Workaround for broken VSync in Simulate on macOS.

OpenGL VSync became broken again in macOS 13 (https://github.com/glfw/glfw/issues/2249). This workaround is similar to https://github.com/glfw/glfw/pull/2277 but is implemented entirely outside of GLFW. PiperOrigin-RevId: 516320722 Change-Id: Ib8a651a942f592c74e00ad3c7b22f2dfd156be5f
2023-03-13 14:18:37 -07:00
parent 3abf2ae2cd
commit 2f0fb1e4ef
9 changed files with 195 additions and 0 deletions
@@ -0,0 +1,75 @@
+// Copyright 2023 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "glfw_corevideo.h"
+
+#include <condition_variable>
+#include <mutex>
+
+#include "glfw_adapter.h"
+#include "glfw_dispatch.h"
+
+// Workaround for perpertually broken OpenGL VSync on macOS,
+// most recently https://github.com/glfw/glfw/issues/2249.
+namespace mujoco {
+namespace {
+static int DisplayLinkCallbackTrampoline(CVDisplayLinkRef display_link,
+                                         const CVTimeStamp* now,
+                                         const CVTimeStamp* output_time,
+                                         CVOptionFlags flags_in,
+                                         CVOptionFlags* flags_out,
+                                         void* user_context) {
+  return static_cast<GlfwCoreVideo*>(user_context)->DisplayLinkCallback();
+}
+}  // namespace
+
+GlfwCoreVideo::GlfwCoreVideo(GLFWwindow* window) : window_(window) {
+  CVDisplayLinkCreateWithActiveCGDisplays(&display_link_);
+  CVDisplayLinkSetOutputCallback(display_link_, &DisplayLinkCallbackTrampoline, this);
+  CVDisplayLinkStart(display_link_);
+}
+
+GlfwCoreVideo::~GlfwCoreVideo() {
+  CVDisplayLinkStop(display_link_);
+  CVDisplayLinkRelease(display_link_);
+}
+
+void GlfwCoreVideo::EnqueueSwap() {
+  std::unique_lock lock(mu_);
+  second_buffer_has_content_ = true;
+}
+
+void GlfwCoreVideo::WaitForSwap() {
+  if (second_buffer_has_content_) {
+    std::unique_lock lock(mu_);
+    cond_.wait(lock, [this]() { return !this->second_buffer_has_content_; });
+  }
+}
+
+int GlfwCoreVideo::DisplayLinkCallback() {
+  if (second_buffer_has_content_) {
+    std::unique_lock lock(mu_);
+    Glfw().glfwSwapBuffers(window_);
+    second_buffer_has_content_ = false;
+    cond_.notify_one();
+  }
+  return kCVReturnSuccess;
+}
+
+void GlfwCoreVideo::UpdateDisplayLink() {
+  NSOpenGLContext* nsgl = Glfw().glfwGetNSGLContext(window_);
+  CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(display_link_, [nsgl CGLContextObj],
+                                                    [nsgl.pixelFormat CGLPixelFormatObj]);
+}
+}  // namespace mujoco