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OpenGL ES 2.0 Survey Question on how to maintain compatibility

Sep 17, 2004

Should the OpenGL ES 2.0 API include the fixed functionality from OpenGL ES 1.X that can be cleanly replaced by programmable vertex and fragment shaders?

OpenGL ES 2.0 will provide vertex and fragment shader
programmability using a close derivative of the desktop OpenGL Shading
Language.  The desktop OpenGL 2.0 API retains full OpenGL 1.5 fixed
functionality to provide full backwards compatibility within a single API.
Desktop OpenGL 2.0 also enables fine-grained mixing of shaders with the
original fixed-function pipeline to enable OpenGL 1.X programs to be
incrementally upgraded with programmability.  The design goals for OpenGL
ES 2.0 place a stronger emphasis on API simplicity and small driver
footprint for embedded markets.  OpenGL ES 2.0 could eliminate the fixed
functionality from OpenGL ES 1.X that can be cleanly replaced by
programmable vertex and fragment shaders - resulting in a smaller, simpler
API.  Platforms that need backwards compatibility with OpenGL ES 1.X
applications could ship a separate OpenGL ES 1.X library.  The source code
of shader programs that emulate the full OpenGL ES 1.X fixed pipeline
could be provided to execute 1.X applications that wish to incrementally
use programmability through modifying those shaders.  Just as with OpenGL
ES 1.X , some software modifications would be necessary to port
applications between desktop OpenGL 2.0 and embedded OpenGL ES 2.0.

Discussion and comments are welcome

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