Remove an useless part of the Util object, and add a poseStack argument to the render function of the Renderable interface.

common/src/main/kotlin/fr/username404/snowygui/gui/Box.kt

@@ -1,9 +1,9 @@
 package fr.username404.snowygui.gui
 
-import fr.username404.snowygui.rendering.Util
+import com.mojang.blaze3d.vertex.PoseStack
 
 class Box(x: Int, y: Int, scale: Int): Element(x, y, 20 * scale, 10 * scale) {
-    override fun render() {
+    override fun render(poseStack: PoseStack?) {
-        Util.UIRect(x, y, this.width, this.height, opacity = 1F)
+
     }
 }

common/src/main/kotlin/fr/username404/snowygui/gui/Element.kt

@@ -1,10 +1,12 @@
 package fr.username404.snowygui.gui
 
-fun interface Renderable { fun render() }
+import com.mojang.blaze3d.vertex.PoseStack
+
+fun interface Renderable { fun render(poseStack: PoseStack?) }
 abstract class Element(
     var x: Int, var y: Int,
     val width: Int, val height: Int
 ): Renderable {
-    fun display() { if (!hidden) render() }
+    fun display(stack: PoseStack? = null) { if (!hidden) render(stack) }
     var hidden: Boolean = false
 }

common/src/main/kotlin/fr/username404/snowygui/gui/SnowyScreen.kt

@@ -9,7 +9,7 @@ abstract class SnowyScreen(translatableString: String = "screen.snowy.gui", priv
     override fun render(poseStack: PoseStack?, i: Int, j: Int, f: Float) {
         if (poseStack != null) {
             components?.forEach {
-                it.display()
+                it.display(poseStack)
             }
         }
     }

common/src/main/kotlin/fr/username404/snowygui/rendering/Util.kt

@@ -1,40 +1,13 @@
 package fr.username404.snowygui.rendering
 
-import com.mojang.blaze3d.platform.GlStateManager
-import com.mojang.blaze3d.systems.RenderSystem
 import com.mojang.blaze3d.vertex.BufferBuilder
-import com.mojang.blaze3d.vertex.DefaultVertexFormat
 import com.mojang.blaze3d.vertex.PoseStack
 import com.mojang.blaze3d.vertex.Tesselator
 import net.minecraft.client.Minecraft
-import org.lwjgl.opengl.GL11
 
 internal object Util {
     private val tessellator: Tesselator = Tesselator.getInstance()
     private val buffer: BufferBuilder = tessellator.builder
-    fun UIRect(x: Int, y: Int, width: Int, height: Int, color: Int = -0x1, opacity: Float) {
-        val r = (color shr 16 and 255) / 255.0f
-        val g = (color shr 8 and 255) / 255.0f
-        val b = (color and 255) / 255.0f
-        RenderSystem.enableBlend()
-        RenderSystem.disableTexture()
-        RenderSystem.blendFuncSeparate(
-            GlStateManager.SourceFactor.SRC_ALPHA,
-            GlStateManager.DestFactor.ONE_MINUS_SRC_ALPHA,
-            GlStateManager.SourceFactor.ONE,
-            GlStateManager.DestFactor.ZERO
-        )
-        with(buffer) {
-            begin(GL11.GL_QUADS, DefaultVertexFormat.POSITION_COLOR)
-            vertex(x.toDouble(), y.toDouble() + height, 0.0).color(r, g, b, opacity).endVertex()
-            vertex(x.toDouble() + width, y.toDouble() + height, 0.0).color(r, g, b, opacity).endVertex()
-            vertex(x.toDouble() + width, y.toDouble(), 0.0).color(r, g, b, opacity).endVertex()
-            vertex(x.toDouble(), y.toDouble(), 0.0).color(r, g, b, opacity).endVertex()
-            tessellator.end()
-            RenderSystem.enableTexture()
-            RenderSystem.disableBlend()
-        }
-    }
     fun UIString(poseStack: PoseStack, string: String, i: Float, j: Float) {
         Minecraft.getInstance().font.draw(poseStack, string, i, j, 10)
     }