axmol/cocos2dx/misc_nodes/CCRibbon.cpp

/****************************************************************************
Copyright (c) 2010-2011 cocos2d-x.org
Copyright (c) 2008-2009 Jason Booth

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#include "CCRibbon.h"
#include "CCTextureCache.h"
#include "CCPointExtension.h"

namespace cocos2d {

/*
* A ribbon is a dynamically generated list of polygons drawn as a single or series
* of triangle strips. The primary use of Ribbon is as the drawing class of Motion Streak,
* but it is quite useful on it's own. When manually drawing a ribbon, you can call addPointAt
* and pass in the parameters for the next location in the ribbon. The system will automatically
* generate new polygons, texture them accourding to your texture width, etc, etc.
*
* Ribbon data is stored in a RibbonSegment class. This class statically allocates enough verticies and
* texture coordinates for 50 locations (100 verts or 48 triangles). The ribbon class will allocate
* new segments when they are needed, and reuse old ones if available. The idea is to avoid constantly
* allocating new memory and prefer a more static method. However, since there is no way to determine
* the maximum size of some ribbons (motion streaks), a truely static allocation is not possible.
*
*/

//
// Ribbon
//
CCRibbon * CCRibbon::ribbonWithWidth(float w, const char *path, float length, ccColor4B color, float fade)
{
	CCRibbon *pRet = new CCRibbon();
	if(pRet && pRet->initWithWidth(w, path, length, color, fade))
	{
		pRet->autorelease();
		return pRet;
	}
	CC_SAFE_DELETE(pRet)
	return NULL;
}

bool CCRibbon::initWithWidth(float w, const char *path, float length, ccColor4B color, float fade)
{
	m_pSegments = new CCMutableArray<CCRibbonSegment*>();
	m_pDeletedSegments = new CCMutableArray<CCRibbonSegment*>();

	/* 1 initial segment */
	CCRibbonSegment* seg = new CCRibbonSegment();
	seg->init();
	m_pSegments->addObject(seg);
	seg->release();

	m_fTextureLength = length;

	m_tColor = color;
	m_fFadeTime = fade;
	m_tLastLocation = CCPointZero;
	m_fLastWidth = w/2;
	m_fTexVPos = 0.0f;

	m_fCurTime = 0;
	m_bPastFirstPoint = false;

	/* XXX:
	Ribbon, by default uses this blend function, which might not be correct
	if you are using premultiplied alpha images,
	but 99% you might want to use this blending function regarding of the texture
	*/
	m_tBlendFunc.src = GL_SRC_ALPHA;
	m_tBlendFunc.dst = GL_ONE_MINUS_SRC_ALPHA;

	m_pTexture = CCTextureCache::sharedTextureCache()->addImage(path);
	CC_SAFE_RETAIN(m_pTexture);

	/* default texture parameter */
	ccTexParams params = { GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT };
	m_pTexture->setTexParameters(&params);
	return true;
}

CCRibbon::~CCRibbon()
{
    CC_SAFE_RELEASE(m_pSegments);
    CC_SAFE_RELEASE(m_pDeletedSegments);
    CC_SAFE_RELEASE(m_pTexture);
}

CCPoint CCRibbon::rotatePoint(CCPoint vec, float rotation)
{
	float xtemp = (vec.x * cosf(rotation)) - (vec.y * sinf(rotation));
	vec.y = (vec.x * sinf(rotation)) + (vec.y * cosf(rotation));
	vec.x = xtemp;
	return vec;
}

void CCRibbon::update(ccTime delta)
{
	m_fCurTime += delta;
	m_fDelta = delta;
}

float CCRibbon::sideOfLine(CCPoint p, CCPoint l1, CCPoint l2)
{
	CCPoint vp = ccpPerp(ccpSub(l1, l2));
	CCPoint vx = ccpSub(p, l1);
	return ccpDot(vx, vp);
}

// adds a new segment to the ribbon
void CCRibbon::addPointAt(CCPoint location, float width)
{
    location.x *= CC_CONTENT_SCALE_FACTOR();
    location.y *= CC_CONTENT_SCALE_FACTOR();

    width = width * 0.5f;
	// if this is the first point added, cache it and return
	if (!m_bPastFirstPoint)
	{
		m_fLastWidth = width;
		m_tLastLocation = location;
		m_bPastFirstPoint = true;
		return;
	}

