first Kotlin version

src/main/kotlin/mods/betterfoliage/client/texture/LeafGenerator.kt

@@ -0,0 +1,77 @@
+package mods.betterfoliage.client.texture
+
+import mods.betterfoliage.BetterFoliageMod
+import mods.octarinecore.client.resource.*
+import mods.octarinecore.stripStart
+import net.minecraft.util.ResourceLocation
+import java.awt.image.BufferedImage
+
+/**
+ * Generate round leaf textures from leaf block textures.
+ * The base texture is tiled 2x2, then parts of it are made transparent by applying a mask to the alpha channel.
+ *
+ * Generator parameter _type_: Leaf type (configurable by user). Different leaf types may have their own alpha mask.
+ *
+ * @param[domain] Resource domain of generator
+ */
+class LeafGenerator(domain: String) : TextureGenerator(domain) {
+
+    override fun generate(params: ParameterList): BufferedImage? {
+        val target = targetResource(params)!!
+        val leafType = params["type"] ?: "default"
+
+        val handDrawnLoc = target.second.stripStart("textures/").stripStart("blocks/").let {
+            ResourceLocation(BetterFoliageMod.DOMAIN, "textures/blocks/${it.resourceDomain}/${it.resourcePath}")
+        }
+        resourceManager[handDrawnLoc]?.loadImage()?.let { return it }
+
+        val baseTexture = resourceManager[target.second]?.loadImage() ?: return null
+        val size = baseTexture.width
+        val frames = baseTexture.height / size
+
+        val maskTexture = (getLeafMask(leafType, size * 2) ?: getLeafMask("default", size * 2))?.loadImage()
+        fun scale(i: Int) = i * maskTexture!!.width / (size * 2)
+
+        val leafTexture = BufferedImage(size * 2, size * 2 * frames, BufferedImage.TYPE_4BYTE_ABGR)
+        val graphics = leafTexture.createGraphics()
+
+        // iterate all frames
+        for (frame in 0 .. frames - 1) {
+            val baseFrame = baseTexture.getSubimage(0, size * frame, size, size)
+            val leafFrame = BufferedImage(size * 2, size * 2, BufferedImage.TYPE_4BYTE_ABGR)
+
+            // tile leaf texture 2x2
+            leafFrame.createGraphics().apply {
+                drawImage(baseFrame, 0, 0, null)
+                drawImage(baseFrame, 0, size, null)
+                drawImage(baseFrame, size, 0, null)
+                drawImage(baseFrame, size, size, null)
+            }
+
+            // overlay alpha mask
+            if (target.first == ResourceType.COLOR && maskTexture != null) {
+                for (x in 0 .. size * 2 - 1) for (y in 0 .. size * 2 - 1) {
+                    val basePixel = leafFrame[x, y].toLong() and 0xFFFFFFFFL
+                    val maskPixel = maskTexture[scale(x), scale(y)].toLong() and 0xFF000000L or 0xFFFFFFL
+                    leafFrame[x, y] = (basePixel and maskPixel).toInt()
+                }
+            }
+
+            // add to animated png
+            graphics.drawImage(leafFrame, 0, size * frame * 2, null)
+        }
+
+        return leafTexture
+    }
+
+    /**
+     * Get the alpha mask to use
+     *
+     * @param[type] Alpha mask type.
+     * @param[maxSize] Preferred mask size.
+     */
+    fun getLeafMask(type: String, maxSize: Int) = getMultisizeTexture(maxSize) { size ->
+        ResourceLocation(BetterFoliageMod.DOMAIN, "textures/blocks/leafmask_${size}_${type}.png")
+    }
+
+}