CCSprite类的东西非常多，只能一部分一部分的分析和学习。
CONTENTS
各种创建方法，最终还是调用了initWithTexture 方法。
CCSprite* CCSprite::createWithTexture(CCTexture2D *pTexture)
{
。。。。。//==>>直接调用initWithTexture
if (pobSprite && pobSprite->initWithTexture(pTexture))
。。。。。
}
CCSprite* CCSprite::createWithTexture(CCTexture2D *pTexture, const CCRect& rect)
{
。。。。。//==>>直接调用initWithTexture
if (pobSprite && pobSprite->initWithTexture(pTexture, rect))
。。。。。
}
CCSprite* CCSprite::create(const char *pszFileName)
{
。。。。。//==>>调用initWithFile，间接调用initWithTexture
if (pobSprite && pobSprite->initWithFile(pszFileName))
。。。。。
}
CCSprite* CCSprite::create(const char *pszFileName, const CCRect& rect)
{
。。。。。//==>>调用initWithFile，间接调用initWithTexture
if (pobSprite && pobSprite->initWithFile(pszFileName, rect))
。。。。。
}
CCSprite* CCSprite::createWithSpriteFrame(CCSpriteFrame *pSpriteFrame)
{
。。。。。//==>>调用initWithSpriteFrame，间接调用initWithTexture
if (pSpriteFrame && pobSprite && pobSprite->initWithSpriteFrame(pSpriteFrame))
。。。。。
}
CCSprite* CCSprite::createWithSpriteFrameName(const char *pszSpriteFrameName)
{
。。。。。//==>>调用createWithSpriteFrame，间接调用initWithTexture
return createWithSpriteFrame(pFrame);
}
CCSprite* CCSprite::create()
{
。。。。。//==>>调用init，间接调用initWithTexture
if (pSprite && pSprite->init())
。。。。。
}
bool CCSprite::init(void)
{
。。。。。//==>>init方法内部调用initWithTexture
return initWithTexture(NULL, CCRectZero);
}
bool CCSprite::initWithTexture(CCTexture2D *pTexture, const CCRect& rect)
{
。。。。。//==>>调用initWithTexture，不旋转
return initWithTexture(pTexture, rect, false);
}
bool CCSprite::initWithTexture(CCTexture2D *pTexture)
{
。。。。。//==>>调用initWithTexture，大小为texture的大小
return initWithTexture(pTexture, rect);
}
bool CCSprite::initWithFile(const char *pszFilename)
{
。。。。。//==>>先把文件读入到texturecache的缓存中去，然后调用initWithTexture
CCTexture2D *pTexture = CCTextureCache::sharedTextureCache()->addImage(pszFilename);
if (pTexture)
{
CCRect rect = CCRectZero;
rect.size = pTexture->getContentSize();
return initWithTexture(pTexture, rect);
。。。。。
}
bool CCSprite::initWithFile(const char *pszFilename, const CCRect& rect)
{
。。。。。//==>>先把文件读入到texturecache的缓存中去，然后调用initWithTexture
CCTexture2D *pTexture = CCTextureCache::sharedTextureCache()->addImage(pszFilename);
if (pTexture)
{
return initWithTexture(pTexture, rect);
。。。。。
}
bool CCSprite::initWithSpriteFrame(CCSpriteFrame *pSpriteFrame)
{
CCAssert(pSpriteFrame != NULL, "");
//==>>从精灵帧中取出texture，然后调用initWithTexture
bool bRet = initWithTexture(pSpriteFrame->getTexture(), pSpriteFrame->getRect());
setDisplayFrame(pSpriteFrame);
return bRet;
}
bool CCSprite::initWithSpriteFrameName(const char *pszSpriteFrameName)
{
。。。。。//==>>从精灵帧缓存中取出精灵帧，然后调用initWithSpriteFrame
CCSpriteFrame *pFrame = CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName(pszSpriteFrameName);
return initWithSpriteFrame(pFrame);
}
initWithTexture代码分析
bool CCSprite::initWithTexture(CCTexture2D *pTexture, const CCRect& rect, bool rotated)
