Examples » Model Viewer » ViewerExample.cpp source

/*
    This file is part of Magnum.

    Original authors — credit is appreciated but not required:

        2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
        2020, 2021, 2022 — Vladimír Vondruš <mosra@centrum.cz>

    This is free and unencumbered software released into the public domain.

    Anyone is free to copy, modify, publish, use, compile, sell, or distribute
    this software, either in source code form or as a compiled binary, for any
    purpose, commercial or non-commercial, and by any means.

    In jurisdictions that recognize copyright laws, the author or authors of
    this software dedicate any and all copyright interest in the software to
    the public domain. We make this dedication for the benefit of the public
    at large and to the detriment of our heirs and successors. We intend this
    dedication to be an overt act of relinquishment in perpetuity of all
    present and future rights to this software under copyright law.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include <Corrade/Containers/Array.h>
#include <Corrade/Containers/Optional.h>
#include <Corrade/Containers/Pair.h>
#include <Corrade/PluginManager/Manager.h>
#include <Corrade/Utility/Arguments.h>
#include <Corrade/Utility/DebugStl.h>
#include <Magnum/ImageView.h>
#include <Magnum/Mesh.h>
#include <Magnum/PixelFormat.h>
#include <Magnum/GL/DefaultFramebuffer.h>
#include <Magnum/GL/Mesh.h>
#include <Magnum/GL/Renderer.h>
#include <Magnum/GL/Texture.h>
#include <Magnum/GL/TextureFormat.h>
#include <Magnum/Math/Color.h>
#include <Magnum/MeshTools/Compile.h>
#include <Magnum/Platform/Sdl2Application.h>
#include <Magnum/SceneGraph/Camera.h>
#include <Magnum/SceneGraph/Drawable.h>
#include <Magnum/SceneGraph/MatrixTransformation3D.h>
#include <Magnum/SceneGraph/Scene.h>
#include <Magnum/Shaders/PhongGL.h>
#include <Magnum/Trade/AbstractImporter.h>
#include <Magnum/Trade/ImageData.h>
#include <Magnum/Trade/MeshData.h>
#include <Magnum/Trade/PhongMaterialData.h>
#include <Magnum/Trade/SceneData.h>
#include <Magnum/Trade/TextureData.h>

namespace Magnum { namespace Examples {

using namespace Math::Literals;

typedef SceneGraph::Object<SceneGraph::MatrixTransformation3D> Object3D;
typedef SceneGraph::Scene<SceneGraph::MatrixTransformation3D> Scene3D;

class ViewerExample: public Platform::Application {
    public:
        explicit ViewerExample(const Arguments& arguments);

    private:
        void drawEvent() override;
        void viewportEvent(ViewportEvent& event) override;
        void mousePressEvent(MouseEvent& event) override;
        void mouseReleaseEvent(MouseEvent& event) override;
        void mouseMoveEvent(MouseMoveEvent& event) override;
        void mouseScrollEvent(MouseScrollEvent& event) override;

        Vector3 positionOnSphere(const Vector2i& position) const;

        Shaders::PhongGL _coloredShader,
            _texturedShader{Shaders::PhongGL::Flag::DiffuseTexture};
        Containers::Array<Containers::Optional<GL::Mesh>> _meshes;
        Containers::Array<Containers::Optional<GL::Texture2D>> _textures;

        Scene3D _scene;
        Object3D _manipulator, _cameraObject;
        SceneGraph::Camera3D* _camera;
        SceneGraph::DrawableGroup3D _drawables;
        Vector3 _previousPosition;
};

class ColoredDrawable: public SceneGraph::Drawable3D {
    public:
        explicit ColoredDrawable(Object3D& object, Shaders::PhongGL& shader, GL::Mesh& mesh, const Color4& color, SceneGraph::DrawableGroup3D& group): SceneGraph::Drawable3D{object, &group}, _shader(shader), _mesh(mesh), _color{color} {}

    private:
        void draw(const Matrix4& transformationMatrix, SceneGraph::Camera3D& camera) override;

