Add default button backgrounds and click sound

src/main/kotlin/net/shadowfacts/asmr/TestCacaoScreen.kt

@@ -39,7 +39,6 @@ class TestCacaoScreen: CacaoScreen() {
 				handler = {
 					println("$it clicked!")
 				}
-				background = NinePatchView(buttonNinePatch)
 			})
 
 			solver.dsl {

src/main/kotlin/net/shadowfacts/cacao/util/RenderHelper.kt

@@ -3,6 +3,8 @@ package net.shadowfacts.cacao.util
 import com.mojang.blaze3d.platform.GlStateManager
 import net.minecraft.client.MinecraftClient
 import net.minecraft.client.gui.DrawableHelper
+import net.minecraft.client.sound.PositionedSoundInstance
+import net.minecraft.sound.SoundEvent
 import net.shadowfacts.cacao.geometry.Rect
 
 /**
@@ -15,6 +17,12 @@ object RenderHelper {
 
 	private val disabled = (System.getProperty("cacao.drawing.disabled") ?: "false").toBoolean()
 
+	// TODO: find a better place for this
+	fun playSound(event: SoundEvent) {
+		if (disabled) return
+		MinecraftClient.getInstance().soundManager.play(PositionedSoundInstance.master(event, 1f))
+	}
+
 	/**
 	 * Draws a solid [rect] filled with the given [color].
 	 */
@@ -65,6 +73,9 @@ object RenderHelper {
 		GlStateManager.translated(x, y, z)
 	}
 
+	/**
+	 * @see org.lwjgl.opengl.GL11.glColor4f
+	 */
 	fun color(r: Float, g: Float, b: Float, alpha: Float) {
 		if (disabled) return
 		GlStateManager.color4f(r, g, b, alpha)

src/main/kotlin/net/shadowfacts/cacao/view/button/AbstractButton.kt

@@ -1,8 +1,13 @@
 package net.shadowfacts.cacao.view.button
 
+import net.minecraft.sound.SoundEvents
+import net.minecraft.util.Identifier
 import net.shadowfacts.cacao.geometry.Point
 import net.shadowfacts.cacao.util.MouseButton
+import net.shadowfacts.cacao.util.NinePatchTexture
 import net.shadowfacts.cacao.util.RenderHelper
+import net.shadowfacts.cacao.util.Texture
+import net.shadowfacts.cacao.view.NinePatchView
 import net.shadowfacts.cacao.view.View
 import net.shadowfacts.kiwidsl.dsl
 
@@ -19,6 +24,12 @@ import net.shadowfacts.kiwidsl.dsl
  */
 abstract class AbstractButton<Impl: AbstractButton<Impl>>(val content: View, val padding: Double = 4.0): View() {
 
+	companion object {
+		val DEFAULT_BG = NinePatchTexture(Texture(Identifier("textures/gui/widgets.png"), 0, 66), 3, 3, 194, 14)
+		val HOVERED_BG = NinePatchTexture(Texture(Identifier("textures/gui/widgets.png"), 0, 86), 3, 3, 194, 14)
+		val DISABLED_BG = NinePatchTexture(Texture(Identifier("textures/gui/widgets.png"), 0, 46), 3, 3, 194, 14)
+	}
+
 	/**
 	 * The function that handles when this button is clicked.
 	 * The parameter is the type of the concrete button implementation that was used.
@@ -40,19 +51,24 @@ abstract class AbstractButton<Impl: AbstractButton<Impl>>(val content: View, val
 	 * If a [backgroundColor] is specified, it will be drawn behind the background View and thus not visible
 	 * unless the background view is not fully opaque.
 	 */
-	var background: View? = null
+	var background: View? = NinePatchView(DEFAULT_BG)
 	/**
 	 * The background to draw when the button is hovered over by the mouse.
 	 * If `null`, the normal [background] will be used.
 	 * @see background
 	 */
-	var hoveredBackground: View? = null
+	var hoveredBackground: View? = NinePatchView(HOVERED_BG)
 	/**
 	 * The background to draw when the button is [disabled].
 	 * If `null`, the normal [background] will be used.
 	 * @see background
 	 */
-	var disabledBackground: View? = null
+	var disabledBackground: View? = NinePatchView(DISABLED_BG)
+
+	/**
+	 * If the button will play the Minecraft button click sound when clicked.
+	 */
+	var clickSoundEnabled = true
 
 	override fun wasAdded() {
 		solver.dsl {
@@ -109,6 +125,10 @@ abstract class AbstractButton<Impl: AbstractButton<Impl>>(val content: View, val
 			// For example, an implementing class may be defined as such: `class Button: AbstractButton<Button>`
 			@Suppress("UNCHECKED_CAST")
 			handler(this as Impl)
+
+			if (clickSoundEnabled) {
+				RenderHelper.playSound(SoundEvents.UI_BUTTON_CLICK)
+			}
 		}
 	}