{
if (CCNodeRGBA::init())
{
m_pobBatchNode = NULL;//==>>不使用批量创建node方法
//==>>m_bRecursiveDirty: Whether all of the sprite's children needs to be updated
m_bRecursiveDirty = false;//==>>级联置脏为false
setDirty(false);//==>>设置m_bDirty为false
m_bOpacityModifyRGB = true;//==>>CCSprite继承自CCNodeRGBA,因此设置该属性为true
m_sBlendFunc.src = CC_BLEND_SRC;//==>>设置混合模式
m_sBlendFunc.dst = CC_BLEND_DST;
m_bFlipX = m_bFlipY = false; //==>>x,y均不翻转
// default transform anchor: center
setAnchorPoint(ccp(0.5f, 0.5f));//==>>设置锚点
// zwoptex default values
m_obOffsetPosition = CCPointZero;//==>>偏移量，默认为0,0
m_bHasChildren = false;//==>>初始化时没有子节点
// clean the Quad
memset(&m_sQuad, 0, sizeof(m_sQuad));//==>>初始化时正方形纹理4个角的信息都为0
// Atlas: Color
ccColor4B tmpColor = { 255, 255, 255, 255 };//==>>初始化时设置正方形纹理4个角的颜色信息
m_sQuad.bl.colors = tmpColor;
m_sQuad.br.colors = tmpColor;
m_sQuad.tl.colors = tmpColor;
m_sQuad.tr.colors = tmpColor;
// shader program //==>>设置shader
setShaderProgram(CCShaderCache::sharedShaderCache()->programForKey(kCCShader_PositionTextureColor));
// update texture (calls updateBlendFunc)
setTexture(pTexture);
setTextureRect(rect, rotated, rect.size);
// by default use "Self Render".
// if the sprite is added to a batchnode, then it will automatically switch to "batchnode Render"
setBatchNode(NULL);
return true;
}
else
{
return false;
}
}
setTexture代码分析
void CCSprite::setTexture(CCTexture2D *texture)
{
//==>>正确性判断，
// If batchnode, then texture id should be the same
CCAssert(! m_pobBatchNode || texture->getName() == m_pobBatchNode->getTexture()->getName(), "CCSprite: Batched sprites should use the same texture as the batchnode");
// accept texture==nil as argument
CCAssert( !texture || dynamic_cast<CCTexture2D*>(texture), "setTexture expects a CCTexture2D. Invalid argument");
//==>>如果texture为NULL 就找一个默认的。
if (NULL == texture)
{
// Gets the texture by key firstly.
texture = CCTextureCache::sharedTextureCache()->textureForKey(CC_2x2_WHITE_IMAGE_KEY);
// If texture wasn't in cache, create it from RAW data.
if (NULL == texture)
{
CCImage* image = new CCImage();
bool isOK = image->initWithImageData(cc_2x2_white_image, sizeof(cc_2x2_white_image), CCImage::kFmtRawData, 2, 2, 8);
CCAssert(isOK, "The 2x2 empty texture was created unsuccessfully.");
texture = CCTextureCache::sharedTextureCache()->addUIImage(image, CC_2x2_WHITE_IMAGE_KEY);
CC_SAFE_RELEASE(image);
}
}
//==>>如果m_pobBatchNode为NULL，并且texture和之前存放的不同，那么就更新下。
if (!m_pobBatchNode && m_pobTexture != texture)
{
CC_SAFE_RETAIN(texture);
CC_SAFE_RELEASE(m_pobTexture);
m_pobTexture = texture;
updateBlendFunc();
}
}
//更新混合模式。
void CCSprite::updateBlendFunc(void)
{
CCAssert (! m_pobBatchNode, "CCSprite: updateBlendFunc doesn't work when the sprite is rendered using a CCSpriteBatchNode");
// it is possible to have an untextured sprite
if (! m_pobTexture || ! m_pobTexture->hasPremultipliedAlpha())
{
