GL_EXT_occlusion_query_boolean

Supported Hardware

Series5XT, Series6, Series6XE, Series6XT

Valid APIs

OpenGL ES 2.0

Description

This extension adds two new mechanisms to OpenGL ES 2.0 - Querying and Boolean Occlusion Queries.

Querying is a mechanism which allows the user to request information from the hardware directly, often allowing access to information that the hardware can gather with easily that would otherwise require expensive software checks. As modern GPUs work asynchronously to the CPU, querying does not instantly return a value; instead, a result is requested, and then at some point in the future the GL implementation will have a response ready. App developers can check when that query is ready, and then access that value.

Boolean occlusion queries use the querying mechanism to allow app developers to find out if an object they've been sending down the pipeline is actually visible or not. The result of the query can then be used in subsequent frames to determine whether or not to draw the object again. This allows a developer to better balance the load between software culling and hardware visibility tests.

Note

This functionality is core to OpenGL ES 3.0.

Registry Link

http://www.khronos.org/registry/gles/extensions/EXT/EXT_occlusion_query_boolean.txt