/*************************************************************************/
/*  shader_gles2.h                                                       */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
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/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
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/*************************************************************************/
#ifndef SHADER_GLES2_H
#define SHADER_GLES2_H

#ifdef GLES2_ENABLED

#include "platform_config.h"
#ifndef GLES2_INCLUDE_H
#include <GLES2/gl2.h>
#else
#include GLES2_INCLUDE_H
#endif

#include "hash_map.h"
#include "map.h"
#include "variant.h"
#include "camera_matrix.h"

/**
	@author Juan Linietsky <reduzio@gmail.com>
*/


class ShaderGLES2 {
protected:	

	struct Enum {

		uint64_t mask;
		uint64_t shift;
		const char *defines[16];
	};

	struct EnumValue {

		uint64_t set_mask;
		uint64_t clear_mask;
	};

	struct AttributePair {

		const char *name;
		int index;
	};

	struct UniformPair {
		const char* name;
		Variant::Type type_hint;
	};

	struct TexUnitPair {

		const char *name;
		int index;
	};

	bool uniforms_dirty;
private:	

	//@TODO Optimize to a fixed set of shader pools and use a LRU
	int uniform_count;
	int texunit_pair_count;
	int conditional_count;
	int vertex_code_start;
	int fragment_code_start;
	int attribute_pair_count;

	struct CustomCode {

		String vertex;
		String vertex_globals;
		String fragment;
		String fragment_globals;
		String light;
		uint32_t version;
		Vector<StringName> custom_uniforms;
		Vector<const char*> custom_defines;

	};


	struct Version {
		
		GLuint id;
		GLuint vert_id;
		GLuint frag_id;					
		GLint *uniform_location;
		Vector<GLint> custom_uniform_locations;
		uint32_t code_version;
		bool ok;
		Version() { code_version=0; ok=false; uniform_location=NULL; }
	};
	
	Version *version;

	union VersionKey {

		struct {
			uint32_t version;
			uint32_t code_version;
		};
		uint64_t key;
		bool operator==(const VersionKey& p_key) const { return key==p_key.key; }
		bool operator<(const VersionKey& p_key) const { return key<p_key.key; }

	};

	struct VersionKeyHash {

		static _FORCE_INLINE_ uint32_t hash( const VersionKey& p_key) { return HashMapHahserDefault::hash(p_key.key); };
	};

	//this should use a way more cachefriendly version..
	HashMap<VersionKey,Version,VersionKeyHash> version_map;

	HashMap<uint32_t,CustomCode> custom_code_map;
	uint32_t last_custom_code;
	
	
	VersionKey conditional_version;
	VersionKey new_conditional_version;
	
	virtual String get_shader_name() const=0;
	
	const char** conditional_defines;
	const char** uniform_names;
	const AttributePair *attribute_pairs;
	const TexUnitPair *texunit_pairs;
	const char* vertex_code;
	const char* fragment_code;
	CharString fragment_code0;
	CharString fragment_code1;
	CharString fragment_code2;
	CharString fragment_code3;

	CharString vertex_code0;
	CharString vertex_code1;
	CharString vertex_code2;

	Version * get_current_version();
	
	static ShaderGLES2 *active;

	_FORCE_INLINE_ void _set_uniform_variant(GLint p_uniform,const Variant& p_value) {

		if (p_uniform<0)
			return; // do none
		switch(p_value.get_type()) {

		case Variant::BOOL:
		case Variant::INT:/* {

			int val=p_value;
			glUniform1i( p_uniform, val );
		} break; */
		case Variant::REAL: {

			real_t val=p_value;
			glUniform1f( p_uniform, val );
		} break;
		case Variant::COLOR: {

			Color val=p_value;
			glUniform4f( p_uniform, val.r, val.g,val.b,val.a );
		} break;
		case Variant::VECTOR2: {

			Vector2 val=p_value;
			glUniform2f( p_uniform, val.x,val.y );
		} break;
		case Variant::VECTOR3: {

			Vector3 val=p_value;
			glUniform3f( p_uniform, val.x,val.y,val.z );
		} break;
		case Variant::PLANE: {

			Plane val=p_value;
			glUniform4f( p_uniform, val.normal.x,val.normal.y,val.normal.z,val.d );
		} break;
		case Variant::QUAT: {

