OpenGL and WebGL in KreaTV 5

Introduction

OpenGL ES, and its HTML equivalent WebGL, is an API that provides operative access to the GPU. KreaTV 5 includes support for these APIs on hardware that supports it. OpenGL ES is used by native applications, including the browser, while WebGL can be used by HTML portals and websites.

For more information regarding OpenGL ES and WebGL, please refer to http://www.khronos.org/opengles/2_X and http://www.khronos.org/webgl.

Enabling OpenGL ES and WebGL

OpenGL ES is enabled by including the kreatv-option-opengl IIP in the boot image configuration file. To enable browser support for OpenGL ES and WebGL, the kreatv-license-ekioh-opengl IIP needs to be included in the boot image as well.

If OpenGL ES is enabled in a KreaTV boot image and the relevant licenses are valid, the browser will utilize it automatically. WebGL is enabled in the same way.

To test whether OpenGL ES and WebGL is enabled in a boot image, load a simple WebGL page in the browser such as http://get.webgl.org and see whether it works as expected.

Advantages of OpenGL ES and WebGL on an STB

The browser tries to accelerate graphics operations where it can in order to improve UI performance. Without OpenGL ES, only simple copy, scale and move operations can be accelerated while more advanced operations such as rotations are done in software. OpenGL ES allows for a wider variety of graphical operations to be hardware accelerated.

Generally speaking, CSS animations tend to be accelerated by the browser engine more often than JavaScript animations and enabling OpenGL ES will allow for a wider variety of operations to be accelerated. Note that due to the heuristics involved in deciding whether or not to accelerate a given element, it is often difficult to determine in advance whether it will be accelerated or not. Careful profiling is needed to determine how much a given portal benefits from using the OpenGL ES backend, if at all.

For advanced use cases, WebGL can render complex scenes with a wide variety of graphical effects. WebGL as a whole depends on GPU access and has no software fallback in KreaTV.

Feature support

OpenGL ES and WebGL have a number of extensions which may or may not be available on the STB. These hardware dependent extensions can be queried from within WebGL via the getSupportedExtensions() function.

The WebGL implementation in KreaTV is not yet fully conformant and may have compatibility issues.