C++

In the last G-Engine post, we got the game loop and frame “delta time” calculations working. We’ve now got a blank, empty game window - yay? Despite the unimpressive result, we’ve got a beating heart under the hood: an update loop being called at roughly 60 frames per second.

Empty windows are no fun, so my next goal is to get something - anything - rendering in the game window. Graphics are a vital and exciting part of any game, and rendering provides us vital visual feedback as we move on to implementing and debugging 3D object placement, cameras, rotations, and data loading for 3D meshes and animations.

This post will focus on rendering a single triangle on screen. Though the result is simple, we’ll cover a lot of ground towards building a 3D rendering system that will be extended and enhanced as we move forward.

In my last G-Engine post, I did some setup work and finally got a basic OS window appearing that could be moved around, minimized/maximized, and closed. Good start!

In this post, we’ll do a bit more planning, and then we’ll structure our code into a high-level class (GEngine) that’ll be more conducive to building an engine than just shoving everything into the main function. We’ll also implement our “delta time” calculations, which will be critical for updating the state of our game as we move forward.

The previous post introduced the G-Engine project. So here we are, ready to build a 3D game engine! This post walks through some early decisions, starting from absolutely nothing to having just an empty application window that can be moved around and closed.

This is not the most exciting end result, but there are plenty of important decisions to be made before we dig into actually writing game engine code.

Standard C++ containers (or collections) are essential tools. Some, like vector, queue, deque, and stack are list-like: elements are accessed by position. Others, such as map or set, are more associative in nature: elements are accessed by a key.

To add an object to a vector, you can call insert or push_back. Stacks and queues both allow you to add elements using push. Map allows insertions with insert or using the [ ] operator.

In C++11 and beyond, all these containers have new functions that seem to behave similarly to the above methods: emplace, emplace_back, and emplace_front.

Which begs the question: what’s the difference between these different methods of adding items to collections?