/cocos/2d/CCMotionStreak.cpp

/****************************************************************************
Copyright (c) 2010-2012 cocos2d-x.org
Copyright (c) 2011 ForzeField Studios S.L.

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
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The above copyright notice and this permission notice shall be included in
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/
#include "CCMotionStreak.h"
#include "CCTextureCache.h"
#include "ccGLStateCache.h"
#include "CCGLProgram.h"
#include "CCShaderCache.h"
#include "ccMacros.h"
#include "CCDirector.h"
#include "CCVertex.h"

NS_CC_BEGIN

MotionStreak::MotionStreak()
: _fastMode(false)
, _startingPositionInitialized(false)
, _texture(NULL)
, _blendFunc(BlendFunc::ALPHA_NON_PREMULTIPLIED)
, _positionR(Point::ZERO)
, _stroke(0.0f)
, _fadeDelta(0.0f)
, _minSeg(0.0f)
, _maxPoints(0)
, _nuPoints(0)
, _previousNuPoints(0)
, _pointVertexes(NULL)
, _pointState(NULL)
, _vertices(NULL)
, _colorPointer(NULL)
, _texCoords(NULL)
{
}

MotionStreak::~MotionStreak()
{
    CC_SAFE_RELEASE(_texture);
    CC_SAFE_FREE(_pointState);
    CC_SAFE_FREE(_pointVertexes);
    CC_SAFE_FREE(_vertices);
    CC_SAFE_FREE(_colorPointer);
    CC_SAFE_FREE(_texCoords);
}

MotionStreak* MotionStreak::create(float fade, float minSeg, float stroke, const Color3B& color, const char* path)
{
    MotionStreak *pRet = new MotionStreak();
    if (pRet && pRet->initWithFade(fade, minSeg, stroke, color, path))
    {
        pRet->autorelease();
        return pRet;
    }

    CC_SAFE_DELETE(pRet);
    return NULL;
}

MotionStreak* MotionStreak::create(float fade, float minSeg, float stroke, const Color3B& color, Texture2D* texture)
{
    MotionStreak *pRet = new MotionStreak();
    if (pRet && pRet->initWithFade(fade, minSeg, stroke, color, texture))
    {
        pRet->autorelease();
        return pRet;
    }

    CC_SAFE_DELETE(pRet);
    return NULL;
}

bool MotionStreak::initWithFade(float fade, float minSeg, float stroke, const Color3B& color, const char* path)
{
    CCASSERT(path != NULL, "Invalid filename");

    Texture2D *texture = Director::getInstance()->getTextureCache()->addImage(path);
    return initWithFade(fade, minSeg, stroke, color, texture);
}

bool MotionStreak::initWithFade(float fade, float minSeg, float stroke, const Color3B& color, Texture2D* texture)
{
    Node::setPosition(Point::ZERO);
    setAnchorPoint(Point::ZERO);
    ignoreAnchorPointForPosition(true);
    _startingPositionInitialized = false;

    _positionR = Point::ZERO;
    _fastMode = true;
    _minSeg = (minSeg == -1.0f) ? stroke/5.0f : minSeg;
    _minSeg *= _minSeg;

    _stroke = stroke;
    _fadeDelta = 1.0f/fade;

    _maxPoints = (int)(fade*60.0f)+2;
    _nuPoints = 0;
    _pointState = (float *)malloc(sizeof(float) * _maxPoints);
    _pointVertexes = (Point*)malloc(sizeof(Point) * _maxPoints);

    _vertices = (Vertex2F*)malloc(sizeof(Vertex2F) * _maxPoints * 2);
    _texCoords = (Tex2F*)malloc(sizeof(Tex2F) * _maxPoints * 2);
    _colorPointer =  (GLubyte*)malloc(sizeof(GLubyte) * _maxPoints * 2 * 4);

    // Set blend mode
    _blendFunc = BlendFunc::ALPHA_NON_PREMULTIPLIED;

    // shader program
    setShaderProgram(ShaderCache::getInstance()->getProgram(GLProgram::SHADER_NAME_POSITION_TEXTURE_COLOR));

    setTexture(texture);
    setColor(color);
    scheduleUpdate();

    return true;
}

void MotionStreak::setPosition(const Point& position)
{
    _startingPositionInitialized = true;
    _positionR = position;
}

void MotionStreak::tintWithColor(const Color3B& colors)
{
    setColor(colors);

    // Fast assignation
    for(unsigned int i = 0; i<_nuPoints*2; i++) 
    {
        *((Color3B*) (_colorPointer+i*4)) = colors;
    }
}

Texture2D* MotionStreak::getTexture(void) const
{
    return _texture;
}

void MotionStreak::setTexture(Texture2D *texture)
{
    if (_texture != texture)
    {
        CC_SAFE_RETAIN(texture);
        CC_SAFE_RELEASE(_texture);
        _texture = texture;
    }
}

void MotionStreak::setBlendFunc(const BlendFunc &blendFunc)
{
    _blendFunc = blendFunc;
}

const BlendFunc& MotionStreak::getBlendFunc(void) const
{
    return _blendFunc;
}

void MotionStreak::setOpacity(GLubyte opacity)
{
    CCASSERT(false, "Set opacity no supported");
}

