Rename toolbox to platform.

PiperOrigin-RevId: 838701951
Change-Id: I339eafd35d919710cb47bb04e9a8e29f92739513

src/experimental/platform/renderer.cc

@@ -0,0 +1,78 @@
+// Copyright 2025 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 "experimental/platform/renderer.h"
+
+#include <chrono>
+#include <string>
+
+#include "experimental/platform/helpers.h"
+#include <mujoco/mujoco.h>
+
+namespace mujoco::platform {
+
+Renderer::Renderer(MakeContextFn make_context_fn)
+    : make_context_fn_(make_context_fn) {
+}
+
+Renderer::~Renderer() { Deinit(); }
+
+void Renderer::Init(const mjModel* model) {
+  Deinit();
+  if (model) {
+    mjr_defaultContext(&render_context_);
+    make_context_fn_(model, &render_context_);
+    mjv_defaultScene(&scene_);
+    mjv_makeScene(model, &scene_, 2000);
+    initialized_ = true;
+  }
+}
+
+void Renderer::Deinit() {
+  if (initialized_) {
+    mjv_freeScene(&scene_);
+    mjr_freeContext(&render_context_);
+    initialized_ = false;
+  }
+}
+
+void Renderer::Render(const mjModel* model, mjData* data,
+                      const mjvPerturb* perturb, mjvCamera* camera,
+                      const mjvOption* vis_option, int width, int height) {
+  if (initialized_) {
+    mjv_updateScene(model, data, vis_option, perturb, camera, mjCAT_ALL,
+                    &scene_);
+  }
+
+  mjrRect main_viewport = {0, 0, width, height};
+  mjr_render(main_viewport, data ? &scene_ : nullptr, &render_context_);
+
+  auto now = std::chrono::steady_clock::now();
+  auto delta_time = now - last_fps_update_;
+  const double interval = std::chrono::duration<double>(delta_time).count();
+
+  ++frames_;
+  if (interval > 0.2) {  // only update FPS stat at most 5 times per second
+    last_fps_update_ = now;
+    fps_ = frames_ / interval;
+    frames_ = 0;
+  }
+}
+
+void Renderer::SaveScreenshot(const std::string& filename, int width,
+                              int height) {
+  SaveScreenshotToWebp(width, height, &render_context_, filename);
+}
+
+}  // namespace mujoco::platform