implement group-based opacity node

app/node/effect/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Olive - Non-Linear Video Editor
+# Copyright (C) 2021 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/>.
+
+add_subdirectory(opacity)
+
+set(OLIVE_SOURCES
+  ${OLIVE_SOURCES}
+  PARENT_SCOPE
+)

app/node/effect/opacity/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Olive - Non-Linear Video Editor
+# Copyright (C) 2021 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/effect/opacity/opacityeffect.cpp
+  node/effect/opacity/opacityeffect.h
+  PARENT_SCOPE
+)

app/node/effect/opacity/opacityeffect.cpp

@@ -0,0 +1,38 @@
+#include "opacityeffect.h"
+
+#include "node/math/math/math.h"
+#include "widget/slider/floatslider.h"
+
+namespace olive {
+
+#define super NodeGroup
+
+OpacityEffect::OpacityEffect()
+{
+  MathNode *math = new MathNode();
+
+  math->SetOperation(MathNode::kOpMultiply);
+
+  SetNodePositionInContext(math, QPointF(0, 0));
+
+  tex_in_pass_ = AddInputPassthrough(NodeInput(math, MathNode::kParamAIn));
+  SetInputDataType(tex_in_pass_, NodeValue::kTexture);
+
+  value_in_pass_ = AddInputPassthrough(NodeInput(math, MathNode::kParamBIn));
+  SetInputProperty(value_in_pass_, QStringLiteral("view"), FloatSlider::kPercentage);
+  SetInputProperty(value_in_pass_, QStringLiteral("min"), 0.0);
+  SetInputProperty(value_in_pass_, QStringLiteral("max"), 1.0);
+  math->SetStandardValue(MathNode::kParamBIn, 1.0);
+
+  SetOutputPassthrough(math);
+}
+
+void OpacityEffect::Retranslate()
+{
+  super::Retranslate();
+
+  SetInputName(tex_in_pass_, tr("Texture"));
+  SetInputName(value_in_pass_, tr("Opacity"));
+}
+
+}

app/node/effect/opacity/opacityeffect.h

@@ -0,0 +1,47 @@
+#ifndef OPACITYEFFECT_H
+#define OPACITYEFFECT_H
+
+#include "node/group/group.h"
+
+namespace olive {
+
+class OpacityEffect : public NodeGroup
+{
+public:
+  OpacityEffect();
+
+  NODE_DEFAULT_DESTRUCTOR(OpacityEffect)
+
+  NODE_COPY_FUNCTION(OpacityEffect)
+
+  virtual QString Name() const override
+  {
+    return tr("Opacity");
+  }
+
+  virtual QString id() const override
+  {
+    return QStringLiteral("org.olivevideoeditor.Olive.opacityeffect");
+  }
+
+  virtual QVector<CategoryID> Category() const override
+  {
+    return {kCategoryFilter, kCategoryVideoEffect};
+  }
+
+  virtual QString Description() const override
+  {
+    return tr("Alter a video's opacity.\n\nThis is equivalent to multiplying a video by a number between 0.0 and 1.0.");
+  }
+
+  virtual void Retranslate() override;
+
+private:
+  QString tex_in_pass_;
+  QString value_in_pass_;
+
+};
+
+}
+
+#endif // OPACITYEFFECT_H