SungJinKang SungJJinKang

CUSTOM GAME ENGINES: A Small Study

A couple of weeks ago I played (and finished) A Plague Tale, a game by Asobo Studio. I was really captivated by the game, not only by the beautiful graphics but also by the story and the locations in the game. I decided to investigate a bit about the game tech and I was surprised to see it was developed with a custom engine by a relatively small studio. I know there are some companies using custom engines but it's very difficult to find a detailed market study with that kind of information curated and updated. So this article.

Nowadays lots of companies choose engines like Unreal or Unity for their games (or that's what lot of people think) because d

Volumetric Clouds Resources List

A. Schneider, "Real-Time Volumetric Cloudscapes," in GPU Pro 7: Advanced Rendering Techniques, 2016, pp. 97-127. (Follow up presentations here, and here.)
S. Hillaire, "Physically Based Sky, Atmosphere and Cloud Rendering in Frostbite" in Physically Based Shading in Theory and Practice course, SIGGRAPH 2016. [video] [course notes] [scatter integral shadertoy]
[R. Högfeldt, "Convincing Cloud Rendering – An Implementation of Real-Time Dynamic Volumetric Clouds in Frostbite"](https://odr.chalmers.se/hand

GPU Optimization for Games

By person (random order)

Emil Persson @Humus
- Blog
- <2013> Low-Level Thinking in High-Level Shading Languages
- <2014> Low-Level Shader Optimization for Next-Gen and DX11
- <2018> Rule of optimization
Matt Pettineo @mynameismjp

GPU Optimization for GameDev

Graphics Pipeline / GPU Architecture Overview

2011 - A trip through the Graphics Pipeline 2011
2015 - Life of a triangle - NVIDIA's logical pipeline
2015 - Render Hell 2.0
2016 - How bad are small triangles on GPU and why?
2017 - GPU Performance for Game Artists
2019 - Understanding the anatomy of GPUs using Pokémon
2020 - GPU ARCHITECTURE RESOURCES

Exploiting a Stack Buffer Overflow (return-to-libc attack)

A stack buffer overflow occurs when a program writes to a memory address on it's call stack outside of the intended structure / space.

In this walk-through, I'm going to cover the ret2libc (return-to-libc) method. This method of exploitation is great because it doesn't require the use of your typical shellcode. It involves making sys calls to the functions provided to us by libc (standard c library). We're going to use the system and exit sys calls for demonstration.

To have a good understanding about how stack overflows work, it's extremely helpful to know how stack data structures work, and more importantly - how the call stack works. For the sake of time, I'm not going to type out how these two things work in great detail. If you want to know how these work, I would recommend watching stack and call stack.

Creating a vulnerable binary to test

Papers I like Pt. 1 Papers I like Pt. 2

Let's start meta:

Lamport - State the Problem Before Describing the Solution (1978). … 1-page memo. Read it.
Herlihy - Wait-free synchronization (1991) … Truly seminal. Lucid + enough good ideas for 4 papers easily.
Cook - How complex systems fail (1998) … 4 pages that anyone working on/with complex systems should read.

	//==============================================================================================================================
	// An optimized AMD FSR 1.0 implementation for Mobiles
	// EASU and RCAS are combined in a single pass.
	// Based on https://github.com/GPUOpen-Effects/FidelityFX-FSR/blob/master/ffx-fsr/ffx_fsr1.h
	// Details can be found: https://atyuwen.github.io/posts/optimizing-fsr/
	// Distributed under the MIT License. Copyright (c) 2021 atyuwen.
	// -- FsrEasuSampleH should be implemented by calling shader, like following:
	// AH3 FsrEasuSampleH(AF2 p) { return MyTex.SampleLevel(LinearSampler, p, 0).xyz; }
	//==============================================================================================================================
	void FsrMobile(

	#include <fcntl.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <string.h>
	#include <sys/ioctl.h>
	#include <unistd.h>

	#define ADRENO_IOC_TYPE 0x09

	#define ADRENO_PERFCOUNTER_GROUP_SP 0xA

	In shader programming, you often run into a problem where you want to iterate an array in memory over all pixels in a compute shader
	group (tile). Tiled deferred lighting is the most common case. 8x8 tile loops over a light list culled for that tile.

	Simplified HLSL code looks like this:

	Buffer<float4> lightDatas;
	Texture2D<uint2> lightStartCounts;
	RWTexture2D<float4> output;

	[numthreads(8, 8, 1)]