        Shaders::PhongGL& _shader;
        GL::Mesh& _mesh;
        Color4 _color;
};

class TexturedDrawable: public SceneGraph::Drawable3D {
    public:
        explicit TexturedDrawable(Object3D& object, Shaders::PhongGL& shader, GL::Mesh& mesh, GL::Texture2D& texture, SceneGraph::DrawableGroup3D& group): SceneGraph::Drawable3D{object, &group}, _shader(shader), _mesh(mesh), _texture(texture) {}

    private:
        void draw(const Matrix4& transformationMatrix, SceneGraph::Camera3D& camera) override;

        Shaders::PhongGL& _shader;
        GL::Mesh& _mesh;
        GL::Texture2D& _texture;
};

ViewerExample::ViewerExample(const Arguments& arguments):
    Platform::Application{arguments, Configuration{}
        .setTitle("Magnum Viewer Example")
        .setWindowFlags(Configuration::WindowFlag::Resizable)}
{
    Utility::Arguments args;
    args.addArgument("file").setHelp("file", "file to load")
        .addOption("importer", "AnySceneImporter")
            .setHelp("importer", "importer plugin to use")
        .addSkippedPrefix("magnum", "engine-specific options")
        .setGlobalHelp("Displays a 3D scene file provided on command line.")
        .parse(arguments.argc, arguments.argv);

    _cameraObject
        .setParent(&_scene)
        .translate(Vector3::zAxis(5.0f));
    (*(_camera = new SceneGraph::Camera3D{_cameraObject}))
        .setAspectRatioPolicy(SceneGraph::AspectRatioPolicy::Extend)
        .setProjectionMatrix(
            Matrix4::perspectiveProjection(35.0_degf, 1.0f, 0.01f, 1000.0f)
        )
        .setViewport(GL::defaultFramebuffer.viewport().size());

    _manipulator.setParent(&_scene);

    /* Setup renderer and shader defaults */
    GL::Renderer::enable(GL::Renderer::Feature::DepthTest);
    GL::Renderer::enable(GL::Renderer::Feature::FaceCulling);
    _coloredShader
        .setAmbientColor(0x111111_rgbf)
        .setSpecularColor(0xffffff_rgbf)
        .setShininess(80.0f);
    _texturedShader
        .setAmbientColor(0x111111_rgbf)
        .setSpecularColor(0x111111_rgbf)
        .setShininess(80.0f);

    /* Load a scene importer plugin */
    PluginManager::Manager<Trade::AbstractImporter> manager;
    Containers::Pointer<Trade::AbstractImporter> importer =
        manager.loadAndInstantiate(args.value("importer"));

    if(!importer || !importer->openFile(args.value("file")))
        std::exit(1);

    /* Load all textures. Textures that fail to load will be NullOpt. */
    _textures = Containers::Array<Containers::Optional<GL::Texture2D>>{
        importer->textureCount()};
    for(UnsignedInt i = 0; i != importer->textureCount(); ++i) {
        Containers::Optional<Trade::TextureData> textureData =
            importer->texture(i);
        if(!textureData || textureData->type() != Trade::TextureType::Texture2D) {
            Warning{} << "Cannot load texture" << i
                << importer->textureName(i);
            continue;
        }

        Containers::Optional<Trade::ImageData2D> imageData =
            importer->image2D(textureData->image());
        if(!imageData || !imageData->isCompressed()) {
            Warning{} << "Cannot load image" << textureData->image()
                << importer->image2DName(textureData->image());
            continue;
        }

        (*(_textures[i] = GL::Texture2D{}))
            .setMagnificationFilter(textureData->magnificationFilter())
            .setMinificationFilter(textureData->minificationFilter(),
                                   textureData->mipmapFilter())
            .setWrapping(textureData->wrapping().xy())
            .setStorage(Math::log2(imageData->size().max()) + 1,
                GL::textureFormat(imageData->format()), imageData->size())
            .setSubImage(0, {}, *imageData)
            .generateMipmap();
    }

