polyvox/examples/OpenGL/main.cpp

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The MIT License (MIT)

Copyright (c) 2015 David Williams and Matthew Williams

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#include "PolyVox/FilePager.h"
#include "PolyVox/MarchingCubesSurfaceExtractor.h"
#include "PolyVox/MaterialDensityPair.h"
#include "PolyVox/LowPassFilter.h"
#include "PolyVox/RawVolume.h"
#include "PolyVox/Mesh.h"
#include "PolyVox/Impl/Utility.h"

#include "Shapes.h"

#include "PolyVoxExample.h"

#ifdef WIN32
#include <windows.h>   // Standard Header For Most Programs
#endif

#include <QApplication>
#include <QTime>

//Some namespaces we need
using namespace std;
using namespace PolyVox;
using namespace std;

const int32_t g_uVolumeSideLength = 128;

class OpenGLExample : public PolyVoxExample
{
public:
	OpenGLExample(QWidget *parent)
		:PolyVoxExample(parent)
	{
	}

protected:
	void initializeExample() override
	{
		RawVolume<MaterialDensityPair88> volData(PolyVox::Region(Vector3DInt32(0, 0, 0), Vector3DInt32(g_uVolumeSideLength - 1, g_uVolumeSideLength - 1, g_uVolumeSideLength - 1)));

		//Make our volume contain a sphere in the center.
		int32_t minPos = 0;
		int32_t midPos = g_uVolumeSideLength / 2;
		int32_t maxPos = g_uVolumeSideLength - 1;

		cout << "Creating sphere 1" << std::endl;
		createSphereInVolume(volData, 60.0f, 5);
		cout << "Creating sphere 2" << std::endl;
		createSphereInVolume(volData, 50.0f, 4);
		cout << "Creating sphere 3" << std::endl;
		createSphereInVolume(volData, 40.0f, 3);
		cout << "Creating sphere 4" << std::endl;
		createSphereInVolume(volData, 30.0f, 2);
		cout << "Creating sphere 5" << std::endl;
		createSphereInVolume(volData, 20.0f, 1);

		cout << "Creating cubes" << std::endl;
		createCubeInVolume(volData, Vector3DInt32(minPos, minPos, midPos + 1), Vector3DInt32(midPos - 1, midPos - 1, maxPos), 0);
		createCubeInVolume(volData, Vector3DInt32(midPos + 1, midPos + 1, midPos + 1), Vector3DInt32(maxPos, maxPos, maxPos), 0);
		createCubeInVolume(volData, Vector3DInt32(minPos, midPos + 1, minPos), Vector3DInt32(midPos - 1, maxPos, midPos - 1), 0);
		createCubeInVolume(volData, Vector3DInt32(midPos + 1, minPos, minPos), Vector3DInt32(maxPos, midPos - 1, midPos - 1), 0);

		createCubeInVolume(volData, Vector3DInt32(1, midPos - 10, midPos - 10), Vector3DInt32(maxPos - 1, midPos + 10, midPos + 10), MaterialDensityPair44::getMaxDensity());
		createCubeInVolume(volData, Vector3DInt32(midPos - 10, 1, midPos - 10), Vector3DInt32(midPos + 10, maxPos - 1, midPos + 10), MaterialDensityPair44::getMaxDensity());
		createCubeInVolume(volData, Vector3DInt32(midPos - 10, midPos - 10, 1), Vector3DInt32(midPos + 10, midPos + 10, maxPos - 1), MaterialDensityPair44::getMaxDensity());

		QSharedPointer<QGLShaderProgram> shader(new QGLShaderProgram);

		if (!shader->addShaderFromSourceFile(QGLShader::Vertex, ":/openglexample.vert"))
		{
			std::cerr << shader->log().toStdString() << std::endl;
			exit(EXIT_FAILURE);
		}

		if (!shader->addShaderFromSourceFile(QGLShader::Fragment, ":/openglexample.frag"))
		{
			std::cerr << shader->log().toStdString() << std::endl;
			exit(EXIT_FAILURE);
		}

		setShader(shader);

		QTime time;
		time.start();
		//openGLWidget.setVolume(&volData);
		cout << endl << "Time taken = " << time.elapsed() / 1000.0f << "s" << endl << endl;

		const int32_t extractedRegionSize = 32;
		int meshCounter = 0;

		for (int32_t z = 0; z < volData.getDepth(); z += extractedRegionSize)
		{
			for (int32_t y = 0; y < volData.getHeight(); y += extractedRegionSize)
			{
				for (int32_t x = 0; x < volData.getWidth(); x += extractedRegionSize)
				{
					// Specify the region to extract based on a starting position and the desired region sze.
					PolyVox::Region regToExtract(x, y, z, x + extractedRegionSize, y + extractedRegionSize, z + extractedRegionSize);

					// If you uncomment this line you will be able to see that the volume is rendered as multiple seperate meshes.
					//regToExtract.shrink(1);

					// Perform the extraction for this region of the volume
					auto mesh = extractMarchingCubesMesh(&volData, regToExtract);

					// The returned mesh needs to be decoded to be appropriate for GPU rendering.
					auto decodedMesh = decodeMesh(mesh);

					// Pass the surface to the OpenGL window. Note that we are also passing an offset in this multi-mesh example. This is because
					// the surface extractors return a mesh with 'local space' positions to reduce storage requirements and precision problems.
					addMesh(decodedMesh, decodedMesh.getOffset());

					meshCounter++;
				}
			}
		}

		cout << "Rendering volume as " << meshCounter << " seperate meshes" << endl;

		setCameraTransform(QVector3D(150.0f, 150.0f, 150.0f), -(PI / 4.0f), PI + (PI / 4.0f));
	}
};

int main(int argc, char *argv[])
{
	//Create and show the Qt OpenGL window
	QApplication app(argc, argv);
	OpenGLExample openGLWidget(0);
	openGLWidget.show();

	//Run the message pump.
	return app.exec();
}