Extra-Sensory Perception (ESP) hacks are a type of game hack that involve showing information to the player that they would not normally see. For example, these types of hacks might display an enemies’ position, their distance from the player, their health, what weapon they are using, and so on. They can also be more elaborate and change the enemies’ model to a more visible color, or draw a bounding box around them. This is all done with the purpose of providing the player with additional information that would not normally be visible to them. A few examples of ESP hacks are shown below which demonstrate this.
This next series of posts will go over how these hacks are created and provide a working proof of concept for an ESP targeting Half-Life 2. The series will start off by talking about a world-to-screen transformation: how models with a three dimensional position in the world get transformed to a two dimensional x and y coordinates system on your screen. Having established that, the series will then go over how to draw information on the game’s screen, and wrap up by showing an ESP proof of concept that draws some text over enemy models.
These posts will heavily leverage what was covered in the creating an aimbot series. It is recommended to read that first to get a better understanding of the Source SDK. Code from that series will also be heavily re-used for this series.
A link to each post is provided below: