visualization/offscreen/main.cxx

Refer to the Offscreen Rendering Example.

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// $Id$
//
// Copyright (C) 2008-2014, Roman Lygin. All rights reserved.
// Copyright (C) 2014-2021, CADEX. All rights reserved.
//
// This file is part of the CAD Exchanger software.
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//
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// modification, are permitted provided that the following conditions are met:
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//   this list of conditions and the following disclaimer.
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#define __CADEX_PREVIEW_VISUALIZATION 1

#include <cadex/Base_Exception.hxx>
#include <cadex/Base_String.hxx>
#include <cadex/Base_Settings.hxx>
#include <cadex/LicenseManager_Activate.h>
#include <cadex/ModelData_Model.hxx>
#include <cadex/ModelPrs_OffscreenViewPort.hxx>
#include <cadex/ModelPrs_Scene.hxx>
#include <cadex/ModelPrs_SceneNode.hxx>
#include <cadex/ModelPrs_SceneNodeFactory.hxx>
#include <cadex/ModelPrs_SceneNodeFactoryParameters.hxx>
#include <cadex/ModelPrs_BackgroundStyle.hxx>
#include <cadex/STEP_Reader.hxx>
#include <cadex/STEP_ReaderParameters.hxx>

#include <iostream>

#include "../../cadex_license.cxx"


using namespace std;
using namespace cadex;

int main (int argc, char *argv[])
{
    auto aKey = LicenseKey::Value();

    // Activate the license (aKey must be defined in cadex_license.cxx)
    if (!CADExLicense_Activate (aKey)) {
        cerr << "Failed to activate CAD Exchanger license." << endl;
        return 1;
    }

    if (argc != 3) {
        cerr << "Usage: " << argv[0] << " <input_file> <output_file>, where:"     << endl;
        cerr << "    <input_file>  is a name of the STEP file to be read"         << endl;
        cerr << "    <output_file> is a name of the PNG  file to be write" << endl;
        return 1;
    }

    const char* aSource = argv[1];
    const char* aDest   = argv[2];

    STEP_Reader aReader;
    STEP_ReaderParameters& aReaderParams = aReader.Parameters();

    // Let's set new parameters
    aReaderParams.PreferredBRepRepresentationType() = STEP_ReaderParameters::AdvancedBRep;

    ModelData_Model aModel;

    // Reading the file
    if (!aReader.ReadFile (aSource)) {
        cerr << "Failed to read the file " << aSource << endl;
        return 1;
    }

    // Making a model data
    if (!aReader.Transfer (aModel)) {
        cerr << "Failed to transfer the file into inner format." << endl;
        return 1;
    }

    // Use exceptions to get human-readable errors on fail
    Base_Settings::Default()->SetValue (Base_Settings::UseExceptions, true);

    try {

        // Setup parameters to display one of available representation
        ModelPrs_SceneNodeFactoryParameters aParameters (ModelData_RM_Any);

        // Convert model into visualisation entities
        ModelPrs_SceneNodeFactory aFactory (aParameters);
        auto aRootNode = aFactory.Create (aModel);
        aRootNode.SetDisplayMode (ModelPrs_DM_ShadedWithBoundaries);

        // Create scene and display all entities
        ModelPrs_Scene aScene;
        aScene.AddRoot (aRootNode);

        // Setup offscreen viewport with transparent background and perspective camera
        ModelPrs_OffscreenViewPort aViewPort;
        aViewPort.Resize (800, 600);
        aViewPort.SetCameraProjectionType (ModelPrs_CPT_Perspective);
        aViewPort.SetCameraPositionType (ModelPrs_CMT_Default);
        ModelData_Color aBackgroundColor (0x00000000);
        ModelPrs_BackgroundStyle aStyle (aBackgroundColor);
        aViewPort.SetBackgroundStyle (aStyle);

        // Attach viewport to the scene.
        if (!aViewPort.AttachToScene (aScene)) {
            cerr << "Unable to attach viewport to scene" << endl;
            return 1;
        }

        // Apply scene changes to viewport and wait until all async operations will be finished
        aScene.Update();
        aScene.Wait();

        // Fit and center model on the image
        aViewPort.FitAll();

        // Grab rendered frame into image
        if (!aViewPort.GrabToImage (aDest)) {
            cerr << "Failed to write the file " << aDest << endl;
            return 1;
        }

    } catch (const Base_Exception& theEx) {
        cerr << theEx.What() << endl;
        return 1;
    }

    return 0;
}