• "Advanced VR Rendering Performance", Game Developers Conference 2016, Alex_Vlachos_Advanced_VR_Rendering_Performance_GDC2016.pdf (14.7 MB)
  Live video of presentation: http://www.gdcvault.com/play/1023522/Advanced-VR-Rendering
  
• "Advanced VR Rendering", Game Developers Conference 2015, Alex_Vlachos_Advanced_VR_Rendering_GDC2015.pdf (8.5 MB)
  Live video of presentation: http://www.gdcvault.com/play/1021771/Advanced-VR
  
• "Water Flow in Portal 2", SIGGRAPH 2010, Vlachos-SIGGRAPH10-WaterFlow.pdf (6.3 MB)
  
• "Rendering Wounds in Left 4 Dead 2", Game Developers Conference 2010, Vlachos-GDC10-Left4Dead2Wounds.pdf (4.3 MB)
  
• "Post Processing in The Orange Box", Game Developers Conference 2008, Vlachos-GDC08-PostProcessingInTheOrangeBox.pdf (3 MB)
  
• "Advanced OpenGL Techniques", Apple Worldwide Developers Conference (WWDC) 2003
  
• "Designing a Portable Shader Library for Current & Future API's", Game Developers Conference 2003
  
• "Advanced Visual Effects with Direct3D", Game Developers Conference 2003
  
• "Fur, Bumps, and Shadows", Game Developers Conference Europe 2002, London, England, Vlachos-GDCE02-FurBumpsShadows.pdf (4.9 MB)
  
• "Designing a Shader Library for Current & Next Generation Hardware", Game Developers Conference 2002
  
• "Preparing Sushi: Graphics Engine for ATI's Demos", Game Developers Conference Europe 2001, London, England
  
• "Curved PN Triangles", 2001 ACM Symposium on Interactive 3D Graphics, CurvedPNTriangles.pdf (3MB)
  
• "Volume Textures and DirectX 8 N-Patches", Microsoft Meltdown Seattle 2000
  
• "DirectX 8 Higher-Order Surfaces", Game Developers Conference 2000
  
• "Using the Direct3D Pixel Pipeline to Evaluate Classical Lighting Equations", Microsoft Meltdown UK 1999, London, England
  

PUBLICATIONS:

• Graphics Section Editor, Game Programming Gems 4, Vlachos, 2004
• "Carving Static Shadows into Geometry", Game Programming Gems 4, Vlachos, 2004
• "Adjusting Real-Time Lighting for Shadow Volumes and Optimized Meshes", Game Programming Gems 4, Vlachos, Oat, 2004
• "Real-Time Motion Blur", ShaderX 2, Isidoro, Tatarchuk, Brennan, Vlachos, 2003
• "Computing Optimized Shadow Volumes", Game Programming Gems 3, Vlachos, Card, 2002
• "Solving Functions with Textures", Game Programming Gems 3, Vlachos, Isidoro, Oat, 2002
• "Rendering Ocean Water", ShaderX, Isidoro, Vlachos, Brennan, 2002
• "Rippling Reflective and Refractive Water", ShaderX, Vlachos, Isidoro, Oat, 2002
• "Texturing Terrain Using Pixel Shaders", ShaderX, Vlachos, 2002
• "UV Flipping Technique to Avoid Repetition", ShaderX, Vlachos, 2002
• "Smooth C2 Quaternion-Based Flythrough Paths", Game Programming Gems 2, Vlachos, Isidoro, 2001
• "Self-Shadowing Characters", Game Programming Gems 2, Vlachos, Gosselin, Mitchell, 2001
• "Approximating Fish Tank Refractions", Game Programming Gems 2, Vlachos, 2001
• "Rendering Print Resolution Screenshots", Game Programming Gems 2, Vlachos, Hart, 2001
• "Curved PN Triangles", 2001 ACM Symposium on Interactive 3D Graphics, Vlachos, Peters, Boyd, Mitchell, 2001 CurvedPNTriangles.pdf (3MB)
• "Refraction Mapping for Liquids in Containers", Game Programming Gems, Vlachos, Mitchell, 2000

PATENTS:

• U.S. Patent No. 11,482,142, "Light Leak Correction For Mixed Reality Devices", Microsoft
  
• U.S. Patent No. 10,733,783, "Motion smoothing for reprojected frames" (SteamVR Motion Smoothing), Valve
  
• U.S. Patent No. 10,600,236, "Prediction and throttling adjustments based on application rendering performance" (SteamVR scheduling), Valve
  
• U.S. Patent No. 10,520,739, "Dynamic panel masking" (VR rendering technique to hide strobing artifacts during reprojection on the leading edge of the panels during head rotation), Valve
  
• U.S. Patent No. 10,311,540, "Radial density masking systems and methods" (VR rendering technology to increase performance by reducing the number of pixels rendered at the periphery), Valve
  
• U.S. Patent No. 10,297,077, "Hidden area stencil mesh rendering systems and methods" (SteamVR Hidden Area Mesh), Valve
  
• U.S. Patent No. 10,241,566, "Sensory feedback systems and methods for guiding users in virtual reality environments" (SteamVR Chaperone System), Valve
  
• U.S. Patent No. 7,145,564, "Method and apparatus for tessellation lighting", ATI
  
• U.S. Patent No. 6,940,503, "Method and apparatus for processing non-planar video graphics primitives," (Curved PN Triangles / N-Patches), ATI
  

EDUCATION: Boston University, Boston, MA. Bachelor of Science (BS), Computer Science (May 1997).

