Houman Meshkin
houmany@hotmail.com
http://www.houmany.com/
Resume also available in doc format and pdf format
Technical Skills
Programming Languages:
C/C++, Objective C, Python, C#, Java, ActionScript 3, ARMv7/8 asm (Neon), Pentium asm (SIMD: SSE, MMX), PowerPC and Altivec VMX intrinsics, STL, Boost, HLSL, GLSL, Cg, DirectX shader assembler, PlayStation2 MIPS assembly, VU microcode and MMI, Xbox pixel shader combiners, HTML/CSS, CGI, JavaScript, Unix C-Shell, Lisp (Scheme), BASIC
Tools/Libraries:
DirectX 8-11, OpenGL ES 2/3, Flash 11/Stage3D, Unity 3D, Unreal Engine, libgcm & libspurs (PS3), RenderWare, IrisGL, Glide (3dfx raster library), MS Visual Studio/Visual C++, Xcode, Android Studio, IntelliJ, FlashBuilder, Xamarin, CodeWarrior, Perforce, SVN, Git, Emacs, VTune, PIX (PC, Xbox 360), Instruments, GPAD & SN Tuner (PS3)
Operating Systems:
Windows, Mac OS, DOS, Linux, Unix, iOS, Android
Work Experience
10/14 – present: ATAP Performer, Google (Advanced Technology and Projects) - Mountain View, CA
SpotlightStories 3D interactive story telling on Android, iOS and VR
- Novel 360 panoramic video format (CubeRect) - codec and renderer
- improved quality and reduced bandwidth relative to equirectangular video
- Multi-platform rendering engine improvement and maintenance
- features, performance, architecture, parallelism
- Android and iOS profiling and optimizations (CPU and GPU)
- Shader optimizations, ARMv7 and ARMv8 Neon asm micro-optimizations
- Porting 32-bit Android app to 64-bit architecture and iOS
- Streaming video player (iOS, Android and Mac)
- Supports hardware decoding and OpenGL rendering of videos
R&D
- Depth buffer compression algorithm (for compositing, relighting, etc.)
- Variable compression, fast decompression
8/11 – 10/14: Lead Graphics Engineer, Rumble Entertainment - San Mateo, CA
Kings Road high-end online game for browsers and mobile devices
- 3D rendering pipeline using Flash 11 Stage3D for hardware accelerated 3D graphics in a browser
- Deferred shading for dynamic lighting
- Streaming of large detailed worlds encoded into multiple textures (depth & color)
- Developed depth encoding algorithms, to store world depth with very low memory usage
- Math libraries in ActionScript 3 (vector, matrix, quaternion, dual-quaternion)
- Asynchronous asset loading (worker objects time sliced from main frame time)
- Shader tool for converting HLSL shaders to AGAL shaders for Stage3D, and GLSL for mobile
- Various shaders and permutations for skinned characters, environment, water, world objects, etc.
- Visual effects pipeline, GPU particles, animated sprites, refraction effects, emissive effects
- Post processing filters, including bloom, blur, vignette, color adjustment, S-curve tone adjustment
- Profiling, optimizations, and compatibility on various platforms (Windows, Mac, iOS) and browsers
- Wrote various art pipeline tools (depth encoding, vfx editing, image processing, mesh and animation compression)
4/10 – 8/11: Principal Graphics Engineer, Turbine (Warner Bros) – Boston, MA (working remote from CA)
Lord of the Rings Online and Dungeons & Dragons Online Massively Multiplayer Online (MMO) games for the PC
- Multi-platform rendering support, including PC DX9, DX10, DX11, PS3 and Xbox 360
- Optimizations of various components, including skinning, rendering pipeline, core parallelism
- Vertex compression improvements on all platforms
- Created a framework for asynchronous SPURS job management
- Synchronization between PPU (core CPU), RSX (GPU), and 6 SPUs
- SPU skinning and culling with Edge libraries
- Architected new shader system, with more code sharing, fewer permutations, and more features
- Implemented HDR rendering pipeline for all platforms, with gamma correct rendering
- Created a post processing system, to enable us to more easily add new filters
- Investigation of features to improve the graphics and performance of our engine
12/09 – 2/10: Chief Technology Officer, VisiDeck – Warrington, UK (working remote from CA)
Real-time visualization software and services
- Analyzed various game engines to find best fit for our requirements and needs
- Competitive analysis, to ensure we provide a better product and services
- Responsible for most of our software and tools development and features
- Miscellaneous fire fighting, helping with asset creation, video presentations, etc.
