Project import generated by Copybara.

PiperOrigin-RevId: 253489161

mediapipe/gpu/gl_simple_calculator.h

@@ -0,0 +1,110 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// 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.
+
+#ifndef MEDIAPIPE_GPU_GL_SIMPLE_CALCULATOR_H_
+#define MEDIAPIPE_GPU_GL_SIMPLE_CALCULATOR_H_
+
+#include <utility>  // for declval
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/gpu/gl_calculator_helper.h"
+
+namespace mediapipe {
+
+// This class saves some boilerplate for the common case of processing one
+// input stream of frames and outputting it as one output stream of frames,
+// processed using OpenGL.
+//
+// If you use tags, both input and output streams should be tagged as VIDEO.
+// Otherwise, this will use the first input and output.
+//
+// Subclasses should define at least:
+// - GlSetup(), which is called once (on the first frame) and should set up any
+//   GL objects the calculator will reuse throughout its life.
+// - GlRender(), which is called for each frame.
+// - A destructor, to destroy the objects created in GlSetup.
+// Note that when GlSetup and GlRender are called, the GL context has already
+// been set, but in the destructor it has not. The destructor should have a
+// local variable set to ContextAutoSetter() to make sure it is doing the
+// destruction in the right GL context.
+//
+// Additionally, you can define a GlBind() method, which will be called to
+// enable shader programs, bind any additional textures you may need, etc.
+// If your calculator shares a context with other calculators, GlBind() will be
+// called before each GlRender(); if it has its own context, it will be called
+// only once.
+
+class GlSimpleCalculator : public CalculatorBase {
+ public:
+  GlSimpleCalculator() : initialized_(false) {}
+  GlSimpleCalculator(const GlSimpleCalculator&) = delete;
+  GlSimpleCalculator& operator=(const GlSimpleCalculator&) = delete;
+  ~GlSimpleCalculator() override = default;
+
+  static ::mediapipe::Status GetContract(CalculatorContract* cc);
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+  ::mediapipe::Status Process(CalculatorContext* cc) override;
+  ::mediapipe::Status Close(CalculatorContext* cc) override;
+
+  // This method is called once on the first frame. Use it to setup any objects
+  // that will be reused throughout the calculator's life.
+  virtual ::mediapipe::Status GlSetup() = 0;
+
+  // You can use this optional method to do any pre-rendering setup that needs
+  // to be redone after the context has been used by another calculator.
+  // If your context is not shared, it will only be called once.
+  virtual ::mediapipe::Status GlBind() { return ::mediapipe::OkStatus(); }
+
+  // Do your rendering here. The source and destination textures have already
+  // been created and bound for you.
+  // - src: source texture (contains input frame); already bound to GL_TEXTURE1.
+  // - dst: destination texture (write output frame here); already bound to
+  //        GL_TEXTURE0 and attached to the framebuffer.
+  virtual ::mediapipe::Status GlRender(const GlTexture& src,
+                                       const GlTexture& dst) = 0;
+
+  // The method is called to delete all the programs.
+  virtual ::mediapipe::Status GlTeardown() = 0;
+
+  // You can override this method to compute the size of the destination
+  // texture. By default, it will take the same size as the source texture.
+  virtual void GetOutputDimensions(int src_width, int src_height,
+                                   int* dst_width, int* dst_height) {
+    *dst_width = src_width;
+    *dst_height = src_height;
+  }
+
+  // Override this to output a different type of buffer.
+  virtual GpuBufferFormat GetOutputFormat() { return GpuBufferFormat::kBGRA32; }
+
+ protected:
+  // Forward invocations of RunInGlContext to the helper.
+  // The decltype part just says that this method returns whatever type the
+  // helper method invocation returns. In C++14 we could remove it and use
+  // return type deduction, i.e.:
+  //   template <typename F> auto RunInGlContext(F&& f) { ... }
+  template <typename F>
+  auto RunInGlContext(F&& f)
+      -> decltype(std::declval<GlCalculatorHelper>().RunInGlContext(f)) {
+    return helper_.RunInGlContext(std::forward<F>(f));
+  }
+
+  GlCalculatorHelper helper_;
+  bool initialized_;
+};
+
+}  // namespace mediapipe
+
+#endif  // MEDIAPIPE_GPU_GL_SIMPLE_CALCULATOR_H_