cheaper/more proper checkerboard background render (still bad)

:trolley:

src/main/kotlin/ru/dbotthepony/mc/otm/client/render/RenderHelper.kt

@@ -105,6 +105,58 @@ fun GuiGraphics.renderRect(
 	renderRect(pose().last().pose(), x, y, width, height, z, color)
 }
 
+@Suppress("NAME_SHADOWING")
+fun renderCheckerboard(
+	matrix: Matrix4f,
+	x: Float,
+	y: Float,
+	width: Float,
+	height: Float,
+	z: Float = 0f,
+	color: RGBAColor = RGBAColor.WHITE
+) {
+	RenderSystem.setShader(GameRenderer::getPositionColorShader)
+
+	RenderSystem.enableBlend()
+	RenderSystem.defaultBlendFunc()
+
+	if (!is3DContext)
+		RenderSystem.depthFunc(GL_ALWAYS)
+
+	val tess = tesselator
+	val builder = tess.builder
+
+	builder.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.POSITION_COLOR)
+
+	for (i in 0 ..< width.toInt()) {
+		val x = x + i.toFloat()
+
+		for (j in 0 ..< height.toInt()) {
+			val y = y + j.toFloat()
+
+			if ((i + j) % 2 == 0) {
+				builder.vertex(matrix, x, y + 1f, z).color(color).endVertex()
+				builder.vertex(matrix, x + 1f, y + 1f, z).color(color).endVertex()
+				builder.vertex(matrix, x + 1f, y, z).color(color).endVertex()
+				builder.vertex(matrix, x, y, z).color(color).endVertex()
+			}
+		}
+	}
+
+	tess.end()
+}
+
+fun GuiGraphics.renderCheckerboard(
+	x: Float,
+	y: Float,
+	width: Float,
+	height: Float,
+	z: Float = 0f,
+	color: RGBAColor = RGBAColor.WHITE
+) {
+	renderCheckerboard(pose().last().pose(), x, y, width, height, z, color)
+}
+
 fun renderTexturedRect(
 	matrix: Matrix4f,
 	x: Float,

src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/decorative/PainterScreen.kt

@@ -13,6 +13,7 @@ import net.minecraftforge.registries.ForgeRegistries
 import ru.dbotthepony.mc.otm.block.entity.decorative.PainterBlockEntity
 import ru.dbotthepony.mc.otm.client.render.FlatRectangleIcon
 import ru.dbotthepony.mc.otm.client.render.ItemStackIcon
+import ru.dbotthepony.mc.otm.client.render.renderCheckerboard
 import ru.dbotthepony.mc.otm.client.render.renderRect
 import ru.dbotthepony.mc.otm.client.screen.MatteryScreen
 import ru.dbotthepony.mc.otm.client.screen.panels.Dock
@@ -53,13 +54,7 @@ class PainterScreen(menu: PainterMenu, inventory: Inventory, title: Component) :
 
 			val color = RGBAColor.rgb(dye?.textColor ?: DyeColor.LIGHT_BLUE.textColor)
 
-			val bgColor = color.copy(alpha = 0.25f)
+			graphics.renderCheckerboard(0f, 0f, width, height, color = color.copy(alpha = 0.25f))
-			for (x in 0 ..< width.toInt()) {
-				for (y in 0 ..< height.toInt()) {
-					if ((x + y) % 2 == 0)
-						graphics.renderRect(x.toFloat(), y.toFloat(), 1f, 1f, color = bgColor)
-				}
-			}
 
 			val multiplier = menu.dyeStoredDirect[dye]!!.toFloat() / (if (dye == null) PainterBlockEntity.MAX_WATER_STORAGE.toFloat() else PainterBlockEntity.MAX_STORAGE.toFloat())
 			graphics.renderRect(0f, height * (1f - multiplier), width, height * multiplier, color = color)