Meta, Software Architect, Redmond, WA

Jan 2024 - Present

Working on mixed reality devices

Microsoft, Partner Architect, Redmond, WA

Jan 2020 - Oct 2023

Worked in Microsoft Mixed Reality on AR and VR products including HoloLens 2, HP Reverb G2, etc.

Valve, Software Architect, Seattle, WA

Oct 2006 - Sep 2019

Notable Projects: SteamVR: Compositor, Chaperone, and other runtime systems (2015-2019) SteamVR Media Player (2017) Dota VR (2016) - First shown at The International Dota 2 Championships 2016 The Lab (2016) The Lab Renderer for Unity (2016) Aperture Science Robot Repair (2014-2015) - HTC Vive VR launch demo first shown publicly at GDC 2015 Dota 2 (2013) Counter-Strike: Global Offensive (2012) Portal 2 (2011) Left 4 Dead 2 (2010) Left 4 Dead (2009) Source 2 rendering systems (2009-2012) Team Fortress 2 (2006-2008) Portal (2006-2008) Half-Life 2: Episode Two (2006-2008) VR Technology Highlights: Motion Smoothing Asynchronous Reprojection Scheduling & Running Start Adaptive Quality SteamVR Auto Resolution Ghost Correction Panel Masking Edge Focal Blur Dynamic Panel Masking Hidden Area Mesh Supersample Filtering Multi-GPU Rendering Algorithms for 2 and 4 GPUs Fixed Foveated Rendering Radial Density Masking Specular Antialiasing Using Roughness Filtered Mip Chains Geometric Specular Antialiasing

Naughty Dog, Lead Visual Effects Programmer, Santa Monica, CA

March 2005 - Oct 2006

I contributed to Uncharted: Drake's Fortune as the Lead Visual Effects Programmer focusing on rendering and shader development.

Game Development Start-up, Boston, MA

Jan 2004 - Feb 2005

I was part of a start-up developing a game prototype for the Sony PSP.

ATI, Lead Programmer, Demo Team & 3D Application Research Group, Boston, MA

Nov 1998 - Jan 2004

RADEON X800 Demo Suite - Lead Programmer & Technical Director:

• Ruby: The Double Cross - This demo was the main launch demo for ATI's latest graphics chip, the RADEON X800. It was also featured at the SIGGRAPH 2004 Animation Theater

• Chimp Demo
• Gargoyle Screen Saver
• Caves Screen Saver
• Engine compiles for DirectX 9.0, OpenGL for Windows, and OpenGL for Mac

• Animusic's Pipe Dream Demo - Showcases Shadow Cutting, a technique I developed and published in Game Programming Gems 4, to be released at GDC 2004.
• Paul Debevec's Rendering With Natural Light in Real-Time
• Car Paint Demo
• Bear with Real-Time Fur Demo
• Non Photorealistic Rendering - Hatch style of rendering
• Dogs Screen Saver
• Bacteria Screen Saver
• Moebius Strip Screen Saver
• Engine compiles for DirectX 9.0, OpenGL for Windows, and OpenGL for Mac

• Implemented full scene stencil shadow volumes, published in Game Programming Gems 3.
• Engine utilizes an advanced shader system for setting all rendering state and loading all vertex and pixel shaders.
• Used multiple renderable textures to render realistic reflective and refractive water.
• Visibility culling is octree based.
• Targeted DirectX 8.1 vertex shaders v1.1 and pixel shaders v1.4
• Engine compiles for DirectX 8.1, OpenGL for Windows, and OpenGL for Mac
• Presented the methods used in this engine at Game Developers Conference Europe 2001
• Published many of the techniques implemented in this project in two books: Game Programming Gems 3, ShaderX.

• Developed the Microsoft DirectX 8 N-Patch higher-order surface. Composed a method to compute a cubic triangular Bezier control mesh based on point and normal information for an arbitrary triangle. This surface is an interpolating, triangular surface that has little impact on the graphics API's and game developers, while giving them improved silhouettes and a closer approximation to Phong shading. Publication: "Curved PN Triangles".

• Designed and implemented a portal-based visibility engine
• 3D Studio MAX 2.5 & 3.1 Plug-ins -- Developed all of the pre-process tools necessary for pre-compiling the scene data.
• Environment Mapped Bump Mapping -- Implemented planar, bumped reflections using a renderable texture updated on a per-frame basis. This technique was used on floors and walls in the engine.
• Glass Reflections -- This is a very interesting problem. The solution implemented is to render the reflections in the glass to a texture and texture the glass from that.
• Dual Paraboloid Environment Mapping -- A viewer independent version of spherical environment mapping. Devised a single-pass method using only 2 multi-texture units.
• Emboss Bump Mapping -- Further developed research on this topic and implemented a numerically correct, single-pass, multi-texture method using only 2 texture units.
• Detail Texturing -- Implemented both Add-Signed and Modulate 2X versions for a side-by-side comparison demo.
• Collision detection -- Object vs. scene, generalized sphere-polygon detection.
• Automated fly through paths based on cubic spline interpolation for position and orientation using quaternions.
• Light map paging
• Water refraction algorithm -- This technique was published in the book, Game Programming Gems, released in 2000

• Authored and implemented tuning algorithms and response curves to optimize the feel of the SpaceOrb.
• Developed the SpaceOrb 360 SDK that included a GUI for creating joystick configuration files.
• Released software patches and game support updates in a timely manner as new games were released.

• Designed and developed an MFC dialog-based GUI. Compiled for Intel and Alpha architectures for Windows 95, 98, NT 4, and 2000.
• Authored and implemented runtime tuning algorithms and filtering methodology of Spaceball data.