    /* Load all materials. Materials that fail to load will be NullOpt. Only a
       temporary array as the material attributes will be stored directly in
       drawables later. */
    Containers::Array<Containers::Optional<Trade::PhongMaterialData>> materials{
        importer->materialCount()};
    for(UnsignedInt i = 0; i != importer->materialCount(); ++i) {
        Containers::Optional<Trade::MaterialData> materialData;
        if(!(materialData = importer->material(i))) {
            Warning{} << "Cannot load material" << i
                << importer->materialName(i);
            continue;
        }

        materials[i] = std::move(*materialData).as<Trade::PhongMaterialData>();
    }

    /* Load all meshes. Meshes that fail to load will be NullOpt. Generate
       normals if not present. */
    _meshes = Containers::Array<Containers::Optional<GL::Mesh>>{
        importer->meshCount()};
    for(UnsignedInt i = 0; i != importer->meshCount(); ++i) {
        Containers::Optional<Trade::MeshData> meshData;
        if(!(meshData = importer->mesh(i))) {
            Warning{} << "Cannot load mesh" << i << importer->meshName(i);
            continue;
        }

        MeshTools::CompileFlags flags;
        if(meshData->hasAttribute(Trade::MeshAttribute::Normal))
            flags |= MeshTools::CompileFlag::GenerateFlatNormals;
        _meshes[i] = MeshTools::compile(*meshData, flags);
    }

    /* The format has no scene support, display just the first loaded mesh with
       a default material (if it's there) and be done with it. */
    if(importer->defaultScene() == -1) {
        if(!_meshes.isEmpty() && _meshes[0])
            new ColoredDrawable{_manipulator, _coloredShader, *_meshes[0],
                0xffffff_rgbf, _drawables};
        return;
    }

    /* Load the scene */
    Containers::Optional<Trade::SceneData> scene;
    if(!(scene = importer->scene(importer->defaultScene())) ||
       !scene->is3D() ||
       !scene->hasField(Trade::SceneField::Parent) ||
       !scene->hasField(Trade::SceneField::Mesh))
    {
        Fatal{} << "Cannot load scene" << importer->defaultScene()
            << importer->sceneName(importer->defaultScene());
    }

    /* Allocate objects that are part of the hierarchy */
    Containers::Array<Object3D*> objects{std::size_t(scene->mappingBound())};
    Containers::Array<Containers::Pair<UnsignedInt, Int>> parents
        = scene->parentsAsArray();
    for(const Containers::Pair<UnsignedInt, Int>& parent: parents)
        objects[parent.first()] = new Object3D{};

    /* Assign parent references */
    for(const Containers::Pair<UnsignedInt, Int>& parent: parents)
        objects[parent.first()]->setParent(parent.second() == -1 ?
            &_manipulator : objects[parent.second()]);

    /* Set transformations. Objects that are not part of the hierarchy are
       ignored, objects that have no transformation entry retain an identity
       transformation. */
    for(const Containers::Pair<UnsignedInt, Matrix4>& transformation:
        scene->transformations3DAsArray())
    {
        if(Object3D* object = objects[transformation.first()])
            object->setTransformation(transformation.second());
    }

    /* Add drawables for objects that have a mesh, again ignoring objects that
       are not part of the hierarchy. There can be multiple mesh assignments
       for one object, simply add one drawable for each. */
    for(const Containers::Pair<UnsignedInt, Containers::Pair<UnsignedInt, Int>>&
        meshMaterial: scene->meshesMaterialsAsArray())
    {
        Object3D* object = objects[meshMaterial.first()];
        Containers::Optional<GL::Mesh>& mesh =
            _meshes[meshMaterial.second().first()];
        if(!object || !mesh) continue;

        Int materialId = meshMaterial.second().second();

        /* Material not available / not loaded, use a default material */
        if(materialId == -1 || !materials[materialId]) {
            new ColoredDrawable{*object, _coloredShader, *mesh, 0xffffff_rgbf,
                _drawables};

