// Copyright (C) 2009-2010 Amundis
// Heavily based on the OpenGL driver implemented by Nikolaus Gebhardt
// and OpenGL ES driver implemented by Christian Stehno
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in Irrlicht.h

#include "IrrCompileConfig.h"
#ifdef _IRR_COMPILE_WITH_OGLES2_

#include "COGLES2SLMaterialRenderer.h"
#include "IGPUProgrammingServices.h"
#include "IShaderConstantSetCallBack.h"
#include "IMaterialRendererServices.h"
#include "IVideoDriver.h"
#include "os.h"
#include "COGLES2Driver.h"
#include "EVertexAttributes.h"
#include "COGLES2Texture.h"

#include <GLES2/gl2.h>

namespace irr
{
namespace video
{

	//! Constructor
	COGLES2SLMaterialRenderer::COGLES2SLMaterialRenderer( video::COGLES2Driver* driver,
			s32& outMaterialTypeNr, const c8* vertexShaderProgram,
			const c8* pixelShaderProgram,
			IShaderConstantSetCallBack* callback,
			video::IMaterialRenderer* baseMaterial, s32 userData )
			: Driver( driver ), CallBack( callback ), BaseMaterial( baseMaterial ), FileSystem( 0 ),
			Program( 0 ), UserData( userData ), UniformStringTable( 0 ), UniformCount( 0 )
	{
#ifdef _DEBUG
		setDebugName( "COGLES2SLMaterialRenderer" );
#endif

		//entry points must always be main, and the compile target isn't selectable
		//it is fine to ignore what has been asked for, as the compiler should spot anything wrong
		//just check that GLSL is available

		if ( BaseMaterial )
			BaseMaterial->grab();

		if ( CallBack )
			CallBack->grab();

		init( outMaterialTypeNr, vertexShaderProgram, pixelShaderProgram );
	}


	//! constructor only for use by derived classes who want to
	//! create a fall back material for example.
	COGLES2SLMaterialRenderer::COGLES2SLMaterialRenderer( COGLES2Driver* driver,
														  io::IFileSystem* fs,
														  IShaderConstantSetCallBack* callback,
														  IMaterialRenderer* baseMaterial,
														  const char* const * uniformStringTable,
														  const u32& uniformCount,
														  s32 userData )
			: Driver( driver ), CallBack( callback ), BaseMaterial( baseMaterial ), FileSystem( fs ),
			Program( 0 ), UserData( userData ), UniformStringTable( uniformStringTable ),
			UniformCount( uniformCount )
	{
		if ( BaseMaterial )
			BaseMaterial->grab();

		if ( CallBack )
			CallBack->grab();
	}


	//! Destructor
	COGLES2SLMaterialRenderer::~COGLES2SLMaterialRenderer()
	{
		if ( CallBack )
			CallBack->drop();

		if ( Program )
		{
			glDeleteProgram( Program );
			Program = 0;
		}

		UniformInfo.clear();

		AttributeInfo.clear();

		if ( BaseMaterial )
			BaseMaterial->drop();
	}

	void COGLES2SLMaterialRenderer::init(s32& outMaterialTypeNr,
			const c8* vertexShaderProgram,
			const c8* pixelShaderProgram,
			bool registerMaterial )
	{
		outMaterialTypeNr = -1;

		if ( Program == 0 && !createProgram() )
			return;

		if ( vertexShaderProgram )
			if ( !createShader( GL_VERTEX_SHADER, vertexShaderProgram, "" ) )
				return;

		if ( pixelShaderProgram )
			if ( !createShader( GL_FRAGMENT_SHADER, pixelShaderProgram, "" ) )
				return;

		if ( !linkProgram() )
			return;

		// register myself as new material
		if ( registerMaterial )
			outMaterialTypeNr = Driver->addMaterialRenderer( this );
	}

	void COGLES2SLMaterialRenderer::initFromFiles( s32 &outMaterialTypeNr,
			const c8 *vertexShaderFile,
			const c8 *pixelShaderFile,
			bool registerMaterial )
	{
		if ( !createProgram() )
		{
			os::Printer::log( "Could not create shader program.", ELL_ERROR );
		}

		if ( !readVertexShader( vertexShaderFile ) )
		{
			os::Printer::log( "Error reading fixed pipeline vertex shader.", ELL_ERROR );
		}

