text renderer: fix crash when text starts with newline + tests

src/integration-test/kotlin/de/bixilon/minosoft/gui/rendering/font/renderer/component/ChatComponentRendererTest.kt

@@ -444,5 +444,25 @@ class ChatComponentRendererTest {
         )
     }
 
+    fun `first line blank`() {
+        val text = TextComponent("\nbcd")
+
+        val info = render(text)
+        info.assert(lineIndex = 1, size = Vec2(5.0f, 22.0f), lines = listOf(
+            LineRenderInfo(BaseComponent(), 0.0f),
+            LineRenderInfo(BaseComponent(TextComponent("bcd")), 5.0f),
+        ))
+    }
+
+    fun `first component blank`() {
+        val text = BaseComponent(TextComponent("\n"), TextComponent("bcd"))
+
+        val info = render(text)
+        info.assert(lineIndex = 1, size = Vec2(5.0f, 22.0f), lines = listOf(
+            LineRenderInfo(BaseComponent(), 0.0f),
+            LineRenderInfo(BaseComponent(TextComponent("bcd")), 5.0f),
+        ))
+    }
+
     // TODO: shadow, formatting (just basic, that is code point renderer's job)
 }

src/main/java/de/bixilon/minosoft/gui/rendering/font/renderer/element/TextRenderInfo.kt

@@ -30,11 +30,11 @@ class TextRenderInfo(
         size.x = maxOf(offset.offset.x - offset.initial.x + width, size.x)
 
         val line: LineRenderInfo
-        if (lineIndex == 0 && lines.isEmpty()) {
+        if ((lineIndex == 0 && lines.isEmpty()) || lineIndex >= lines.size) {
             // first char of all lines
             line = LineRenderInfo()
             lines += line
-            size.y = properties.lineHeight
+            size.y += properties.lineHeight
         } else {
             line = lines[lineIndex]
         }