filled out alpha over and opacity nodes

app/node/blend/alphaover/alphaover.cpp

@@ -1,8 +1,32 @@
+/***
+
+  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/>.
+
+***/
+
 #include "alphaover.h"
 
+#include "node/processor/renderer/renderer.h"
+#include "render/gl/functions.h"
 #include "render/rendertexture.h"
+#include "render/gl/shadergenerators.h"
 
-AlphaOverBlend::AlphaOverBlend()
+AlphaOverBlend::AlphaOverBlend() :
+  shader_(nullptr)
 {
 
 }
@@ -22,10 +46,54 @@ QString AlphaOverBlend::Description()
   return tr("A blending node that composites one texture over another using its alpha channel.");
 }
 
+void AlphaOverBlend::Release()
+{
+  shader_ = nullptr;
+}
+
 QVariant AlphaOverBlend::Value(NodeOutput *param, const rational &time)
 {
-  Q_UNUSED(param)
-  Q_UNUSED(time)
+  // Find the current Renderer instance
+  RenderInstance* renderer = RendererProcessor::CurrentInstance();
+
+  // If nothing is available, don't return a texture
+  if (renderer == nullptr) {
+    return 0;
+  }
+
+  // The only parameter should be texture output, but for future proofing we put this here
+  if (param == texture_output()) {
+    RenderTexturePtr base = base_input()->get_value(time).value<RenderTexturePtr>();
+    RenderTexturePtr blend = blend_input()->get_value(time).value<RenderTexturePtr>();
+
+    // Set compositing strategy to alpha over
+    renderer->context()->functions()->glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+
+    // Attach framebuffer to the backbuffer of base
+    renderer->buffer()->Attach(base);
+    renderer->buffer()->Bind();
+
+    // Bind blend
+    blend->Bind();
+
+    // Get default pipeline shader
+    // FIXME: Come up with a good way to share pipeline shaders since a lot of nodes will just use the default
+    if (shader_ == nullptr) {
+      shader_ = olive::ShaderGenerator::DefaultPipeline();
+    }
+
+    // Draw blend on base
+    olive::gl::Blit(shader_);
+
+    // Release all
+    blend->Release();
+    renderer->buffer()->Detach();
+    renderer->buffer()->Release();
+
+    // Return base texture which now has blend composited on top
+    // NOTE: Blend texture will be implicitly deleted here (if it's not used anywhere else)
+    return QVariant::fromValue(base);
+  }
 
   return 0;
 }