/*************************************************************************/
/*  shader.h                                                             */
/*************************************************************************/
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#ifndef SHADER_H
#define SHADER_H

#include "core/io/resource.h"
#include "core/io/resource_loader.h"
#include "core/io/resource_saver.h"
#include "scene/resources/texture.h"

class Shader : public Resource {
	GDCLASS(Shader, Resource);
	OBJ_SAVE_TYPE(Shader);

public:
	enum Mode {
		MODE_SPATIAL,
		MODE_CANVAS_ITEM,
		MODE_PARTICLES,
		MODE_SKY,
		MODE_MAX
	};

private:
	RID shader;
	Mode mode = MODE_SPATIAL;

	// hack the name of performance
	// shaders keep a list of ShaderMaterial -> RenderingServer name translations, to make
	// conversion fast and save memory.
	mutable bool params_cache_dirty = true;
	mutable Map<StringName, StringName> params_cache; //map a shader param to a material param..
	Map<StringName, Ref<Texture2D>> default_textures;

	virtual void _update_shader() const; //used for visual shader
protected:
	static void _bind_methods();

public:
	//void set_mode(Mode p_mode);
	virtual Mode get_mode() const;

	void set_code(const String &p_code);
	String get_code() const;

	void get_param_list(List<PropertyInfo> *p_params) const;
	bool has_param(const StringName &p_param) const;

	void set_default_texture_param(const StringName &p_param, const Ref<Texture2D> &p_texture);
	Ref<Texture2D> get_default_texture_param(const StringName &p_param) const;
	void get_default_texture_param_list(List<StringName> *r_textures) const;

	virtual bool is_text_shader() const;

	_FORCE_INLINE_ StringName remap_param(const StringName &p_param) const {
		if (params_cache_dirty) {
			get_param_list(nullptr);
		}

		const Map<StringName, StringName>::Element *E = params_cache.find(p_param);
		if (E) {
			return E->get();
		}
		return StringName();
	}

	virtual RID get_rid() const override;

	Shader();
	~Shader();
};

VARIANT_ENUM_CAST(Shader::Mode);

class ResourceFormatLoaderShader : public ResourceFormatLoader {
public:
	virtual RES load(const String &p_path, const String &p_original_path = "", Error *r_error = nullptr, bool p_use_sub_threads = false, float *r_progress = nullptr, bool p_no_cache = false);
	virtual void get_recognized_extensions(List<String> *p_extensions) const;
	virtual bool handles_type(const String &p_type) const;
	virtual String get_resource_type(const String &p_path) const;
};

class ResourceFormatSaverShader : public ResourceFormatSaver {
public:
	virtual Error save(const String &p_path, const RES &p_resource, uint32_t p_flags = 0);
	virtual void get_recognized_extensions(const RES &p_resource, List<String> *p_extensions) const;
	virtual bool recognize(const RES &p_resource) const;
};

#endif // SHADER_H