add support for resetting the imgui renderer's texture map

ggdt_imgui/src/renderer.rs

@@ -2,13 +2,7 @@ use ggdt::graphics::{BlendFunction, RgbaBitmap, RgbaPixelFormat, RGBA};
 use ggdt::math::{Rect, Vector2};
 use imgui::internal::RawWrapper;
 
-#[derive(Debug)]
-pub struct Renderer {
-	pub texture_map: imgui::Textures<RgbaBitmap>,
-}
-
-impl Renderer {
-	pub fn new(context: &mut imgui::Context) -> Self {
+fn create_default_texture_map(context: &mut imgui::Context) -> imgui::Textures<RgbaBitmap> {
 	let mut texture_map = imgui::Textures::new();
 
 	// set up a bitmap with the imgui font atlas texture pixels and register a bitmap->texture mapping for it
@@ -25,7 +19,17 @@ impl Renderer {
 		.unwrap(),
 	);
 
-		Renderer { texture_map }
+	texture_map
+}
+
+#[derive(Debug)]
+pub struct Renderer {
+	pub texture_map: imgui::Textures<RgbaBitmap>,
+}
+
+impl Renderer {
+	pub fn new(context: &mut imgui::Context) -> Self {
+		Renderer { texture_map: create_default_texture_map(context) }
 	}
 
 	pub fn render(&mut self, draw_data: &imgui::DrawData, dest: &mut RgbaBitmap) {
@@ -81,4 +85,8 @@ impl Renderer {
 		}
 		dest.set_clip_region(&original_clip_rect);
 	}
+
+	pub fn reset_textures(&mut self, context: &mut imgui::Context) {
+		self.texture_map = create_default_texture_map(context);
+	}
 }