Embedded 3D graphics is here, but 2D is still important: Here’s why

Waqar Saleem, Fujitsu Semiconductor

April 15, 2012

Waqar Saleem, Fujitsu Semiconductor

Alternate Approach
An alternative to these extreme approaches is an architecture based on the rendering process, but with the ability to process the pixels being rendered to scale, rotate, and perform other operations.

This helps get rid of both the extensive bandwidth requirement of a pure raster (BLT) engine and the intensive mathematical calculations required by a pure vector engine. This balancing act simplifies the design complexity and cost and, at the same time, keeps the required graphics memory requirement within reasonable bounds.

To be effective, this architecture must be very flexible. It must quickly fetch the bitmap to be processed from the source, and then rapidly process the incoming pixels to perform operations such as rotations, scaling, and alpha blending.

The architecture also needs to be versatile enough to handle different color formats, and must be able to convert data of one type into another as needed. It has to either store the processed pixels in another location in memory or send them to the display pipeline. The architecture also has to drive the display panel at the required timing requirements.

Iris Provides a Balanced Approach

We have balanced the two approaches in the Iris graphics engine. This IP combines the best of the two worlds: raster and vector graphics. Since the engine is based inherently on raster graphics, it is simpler than vector engines and has significantly less IP design and development cost.

At the same time, through its bitmap-rotation and scaling capability, Iris requires much less memory and bandwidth than conventional 2D raster engines. The rotation and scaling capability allows it to show sophisticated and dynamic effects, such as needle draw or album cover turnstile, at a high frame rate.

Iris is a fast pixel engine that can rotate and scale pre-rendered graphics data, and handle compressed bitmaps. A block diagram is shown in Figure 4 below.

Click on image to enlarge.

All units in the pipeline work in synchronization with each other, courtesy of a signal that flows from display to start of the pipeline. Consequently, there is no need to flush the pipeline.