		if ( !readFragmentShader( pixelShaderFile ) )
		{
			os::Printer::log( "Error reading fixed pipeline fragment shader.", ELL_ERROR );
		}

		for ( size_t i = 0; i < EVA_COUNT; ++i )
			glBindAttribLocation( Program, i, sBuiltInVertexAttributeNames[i] );

		if ( !linkProgram() )
		{
			os::Printer::log( "Error linking fixed pipeline shader program.", ELL_ERROR );
		}

		if ( registerMaterial )
			outMaterialTypeNr = Driver->addMaterialRenderer( this );
	}

	void COGLES2SLMaterialRenderer::reloadFromFiles( const c8 *vertexShaderFile,
			const c8 *pixelShaderFile )
	{
		GLsizei shaderCount;
		GLuint shaderHandles[2];
		glGetAttachedShaders( Program, 2, &shaderCount, shaderHandles );
		glDetachShader( Program, shaderHandles[0] );
		glDeleteShader( shaderHandles[0] );
		glDetachShader( Program, shaderHandles[1] );
		glDeleteShader( shaderHandles[1] );
		if ( !readVertexShader( vertexShaderFile ) )
		{
			os::Printer::log( "Error reading fixed pipeline vertex shader.", ELL_ERROR );
		}

		if ( !readFragmentShader( pixelShaderFile ) )
		{
			os::Printer::log( "Error reading fixed pipeline fragment shader.", ELL_ERROR );
		}

		if ( !linkProgram() )
		{
			os::Printer::log( "Error linking fixed pipeline shader program.", ELL_ERROR );
		}
	}


	bool COGLES2SLMaterialRenderer::readShader( GLenum shaderType, const c8* shaderFile )
	{
		io::IReadFile* file = FileSystem->createAndOpenFile(shaderFile);
		if (!file)
		{
			os::Printer::log("Could not open shader file", shaderFile, ELL_ERROR);
			return false;
		}
		const long size = file->getSize();
		if (!size)
		{
			os::Printer::log( "Shader file is empty", shaderFile, ELL_ERROR );
			file->drop();
			return false;
		}

		c8* shader = new c8[size+1];
		file->read(shader, size);
		shader[size] = 0;

		bool success = createShader(shaderType, shader, shaderFile);
		file->drop();
		delete shader;
		return success;
	}

	bool COGLES2SLMaterialRenderer::readVertexShader( const c8 *vertexShaderFile )
	{
		return readShader( GL_VERTEX_SHADER, vertexShaderFile );
	}

	bool COGLES2SLMaterialRenderer::readFragmentShader( const c8 *fragmentShaderFile )
	{
		return readShader( GL_FRAGMENT_SHADER, fragmentShaderFile );
	}

	bool COGLES2SLMaterialRenderer::OnRender( IMaterialRendererServices* service,
			E_VERTEX_TYPE vtxtype )
	{
		// call callback to set shader constants and attributes
		if ( CallBack && Program )
		{
			CallBack->OnSetAttribute( this, UserData );
			CallBack->OnSetConstants( this, UserData );
		}

		return true;
	}


	bool COGLES2SLMaterialRenderer::PostRender( IMaterialRendererServices* service,
			E_VERTEX_TYPE vtxtype )
	{
		// call callback to unset shader attributes
		if ( CallBack && Program )
			CallBack->OnUnSetAttribute( this, UserData );

		return true;
	}

	void COGLES2SLMaterialRenderer::OnSetMaterial( const video::SMaterial& material,
			const video::SMaterial& lastMaterial,
			bool resetAllRenderstates,
			video::IMaterialRendererServices* services )
	{
		if ( material.MaterialType != lastMaterial.MaterialType || resetAllRenderstates )
		{
			if ( Program )
				glUseProgram( Program );

			//let callback know used material
			if ( CallBack )
				CallBack->OnSetMaterial( material );
		}
		//if (BaseMaterial)
		//BaseMaterial->OnSetMaterial(material, material, true, this);

		//for (u32 i=0; i<MATERIAL_MAX_TEXTURES; ++i)
		//  Driver->setActiveTexture(i, material.getTexture(i));
		Driver->setBasicRenderStates( material, lastMaterial, resetAllRenderstates );
	}


	void COGLES2SLMaterialRenderer::OnUnsetMaterial()
	{
		glUseProgram( 0 );

