/*************************************************************************/
/*  shader_rd.h                                                          */
/*************************************************************************/
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/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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#ifndef SHADER_RD_H
#define SHADER_RD_H

#include "core/os/mutex.h"
#include "core/string/string_builder.h"
#include "core/templates/hash_map.h"
#include "core/templates/local_vector.h"
#include "core/templates/map.h"
#include "core/templates/rid_owner.h"
#include "core/variant/variant.h"
#include "servers/rendering_server.h"

class ShaderRD {
	//versions
	CharString general_defines;
	Vector<CharString> variant_defines;
	Vector<bool> variants_enabled;

	struct Version {
		CharString uniforms;
		CharString vertex_globals;
		CharString compute_globals;
		CharString fragment_globals;
		Map<StringName, CharString> code_sections;
		Vector<CharString> custom_defines;

		Vector<uint8_t> *variant_data = nullptr;
		RID *variants = nullptr; //same size as version defines

		bool valid;
		bool dirty;
		bool initialize_needed;
	};

	Mutex variant_set_mutex;

	void _compile_variant(uint32_t p_variant, Version *p_version);

	void _clear_version(Version *p_version);
	void _compile_version(Version *p_version);

	RID_Owner<Version> version_owner;

	struct StageTemplate {
		struct Chunk {
			enum Type {
				TYPE_VERSION_DEFINES,
				TYPE_MATERIAL_UNIFORMS,
				TYPE_VERTEX_GLOBALS,
				TYPE_FRAGMENT_GLOBALS,
				TYPE_COMPUTE_GLOBALS,
				TYPE_CODE,
				TYPE_TEXT
			};

			Type type;
			StringName code;
			CharString text;
		};
		LocalVector<Chunk> chunks;
	};

	bool is_compute = false;

	String name;

	CharString base_compute_defines;

	String base_sha256;

	static String shader_cache_dir;
	static bool shader_cache_cleanup_on_start;
	static bool shader_cache_save_compressed;
	static bool shader_cache_save_compressed_zstd;
	static bool shader_cache_save_debug;
	bool shader_cache_dir_valid = false;

	enum StageType {
		STAGE_TYPE_VERTEX,
		STAGE_TYPE_FRAGMENT,
		STAGE_TYPE_COMPUTE,
		STAGE_TYPE_MAX,
	};

	StageTemplate stage_templates[STAGE_TYPE_MAX];

	void _build_variant_code(StringBuilder &p_builder, uint32_t p_variant, const Version *p_version, const StageTemplate &p_template);

	void _add_stage(const char *p_code, StageType p_stage_type);

	String _version_get_sha1(Version *p_version) const;
	bool _load_from_cache(Version *p_version);
	void _save_to_cache(Version *p_version);

protected:
	ShaderRD();
	void setup(const char *p_vertex_code, const char *p_fragment_code, const char *p_compute_code, const char *p_name);

public:
	RID version_create();

	void version_set_code(RID p_version, const Map<String, String> &p_code, const String &p_uniforms, const String &p_vertex_globals, const String &p_fragment_globals, const Vector<String> &p_custom_defines);
	void version_set_compute_code(RID p_version, const Map<String, String> &p_code, const String &p_uniforms, const String &p_compute_globals, const Vector<String> &p_custom_defines);

	_FORCE_INLINE_ RID version_get_shader(RID p_version, int p_variant) {
		ERR_FAIL_INDEX_V(p_variant, variant_defines.size(), RID());
		ERR_FAIL_COND_V(!variants_enabled[p_variant], RID());

		Version *version = version_owner.get_or_null(p_version);
		ERR_FAIL_COND_V(!version, RID());

		if (version->dirty) {
			_compile_version(version);
		}

		if (!version->valid) {
			return RID();
		}

		return version->variants[p_variant];
	}

	bool version_is_valid(RID p_version);

	bool version_free(RID p_version);

	void set_variant_enabled(int p_variant, bool p_enabled);
	bool is_variant_enabled(int p_variant) const;

	static void set_shader_cache_dir(const String &p_dir);
	static void set_shader_cache_save_compressed(bool p_enable);
	static void set_shader_cache_save_compressed_zstd(bool p_enable);
	static void set_shader_cache_save_debug(bool p_enable);

	RS::ShaderNativeSourceCode version_get_native_source_code(RID p_version);

	void initialize(const Vector<String> &p_variant_defines, const String &p_general_defines = "");
	virtual ~ShaderRD();
};

#endif // SHADER_RD_H