Summarized from: PowerVR Global

PowerVR Series2 Overview


Original Author: John Smith of NEC 
First Shown: Computer Games Developers' Conference (CGDC) at Long Beach, California (May 5-7, 1998)  
HTML Implementation: PowerVR Global, May 6th, 1998 
  • Focus on discussing 3D core technology and features of PowerVR Series2 hardware.
  • 3D core used in a number of parts including PC, console and arcade
  • PC 2D/3D product available Summer 98 with development systems available E3
  • First development units delivered in Feb 98

Topics to be covered 

  • The Architecture

  • Differences between first and second generation platform described. As well as a discussion about where the architecture is heading. 
  • Performance

  • Where focus was placed 
  • Image Quality

  • What enhancements were made 
  • Development

Architecture 101 

Same fundamentals as first generation 

  • Tile based: Screen broken down into 32x16 tiles
  • (PCX2 internally rendered at 32x1)
  • Deferred Texturing: Only display visible pixels.
  • On chip HSR: Faster method of Z -buffering
  • Low Memory Bandwidth: Due to features above.
  • Low cost: Single chip (~$30), Inexpensive memory
  • Asynchoronous Rendering: Host CPU free during render

New Enhancements 

  • Full 32bit floating point geometry and texture setup engine 
  • Hardware tiling engine 
  • 2 On chip accumulation buffers 
  • Unified memory architecture (2D & 3D part) 
  • PCI or AGP 2x with side band 
  • 1600 x 1200 Resolution (Super sampling up to 2048x2048) 
  • Increased Z compare modes (ignore, <, =, <=, >, !=, >=, always) 

Performance 102 - The Numbers 

  • Sustained 1.2 million front facing, lit, textured, shaded, Z sorted polygons per second on a Intel P2-333. 
  • Actual screen fill rate of 100mpps(1clk/pixel). 
  • Using conventional fill rate methodology this translates to PowerVR SG having a much higher fill rate. At 1.5x overdraw this translates to a conventional fill rate of 150mpps. 
  • Or another way to put it: 
  • 1024x768 @ 60 fps with 'n' overdraw & 25% translucency=~59mpps (room to spare!) 

Performance 102 - Silicon Enhancements 

  • Hardware Tiling Engine - Tiles no longer clipped within software. 
  • Increased Processing Elements - Tiles are now rendered at 32x16 pixels instead of 32x1 as on PCX2. 
  • Per-pixel hardware translucency sorting - No longer expects translucent polygons to be pre-sorted in software. 
  • Increased clock rate and shrunk die size - Now 100 MHz at 0.25 microns. 

Performance 102 - Maximizing Performance 

  • Strips/Fans - Both reduce amount of vertex data. Strips directly supported in hardware. Fans done by using Strips internally. A Strip is a polygon that shares two of it's vetices with another polygon. A Fan is a polygon that shares one of it's vertices with another polygon. 
  • Compressed Textures -  Large textures should be compressed to reduce the amount of bus and memory transfer time. 
  • Overlap - Asynchronous rendering, freeing up host CPU to continue with your game code. 
  • Enable Super Sampling & Higher filtering modes - Affects performance but can improve image quality significantly! 

Image Quality - Features 

  • Additional Fog Support - per pixel, Vertex Fog, and/or Fixed/Loadable Table 
  • Perspective correct RGBA Gouraud Shading as well as intensity 
  • Specular Highlights with Offset Color 
  • Advanced Image Filtering Modes (per polygon) - Point Sample Bilinear (1 cycle), Trilinear (2 cycles), Anisotropic (4 cycles). 
  • 32-bit Floating Point Z-buffer Accuracy - Reduce shimmering, tears and artifacts. 
  • Full Multi-Texture and Multi-Pass Rendering 
  • Texture sizes up to 1024x1024 

Image Quality - Texture formats & Blended Modes 

    Texture Formats 

    • 8-bit Palletized (including 8888 palettes) 
    • 555 RGB, 565 RGB 
    • 5551 RGBA, 4444 RGBA 
    • 422 YUV 
    • VQ Compression (up to an 8:1 compression ratio) 
    • Bump maps 

    Blending Modes  
    OpenGL and D3D blending modes are supported  
    All blending done internally at 32 bits of color to reduce artifacts 

Image Quality - Bump Mapping 

  • Full hardware bump mapping support 
  • Bump maps are supplied using a Height Map 
  • Bump map is internally converted to an intermediate light map 
  • Since you have the light map you then may specify how it should be blended with the original texture 
  • Accessible in SGL Direct (native api) as well as DirectX 6 

Image Quality - Vector Quatization 

  • Texture Compression delivering up to an 8:1 lossy image 
  • Front end compression required (typically 3 sec/texture) 
  • Code book is a variable size up to 256x4 entries (RGBA @ 16bits each) 
  • Decompression quick and basically for free 
  • Able to use with a mix of compressed and non compressed textures 

Image Quality - Full Scene Super Sampling 

  • Image is rendered to a specified resolution and then is scaled to the users view port using a bi-cubic filter (similar to Photo Shop). 
  • You may specify any X and/or Y screen size up to 2048x2048 - the maximum screen output resolution for PowerVR is 1600x1200. 
  • Benefit is very easy to use - no need to track edges and specify which are aliased. Simply turn it on and specify the resolution. 
  • Only penalty for performance is fill rate - however it is not equivalent to the full proportional to the extra pixels. 

Image Quality - Generalized Modifier Volumes 

  • Extension to what was known on PowerVR first generation as light and shadow volumes 
  • Sample images from a demo available in our SDK which shows how one may use modifier volumes 
  • A second set of parameter data is supplied per modifiable ploygon/model. When the object is in/out of the specified volume, the second set of parameters may then be used. 
  • Examples of usage - X-Ray guns, ships whose cloaks start to fail as they pass through the tail of a comet 


  • Full support for DirectX 5/6 (some features only accessible under 6 - such as multi-texturing, bump mapping), OpenGL certified ICD, and SGL Direct (native API) 
  • Very thin API - much of the previous work done in the drivers with the PCX2 has now been brought down into the silicon 
  • World wide developer support with local staff in Silicon Valley, Austin, London, Australia and Japan 
  • Development kits available to all qualified developers this summer. Either contact me or go to our web site at 

Development - WWW site 

  • This web site is currently only available to qualified developers under NDA 
  • Look forward to announcements soon regarding publicly available developers materials 
  • Documentation & Reference Manuals 
  • Programming Guides, Optimization Docs 
  • Technology Information & News 
  • Lastest Drivers, Debug & Timing Utilities 
  • General Tools & Utilities 
  • FAQ Section 
  • Tips & Tricks Section 
  • Example Programs 
  • Special Events, e.g. Competitions