implemented volume and pan effects

This commit implements a structure for sample processing and two implemenations
of this structure in volume and pan effects.

app/node/audio/volume/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Olive - Non-Linear Video Editor
+# Copyright (C) 2019 Olive Team
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set(OLIVE_SOURCES
+  ${OLIVE_SOURCES}
+  node/audio/volume/volume.h
+  node/audio/volume/volume.cpp
+  PARENT_SCOPE
+)

app/node/audio/volume/volume.cpp

@@ -0,0 +1,52 @@
+#include "volume.h"
+
+VolumeNode::VolumeNode()
+{
+  samples_input_ = new NodeInput("samples_in");
+  samples_input_->set_data_type(NodeParam::kSamples);
+  AddInput(samples_input_);
+
+  volume_input_ = new NodeInput("volume_in");
+  volume_input_->set_data_type(NodeParam::kFloat);
+  volume_input_->set_minimum(0);
+  volume_input_->set_maximum(1);
+  volume_input_->set_value_at_time(0, 1);
+  AddInput(volume_input_);
+}
+
+Node *VolumeNode::copy() const
+{
+  return new VolumeNode();
+}
+
+QString VolumeNode::Name() const
+{
+  return tr("Volume");
+}
+
+QString VolumeNode::id() const
+{
+  return "org.olivevideoeditor.Olive.volume";
+}
+
+QString VolumeNode::Category() const
+{
+  return tr("Audio");
+}
+
+QString VolumeNode::Description() const
+{
+  return tr("Adjusts the volume of an audio source.");
+}
+
+bool VolumeNode::ProcessesSamples() const
+{
+  return true;
+}
+
+void VolumeNode::ProcessSamples(const NodeValueDatabase& values, const AudioRenderingParams& params, const float* input, float* output, int index) const
+{
+  float volume_val = values[volume_input_].Get(NodeParam::kFloat).toFloat();
+
+  output[index] = input[index] * volume_val;
+}

app/node/audio/volume/volume.h

@@ -0,0 +1,27 @@
+#ifndef VOLUMENODE_H
+#define VOLUMENODE_H
+
+#include "node/node.h"
+
+class VolumeNode : public Node
+{
+public:
+  VolumeNode();
+
+  virtual Node* copy() const override;
+
+  virtual QString Name() const override;
+  virtual QString id() const override;
+  virtual QString Category() const override;
+  virtual QString Description() const override;
+
+  virtual bool ProcessesSamples() const override;
+  virtual void ProcessSamples(const NodeValueDatabase& values, const AudioRenderingParams& params, const float* input, float* output, int index) const override;
+
+private:
+  NodeInput* samples_input_;
+  NodeInput* volume_input_;
+
+};
+
+#endif // VOLUMENODE_H