1224246 - Remove "Drawing to a destination rect smaller than the viewport rect. " warning

Status: RESOLVED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Jeff Muizelaar [:jrmuizel]]

We spend 6.2% of the glDrawElements time in CurValidFBRectObject which is called so that we can give this warning. I don't think it's worth taking this performance hit for that warning.

Here's the profile from the unity benchmarks showing this:
http://people.mozilla.org/~bgirard/cleopatra/#report=2540877866e46fdf5d1c78bca3d1b7720fedd8cb&filter=[{%22type%22%3A%22RangeSampleFilter%22,%22start%22%3A484578,%22end%22%3A489291},{%22type%22%3A%22FocusedCallstackPrefixSampleFilter%22,%22name%22%3A%22_glDrawElements%28%29%20%40%202015-08-25-WebGLBenchmark-u5.1.3f1_hg-e1.34.6-release-prof.js%3A1%22,%22focusedCallstack%22%3A[0,1698,889,114,4,1699,1700,1701,1702,1703,1704,1705,1706,1707,1708,1709,1710,1711,1712,1713,1714,1715,1716,1717,1718,1719,1720,1721,1722,1723],%22appliesToJS%22%3Afalse}]&selection=1723,1724,1725,1726,1778,1779

Comment 1

[Kelsey Gilbert [:jgilbert]]

This was optimized to O(1):
https://searchfox.org/mozilla-central/rev/358f816f63da072145c593e9e2ac36b7250ecd25/dom/canvas/WebGLContextDraw.cpp#794