/****************************************************************************
Copyright (c) 2010-2011 cocos2d-x.org
Copyright (c) 2011      Ricardo Quesada
Copyright (c) 2011      Zynga Inc.

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/

#include "ccGLStateCache.h"
#include "CCGLProgram.h"
#include "CCDirector.h"
#include "ccConfig.h"

// extern
#include "kazmath/GL/matrix.h"
#include "kazmath/kazmath.h"

NS_CC_BEGIN

static GLuint	_ccCurrentProjectionMatrix = -1;
static bool		_vertexAttribPosition = false;
static bool		_vertexAttribColor = false;
static bool		_vertexAttribTexCoords = false;

#if CC_ENABLE_GL_STATE_CACHE
#define kCCMaxActiveTexture 16
static GLuint	_ccCurrentShaderProgram = -1;
static GLuint	_ccCurrentBoundTexture[kCCMaxActiveTexture] =  {-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, };
static GLenum	_ccCurrentActiveTexture = (GL_TEXTURE0 - GL_TEXTURE0);
static GLenum	_ccBlendingSource = -1;
static GLenum	_ccBlendingDest = -1;
static int      _ccGLServerState = 0;
#endif // CC_ENABLE_GL_STATE_CACHE

//#pragma mark - GL State Cache functions

void ccGLInvalidateStateCache( void )
{
	kmGLFreeAll();
	_ccCurrentProjectionMatrix = -1;
	_vertexAttribPosition = false;
	_vertexAttribColor = false;
	_vertexAttribTexCoords = false;
#if CC_ENABLE_GL_STATE_CACHE
	_ccCurrentShaderProgram = -1;
	for( int i=0; i < kCCMaxActiveTexture; i++ )
		_ccCurrentBoundTexture[i] = -1;
	_ccCurrentActiveTexture = (GL_TEXTURE0 - GL_TEXTURE0);
	_ccBlendingSource = -1;
	_ccBlendingDest = -1;
	_ccGLServerState = 0;
#endif
}

void ccGLDeleteProgram( GLuint program )
{
#if CC_ENABLE_GL_STATE_CACHE
	if( program == _ccCurrentShaderProgram )
		_ccCurrentShaderProgram = -1;
#endif // CC_ENABLE_GL_STATE_CACHE

	glDeleteProgram( program );
}

void ccGLUseProgram( GLuint program )
{
#if CC_ENABLE_GL_STATE_CACHE
	if( program != _ccCurrentShaderProgram ) {
		_ccCurrentShaderProgram = program;
		glUseProgram(program);
	}
#else
	glUseProgram(program);
#endif // CC_ENABLE_GL_STATE_CACHE
}


void ccGLBlendFunc(GLenum sfactor, GLenum dfactor)
{
#if CC_ENABLE_GL_STATE_CACHE
	if( sfactor != _ccBlendingSource || dfactor != _ccBlendingDest ) {
		_ccBlendingSource = sfactor;
		_ccBlendingDest = dfactor;
		glBlendFunc( sfactor, dfactor );
	}
#else
	glBlendFunc( sfactor, dfactor );
#endif // CC_ENABLE_GL_STATE_CACHE
}

GLenum ccGLGetActiveTexture( void )
{
#if CC_ENABLE_GL_STATE_CACHE
	return _ccCurrentActiveTexture + GL_TEXTURE0;
#else
	GLenum activeTexture;
	glGetIntegerv(GL_ACTIVE_TEXTURE, (GLint*)&activeTexture);
	return activeTexture;
#endif
}

void ccGLActiveTexture( GLenum textureEnum )
{
#if CC_ENABLE_GL_STATE_CACHE
	CCAssert( (textureEnum - GL_TEXTURE0) < kCCMaxActiveTexture, "cocos2d ERROR: Increase kCCMaxActiveTexture to %d!", (textureEnum-GL_TEXTURE0) );
	if( (textureEnum - GL_TEXTURE0) != _ccCurrentActiveTexture ) {
		_ccCurrentActiveTexture = (textureEnum - GL_TEXTURE0);
		glActiveTexture( textureEnum );
	}
#else
	glActiveTexture( textureEnum );
#endif
}

void ccGLBindTexture2D( GLuint textureId )
{
#if CC_ENABLE_GL_STATE_CACHE
	if( _ccCurrentBoundTexture[ _ccCurrentActiveTexture ] != textureId )
	{
		_ccCurrentBoundTexture[ _ccCurrentActiveTexture ] = textureId;
		glBindTexture(GL_TEXTURE_2D, textureId );
	}
#else
	glBindTexture(GL_TEXTURE_2D, textureId );
#endif
}


void ccGLDeleteTexture( GLuint textureId )
{
#if CC_ENABLE_GL_STATE_CACHE
	if( textureId == _ccCurrentBoundTexture[ _ccCurrentActiveTexture ] )
	   _ccCurrentBoundTexture[ _ccCurrentActiveTexture ] = -1;
#endif
	glDeleteTextures(1, &textureId );
}

void ccGLEnable( ccGLServerState flags )
{
#if CC_ENABLE_GL_STATE_CACHE

	bool enabled = false;

	/* GL_BLEND */
	if( (enabled=(flags & CC_GL_BLEND)) != (_ccGLServerState & CC_GL_BLEND) ) {
		if( enabled ) {
			glEnable( GL_BLEND );
			_ccGLServerState |= CC_GL_BLEND;
		} else {
			glDisable( GL_BLEND );
			_ccGLServerState &=  ~CC_GL_BLEND;
		}
	}

#else
	if( flags & CC_GL_BLEND )
		glEnable( GL_BLEND );
	else
		glDisable( GL_BLEND );
#endif
}

//#pragma mark - GL Vertex Attrib functions

void ccGLEnableVertexAttribs( unsigned int flags )
{
	/* Position */
	bool enablePosition = flags & kCCVertexAttribFlag_Position;

	if( enablePosition != _vertexAttribPosition ) {
		if( enablePosition )
			glEnableVertexAttribArray( kCCVertexAttrib_Position );
		else
			glDisableVertexAttribArray( kCCVertexAttrib_Position );

		_vertexAttribPosition = enablePosition;
	}

	/* Color */
	bool enableColor = (flags & kCCVertexAttribFlag_Color) != 0 ? true : false;

	if( enableColor != _vertexAttribColor ) {
		if( enableColor )
			glEnableVertexAttribArray( kCCVertexAttrib_Color );
		else
			glDisableVertexAttribArray( kCCVertexAttrib_Color );

		_vertexAttribColor = enableColor;
	}

	/* Tex Coords */
	bool enableTexCoords = (flags & kCCVertexAttribFlag_TexCoords) != 0 ? true : false;

	if( enableTexCoords != _vertexAttribTexCoords ) {
		if( enableTexCoords )
			glEnableVertexAttribArray( kCCVertexAttrib_TexCoords );
		else
			glDisableVertexAttribArray( kCCVertexAttrib_TexCoords );

		_vertexAttribTexCoords = enableTexCoords;
	}
}

//#pragma mark - GL Uniforms functions

void ccSetProjectionMatrixDirty( void )
{
	_ccCurrentProjectionMatrix = -1;
}

NS_CC_END