        /* Textured material, if the texture loaded correctly */
        } else if(materials[materialId]->hasAttribute(
                Trade::MaterialAttribute::DiffuseTexture
            ) && _textures[materials[materialId]->diffuseTexture()])
        {
            new TexturedDrawable{*object, _texturedShader, *mesh,
                *_textures[materials[materialId]->diffuseTexture()],
                _drawables};

        /* Color-only material */
        } else {
            new ColoredDrawable{*object, _coloredShader, *mesh,
                materials[materialId]->diffuseColor(), _drawables};
        }
    }
}

void ColoredDrawable::draw(const Matrix4& transformationMatrix, SceneGraph::Camera3D& camera) {
    _shader
        .setDiffuseColor(_color)
        .setLightPositions({
            {camera.cameraMatrix().transformPoint({-3.0f, 10.0f, 10.0f}), 0.0f}
        })
        .setTransformationMatrix(transformationMatrix)
        .setNormalMatrix(transformationMatrix.normalMatrix())
        .setProjectionMatrix(camera.projectionMatrix())
        .draw(_mesh);
}

void TexturedDrawable::draw(const Matrix4& transformationMatrix, SceneGraph::Camera3D& camera) {
    _shader
        .setLightPositions({
            {camera.cameraMatrix().transformPoint({-3.0f, 10.0f, 10.0f}), 0.0f}
        })
        .setTransformationMatrix(transformationMatrix)
        .setNormalMatrix(transformationMatrix.normalMatrix())
        .setProjectionMatrix(camera.projectionMatrix())
        .bindDiffuseTexture(_texture)
        .draw(_mesh);
}

void ViewerExample::drawEvent() {
    GL::defaultFramebuffer.clear(GL::FramebufferClear::Color|GL::FramebufferClear::Depth);

    _camera->draw(_drawables);

    swapBuffers();
}

void ViewerExample::viewportEvent(ViewportEvent& event) {
    GL::defaultFramebuffer.setViewport({{}, event.framebufferSize()});
    _camera->setViewport(event.windowSize());
}

void ViewerExample::mousePressEvent(MouseEvent& event) {
    if(event.button() == MouseEvent::Button::Left)
        _previousPosition = positionOnSphere(event.position());
}

void ViewerExample::mouseReleaseEvent(MouseEvent& event) {
    if(event.button() == MouseEvent::Button::Left)
        _previousPosition = Vector3();
}

void ViewerExample::mouseScrollEvent(MouseScrollEvent& event) {
    if(!event.offset().y()) return;

    /* Distance to origin */
    const Float distance = _cameraObject.transformation().translation().z();

    /* Move 15% of the distance back or forward */
    _cameraObject.translate(Vector3::zAxis(
        distance*(1.0f - (event.offset().y() > 0 ? 1/0.85f : 0.85f))));

    redraw();
}

Vector3 ViewerExample::positionOnSphere(const Vector2i& position) const {
    const Vector2 positionNormalized = Vector2{position}/Vector2{_camera->viewport()} - Vector2{0.5f};
    const Float length = positionNormalized.length();
    const Vector3 result(length > 1.0f ? Vector3(positionNormalized, 0.0f) : Vector3(positionNormalized, 1.0f - length));
    return (result*Vector3::yScale(-1.0f)).normalized();
}

void ViewerExample::mouseMoveEvent(MouseMoveEvent& event) {
    if(!(event.buttons() & MouseMoveEvent::Button::Left)) return;

    const Vector3 currentPosition = positionOnSphere(event.position());
    const Vector3 axis = Math::cross(_previousPosition, currentPosition);

    if(_previousPosition.length() < 0.001f || axis.length() < 0.001f) return;

    _manipulator.rotate(Math::angle(_previousPosition, currentPosition), axis.normalized());
    _previousPosition = currentPosition;

    redraw();
}

}}

MAGNUM_APPLICATION_MAIN(Magnum::Examples::ViewerExample)