The fundamental issue is that rendering to an FP framebuffer takes a lot of additional transistors. Because of this, I doubt if any OpenGL ES 2.0 implementations support rendering to an FP framebuffer. It is likely found only on desktop OpenGL. This is also why OES_texture_floatadds only float texture support not FP framebuffer support.
Understood -- I was actually looking at the 2.0.25 spec. To resolve the issue of rendering to floating-point textures, I propose defining a pair of OpenGL ES 2.0 extensions ("OES_render_texture_float" / "OES_render_texture_half_float"?) which define support for FLOAT and HALF_FLOAT_OES texture attachments to FBOs. Does that sound like a reasonable path to take at this point in time? I think that adding the minimal amount of spec text and functionality would be the best direction to take. For example, it doesn't seem necessary to provide control over clamping behavior. Another option would be to extend the WebGL extensions exposing OES_texture_float and OES_texture_half_float (, ) with enough language to allow, but not require, an implementation to support these texture types as FBO color attachments. I think that we should preserve the capability to render to floating-point textures from WebGL wherever possible. Existing use cases (, , , , and I'm sure there are more) demonstrate how compelling this capability is.  http://www.khronos.org/registry/webgl/extensions/OES_texture_float/  http://www.khronos.org/registry/webgl/extensions/OES_texture_half_float/  http://www.ibiblio.org/e-notes/webgl/gpu/contents.htm  http://madebyevan.com/webgl-path-tracing/  http://madebyevan.com/webgl-water/  http://webglsamples.googlecode.com/hg/hdr/hdr.html -Ken
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