kc3-lang/angle

2025-07-02T13:23:31

Remove sharedContextLock from {Enable|Disable}VertexAttribArray VertexArray objects are per context objects. In theory they do not need to protected by shared context lock. The reason we are taking locks because all these functions end up accessing Buffer object which are shared. In prior CLs we have removed subject observer usage from VertexArray which means VertexArray no longer accessed from other thread. In prior CLs we also split VertexArray into two classes: VertexArrayPrivate which has no buffer, and VertexArray which is subclass from VertexArrayPrivate and owns buffer. In this CL, glEnableVertexAttribArray and glDisableVertexAttribArray calls no longer take shared context lock. ContextPrivateEnableVertexAttribArray and ContextPrivateDisableVertexAttribArray are called from these two APIs and they only have access to StatePrivate. State Private holds a VertexArrayPrivate pointer, which means they do not have anyway to access buffer objects. The main challenge I run into here is mCachedActiveClientAttribsMask, mCachedActiveBufferedAttribsMask, mCachedActiveDefaultAttribsMask, mCachedHasAnyEnabledClientAttrib, mCachedNonInstancedVertexElementLimit, mCachedInstancedVertexElementLimit. These StateCache variable needs to be updated when these two APIs are called, and calculating these variable needs access to buffer object. The solution here is adding a bool mIsCachedActiveAttribMasksValid in the PrivateStateCache so that instead of immediately update these mCached* variable, we just set mIsCachedActiveAttribMasksValid to false. Then whenever any of these mCached* variable is needed, we will check mIsCachedActiveAttribMasksValid and calculate these cached variables. It adds one if check when accessing these caches, but the other benefit is that we may have avoided duplicated calculation when multiple states changed. Bug: b/433331119 Change-Id: I3227c72bc40501712db93fb3d540b835f07150b5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4514436 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com>