[text_renderer] fixed a nasty gpu crash (device lost) which was cause…

…d whenever the internal string buffer got resized coz it needs more space. the new string_locators in the expanded buffer did not have their memory zero'd, causing them to have indeterminate values and causing the compute shader to iterate over them and read garbage memory (and then go on to read out of bounds which causes a device-lost)

src/tz/ren/text.cpp

@@ -317,13 +317,22 @@ namespace tz::ren
 		{
 			return;
 		}
+		std::vector<string_locator> new_empties;
+		new_empties.resize(string_count - old_cap);
+		std::span<const string_locator> new_empties_span = new_empties;
 		tz::gl::get_device().get_renderer(rh).edit(
 			tz::gl::RendererEditBuilder{}
 			.buffer_resize
 			({
 				.buffer_handle = this->string_buffer,
 				.size = string_count * sizeof(string_locator)
 			})
+			.write
+			({
+				.resource = this->string_buffer,
+				.data = std::as_bytes(new_empties_span),
+				.offset = old_cap * sizeof(string_locator),
+			})
 			.build()
 		);
 		tz::gl::get_device().get_renderer(ch).edit(