2017-05
http://blog.qt.io/blog/2017/05/24/qt3d/
Qt3D future
    5.9
        Use Qt Quick or QPainter to render into a texture
        Embed Qt Quick into Qt3D, including input handling
        Level of Detail support for meshes
        Text support - 2D and 3D
        Additional materials such as PBR materials
    others
        Generating and filling buffers out of QAbstractItemModels
        Billboards - camera facing entities
        Particle systems
        VR support
    new aspects:
        碰撞检测
        动画：关键帧动画；骨骼动画；Morph target animation; Removes animation workload from main thread
        物理：刚体／柔体物理模拟
        AI: 
        三维位置音效：如喇叭，越近越响
    工具
        设计时工具：场景设计器
        Qt 3D Studio
        编译时工具：资产状态监控
    More
        贴图控制
        可yizhi算法（OpenGL）
        各种3d模型的加载

2d ui嵌入到 3d里面用Scene2D
    Scene2D {
        id: qmlTexture
        output: RenderTargetOutput {
            attachmentPoint: RenderTargetOutput.Color0
            texture: Texture2D { id: offscreenTexture }
        }
        entities: [ cube ]
        Item {
            id: customQtQuickStuff
        }
    }
        

纹理加载器
    TextureLoader {
        source: "qrc:/assets/textures/pbr-default/pbr-default-metallic.png"
        minificationFilter: Texture.LinearMipMapLinear
        magnificationFilter: Texture.Linear
        wrapMode {
            x: WrapMode.ClampToEdge
            y: WrapMode.ClampToEdge
        }
        generateMipMaps: true
    }
    
新增材质
    粗糙金属材质
        MetalRoughMaterial
    粗糙金属纹理材质
        TexturedMetalRoughMaterial {
            baseColor: TextureLoader {
                format: Texture.SRGB8_Alpha8
                source: "qrc:/assets/powerup/basecolor.png"
            }
            metalness: TextureLoader { source: "qrc:/assets/powerup/metalness.png" }
            roughness: TextureLoader { source: "qrc:/assets/powerup/roughness.png" }
            normal: TextureLoader { source: "qrc:/assets/powerup/normal.png" }
            ambientOcclusion: TextureLoader { source: "qrc:/assets/powerup/ambientocclusion.png" }
        }
        
新增环境光    
    EnvironmentLight {
        id: envLight
        irradiance: TextureLoader {
            source: "qrc:/assets/envmaps/wobbly-bridge/wobbly_bridge_4k" + _envmapFormat + "_cube_irradiance.dds"

            minificationFilter: Texture.LinearMipMapLinear
            magnificationFilter: Texture.Linear
            wrapMode {
                x: WrapMode.ClampToEdge
                y: WrapMode.ClampToEdge
            }
            generateMipMaps: false
        }
        specular: TextureLoader {
            source: "qrc:/assets/envmaps/wobbly-bridge/wobbly_bridge_4k" + _envmapFormat + "_cube_specular.dds"

            minificationFilter: Texture.LinearMipMapLinear
            magnificationFilter: Texture.Linear
            wrapMode {
                x: WrapMode.ClampToEdge
                y: WrapMode.ClampToEdge
            }
            generateMipMaps: false
        }
    }
            

天空盒实体
    SkyboxEntity {
        baseName: "qrc:/assets/envmaps/wobbly-bridge/wobbly_bridge_4k" + _envmapFormat + "_cube_radiance"
        extension: ".dds"
        gammaCorrect: true
    }            
    

相机增加曝光度属性
    Camera {
        id: mainCamera
        position: Qt.vector3d(-10, 0, 0)
        viewCenter: Qt.vector3d(0, 0, 0)
        exposure: 1.4  // 曝光度
    }

加载预设的动画    
    import Qt3D.Animation 2.9
    ClipAnimator {
        id: animator
        loops: 3
        clip: AnimationClipLoader { source: "qrc:/jumpinganimation.json" }
        channelMapper: ChannelMapper {
            mappings: [
                ChannelMapping { channelName: "Location"; target: cubeTransform; property: "translation" },
                ChannelMapping { channelName: "Rotation"; target: cubeTransform; property: "rotation" },
                ChannelMapping { channelName: "Scale"; target: cubeTransform; property: "scale3D" }
            ]
        }
    }
对象选择器
    ObjectPicker { onClicked: animator.running = true;}


根据远近来动态调整场景（volumeOverride）
    LevelOfDetail
        Entity {
            components: [
                CylinderMesh {
                    radius: 1
                    length: 3
                    rings: 2
                    slices: sliceValues[lod.currentIndex]
                    property var sliceValues: [20, 10, 6, 4]
                },
                Transform {
                    rotation: fromAxisAndAngle(Qt.vector3d(1, 0, 0), 45)
                },
                PhongMaterial {
                    diffuse: "lightgreen"
                },
                LevelOfDetail {
                    id: lod
                    camera: camera
                    thresholds: [1000, 600, 300, 180]
                    thresholdType: LevelOfDetail.ProjectedScreenPixelSizeThreshold
                    volumeOverride: lod.createBoundingSphere(Qt.vector3d(0, 0, 0), 2.0)
                }
            ]
        }
    LevelOfDetailSwitch
        Entity {
            components: [
                LevelOfDetailSwitch {
                    camera: camera
                    thresholds: [20, 35, 50]
                    thresholdType: LevelOfDetail.DistanceToCameraThreshold
                }
            ]
            HighDetailEntity { enabled: false }
            MediumDetailEntity { enabled: false }
            LowDetailEntity { enabled: false }
        }
    LevelOfDetailLoader
        LevelOfDetailLoader {
            id: lodLoader
            camera: camera
            thresholds: [20, 35, 50]
            thresholdType: LevelOfDetail.DistanceToCameraThreshold
            volumeOverride: lodLoader.createBoundingSphere(Qt.vector3d(0, 0, 0), -1)
            sources: ["qrc:/HighDetailEntity.qml", "qrc:/MediumDetailEntity.qml", "qrc:/LowDetailEntity.qml"]
        }
    

渲染文本
    Text2DEntity
        Text2DEntity {
            id: text
            text: "Hello World"
            width: 20
            height: 10
        }
    ExtrudedTextMesh
        auto *text = new Qt3DCore::QEntity(root);
        auto *textTransform = new Qt3DCore::QTransform();
        auto *textMesh = new Qt3DExtras::QExtrudedTextMesh();
        textMesh->setDepth(.45f);
        QFont font(family, 32, -1, false);
        textMesh->setFont(font);
        textMesh->setText(QString(family));
        auto *textMaterial = new Qt3DExtras::QPhongMaterial(root);
        textMaterial->setDiffuse(QColor(111, 150, 255));
        text->addComponent(textTransform);
        text->addComponent(textMesh);
        text->addComponent(textMaterial);