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**
** Copyright (C) 2008-2012 NVIDIA Corporation.
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
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** This file is part of Qt 3D Studio.
**
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** General Public License version 3 or (at your option) any later version
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** the Free Software Foundation and appearing in the file LICENSE.GPL3
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#include "Qt3DSRender.h"
#include "Qt3DSRenderScene.h"
#include "Qt3DSRenderLayer.h"
#include "Qt3DSRenderContextCore.h"
#include "render/Qt3DSRenderContext.h"

using namespace qt3ds::render;

SScene::SScene()
    : SGraphObject(GraphObjectTypes::Scene)
    , m_Presentation(NULL)
    , m_FirstChild(NULL)
    , m_ClearColor(0.0f)
    , m_UseClearColor(true)
    , m_Dirty(true)
{
}

void SScene::AddChild(SLayer &inLayer)
{
    if (m_FirstChild == NULL)
        m_FirstChild = &inLayer;
    else
        GetLastChild()->m_NextSibling = &inLayer;
    inLayer.m_Scene = this;
}

SLayer *SScene::GetLastChild()
{
    // empty loop intentional
    SLayer *child;
    for (child = m_FirstChild; child && child->m_NextSibling;
         child = (SLayer *)child->m_NextSibling) {
    }

    return child;
}

bool SScene::PrepareForRender(const QT3DSVec2 &inViewportDimensions, IQt3DSRenderContext &inContext,
                              const SRenderInstanceId id)
{
    // We need to iterate through the layers in reverse order and ask them to render.
    bool wasDirty = m_Dirty;
    m_Dirty = false;
    if (m_FirstChild) {
        wasDirty |=
            inContext.GetRenderer().PrepareLayerForRender(*m_FirstChild, inViewportDimensions,
                                                          true, id);
    }
    return wasDirty;
}

void SScene::Render(const QT3DSVec2 &inViewportDimensions, IQt3DSRenderContext &inContext,
                    RenderClearCommand inClearColorBuffer, const SRenderInstanceId id)
{
    if ((inClearColorBuffer == SScene::ClearIsOptional && m_UseClearColor)
        || inClearColorBuffer == SScene::AlwaysClear) {
        QT3DSF32 clearColorAlpha
                = inContext.IsInSubPresentation() && !m_UseClearColor ? 0.0f : 1.0f;
        QT3DSVec4 clearColor(0.0f, 0.0f, 0.0f, clearColorAlpha);
        if (m_UseClearColor) {
            clearColor.x = m_ClearColor.x;
            clearColor.y = m_ClearColor.y;
            clearColor.z = m_ClearColor.z;
            clearColor.w = m_ClearColor.w;
        }
        // Maybe clear and reset to previous clear color after we leave.
        qt3ds::render::NVRenderContextScopedProperty<QT3DSVec4> __clearColor(
            inContext.GetRenderContext(), &NVRenderContext::GetClearColor,
            &NVRenderContext::SetClearColor, clearColor);
        inContext.GetRenderContext().Clear(qt3ds::render::NVRenderClearValues::Color);
    }
    if (m_FirstChild) {
        inContext.GetRenderer().RenderLayer(*m_FirstChild, inViewportDimensions, m_UseClearColor,
                                            m_ClearColor, true, id);
    }
}
void SScene::RenderWithClear(const QT3DSVec2 &inViewportDimensions,
                             IQt3DSRenderContext &inContext,
                             RenderClearCommand inClearColorBuffer,
                             QT3DSVec4 inClearColor,
                             const SRenderInstanceId id)
{
    // If this scene is not using clear color, we set the color
    // to background color from parent layer. This allows
    // fully transparent subpresentations (both scene and layer(s) transparent)
    // to inherit color from the layer that contains them.
    if (!m_UseClearColor) {
        m_ClearColor = inClearColor;
        m_UseClearColor = true;
    }
    Render(inViewportDimensions, inContext, inClearColorBuffer, id);
}