	CCPoint sub = ccpSub(m_tLastLocation, location);
	float r = ccpToAngle(sub) + (float)M_PI_2;
	CCPoint p1 = ccpAdd(this->rotatePoint(ccp(-width, 0), r), location);
	CCPoint p2 = ccpAdd(this->rotatePoint(ccp(+width, 0), r), location);
	float len = sqrtf(powf(m_tLastLocation.x - location.x, 2) + powf(m_tLastLocation.y - location.y, 2));
	float tend = m_fTexVPos + len/m_fTextureLength;
	CCRibbonSegment* seg;
	// grab last segment
	seg = m_pSegments->getLastObject();
	// lets kill old segments
	if (m_pSegments && m_pSegments->count()>0)
	{
		CCMutableArray<CCRibbonSegment*>::CCMutableArrayIterator it;
		for (it = m_pSegments->begin(); it != m_pSegments->end(); ++it)
		{
			if (*it != seg && (*it)->m_bFinished)
			{
				m_pDeletedSegments->addObject(*it);
			}
		}
	}
	
	m_pSegments->removeObjectsInArray(m_pDeletedSegments);
	// is the segment full?
	if (seg->m_uEnd >= 50)
	{
		m_pSegments->removeObjectsInArray(m_pDeletedSegments);
	}
	// grab last segment and append to it if it's not full
	seg = m_pSegments->getLastObject();
	// is the segment full?
	if (seg->m_uEnd >= 50)
	{
		CCRibbonSegment* newSeg;
		// grab it from the cache if we can
		if (m_pDeletedSegments->count() > 0)
		{
			newSeg = m_pDeletedSegments->getObjectAtIndex(0);
			newSeg->retain();							// will be released later
			m_pDeletedSegments->removeObject(newSeg);
			newSeg->reset();
		}
		else
		{
			newSeg = new CCRibbonSegment(); // will be released later
			newSeg->init();
		}

		newSeg->m_pCreationTime[0] = seg->m_pCreationTime[seg->m_uEnd- 1];
		int v = (seg->m_uEnd-1)*6;
		int c = (seg->m_uEnd-1)*4;	
		newSeg->m_pVerts[0] = seg->m_pVerts[v];
		newSeg->m_pVerts[1] = seg->m_pVerts[v+1];
		newSeg->m_pVerts[2] = seg->m_pVerts[v+2];
		newSeg->m_pVerts[3] = seg->m_pVerts[v+3];
		newSeg->m_pVerts[4] = seg->m_pVerts[v+4];
		newSeg->m_pVerts[5] = seg->m_pVerts[v+5];

		newSeg->m_pCoords[0] = seg->m_pCoords[c];
		newSeg->m_pCoords[1] = seg->m_pCoords[c+1];
		newSeg->m_pCoords[2] = seg->m_pCoords[c+2];
		newSeg->m_pCoords[3] = seg->m_pCoords[c+3];	  
		newSeg->m_uEnd++;
		seg = newSeg;
		m_pSegments->addObject(seg);
		newSeg->release();// it was retained before
	}  
	if (seg->m_uEnd == 0)
	{
		// first edge has to get rotation from the first real polygon
		CCPoint lp1 = ccpAdd(this->rotatePoint(ccp(-m_fLastWidth, 0), r), m_tLastLocation);
		CCPoint lp2 = ccpAdd(this->rotatePoint(ccp(+m_fLastWidth, 0), r), m_tLastLocation);
		seg->m_pCreationTime[0] = m_fCurTime - m_fDelta;
		seg->m_pVerts[0] = lp1.x;
		seg->m_pVerts[1] = lp1.y;
		seg->m_pVerts[2] = 0.0f;
		seg->m_pVerts[3] = lp2.x;
		seg->m_pVerts[4] = lp2.y;
		seg->m_pVerts[5] = 0.0f;
		seg->m_pCoords[0] = 0.0f;
		seg->m_pCoords[1] = m_fTexVPos;
		seg->m_pCoords[2] = 1.0f;
		seg->m_pCoords[3] = m_fTexVPos;
		seg->m_uEnd++;
	}

	int v = seg->m_uEnd*6;
	int c = seg->m_uEnd*4;
	// add new vertex
	seg->m_pCreationTime[seg->m_uEnd] = m_fCurTime;
	seg->m_pVerts[v] = p1.x;
	seg->m_pVerts[v+1] = p1.y;
	seg->m_pVerts[v+2] = 0.0f;
	seg->m_pVerts[v+3] = p2.x;
	seg->m_pVerts[v+4] = p2.y;
	seg->m_pVerts[v+5] = 0.0f;


	seg->m_pCoords[c] = 0.0f;
	seg->m_pCoords[c+1] = tend;
	seg->m_pCoords[c+2] = 1.0f;
	seg->m_pCoords[c+3] = tend;

	m_fTexVPos = tend;
	m_tLastLocation = location;
	m_tLastPoint1 = p1;
	m_tLastPoint2 = p2;
	m_fLastWidth = width;
	seg->m_uEnd++;
}

void CCRibbon::draw()
{
	if (m_pSegments->count() > 0)
	{
		// Default GL states: GL_TEXTURE_2D, GL_VERTEX_ARRAY, GL_COLOR_ARRAY, GL_TEXTURE_COORD_ARRAY
		// Needed states: GL_TEXTURE_2D, GL_VERTEX_ARRAY, GL_TEXTURE_COORD_ARRAY
		// Unneeded states: GL_COLOR_ARRAY
		glDisableClientState(GL_COLOR_ARRAY);

