New Custom Player Icon support (if black/white pixel set at 31, 49), uses…

New Custom Player Icon support (if black/white pixel set at 31, 49), uses certain empty UV coordinates in player skin file.

CHANGELOG.md

@@ -7,6 +7,8 @@ All notable changes to **CreatureChat** are documented in this file. The format
 ## Unreleased
 
 ### Added
+- New Custom Player Icon support (if black/white pixel set at 31, 49), uses certain empty UV coordinates in player skin file.
+- New mixin to extend PlayerSkinTexture to make a copy of the NativeImage (used later for custom skin rendering)
 - Rate limiter for LLM unit tests (to prevent rate limit issues from certain providers when running all tests)
 - Check friendship direction (+ or -) in LLM unit tests (to verify friendship is output correctly)
 

src/client/java/com/owlmaddie/mixin/client/MixinPlayerSkinTexture.java

+package com.owlmaddie.mixin.client;
+
+import com.owlmaddie.utils.IPlayerSkinTexture;
+import net.minecraft.client.texture.NativeImage;
+import net.minecraft.client.texture.PlayerSkinTexture;
+import net.minecraft.client.texture.ResourceTexture;
+import net.minecraft.util.Identifier;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/**
+ * The {@code MixinPlayerSkinTexture} class injects code into the PlayerSkinTexture class, to make a copy
+ * of the player's skin native image, so we can later use it for pixel checking (black/white key) for
+ * loading custom player icons in the unused UV coordinates of the player skin image.
+ */
+@Mixin(PlayerSkinTexture.class)
+public abstract class MixinPlayerSkinTexture extends ResourceTexture implements IPlayerSkinTexture {
+
+    @Unique
+    private NativeImage cachedSkinImage;
+
+    public MixinPlayerSkinTexture(Identifier location) {
+        super(location);
+    }
+
+    @Inject(method = "onTextureLoaded", at = @At("HEAD"))
+    private void captureNativeImage(NativeImage image, CallbackInfo ci) {
+        // Instead of image.copy(), we do a manual clone
+        this.cachedSkinImage = cloneNativeImage(image);
+    }
+
+    @Override
+    public NativeImage getLoadedImage() {
+        return this.cachedSkinImage;
+    }
+
+    // Example of the utility method in the same class (or in a separate helper):
+    private static NativeImage cloneNativeImage(NativeImage source) {
+        NativeImage copy = new NativeImage(
+                source.getFormat(),
+                source.getWidth(),
+                source.getHeight(),
+                false
+        );
+        copy.copyFrom(source);
+        return copy;
+    }
+}
+

src/client/java/com/owlmaddie/utils/IPlayerSkinTexture.java

+package com.owlmaddie.utils;
+
+import net.minecraft.client.texture.NativeImage;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * The {@code IPlayerSkinTexture} interface adds a new getLoadedImage method to PlayerSkinTexture instances
+ */
+public interface IPlayerSkinTexture {
+    @Nullable
+    NativeImage getLoadedImage();
+}
\ No newline at end of file

src/client/resources/creaturechat.client.mixins.json

@@ -3,7 +3,8 @@
 	"package": "com.owlmaddie.mixin.client",
 	"compatibilityLevel": "JAVA_17",
 	"client": [
-		"EntityRendererMixin"
+		"EntityRendererMixin",
+		"MixinPlayerSkinTexture"
 	],
 	"injectors": {
 		"defaultRequire": 1