GLubyte MotionStreak::getOpacity(void) const
{
    CCASSERT(false, "Opacity no supported");
    return 0;
}

void MotionStreak::setOpacityModifyRGB(bool bValue)
{
    CC_UNUSED_PARAM(bValue);
}

bool MotionStreak::isOpacityModifyRGB(void) const
{
    return false;
}

void MotionStreak::update(float delta)
{
    if (!_startingPositionInitialized)
    {
        return;
    }
    
    delta *= _fadeDelta;

    unsigned int newIdx, newIdx2, i, i2;
    unsigned int mov = 0;

    // Update current points
    for(i = 0; i<_nuPoints; i++)
    {
        _pointState[i]-=delta;

        if(_pointState[i] <= 0)
            mov++;
        else
        {
            newIdx = i-mov;

            if(mov>0)
            {
                // Move data
                _pointState[newIdx] = _pointState[i];

                // Move point
                _pointVertexes[newIdx] = _pointVertexes[i];

                // Move vertices
                i2 = i*2;
                newIdx2 = newIdx*2;
                _vertices[newIdx2] = _vertices[i2];
                _vertices[newIdx2+1] = _vertices[i2+1];

                // Move color
                i2 *= 4;
                newIdx2 *= 4;
                _colorPointer[newIdx2+0] = _colorPointer[i2+0];
                _colorPointer[newIdx2+1] = _colorPointer[i2+1];
                _colorPointer[newIdx2+2] = _colorPointer[i2+2];
                _colorPointer[newIdx2+4] = _colorPointer[i2+4];
                _colorPointer[newIdx2+5] = _colorPointer[i2+5];
                _colorPointer[newIdx2+6] = _colorPointer[i2+6];
            }else
                newIdx2 = newIdx*8;

            const GLubyte op = (GLubyte)(_pointState[newIdx] * 255.0f);
            _colorPointer[newIdx2+3] = op;
            _colorPointer[newIdx2+7] = op;
        }
    }
    _nuPoints-=mov;

    // Append new point
    bool appendNewPoint = true;
    if(_nuPoints >= _maxPoints)
    {
        appendNewPoint = false;
    }

    else if(_nuPoints>0)
    {
        bool a1 = _pointVertexes[_nuPoints-1].getDistanceSq(_positionR) < _minSeg;
        bool a2 = (_nuPoints == 1) ? false : (_pointVertexes[_nuPoints-2].getDistanceSq(_positionR)< (_minSeg * 2.0f));
        if(a1 || a2)
        {
            appendNewPoint = false;
        }
    }

    if(appendNewPoint)
    {
        _pointVertexes[_nuPoints] = _positionR;
        _pointState[_nuPoints] = 1.0f;

        // Color assignment
        const unsigned int offset = _nuPoints*8;
        *((Color3B*)(_colorPointer + offset)) = _displayedColor;
        *((Color3B*)(_colorPointer + offset+4)) = _displayedColor;

        // Opacity
        _colorPointer[offset+3] = 255;
        _colorPointer[offset+7] = 255;

        // Generate polygon
        if(_nuPoints > 0 && _fastMode )
        {
            if(_nuPoints > 1)
            {
                ccVertexLineToPolygon(_pointVertexes, _stroke, _vertices, _nuPoints, 1);
            }
            else
            {
                ccVertexLineToPolygon(_pointVertexes, _stroke, _vertices, 0, 2);
            }
        }

        _nuPoints ++;
    }

    if( ! _fastMode )
    {
        ccVertexLineToPolygon(_pointVertexes, _stroke, _vertices, 0, _nuPoints);
    }

    // Updated Tex Coords only if they are different than previous step
    if( _nuPoints  && _previousNuPoints != _nuPoints ) {
        float texDelta = 1.0f / _nuPoints;
        for( i=0; i < _nuPoints; i++ ) {
            _texCoords[i*2] = Tex2F(0, texDelta*i);
            _texCoords[i*2+1] = Tex2F(1, texDelta*i);
        }

        _previousNuPoints = _nuPoints;
    }
}

void MotionStreak::reset()
{
    _nuPoints = 0;
}

void MotionStreak::draw()
{
    if(_nuPoints <= 1)
        return;

    CC_NODE_DRAW_SETUP();

    GL::enableVertexAttribs(GL::VERTEX_ATTRIB_FLAG_POS_COLOR_TEX );
    GL::blendFunc( _blendFunc.src, _blendFunc.dst );

    GL::bindTexture2D( _texture->getName() );

#ifdef EMSCRIPTEN
    // Size calculations from ::initWithFade
    setGLBufferData(_vertices, (sizeof(Vertex2F) * _maxPoints * 2), 0);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, 0);

    setGLBufferData(_texCoords, (sizeof(Tex2F) * _maxPoints * 2), 1);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORDS, 2, GL_FLOAT, GL_FALSE, 0, 0);

    setGLBufferData(_colorPointer, (sizeof(GLubyte) * _maxPoints * 2 * 4), 2);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, 0);
#else
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, _vertices);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORDS, 2, GL_FLOAT, GL_FALSE, 0, _texCoords);
    glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, _colorPointer);
#endif // EMSCRIPTEN

    glDrawArrays(GL_TRIANGLE_STRIP, 0, (GLsizei)_nuPoints*2);

    CC_INCREMENT_GL_DRAWS(1);
}

NS_CC_END