OpenGL ES 入門指南 - Getting Started with OpenGL ES
<a target="_blank" href="http://blog.csdn.net/opengl_es">轉載請保留此句：太陽火神的美麗人生 - 本部落格專注于 靈活開發及移動和物聯裝置研究：iOS、Android、Html5、Arduino、pcDuino，否則，出自本部落格的文章拒絕轉載或再轉載，謝謝合作。</a>
原來還有這麼好的文章，現在都過了這個階段了。
不過也說了，
沒過這個階段的時侯，
拿再多的這樣優秀的資源，
你還是看不懂的，
因為你沒有這樣的概念。
經曆過了，就懂得了，
再回顧，并不是多餘，而是更深刻的了解！
建議初學者和剛入門的難兄難弟，
一定要好好看看這個，才不緻于在 OpenGL ES 的大海中迷失自已，才有可能找向正确的行進方向！
有時間再翻譯，本貼先标為 原創，翻譯完，再改文章類型。
OpenGL® ES is a royalty-free, cross-platform API for full-function 2D and 3D graphics on embedded systems - including consoles, phones, appliances and vehicles. It consists of well-defined subsets of desktop OpenGL, creating a flexible and powerful low-level
interface between software and graphics acceleration. OpenGL ES includes profiles for floating-point and fixed-point systems and the EGL™ specification for portably binding to native windowing systems. OpenGL ES 1.X is for fixed function hardware and offers
acceleration, image quality and performance. OpenGL ES 2.X enables full programmable 3D graphics. OpenGL SC is tuned for the safety critical market.
<a target="_blank" href="http://www.khronos.org/opengles/3_X/">Learn More...</a>
OpenGL® ES is a low-level, lightweight API for advanced embedded graphics using well-defined subset profiles of OpenGL. It provides a low-level applications programming interface (API) between software applications and hardware or software graphics
engines.
This standard 3D graphics API for embedded systems makes it easy and affordable to offer a variety of advanced 3D graphics and games across all major mobile and embedded platforms. Since OpenGL ES (OpenGL for Embedded Systems) is based on OpenGL, no new technologies
are needed. This ensures synergy with, and a migration path to and from desktop OpenGL -- the most widely adopted cross-platform graphics API.
Developer Advantages
Industry Standard and Royalty Free
Anyone can download the OpenGL ES specification and implement and ship products based on OpenGL ES. With broad industry support, OpenGL ES is the only truly open, vendor-neutral, multi-platform embedded graphics standard. The standardized higher level of abstraction
that it offers means developers can concentrate more on content and less on the minor code and platform details.
Small footprint & low power consumption
The embedded space varies widely, ranging from 400Mhz PDAs with 64MB RAM to 50MHz mobile phones with 1 MB RAM. OpenGL ES is designed to accommodate these differences by requiring a minimum footprint with minimum data storage requirements, minimized instruction/data
traffic, and is both integer and floating point friendly. For users this means smaller binaries to download that take up less storage on the device.
Seamless transition from software to hardware rendering
Although the OpenGL ES specification defines a particular graphics processing pipeline, individual calls can be executed on dedicated hardware, run as software routines on the system CPU, or implemented as a combination of both dedicated hardware and software
routines. This means that software developers can ship a conformant software 3D engine today, that lets applications and tools seamlessly transition over to using OpenGL ES hardware-acceleration in higher powered devices.
Extensible & Evolving
OpenGL ES allows new hardware innovations to be accessible through the API via the OpenGL extension mechanism and for the API to be easily updated. As extensions become widely accepted, they are considered for inclusion into the core OpenGL ES standard. This
process allows OpenGL ES to evolve in a controlled yet innovative manner.
Easy to use
Based on OpenGL, OpenGL ES is well structured with an intuitive design and logical commands.
Well-documented
Because OpenGL ES is based on OpenGL, there are numerous relevant books, and a great deal of relevant sample code, making information about OpenGL ES inexpensive and easy to find. With the introduction of OpenGL ES, a developer can now write basically the same
code for cell phones to supercomputers.
The OpenGL ES roadmap has been tailored to the diverse needs of the embedded industry and contains two tracks with "1.X" and "2.X" specification roadmaps that will evolve in parallel. The 1.X roadmap will continue to be developed for new-generation fixed function
3D accelerators while the 2.X roadmap will enable emerging programmable 3D pipelines. This dual-track roadmap enables OpenGL ES to meet the graphics requirements of a huge range of 3D enabled device and platforms in embedded markets - from low-end cell-phones
to high-end gaming consoles. Khronos is committed to providing backwards compatibility between successive versions of the APIs in each of the 1.X and 2.X tracks to ensure that applications can be trivially ported from one version to the next.
Profiles:
The OpenGL ES specification includes the definition of several profiles. Each profile is a subset of a version of the desktop OpenGL specification plus some additional OpenGL ES-specific extensions. The OpenGL ES profiles are part of a wider family of OpenGL-derived
application programming interfaces. As such, the profiles share a similar processing pipeline, command structure, and the same OpenGL name space. Where necessary, extensions are created to augment the existing desktop OpenGL functionality. OpenGL ES-specific
extensions play a role in OpenGL ES profiles similar to that played by OpenGL ARB extensions relative to the OpenGL specification. OpenGL ES-specific extensions are either precursors of functionality destined for inclusion in future core profile revisions,
or formalization of important but non-mainstream functionality. Each profile definition implies a distinct header file and link/runtime library defining the commands and tokens in the profile. To simplify maintenance a single superset header can be defined
with appropriate conditional preprocessing directives to control the visibility of tokens and command prototypes. At run-time an application can determine which profile is running using the OpenGL version string query.
The Common Profile is intended for consumer entertainment and related devices such as telephone handsets, PDAs, set-top boxes, game consoles, etc. It addresses the broadest range
of the market including support for platforms with varying capability.
Minimum footprint full function 3D with texture-mapping
Good gaming platform
Implementable on cell phones
The Safety Critical Profile is intended for consumer and industrial applications where reliability and certifiability are the primary constraints.
Absolute minimum 3D to ease safety certifications
Used in avionics and automotive displays
Extensions:
OpenGL ES implementations may include extensions that add new features to the implementation. An OpenGL ES profile consists of two parts: a subset of the full OpenGL pipeline, and some extended functionality that is drawn from a set of OpenGL ES-specific extensions
to the full OpenGL specification. Each extension is pruned to match the profile's command subset and added to the profile as either a core addition or a profile extension. Core additions differ from profile extensions in that the commands and tokens do not
include extension suffixes in their names. Profile extensions are further divided into required (mandatory) and optional extensions. Required extensions must be implemented as part of a conforming implementation, whereas the implementation of optional extensions
is left to the discretion of the implementor.
Native Platform Graphics Interface Layer - EGL:
OpenGL ES also includes a specification of a common platform interface layer, called EGL. This layer is platform independent and may optionally be included as part of a vendor's OpenGL ES distribution. The platform binding also has an associated conformance
test. Alternatively, a vendor may choose to define their own platform-specific embedding layer.
Intel
Sony Computer Entertainment Inc.
Apple, Inc.
QUALCOMM
Vivante Corporation
NVIDIA Corporation
NVIDIA
ITRI
Digital Media Professionals
Marvell
ARM
Imagination Technologies
Creative Technology Ltd
MediaTek Inc
NOKIA OYJ
Panasonic
Broadcom Corporation
Google, Inc.
HISILICON TECHNOLOGIES CO.,LTD.
Fujitsu