		//if (BaseMaterial)
		//  BaseMaterial->OnUnsetMaterial();
	}

	//! Returns if the material is transparent.
	bool COGLES2SLMaterialRenderer::isTransparent() const
	{
		return BaseMaterial ? BaseMaterial->isTransparent() : false;
	}

	bool COGLES2SLMaterialRenderer::createProgram()
	{
		Program = glCreateProgram();
		return true;
	}

	bool COGLES2SLMaterialRenderer::createShader( GLenum shaderType, const char* shader, const char* shaderFile )
	{
		GLuint shaderHandle = glCreateShader( shaderType );

		os::Printer::log("Loading shader", shaderFile);
		glShaderSource( shaderHandle, 1, &shader, NULL );
		glCompileShader( shaderHandle );

		int status = 0;

		glGetShaderiv( shaderHandle, GL_COMPILE_STATUS, &status );

		if ( !status )
		{
			os::Printer::log("GLSL shader failed to compile", shaderFile, ELL_ERROR);

			// check error message and log it
			int maxLength = 0;
			GLsizei length;

			glGetShaderiv( shaderHandle, GL_INFO_LOG_LENGTH, &maxLength );

			char *pInfoLog = new char[maxLength];
			glGetShaderInfoLog( shaderHandle, maxLength, &length, pInfoLog );
			os::Printer::log(pInfoLog, ELL_ERROR);
			delete [] pInfoLog;

			return false;
		}

		glAttachShader(Program, shaderHandle);

		return true;
	}

	bool COGLES2SLMaterialRenderer::linkProgram()
	{
		glLinkProgram( Program );

		int status = 0;

		glGetProgramiv( Program, GL_LINK_STATUS, &status );

		if ( !status )
		{
			os::Printer::log( "GLSL shader program failed to link", ELL_ERROR );
			// check error message and log it
			int maxLength = 0;
			GLsizei length;

			glGetProgramiv( Program, GL_INFO_LOG_LENGTH, &maxLength );

			char *pInfoLog = new char[maxLength];
			glGetProgramInfoLog( Program, maxLength, &length, pInfoLog );
			os::Printer::log(pInfoLog, ELL_ERROR);
			delete [] pInfoLog;

			return false;
		}

		// get uniforms information

		int num = 0;
		glGetProgramiv( Program, GL_ACTIVE_UNIFORMS, &num );

		int maxlen = 0;
		glGetProgramiv( Program, GL_ACTIVE_UNIFORM_MAX_LENGTH, &maxlen );

		if ( maxlen == 0 && num != 0 )
		{
			os::Printer::log( "GLSL: failed to retrieve uniform information", ELL_ERROR );
			return false;
		}

		c8 *buf = new c8[maxlen];

		UniformInfo.clear();
		UniformInfo.reallocate( num );

		core::array<core::stringc> names( num );
		core::array<SUniformInfo> uni( num );

		for ( int i = 0; i < num; ++i )
		{
			memset( buf, 0, maxlen );
			GLint size;
			SUniformInfo ui;
			glGetActiveUniform( Program, i, maxlen, 0, &size, &ui.type, reinterpret_cast<char*>( buf ) );
			ui.location = glGetUniformLocation( Program, buf );
			uni.push_back( ui );
			names.push_back( buf );
		}

		delete [] buf;

		for ( int i = 0; i < UniformCount; ++i )
		{
			int j;
			for ( j = 0; j < num; ++j )
			{
				if ( names[j] == UniformStringTable[i] )
					break;
			}
			if ( j < num )
			{
				UniformInfo.push_back( uni[j] );
			}
			else
			{
				wchar_t buf[512];
				swprintf( buf, 512, L"Unable to find uniform : %S", UniformStringTable[i] );
				os::Printer::log( buf, ELL_WARNING );
				SUniformInfo blank;
				blank.location = -1;
				blank.type = GL_INVALID_ENUM;
				UniformInfo.push_back( blank );
			}
		}

		return true;
	}


	void COGLES2SLMaterialRenderer::setBasicRenderStates( const SMaterial& material,
			const SMaterial& lastMaterial,
			bool resetAllRenderstates )
	{
		// forward
		Driver->setBasicRenderStates( material, lastMaterial, resetAllRenderstates );
	}


	bool COGLES2SLMaterialRenderer::setVertexShaderConstant( const c8* name, const f32* floats, int count )
	{
		return setPixelShaderConstant( name, floats, count );
	}


