While these days most of us take Gamit with mobile devices for granted, many people remember with great certainly that such developments are still quite young. It wasn’t 20 years ago that games like Snake (also as 3D configurator) were considered innovative on simple Nokia phones. In fact, it is still seen today as a cool “retro game”.
Today, however, we can enjoy visually complex games on our mobile devices that are comparable to what can be achieved on a desktop – and as the first mobile graphics processor to deliver true graphics performance, PowerVR technology has been the key from the beginning. The displays on our smartphones are getting bigger and better, so mobile devices offer an even better platform to enjoy graphically appealing games.
What makes a game a competitor of what a user would see on a desktop computer or console? The answer is not just pixels and resolution (although they are important of course). Rather, visual effects that filters apply to what is drawn on the screen, such as blossom, color gradation or vignette.
Depth of field.
Another key technique is to apply the depth of field that anyone familiar with serious photography is familiar with. It is a technique known as bokeh, where you control the focus of the scene by usually blurring the background and bringing the foreground into a sharp relief. It can be used to direct the user’s attention to a particular part of the scene or to improve the mood or emotion in games – a subject so involved that books have been written about it.
Depth of field is indeed a complex thing to achieve in graphics and especially in smartphones, where performance is of course limited by mobile energy budgets. However, it can be implemented and this was impressively demonstrated at the last Game Develop Conference by the depth of field with PowerVR.
This effect is traditionally achieved with a simple blur pass over a standard dynamic range image (SDR image). This can be done quite efficiently, but it doesn’t cut quite aesthetically because the image is relatively smooth and uniform instead of having the sharp highlights you’d want in the ideal case.
A more modern real-time depth of field setting is one that manages to show sharp bokeh shapes with more complex blur on high dynamic range (HDR) images. Such a method has become very popular in AAA games both on the PC and on the console, but less so on the mobile phone.
The reason for this is bandwidth: the amount of data that has to be redirected when filtering HDR images is usually doubled, so the GPU constantly waits for the availability of this data, resulting in poor performance.
As it turns out, modern mobile devices have come a long way and with a few changes in depth of field, real-time performance can be achieved with a few small compromises. In the case of the Sky Lantern demo, the HDR color information was packed into the same amount of data as a standard SDR image, meaning that bandwidth requirements were substantially halved.
Since I’m sure you’ll agree to watching the video, even in this relatively simplified implementation the effect is visually appealing and offers a sophisticated look that can enhance either cutscenes or even real-time gameplay. It provides an extra glow to complete mobile games with desktop and console.
This demo was produced on a Meizu Pro 7 device with a MediaTek X30 chipset with PowerVR Series 7XTP graphics. Our world-class Furian architecture offers breakthrough performance and with future devices based on it, it won’t be long before end users can enjoy games they didn’t think possible just a few years ago, which is even less reason to put up with Snake on the train. Thanks to PowerVR, mobile gaming has a great future ahead of it.