defer texture atlas update to start of frame

com/danitheskunk/skunkworks/GLTextureAtlas.java

@@ -13,6 +13,7 @@ import static org.lwjgl.opengl.GL11.*;
 
 class GLTextureAtlas {
 	private Image img;
+	boolean shouldUpdate;
 	private int textureID;
 	private List<GLTexture> textures;
 
@@ -20,6 +21,7 @@ class GLTextureAtlas {
 		img = new Image(new Vec2i(32, 32));
 		textureID = glGenTextures();
 		textures = new ArrayList<>();
+		shouldUpdate = false;
 
 		glBindTexture(GL_TEXTURE_2D, textureID);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
@@ -32,9 +34,7 @@ class GLTextureAtlas {
 		//this.img = img;
 		var texture = new GLTexture(new Recti(new Vec2i(0, 0), img.getSize()), img);
 		textures.add(texture);
-		repack();
-		updateImage();
-		uploadToGpu();
+		shouldUpdate = true;
 		return texture;
 	}
 
@@ -43,6 +43,14 @@ class GLTextureAtlas {
 		System.out.printf("Resized atlas to %dx%d\n", img.getSize().getX(), img.getSize().getY());
 	}
 
+	public void update() {
+		if(shouldUpdate) {
+			repack();
+			updateImage();
+			uploadToGpu();
+			shouldUpdate = false;
+		}
+	}
 	void repack() {
 		int x = 0;
 		int y = 0;

com/danitheskunk/skunkworks/GLWindow.java

@@ -92,6 +92,7 @@ public class GLWindow implements IWindow {
 
 	@Override
 	public IRenderContext renderStart() {
+		textureAtlas.update();
 		glClearColor(0.1f, 0.2f, 0.3f, 1.0f);
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 		glBegin(GL_TRIANGLES);