// This file may be redistributed and modified only under the terms of
// the GNU General Public License (See COPYING for details).
// Copyright (C) 2003 Alistair Riddoch

#ifndef MERCATOR_FILL_THRESHOLD_SHADER_H
#define MERCATOR_FILL_THRESHOLD_SHADER_H

#include "Shader.h"

namespace Mercator {

/// \brief Surface shader that defines the surface above a given level.
class HighShader : public Shader {
private:
	/// The level above which the shader renders.
	float m_threshold;
public:
	/// Key string used when specifying the threshold parameter.
	static const std::string key_threshold;

	/// Default level above which the shader renders.
	static const float default_threshold;

	/// \brief Constructor
	///
	/// @param threshold level below which the shader renders.
	explicit HighShader(float threshold = default_threshold);

	/// \brief Constructor
	///
	/// @param params a map of parameters for the shader.
	explicit HighShader(const Parameters& params);

	~HighShader() override;

	/// Accessor for level above which the shader renders.
	float threshold() const { return m_threshold; }

	bool checkIntersect(const Segment&) const override;

	void shade(Surface&) const override;
};

/// \brief Surface shader that defines the surface below a given level.
class LowShader : public Shader {
private:
	/// The level below which the shader renders.
	float m_threshold;
public:
	/// Key string used when specifying the threshold parameter.
	static const std::string key_threshold;

	/// Default level below which the shader renders.
	static const float default_threshold;

	/// \brief Constructor
	///
	/// @param threshold level below which the shader renders.
	explicit LowShader(float threshold = default_threshold);

	/// \brief Constructor
	///
	/// @param params a map of parameters for the shader.
	explicit LowShader(const Parameters& params);

	~LowShader() override;

	/// Accessor for level below which the shader renders.
	float threshold() const { return m_threshold; }

	bool checkIntersect(const Segment&) const override;

	void shade(Surface&) const override;
};

/// \brief Surface shader that defines the surface between two levels.
class BandShader : public Shader {
private:
	/// The level above which the shader renders.
	float m_lowThreshold;
	/// The level below which the shader renders.
	float m_highThreshold;
public:
	/// Key string used when specifying the low threshold parameter.
	static const std::string key_lowThreshold;
	/// Key string used when specifying the high threshold parameter.
	static const std::string key_highThreshold;

	/// Default level above which the shader renders.
	static const float default_lowThreshold;
	/// Default level below which the shader renders.
	static const float default_highThreshold;

	/// \brief Constructor
	///
	/// @param low_threshold level above which the shader renders.
	/// @param high_threshold level below which the shader renders.
	explicit BandShader(float low_threshold = default_lowThreshold,
						float high_threshold = default_highThreshold);

	/// \brief Constructor
	///
	/// @param params a map of parameters for the shader.
	explicit BandShader(const Parameters& params);

	~BandShader() override;

	/// Accessor for the level above which the shader renders.
	float lowThreshold() const { return m_lowThreshold; }

	/// Accessor for the level below which the shader renders.
	float highThreshold() const { return m_highThreshold; }

	bool checkIntersect(const Segment&) const override;

	void shade(Surface&) const override;
};

} // namespace Mercator

#endif // MERCATOR_FILL_THRESHOLD_SHADER_H