m_sBlendFunc.src = GL_SRC_ALPHA;
m_sBlendFunc.dst = GL_ONE_MINUS_SRC_ALPHA;
setOpacityModifyRGB(false);
}
else
{
m_sBlendFunc.src = CC_BLEND_SRC;
m_sBlendFunc.dst = CC_BLEND_DST;
setOpacityModifyRGB(true);
}
}
//==>>设置RGB模式
void CCSprite::setOpacityModifyRGB(bool modify)
{
if (m_bOpacityModifyRGB != modify)
{
m_bOpacityModifyRGB = modify;
updateColor();
}
}
//==>>更新颜色
void CCSprite::updateColor(void)
{
ccColor4B color4 = { _displayedColor.r, _displayedColor.g, _displayedColor.b, _displayedOpacity };
// special opacity for premultiplied textures
if (m_bOpacityModifyRGB)
{
color4.r *= _displayedOpacity/255.0f;
color4.g *= _displayedOpacity/255.0f;
color4.b *= _displayedOpacity/255.0f;
}
//==>>更新正方形4个角的颜色值
m_sQuad.bl.colors = color4;
m_sQuad.br.colors = color4;
m_sQuad.tl.colors = color4;
m_sQuad.tr.colors = color4;
// renders using batch node
if (m_pobBatchNode)
{
if (m_uAtlasIndex != CCSpriteIndexNotInitialized)
{
m_pobTextureAtlas->updateQuad(&m_sQuad, m_uAtlasIndex);
}
else
{
// no need to set it recursively
// update dirty_, don't update recursiveDirty_
setDirty(true);
}
}
// self render
// do nothing
}
setTextureRect代码分析
void CCSprite::setTextureRect(const CCRect& rect, bool rotated, const CCSize& untrimmedSize)
{
m_bRectRotated = rotated;//==>>设置是否旋转
//==>>设置大小，设置顶点矩阵大小，计算纹理坐标
setContentSize(untrimmedSize);
setVertexRect(rect);
setTextureCoords(rect);
CCPoint relativeOffset = m_obUnflippedOffsetPositionFromCenter;
// issue #732
if (m_bFlipX)
{
relativeOffset.x = -relativeOffset.x;
}
if (m_bFlipY)
{
relativeOffset.y = -relativeOffset.y;
}
m_obOffsetPosition.x = relativeOffset.x + (m_obContentSize.width - m_obRect.size.width) / 2;
m_obOffsetPosition.y = relativeOffset.y + (m_obContentSize.height - m_obRect.size.height) / 2;
// rendering using batch node
if (m_pobBatchNode)
{
// update dirty_, don't update recursiveDirty_
setDirty(true);
}
else
{
// self rendering
// Atlas: Vertex
float x1 = 0 + m_obOffsetPosition.x;
float y1 = 0 + m_obOffsetPosition.y;
float x2 = x1 + m_obRect.size.width;
float y2 = y1 + m_obRect.size.height;
//==>>设置正方形顶点坐标
// Don't update Z.
m_sQuad.bl.vertices = vertex3(x1, y1, 0);
m_sQuad.br.vertices = vertex3(x2, y1, 0);
m_sQuad.tl.vertices = vertex3(x1, y2, 0);
m_sQuad.tr.vertices = vertex3(x2, y2, 0);
}
}
void CCNode::setContentSize(const CCSize & size)
{
//==>>如果大小没变，就直接返回。如果变了，就更新下大小，然后根据锚点比例，重新计算锚点的实际位置，将dirty置true。
if ( ! size.equals(m_obContentSize))
{
m_obContentSize = size;
//==>>m_obAnchorPoint就是我们经常在程序中设置的锚点比例。
//==>>m_obAnchorPointInPoints是实际的锚点位置
m_obAnchorPointInPoints = ccp(m_obContentSize.width * m_obAnchorPoint.x, m_obContentSize.height * m_obAnchorPoint.y );
m_bTransformDirty = m_bInverseDirty = true;
}
}
/**
* Sets the vertex rect.
* It will be called internally by setTextureRect.
* Useful if you want to create 2x images from SD images in Retina Display.
* Do not call it manually. Use setTextureRect instead.