10/07 – 12/09: Principal Graphics Engineer, Shaba Games (Activision)– San Francisco, CA
7/09: DJ Hero for Xbox 360 and PlayStation3
- various rendering optimizations
- eliminated CPU and GPU stalls on the Xbox 360 for improved parallelism
- implemented and improved some post processing filter effects for Xbox 360 and PS3
10/08: Spiderman: Web of Shadows for Xbox 360 and PlayStation3
- improved and maintained rendering pipeline and shader architecture
- optimized graphics pipeline and shaders
- implemented HDR rendering, with high quality bloom and tone mapping
- implemented new post processing system, with numerous filters, including depth-of-field and radial blur
- added more realistic lighting via image-based lighting techniques
- responsible for the majority of the PlayStation3 graphics, nearly full parity with Xbox 360 graphics
- SPU code improvement and increased utilization to relieve the PPU
Graphics R&D
- efficient deferred lighting, supporting 100s of light sources and still maintaining framerate
- experimented with tiled lighting and pass per light with stenciling
- real-time computation of line light sources, can be later extended to area light sources
- multiple methods of doing real-time ambient occlusion in screen space
- vector and matrix library fully optimized using Altivec VMX intrinsics
8/05 - 9/07: Senior Graphics Engineer, Perpetual Entertainment - San Francisco, CA
Gods & Heroes - Rome Rising: Massively Multiplayer Online (MMO) game for the PC
- mainly responsible for the rendering pipeline and shader architecture
- improved shadow rendering algorithm by increasing effective resolution of the shadow map
- post-process filtering architecture for easily adding post-render full screen effects (e.g. bloom, radial blur)
- extensive profiling and optimizations of various systems (shaders, rendering pipeline, vector, matrix and math libraries, etc.)
- geometry batching for reduced D3D draw calls, which leads to higher performance
- geometry compression for saving memory
- re-designed the shader architecture and replaced RenderWare's D3D rendering structures
- memory usage optimizations, memory managing, memory tracking
- numerous profiling and visual debugging tools to help programmers and artists improve the game
- multi-threaded asynchronous asset loading / streaming, highly optimized with minimal thread contention
- fully memory mapped file system, with and without packed files, with optional compression
7/00 - 8/05: Senior Graphics Technology Engineer, Rainbow Studios (THQ) - Phoenix, AZ (remote office in Emeryville, CA)
Shipped games:
multi-platform rendering engine (PS2, Xbox, PC):
- shader architecture enabling hundreds of combinations of shaders
- VU1 microcode for PS2, DirectX shaders for Xbox and PC
- shader generators used to maximize code sharing, and minimize rewrites
- one can easily and quickly create a new shader for a new effect
- various lighting techniques (diffuse, specular, iridescent, etc.)
- various texture mappings (environment mapping, projected texturing, etc.)
- terrain renderer microprograms
- vector and matrix library (highly optimized for Pentium3/Xbox using SSE and for the PS2 using VU and MMI)
- quaternion library
- math library
- code optimization (algorithmic optimizations and instructional optimizations using Pentium and MIPS assembly, SSE, VU, MMI)
- portals for visibility culling
- hierarchy of matrices and bounding boxes for models
- wake water physics simulation optimization in SSE
- VU0 micromode vector and matrix library (runs in parallel with CPU)
- octree spatial subdivision for fast scene search and traversal
- efficient triangle stripping and vertex caching algorithm
- shader convertor that takes PS2 multi-pass blended shaders into single pass Xbox pixel shader combiners (highly optimized)
3D graphics research and development: [demos]
- Procedurally generated and animated clouds and smoke volumes
- Dynamically renders and animates layers of clouds using dynamically generated noise
- Smoke volume represented as slices of a procedurally generated noise volume texture
- Post-processing filter architecture
- Highly optimal and extensible system for rendering multiple filter passes
- Includes filters such as bloom, Gaussian blur, radial blur, spherize, and noise
- Multiple detail layered terrain rendering
- Spline for low frequency hill details
- Displacement map for next level of details
- Bumpmap for finer details
- Procedural noise textures for minute details, with numerous levels of detail
- Water simulation and rendering on the GPU
- Computes motion of water with forces applied to it as a spring based force simulation
- Renders water as a dynamically displaced height field
- Sort independent alpha blending
- Dissecting the alpha blend formula and using higher precision render targets
(16-bits per channel) we can achieve a close approximation to the final
color of multiple passes of alpha blending without having to do any sorting
- Bicubic spline surface rendering
- renders bicubic Catmul-Rom spline surface
- could render different uniform splines just by changing basis function matrix
- dynamic lod tesselation
- each surface patch has 4 edge lods and a separate center lod, to avoid cracks between adjacent patches with different lods
- Deferred lighting
