Most CoD2 wallhacks functioned using a technique called . The cheat would replace or "hook" into the game's core graphics library (opengl32.dll). By injecting its own code, the hack could intercept and alter the rendering pipeline, instructing the GPU to draw enemy models even when they were hidden behind walls. This was achieved by disabling the depth test (z-buffer) that normally instructs the engine which objects are in the foreground and which are behind obstacles.
Elias smirked. By the tenth round, the praise turned to suspicion. He was tracking movements with impossible precision, snapping his crosshairs onto targets before they even emerged from the fog of war. He was playing a different game—a game of geometry and silhouettes, while everyone else was playing a game of luck and reflexes. CoD2 Wallhack