		glBindTexture(GL_TEXTURE_2D, m_pTexture->getName());

        bool newBlend = ( m_tBlendFunc.src != CC_BLEND_SRC || m_tBlendFunc.dst != CC_BLEND_DST ) ? true : false;
        if( newBlend )
        {
            glBlendFunc( m_tBlendFunc.src, m_tBlendFunc.dst );
        }

		if(m_pSegments && m_pSegments->count() > 0)
		{
			CCRibbonSegment* seg;
			CCMutableArray<CCRibbonSegment*>::CCMutableArrayIterator it;
			for( it = m_pSegments->begin(); it != m_pSegments->end(); it++)
			{
				seg = (CCRibbonSegment*)*it;
				seg->draw(m_fCurTime, m_fFadeTime, m_tColor);
			}
		}

		if( newBlend )
		{
			glBlendFunc(CC_BLEND_SRC, CC_BLEND_DST);
		}

		// restore default GL state
		glEnableClientState( GL_COLOR_ARRAY );
	}
}

// Ribbon - CocosNodeTexture protocol
void CCRibbon::setTexture(CCTexture2D* var)
{
	CC_SAFE_RETAIN(var);
	CC_SAFE_RELEASE(m_pTexture);
	m_pTexture = var;
	this->setContentSize(m_pTexture->getContentSizeInPixels());
	/* XXX Don't update blending function in Ribbons */
}

CCTexture2D *CCRibbon::getTexture()
{
	return m_pTexture;
}

void CCRibbon::setTextureLength(float var)
{
	m_fTextureLength = var;
}

float CCRibbon::getTextureLength()
{
	return m_fTextureLength;
}
void CCRibbon::setBlendFunc(ccBlendFunc var)
{
	m_tBlendFunc = var;
}

ccBlendFunc CCRibbon::getBlendFunc()
{
	return m_tBlendFunc;
}

void CCRibbon::setColor(ccColor4B var)
{
	m_tColor = var;
}
ccColor4B CCRibbon::getColor()
{
	return m_tColor;
} 

//
//RibbonSegment
//
bool CCRibbonSegment::init()
{
	this->reset();
	return true;
}

char * CCRibbonSegment::description()
{
	char *ret = new char[100] ;
	sprintf(ret, "<CCRibbonSegment | end = %u, begin = %u>", m_uEnd, m_uBegin);
	return ret;
}

CCRibbonSegment::~CCRibbonSegment()
{
	CCLOGINFO("cocos2d: deallocing.");
}

void CCRibbonSegment::reset()
{
	m_uEnd = 0;
	m_uBegin = 0;
	m_bFinished = false;
}

void CCRibbonSegment::draw(float curTime, float fadeTime, ccColor4B color)
{
	GLubyte r = color.r;
	GLubyte g = color.g;
	GLubyte b = color.b;
	GLubyte a = color.a;

	if (m_uBegin < 50)
	{
		// the motion streak class will call update and cause time to change, thus, if curTime_ != 0
		// we have to generate alpha for the ribbon each frame.
		if (curTime == 0)
		{
			// no alpha over time, so just set the color
			glColor4ub(r,g,b,a);
		}
		else
		{
			// generate alpha/color for each point
			glEnableClientState(GL_COLOR_ARRAY);
			unsigned int i = m_uBegin;
			for (; i < m_uEnd; ++i)
			{
				int idx = i*8;
				m_pColors[idx] = r;
				m_pColors[idx+1] = g;
				m_pColors[idx+2] = b;
				m_pColors[idx+4] = r;
				m_pColors[idx+5] = g;
				m_pColors[idx+6] = b;
				float alive = ((curTime - m_pCreationTime[i]) / fadeTime);
				if (alive > 1)
				{
					m_uBegin++;
					m_pColors[idx+3] = 0;
					m_pColors[idx+7] = 0;
				}
				else
				{
					m_pColors[idx+3] = (GLubyte)(255.f - (alive * 255.f));
					m_pColors[idx+7] = m_pColors[idx+3];
				}
			}
			glColorPointer(4, GL_UNSIGNED_BYTE, 0, &m_pColors[m_uBegin*8]);
		}
		glVertexPointer(3, GL_FLOAT, 0, &m_pVerts[m_uBegin*6]);
		glTexCoordPointer(2, GL_FLOAT, 0, &m_pCoords[m_uBegin*4]);
		glDrawArrays(GL_TRIANGLE_STRIP, 0, (m_uEnd - m_uBegin) * 2);
	}
	else
	{
		m_bFinished = true;
	}
}

}// namespace cocos2d