*/
void CCSprite::setVertexRect(const CCRect& rect)
{//==>>设置顶点矩阵的大小
m_obRect = rect;
}
//==>>根据纹理的大小和sprite的大小设置纹理坐标
void CCSprite::setTextureCoords(CCRect rect)
{
//==>>首先将sprite的大小转换为像素大小
rect = CC_RECT_POINTS_TO_PIXELS(rect);
//==>>获取纹理，并且获取纹理的像素宽，像素高
CCTexture2D *tex = m_pobBatchNode ? m_pobTextureAtlas->getTexture() : m_pobTexture;
if (! tex)
{
return;
}
float atlasWidth = (float)tex->getPixelsWide();
float atlasHeight = (float)tex->getPixelsHigh();
float left, right, top, bottom;
if (m_bRectRotated)
{
。。。。。
//==>>旋转后的纹理坐标设置，和不旋转的代码差不多，只是坐标点是反的。
。。。。。
}
else
{
#if CC_FIX_ARTIFACTS_BY_STRECHING_TEXEL
left = (2*rect.origin.x+1)/(2*atlasWidth);
right = left + (rect.size.width*2-2)/(2*atlasWidth);
top = (2*rect.origin.y+1)/(2*atlasHeight);
bottom = top + (rect.size.height*2-2)/(2*atlasHeight);
#else
//==>> 根据sprite的像素大小和纹理的像素宽高计算正方形纹理坐标的4个点。
left = rect.origin.x/atlasWidth;
right = (rect.origin.x + rect.size.width) / atlasWidth;
top = rect.origin.y/atlasHeight;
bottom = (rect.origin.y + rect.size.height) / atlasHeight;
#endif // ! CC_FIX_ARTIFACTS_BY_STRECHING_TEXEL
//==>>如果左右翻转，那么左右点翻转
if(m_bFlipX)
{
CC_SWAP(left,right,float);
}
//==>>如果上下翻转，那么上下点翻转
if(m_bFlipY)
{
CC_SWAP(top,bottom,float);
}
//==>>将计算好的4个点根据规则设置到正方形纹理的4个角中。
//==>>参考网址【 http://blog.sina.com.cn/s/blog_6d8189930100nfvw.html 】
m_sQuad.bl.texCoords.u = left;
m_sQuad.bl.texCoords.v = bottom;
m_sQuad.br.texCoords.u = right;
m_sQuad.br.texCoords.v = bottom;
m_sQuad.tl.texCoords.u = left;
m_sQuad.tl.texCoords.v = top;
m_sQuad.tr.texCoords.u = right;
m_sQuad.tr.texCoords.v = top;
}
}
更新==》》
draw代码分析
在分析draw方法前，先看先以前的一部分学习记录：
首先是CCSprite使用的shader：
bool CCSprite::initWithTexture(CCTexture2D *pTexture, const CCRect& rect, bool rotated)
{
。。。。。
setShaderProgram(CCShaderCache::sharedShaderCache()->programForKey(kCCShader_PositionTextureColor));
。。。。。
}
我们在回过头来看下kCCUniformSampler中的Shader_PositionTextureColor的有关代码：
void CCShaderCache::loadDefaultShader(CCGLProgram *p, int type)
{
switch (type) {
case kCCShaderType_PositionTextureColor:
p->initWithVertexShaderByteArray(ccPositionTextureColor_vert, ccPositionTextureColor_frag);
p->addAttribute(kCCAttributeNamePosition, kCCVertexAttrib_Position);
p->addAttribute(kCCAttributeNameColor, kCCVertexAttrib_Color);
p->addAttribute(kCCAttributeNameTexCoord, kCCVertexAttrib_TexCoords);
break;
。。。。。
p->updateUniforms();
。。。。。
}
CCGLProgram中的有关代码：
void CCGLProgram::updateUniforms()
{
m_uUniforms[kCCUniformPMatrix] = glGetUniformLocation(m_uProgram, kCCUniformPMatrix_s);
m_uUniforms[kCCUniformMVMatrix] = glGetUniformLocation(m_uProgram, kCCUniformMVMatrix_s);
m_uUniforms[kCCUniformMVPMatrix] = glGetUniformLocation(m_uProgram, kCCUniformMVPMatrix_s);
m_uUniforms[kCCUniformTime] = glGetUniformLocation(m_uProgram, kCCUniformTime_s);
m_uUniforms[kCCUniformSinTime] = glGetUniformLocation(m_uProgram, kCCUniformSinTime_s);
m_uUniforms[kCCUniformCosTime] = glGetUniformLocation(m_uProgram, kCCUniformCosTime_s);
m_bUsesTime = (
m_uUniforms[kCCUniformTime] != -1 ||
m_uUniforms[kCCUniformSinTime] != -1 ||
m_uUniforms[kCCUniformCosTime] != -1
);
m_uUniforms[kCCUniformRandom01] = glGetUniformLocation(m_uProgram, kCCUniformRandom01_s);
m_uUniforms[kCCUniformSampler] = glGetUniformLocation(m_uProgram, kCCUniformSampler_s);
this->use();
// Since sample most probably won't change, set it to 0 now.
