knew that creating this wasn't going to be easy, but this is a lot of work! With The Division launching soon, I honestly don't think I'll be working on this much longer. I've opted to use getMapColor() (despite what I said) in lieu of starting a huge project. I have created a much better way to draw the map, although is there a way to update the DynamicTexture without making a new one every time? My game starts to lag after a while and updateDynamicTexture() doesn't seem to do the trick.

 

MiniMapHandler:

public class MiniMapHandler
{
   private static final Minecraft MC = Minecraft.getMinecraft();
   public static final BufferedImage MAP = new BufferedImage(75, 75, BufferedImage.TYPE_INT_RGB);

   @SubscribeEvent
   public void onTick(PlayerTickEvent event)
   {
      BlockPos center = MC.thePlayer.getPosition();

      for (int z = center.getZ() - 37; z < center.getZ() + 38; z++)
      {
         for (int x = center.getX() - 37; x < center.getX() + 38; x++)
         {
            IBlockState state = MC.theWorld.getBlockState(new BlockPos(x, center.getY(), z));
            int color = state.getBlock().getMapColor(state).colorValue;

            MAP.setRGB(x - center.getX() + 37, z - center.getZ() + 37, color);
         }
      }
   }
}

 

Inside onRenderGui(RenderGameOverlayEvent event):

TEXTURE = new DynamicTexture(MiniMapHandler.MAP);
MC.getTextureManager().bindTexture(MC.getTextureManager().getDynamicTextureLocation("minimap", TEXTURE));
drawModalRectWithCustomSizedTexture(MC.displayWidth / 2 - 78, 13, 0, 0, 75, 75, 75, 75);

 

The map reminds me of NetHack...

 

[Draco18s]

While using the player's current Y position seems like a logical choice, that map is utterly worthless to me, as a player.  In looking at it and looking at what's in front of the player in that screenshot, I have literally no idea where I am or what direction I'm facing.

[bkvaluemeal]

That's true. Haha! Could you suggest a way to get the topmost block or perhaps a better way to draw the map without crashing my client? I'm most concerned about the latter.

 

Edit:

I made the map look better. It checks blocks above and below the player.

 

public class MiniMapHandler
{
private static final Minecraft MC = Minecraft.getMinecraft();
public static final BufferedImage MAP = new BufferedImage(75, 75, BufferedImage.TYPE_INT_RGB);

@SubscribeEvent
public void onTick(PlayerTickEvent event)
{
	BlockPos center = MC.thePlayer.getPosition();
	MAP.flush();

	for (int z = center.getZ() - 37; z < center.getZ() + 38; z++)
	{
		for (int x = center.getX() - 37; x < center.getX() + 38; x++)
		{
			for (int y = center.getY() + 10; y > center.getY() - 10; y--)
			{
				BlockPos pos = new BlockPos(x, y, z);
				IBlockState state = MC.theWorld.getBlockState(pos);

				if (!state.getBlock().isAir(MC.theWorld.init(), pos))
				{
					int color = state.getBlock().getMapColor(state).colorValue;

					MAP.setRGB(x - center.getX() + 37, z - center.getZ() + 37, color);

					break;
				}
			}
		}
	}

	MAP.setRGB(37, 37, 0xFFFFFF);
}
}

 

[Draco18s]

If it crashes, include the line that it crashes at.

[bkvaluemeal]

No, it "crashes" because Java's memory fills up and the server shuts down. I get messages saying the server jumped ahead X number of ticks. I'm not handling the dynamic textures properly. I don't exactly know how other than to create a new one and load it.

[Draco18s]

That's because you're creating 118125 BlockPos objects and 118125 IBlockState references every tick, all of which need to be garbage collected.

[bkvaluemeal]

Even when I take out the for loops and render a black box, I still lag and break the game. I have no doubt that all that cleanup is a problem, but there has to be a way to reuse the dynamic texture. Unless, I'm approaching this in entirely the wrong way.

[Draco18s]

Would probably help if...

 

1) Didn't use MAP.flush();

2) Didn't check for changes every tick (seriously, scanning 118125 blocks every tick is dumb)

[bkvaluemeal]

I have the minimap updating at 5 FPS. This seems to work a lot better, but only appears to be delaying the inevitable. This was mainly a proof of concept for me. I may decide to work on this more later, but for now I am finished.

[Draco18s]

You still don't need MAP.flush()

 

You may as well think of it as MAP.garbageCollect(), the method exists to mark the memory it uses as free, but you're using it to reset the colors.

[bkvaluemeal]

I took that out and instead told it to write the pixel black. There was an issue with the map looking like an acid trip. Everything was kinda... melting.