			Quat val=p_value;
			glUniform4f( p_uniform, val.x,val.y,val.z,val.w );
		} break;

		case Variant::MATRIX32: {

			Matrix32 tr=p_value;
			GLfloat matrix[16]={ /* build a 16x16 matrix */
				tr.elements[0][0],
				tr.elements[0][1],
				0,
				0,
				tr.elements[1][0],
				tr.elements[1][1],
				0,
				0,
				0,
				0,
				1,
				0,
				tr.elements[2][0],
				tr.elements[2][1],
				0,
				1
			};

			glUniformMatrix4fv(p_uniform,1,false,matrix);

		} break;
		case Variant::MATRIX3:
		case Variant::TRANSFORM: {

			Transform tr=p_value;
			GLfloat matrix[16]={ /* build a 16x16 matrix */
				tr.basis.elements[0][0],
				tr.basis.elements[1][0],
				tr.basis.elements[2][0],
				0,
				tr.basis.elements[0][1],
				tr.basis.elements[1][1],
				tr.basis.elements[2][1],
				0,
				tr.basis.elements[0][2],
				tr.basis.elements[1][2],
				tr.basis.elements[2][2],
				0,
				tr.origin.x,
				tr.origin.y,
				tr.origin.z,
				1
			};


			glUniformMatrix4fv(p_uniform,1,false,matrix);
		} break;
		default: { ERR_FAIL(); } // do nothing

		}	
	}

	Map<uint32_t,Variant> uniform_defaults;
	Map<uint32_t,CameraMatrix> uniform_cameras;


protected:	

	_FORCE_INLINE_ int _get_uniform(int p_which) const;
	_FORCE_INLINE_ void _set_conditional(int p_which, bool p_value);
	
	void setup(const char** p_conditional_defines, int p_conditional_count,const char** p_uniform_names,int p_uniform_count, const AttributePair* p_attribute_pairs, int p_attribute_count, const TexUnitPair *p_texunit_pairs, int p_texunit_pair_count,const char*p_vertex_code, const char *p_fragment_code,int p_vertex_code_start,int p_fragment_code_start);
	
	ShaderGLES2();
public:
	
	enum {
		CUSTOM_SHADER_DISABLED=0
	};

	GLint get_uniform_location(const String& p_name) const;
	GLint get_uniform_location(int p_uniform) const;
	
	static _FORCE_INLINE_ ShaderGLES2 *get_active() { return active; };
	bool bind();
	void unbind();
	void bind_uniforms();

	
	inline GLuint get_program() const { return version?version->id:0; }
	
	void clear_caches();

	uint32_t create_custom_shader();
	void set_custom_shader_code(uint32_t p_id,const String& p_vertex, const String& p_vertex_globals,const String& p_fragment,const String& p_p_light,const String& p_fragment_globals,const Vector<StringName>& p_uniforms,const Vector<const char*> &p_custom_defines);
	void set_custom_shader(uint32_t p_id);
	void free_custom_shader(uint32_t p_id);

	void set_uniform_default(int p_idx, const Variant& p_value) {

		if (p_value.get_type()==Variant::NIL) {

			uniform_defaults.erase(p_idx);
		} else {

			uniform_defaults[p_idx]=p_value;
		}
		uniforms_dirty = true;
	};

	uint32_t get_version() const { return new_conditional_version.version; }

	void set_uniform_camera(int p_idx, const CameraMatrix& p_mat) {

		uniform_cameras[p_idx] = p_mat;
		uniforms_dirty = true;
	};

	_FORCE_INLINE_ void set_custom_uniform(int p_idx, const Variant& p_value) {

		ERR_FAIL_COND(!version);
		ERR_FAIL_INDEX(p_idx,version->custom_uniform_locations.size());
		_set_uniform_variant( version->custom_uniform_locations[p_idx], p_value );
	}
	
	_FORCE_INLINE_ GLint get_custom_uniform_location(int p_idx) {

		ERR_FAIL_COND_V(!version,-1);
		ERR_FAIL_INDEX_V(p_idx,version->custom_uniform_locations.size(),-1);
		return version->custom_uniform_locations[p_idx];
	}

	virtual void init()=0;
	void finish();

	virtual ~ShaderGLES2();

};


// called a lot, made inline 


int ShaderGLES2::_get_uniform(int p_which) const {
	
	ERR_FAIL_INDEX_V( p_which, uniform_count,-1 );
	ERR_FAIL_COND_V( !version, -1 );
	return version->uniform_location[p_which];
}

void ShaderGLES2::_set_conditional(int p_which, bool p_value) {
	
	ERR_FAIL_INDEX(p_which,conditional_count);
	if (p_value)
		new_conditional_version.version|=(1<<p_which);
	else
		new_conditional_version.version&=~(1<<p_which);
}

#endif
#endif