this->setUniformLocationWith1i(m_uUniforms[kCCUniformSampler], 0);
}
void CCGLProgram::setUniformLocationWith1i(GLint location, GLint i1)
{
。。。。。
glUniform1i( (GLint)location, i1);
。。。。。
}
其中，kCCUniformSampler_s这个宏的定义为
#define kCCUniformSampler_s "CC_Texture0"
再翻下shader的代码：
ccShader_PositionTextureColor_frag.h
" \n\
#ifdef GL_ES \n\
precision lowp float; \n\
#endif \n\
\n\
varying vec4 v_fragmentColor; \n\
varying vec2 v_texCoord; \n\
uniform sampler2D CC_Texture0; \n\
\n\
void main() \n\
{ \n\
gl_FragColor = v_fragmentColor * texture2D(CC_Texture0, v_texCoord); \n\
} \n\
";
到了这里就很清楚了，在把shader读入到缓存的过程中，CC_Texture0这个uniform 最终被绑定到了‘0’这个位置上。
这里在分析一个draw中用到的一个函数：
//==>>如果调用了ccGLBindTexture2D，那么就直接将图像纹理textureId绑定到位置0上
void ccGLBindTexture2D(GLuint textureId)
{
ccGLBindTexture2DN(0, textureId);
}
//==>>将纹理textureId绑定到位置textureUnit上
void ccGLBindTexture2DN(GLuint textureUnit, GLuint textureId)
{
#if CC_ENABLE_GL_STATE_CACHE
CCAssert(textureUnit < kCCMaxActiveTexture, "textureUnit is too big");
if (s_uCurrentBoundTexture[textureUnit] != textureId)
{
s_uCurrentBoundTexture[textureUnit] = textureId;
//==>>glActiveTexture 函数设定当前的贴图单元，以至于后面的函数glBindTexture 绑定贴图到当前的单元
glActiveTexture(GL_TEXTURE0 + textureUnit);
glBindTexture(GL_TEXTURE_2D, textureId);//==>>将纹理textureId绑定到已经激活的位置上
}
#else
glActiveTexture(GL_TEXTURE0 + textureUnit);
glBindTexture(GL_TEXTURE_2D, textureId);
#endif
}
然后来看下draw方法，就比较简单了。
void CCSprite::draw(void)
{
CC_PROFILER_START_CATEGORY(kCCProfilerCategorySprite, "CCSprite - draw");
CCAssert(!m_pobBatchNode, "If CCSprite is being rendered by CCSpriteBatchNode, CCSprite#draw SHOULD NOT be called");
CC_NODE_DRAW_SETUP();
//==>>设置混合模式
ccGLBlendFunc( m_sBlendFunc.src, m_sBlendFunc.dst );
//==>>将纹理绑定到opengl上
ccGLBindTexture2D( m_pobTexture->getName() );
//==>>允许顶点，纹理位置，颜色等坐标输入
ccGLEnableVertexAttribs( kCCVertexAttribFlag_PosColorTex );
#define kQuadSize sizeof(m_sQuad.bl)
#ifdef EMSCRIPTEN
long offset = 0;
setGLBufferData(&m_sQuad, 4 * kQuadSize, 0);
#else
long offset = (long)&m_sQuad;
#endif // EMSCRIPTEN
//==>>我们知道了ccV3F_C4B_T2F这个结构体的类型和指针，那么就可以通过offset方式来获取到里面指定成员变量的位置，然后就可以
//==>>通过(void*) (offset + diff)获取指定成员变量的位置。
// vertex
int diff = offsetof( ccV3F_C4B_T2F, vertices);
glVertexAttribPointer(kCCVertexAttrib_Position, 3, GL_FLOAT, GL_FALSE, kQuadSize, (void*) (offset + diff));
// texCoods
diff = offsetof( ccV3F_C4B_T2F, texCoords);
glVertexAttribPointer(kCCVertexAttrib_TexCoords, 2, GL_FLOAT, GL_FALSE, kQuadSize, (void*)(offset + diff));
// color
diff = offsetof( ccV3F_C4B_T2F, colors);
glVertexAttribPointer(kCCVertexAttrib_Color, 4, GL_UNSIGNED_BYTE, GL_TRUE, kQuadSize, (void*)(offset + diff));
//==>>画图
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
。。。。。
。。。。。
}
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