	void COGLES2SLMaterialRenderer::setVertexShaderConstant( const f32* data, s32 startRegister, s32 constantAmount )
	{
		os::Printer::log( "Cannot set constant, please use high level shader call instead.", ELL_WARNING );
	}

	bool COGLES2SLMaterialRenderer::setVertexShaderPointer( const c8* name, const void* pointer,
			s32 size, bool normalized, u16 stride )
	{
		os::Printer::log( "Cannot set constant, use high level shader call.", ELL_WARNING );

		return false;
	}

	void COGLES2SLMaterialRenderer::enableVertexShaderPointer( const c8* name )
	{
		os::Printer::log( "Cannot set constant, use high level shader call.", ELL_WARNING );
	}

	void COGLES2SLMaterialRenderer::disableVertexShaderPointer( const c8* name )
	{
		os::Printer::log( "Cannot set constant, use high level shader call.", ELL_WARNING );
	}

	bool COGLES2SLMaterialRenderer::setPixelShaderConstant( const c8* name, const f32* floats, int count )
	{
		os::Printer::log( "Cannot set constant, use high level shader call.", ELL_WARNING );
		return false;
	}

	bool COGLES2SLMaterialRenderer::setUniform( int index, const void* data, int count )
	{
		SUniformInfo& ui = UniformInfo[index];
		if ( ui.location == -1 )
			return false;
		switch ( ui.type )
		{
			case GL_FLOAT:
				glUniform1fv( ui.location, count, static_cast<const GLfloat*>( data ) );
				break;
			case GL_FLOAT_VEC2:
				glUniform2fv( ui.location, count, static_cast<const GLfloat*>( data ) );
				break;
			case GL_FLOAT_VEC3:
				glUniform3fv( ui.location, count, static_cast<const GLfloat*>( data ) );
				break;
			case GL_FLOAT_VEC4:
				glUniform4fv( ui.location, count, static_cast<const GLfloat*>( data ) );
				break;
			case GL_FLOAT_MAT2:
				glUniformMatrix2fv( ui.location, count, false, static_cast<const GLfloat*>( data ) );
				break;
			case GL_FLOAT_MAT3:
				glUniformMatrix3fv( ui.location, count, false, static_cast<const GLfloat*>( data ) );
				break;
			case GL_FLOAT_MAT4:
				glUniformMatrix4fv( ui.location, count, false, static_cast<const GLfloat*>( data ) );
				break;
			default:
				glUniform1iv( ui.location, count, static_cast<const GLint*>( data ) );
				break;
		}
		return !Driver->testGLError();
	}

	bool COGLES2SLMaterialRenderer::setTextureUnit( const c8* name, int unit )
	{
		os::Printer::log( "Cannot set constant, use high level shader call.", ELL_WARNING );
		return false;
	}

	bool COGLES2SLMaterialRenderer::enableMaterialTexture( const c8* name, int materialId )
	{
		ITexture * t = Driver->getTextureByIndex( materialId );
		COGLES2Texture * tex = reinterpret_cast<COGLES2Texture*>( t );
		if ( !tex )
			return false;
		const GLuint unit = tex->getOGLES2TextureName();

		glActiveTexture( GL_TEXTURE0 + unit );
		glBindTexture( GL_TEXTURE_2D, unit );

		return setTextureUnit( name, unit );
	}

	bool COGLES2SLMaterialRenderer::disableMaterialTexture( int materialId )
	{
		COGLES2Texture * tex = reinterpret_cast<COGLES2Texture*>( Driver->getTextureByIndex( materialId ) );
		if ( !tex )
			return false;

		const GLuint unit = tex->getOGLES2TextureName();

		glActiveTexture( GL_TEXTURE0 + unit );
		glBindTexture( GL_TEXTURE_2D, 0 );

		return true;
	}

	void COGLES2SLMaterialRenderer::setPixelShaderConstant( const f32* data, s32 startRegister, s32 constantAmount )
	{
		os::Printer::log( "Cannot set constant, use high level shader call.", ELL_WARNING );
	}

	IVideoDriver* COGLES2SLMaterialRenderer::getVideoDriver()
	{
		return Driver;
	}

	void COGLES2SLMaterialRenderer::useProgram()
	{
		glUseProgram( Program );
	}

} // end namespace video
} // end namespace irr

#endif //_IRR_COMPILE_WITH_OPENGLES2_