Detect read-only GL persistent maps & skip intercepting them. Refs #1128

renderdoc/driver/gl/wrappers/gl_buffer_funcs.cpp

@@ -449,7 +449,8 @@ void WrappedOpenGL::Common_glNamedBufferStorageEXT(ResourceId id, GLsizeiptr siz
     // because the user code isn't writing into them anyway and we're inserting invisible sync
     // points - so there's no need for it to be coherently mapped (and there's no requirement
     // that a buffer declared as coherent must ALWAYS be mapped as coherent).
-    if(flags & GL_MAP_PERSISTENT_BIT)
+    uint32_t persistentWriteFlags = GL_MAP_PERSISTENT_BIT | GL_MAP_WRITE_BIT;
+    if((flags & persistentWriteFlags) == persistentWriteFlags)
     {
       record->Map.persistentPtr = (byte *)GL.glMapNamedBufferRangeEXT(
           record->Resource.name, 0, size,
@@ -1900,14 +1901,20 @@ void *WrappedOpenGL::glMapNamedBufferRangeEXT(GLuint buffer, GLintptr offset, GL
        IsBackgroundCapturing(m_State))
       directMap = true;
 
-    // persistent maps must ALWAYS be intercepted
-    if((access & GL_MAP_PERSISTENT_BIT) || record->Map.persistentPtr)
+    // read-only persistent maps can also be made directly
+    uint32_t persistentReadFlags = GL_MAP_PERSISTENT_BIT | GL_MAP_READ_BIT;
+    if((access & persistentReadFlags) == persistentReadFlags)
+      directMap = true;
+
+    // persistent maps must ALWAYS be intercepted if they are writeable. if it's a read-only
+    // persistent map we never allocated a persistent pointer so we can skip this
+    if(record->Map.persistentPtr)
       directMap = false;
 
     bool verifyWrite = (RenderDoc::Inst().GetCaptureOptions().verifyMapWrites != 0);
 
     // must also intercept to verify writes
-    if(verifyWrite)
+    if(verifyWrite && (access & GL_MAP_WRITE_BIT))
       directMap = false;
 
     if(directMap)
@@ -1922,8 +1929,9 @@ void *WrappedOpenGL::glMapNamedBufferRangeEXT(GLuint buffer, GLintptr offset, GL
     record->Map.invalidate = invalidateMap;
     record->Map.verifyWrite = verifyWrite;
 
-    // store a list of all persistent maps, and subset of all coherent maps
-    if(access & GL_MAP_PERSISTENT_BIT)
+    // store a list of all persistent writing maps, and subset of all coherent maps
+    uint32_t persistentWriteFlags = GL_MAP_PERSISTENT_BIT | GL_MAP_WRITE_BIT;
+    if((access & persistentWriteFlags) == persistentWriteFlags)
     {
       Atomic::Inc64(&record->Map.persistentMaps);
       m_PersistentMaps.insert(record);