ItemFeature: render multiple items

src/main/java/de/bixilon/minosoft/gui/rendering/entities/feature/block/BlockMesh.kt

@@ -25,6 +25,7 @@ import de.bixilon.minosoft.gui.rendering.util.mesh.MeshStruct
 
 class BlockMesh(context: RenderContext) : Mesh(context, BlockMeshStruct), BlockVertexConsumer {
     override val order = context.system.quadOrder
+    val offset = Vec3()
 
     override fun ensureSize(size: Int) {
         data.ensureSize(size)
@@ -33,7 +34,7 @@ class BlockMesh(context: RenderContext) : Mesh(context, BlockMeshStruct), BlockV
     override fun addVertex(position: FloatArray, uv: Vec2, texture: ShaderTexture, tintColor: Int, light: Int) {
         data.ensureSize(BlockMeshStruct.FLOATS_PER_VERTEX)
         val transformedUV = texture.transformUV(uv).array
-        data.add(position)
+        data.add(position[0] + offset.x, position[1] + offset.y, position[2] + offset.z)
         data.add(transformedUV)
         data.add(
             texture.shaderId.buffer(),
@@ -43,7 +44,7 @@ class BlockMesh(context: RenderContext) : Mesh(context, BlockMeshStruct), BlockV
 
     override inline fun addVertex(x: Float, y: Float, z: Float, u: Float, v: Float, textureId: Float, lightTint: Float) {
         data.add(
-            x, y, z,
+            x + offset.x, y + offset.y, z + offset.z,
             u, v,
             textureId, lightTint,
         )

src/main/java/de/bixilon/minosoft/gui/rendering/entities/feature/item/ItemFeature.kt

@@ -14,6 +14,7 @@
 package de.bixilon.minosoft.gui.rendering.entities.feature.item
 
 import de.bixilon.kotlinglm.mat4x4.Mat4
+import de.bixilon.kutil.random.RandomUtil.nextFloat
 import de.bixilon.minosoft.data.container.stack.ItemStack
 import de.bixilon.minosoft.gui.rendering.entities.feature.block.BlockMesh
 import de.bixilon.minosoft.gui.rendering.entities.feature.properties.MeshedFeature
@@ -21,9 +22,11 @@ import de.bixilon.minosoft.gui.rendering.entities.renderer.EntityRenderer
 import de.bixilon.minosoft.gui.rendering.entities.visibility.EntityLayer
 import de.bixilon.minosoft.gui.rendering.models.item.ItemRenderUtil.getModel
 import de.bixilon.minosoft.gui.rendering.models.raw.display.DisplayPositions
+import de.bixilon.minosoft.gui.rendering.util.mat.mat4.Mat4Util.EMPTY_INSTANCE
 import de.bixilon.minosoft.gui.rendering.util.mat.mat4.Mat4Util.reset
 import de.bixilon.minosoft.gui.rendering.util.mat.mat4.Mat4Util.translateXAssign
 import de.bixilon.minosoft.gui.rendering.util.mat.mat4.Mat4Util.translateZAssign
+import java.util.*
 
 open class ItemFeature(
     renderer: EntityRenderer<*>,
@@ -31,6 +34,7 @@ open class ItemFeature(
     val display: DisplayPositions,
 ) : MeshedFeature<BlockMesh>(renderer) {
     private var matrix = Mat4()
+    private var displayMatrix: Mat4 = Mat4.EMPTY_INSTANCE
     var stack: ItemStack? = stack
         set(value) {
             if (field == value) return
@@ -53,23 +57,51 @@ open class ItemFeature(
 
     private fun createMesh(stack: ItemStack) {
         val model = stack.item.item.getModel(renderer.renderer.connection) ?: return
+        val display = model.getDisplay(display)
+        this.displayMatrix = display?.matrix ?: Mat4.EMPTY_INSTANCE
         val mesh = BlockMesh(renderer.renderer.context)
 
         val tint = renderer.renderer.context.tints.getItemTint(stack)
 
+        val count = count(stack.item.count)
+        model.render(mesh, stack, tint) // 0 without offset
+
+        if (count > 1) {
+            val random = Random(1234567890123456789L)
+            for (i in 0 until count - 1) {
+                mesh.offset.x = random.nextFloat(-0.1f, 0.1f)
+                mesh.offset.y = random.nextFloat(-0.1f, 0.1f)
+                mesh.offset.z = random.nextFloat(-0.1f, 0.1f)
+
                 model.render(mesh, stack, tint)
+            }
+        }
+        // TODO: enchantment glint, ...
 
         this.mesh = mesh
     }
 
+    private fun count(count: Int): Int {
+        // that is not like vanilla, but imho better
+        return when {
+            count <= 0 -> 0
+            count == 1 -> 1
+            count < 16 -> 2
+            count < 32 -> 3
+            count < 48 -> 4
+            else -> 5
+        }
+    }
+
     private fun updateMatrix() {
         this.matrix.reset()
         this.matrix
             .translateXAssign(-0.5f).translateZAssign(-0.5f)
 
-        // TODO: rotate?
+        // TODO
 
-        this.matrix = renderer.matrix * matrix
+
+        this.matrix = renderer.matrix * displayMatrix * matrix
     }
 
     override fun draw(mesh: BlockMesh) {
@@ -79,4 +111,8 @@ open class ItemFeature(
         shader.tint = renderer.light.value
         super.draw(mesh)
     }
+
+    override fun unload() {
+        this.displayMatrix = Mat4.EMPTY_INSTANCE
+    }
 }