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Diffstat (limited to 'src/library_gl.js')
| -rw-r--r-- | src/library_gl.js | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/src/library_gl.js b/src/library_gl.js index 6f99969e..29e8423f 100644 --- a/src/library_gl.js +++ b/src/library_gl.js @@ -1,4 +1,26 @@ -//"use strict"; +/* + * GL support. + * + * Emscripten supports the WebGL-friendly subset of OpenGL, basically what + * maps directly to WebGL. This includes almost all of OpenGL ES 2.0, + * except for client-side arrays. The reason they are missing from WebGL + * is because they are less efficient than properly using GPU-side data. + * Similarly, if we emulated client-side arrays here, we would end up + * with very bad performance, since we would need to upload the data + * on each call to glDrawArrays etc. (Even if there are two calls one + * after the other, we can't know the data did not change!) So in + * practical terms full OpenGL ES 2.0 emulation would be convenient, + * but lead to bad performance so in practice you would need to properly + * rewrite your code to a WebGL-friendly subset anyhow. + * + * Thankfully, rewriting to that subset is general fairly easy. See + * the files in tests/glbook for some simple examples ported to that + * subset. + * + * Regarding OpenGL aspects present on desktop GL or on OpenGL ES prior + * to 2.0, we also do not support immediate mode (glBegin/glEnd), GL_QUADS, + * etc. Some of these might make sense to emulate, some might not. + */ var LibraryGL = { $GL: { |