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3rdparty/osgXR/src/CompositionLayer.cpp

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+// SPDX-License-Identifier: LGPL-2.1-only
+// Copyright (C) 2022 James Hogan <james@albanarts.com>
+
+#include "CompositionLayer.h"
+
+#include "XRState.h"
+
+using namespace osgXR;
+
+// Internal API
+
+CompositionLayer::Private::Private(XRState *state) :
+    _state(state),
+    _visible(true),
+    _order(1), // in front of perspective layer
+    _alphaMode(BLEND_NONE)
+{
+    state->addCompositionLayer(this);
+}
+
+CompositionLayer::Private::~Private()
+{
+    XRState *state = _state.get();
+    if (state)
+        state->removeCompositionLayer(this);
+}
+
+void CompositionLayer::Private::setVisible(bool visible)
+{
+    _visible = visible;
+}
+
+bool CompositionLayer::Private::getVisible() const
+{
+    return _visible;
+}
+
+void CompositionLayer::Private::setOrder(int order)
+{
+    _order = order;
+    // FIXME reorder
+}
+
+int CompositionLayer::Private::getOrder() const
+{
+    return _order;
+}
+
+void CompositionLayer::Private::setAlphaMode(AlphaMode mode)
+{
+    _alphaMode = mode;
+}
+
+CompositionLayer::AlphaMode CompositionLayer::Private::getAlphaMode() const
+{
+    return _alphaMode;
+}
+
+bool CompositionLayer::Private::writeCompositionLayer(OpenXR::Session *session,
+                                                      OpenXR::CompositionLayer *layer,
+                                                      bool disableAlpha) const
+{
+    if (!_visible)
+        return false;
+
+    XrCompositionLayerFlags flags = 0;
+    AlphaMode alphaMode = disableAlpha ? BLEND_NONE : _alphaMode;
+    switch (alphaMode)
+    {
+    case BLEND_NONE:
+        break;
+    case BLEND_ALPHA_PREMULT:
+        flags |= XR_COMPOSITION_LAYER_BLEND_TEXTURE_SOURCE_ALPHA_BIT;
+        break;
+    case BLEND_ALPHA_UNPREMULT:
+        flags |= XR_COMPOSITION_LAYER_BLEND_TEXTURE_SOURCE_ALPHA_BIT |
+                 XR_COMPOSITION_LAYER_UNPREMULTIPLIED_ALPHA_BIT;
+        break;
+    }
+
+    layer->setLayerFlags(flags);
+    layer->setSpace(session->getLocalSpace());
+    return true;
+}
+
+// Public API
+
+CompositionLayer::CompositionLayer(Private *priv) :
+    _private(priv)
+{
+}
+
+CompositionLayer::~CompositionLayer()
+{
+}
+
+void CompositionLayer::setVisible(bool visible)
+{
+    _private->setVisible(visible);
+}
+
+bool CompositionLayer::getVisible() const
+{
+    return _private->getVisible();
+}
+
+void CompositionLayer::setOrder(int order)
+{
+    _private->setOrder(order);
+}
+
+int CompositionLayer::getOrder() const
+{
+    return _private->getOrder();
+}
+
+void CompositionLayer::setAlphaMode(AlphaMode mode)
+{
+    _private->setAlphaMode(mode);
+}
+
+CompositionLayer::AlphaMode CompositionLayer::getAlphaMode() const
+{
+    return _private->getAlphaMode();
+}