- uses floating-point render targets and cube texture maps, in addition to multiple render targets
- per-pixel lighting and shadowing for multiple point light sources done as a fullscreen post process
- depth buffer shadow mapping supports self shadowing, and works in a single pass for 4 lights, computed at the same time as the lighting
- Procedural texture mapping
- procedurally generated noise texture maps
- completely generated in a pixel shader
- pixel shader generates random colors and computes noise function
- virtually unlimited texture resolution at essentially zero memory cost
- Procedural volumetric lightmap with bumpmapping and offset displacement mapping
- per-pixel lighting for 8 point lights
- volumetric lightmap generated procedurally in pixel shader
- texture coordinates are moved away from view direction to give a visual effect of per-pixel depth using a displacement map (matching the normal map used for the bumpmap lighting)
- Shadow mapping
- depth buffer shadow mapping with self shadowing
- improved perceptual resolution with a trapezoidal projection warping
- multiple levels of percentage closest filtering (PCF) for smoother shadow edges
- Displaced subdivision surface
- subdivision surface with displacement mapping
- triangles are treated as barycentric Bézier patches
- Slick surface
- surface defined by a displaced cylindrical shape following a cubic Cardinal spline as the center axis
- each section of the base spline is tesselated by a section of a displaced, scaled and twisted cylinder
- Displacement mapping
- mapping a displacement to an arbitrary triangle
- normals are quickly and efficiently interpolated across the triangle, using spherical linear interpolation (quaternions)
- interpolated normals don't require re-normalization
- almost all work is done on the GPU, including transformation to tangent space, displacement, and surface normal computation from the displaced surface
- CPU is only used for tesselation (dynamic), displacement map lookup, and normal interpolation
- next generation shader model 3.0 will allow texture lookup in vertex shaders, which will further speed up performance
- DX9 shader effects
- uses HLSL shader language
- per-pixel effects, including bumpmapped lighting, bumpy environment mapping, parallax displacement mapping
2/98 - 7/00: Software Engineer, 3dfx Interactive Inc. - San Jose, CA
3D graphics research and development: [demos]
- Donut demo:
multi-texturing techniques - environment mapping, bump mapping, specular lighting
- Surf Demo:
rendering spline surfaces (B-Spline and Bézier) with dynamic level of detail patch tessellation
- Scene Renderer:
fast high polygon scene rendering (highly optimized for PentiumIII KNI SIMD)
- Displacement mapping:
mapping a height field to an arbitrary quad (using quaternions to interpolate the normals)
- Terrain Engine:
rendering a uniform height field terrain
- Water Simulation:
simulates the motion of water using a highly tessellated grid
- Skinned Animation:
vertex animation using hierarchical bones and weighted vertices for organic animation effects
- Lightmapping:
lightmaps generated from multiple dynamic colored light sources
- Shadow Volume:
real-time pixel accurate shadow casting algorithm
Game porting/helping:
- Unreal: helped make the game run properly on Voodoo Rush
- Half-Life: ported the MiniGL version of the game to Glide3; also added detail texturing
Driver work:
- 3dfx Splash Screen: added clipping, anti-aliasing, lighting, and environment mapping; minor optimizations
- MiniGL driver: unifying the MiniGL for all MiniGL based games; helping with AMD’s 3DNow optimizations
1/96 - 1/98: Software Engineer, Cyclone Studios (a subsidiary of 3DO) - San Mateo, CA
Uprising (action/strategy PC game, released 10/97):
- The Level Editor:
3D pipeline used to render and modify a terrain database
- The Game:
Special effects, special weapons, rasterizers, hardware support
Third Domain (3D terrain strategy game - cancelled):
- 3D terrain engine; optimizations
2/95 - 12/95: Software Engineer, Integrated Manufacturing Laboratory - UC Berkeley, CA
Milling Machine Software Utilities:
- Milling machine graphical simulator and path generator
- Tool picking algorithm for the milling machine
Research/Publications
3/07: Sort-Independent Alpha Blending
GDC 2007 - using modern graphics hardware, we can render alpha blended objects without needing to sort
3/00: Advanced Lighting Effects - Overbright halos (high dynamic range lighting, aka HDR)
Total Immersion 2000 - using numerous texture passes to create overbright halo effects (simulate Gaussian blur)
3/00: Dynamic Lightmaps
Total Immersion 2000 - multiple colored lightmaps for real-time applications
3/98: B-Spline Surfaces
Total Immersion 1998 - fast rendering of spline surfaces, using variable patch subdivision (adjacent patch stitching)
4/97: Interactive Generation of Scherk-Collins Sculptures
Proceedings of the 1997 Symposium on Interactive 3D Graphics (SI3D'97)
8/95 - 8/97: Professor Carlo H. Séquin - UC Berkeley, CA
Complex single-sided Scherk Surface generator/renderer written on IrisGL and OpenGL
Education
Interests
Video games, Computer Graphics, Programming, Code Optimization, Sports Cars, User Interface, Electronics, Astronomy
Organizations
Demos and references are available upon request.
