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cocos2d-x游戏开发(十四)用shader使图片背景透明

2019-05-18 Cocos2d-x 前端之家

前端之家收集整理的这篇文章主要介绍了cocos2d-x游戏开发(十四)用shader使图片背景透明，前端之家小编觉得挺不错的，现在分享给大家，也给大家做个参考。

欢迎转载，地址：http://blog.csdn.net/fylz1125/article/details/8631783

好吧，终于抽时间写这篇文章了。

手头上有很多人物行走图，技能特效图等，但这些图都有个纯黑色背景，怎么样将内容显示出来，让背景透明呢？前段时间搞了一下，感谢群里的童鞋们，提供了思路和方法。

这里用shader处理了像素，使黑色背景透明，直接上代码

ShaderSprite.h

[cpp]view plaincopyprint? 
   
 #ifndef__TestShader__ShaderSprite__
 #define__TestShader__ShaderSprite__
 
 #include"cocos2d.h"
 USING_NS_CC;
 
 classShaderSprite:publicCCSprite{
 public:
 staticShaderSprite*create(constchar*pszFileName);
 virtualboolinitWithTexture(CCTexture2D*pTexture,constCCRect&rect);
 virtualvoiddraw(void);
 };
 #endif/*defined(__TestShader__ShaderSprite__)*/

ShaderSprite.cpp

?

#include"ShaderSprite.h"

staticCC_DLLconstGLchar*transparentshader=
#include"tansparentshader.h"
ShaderSprite*ShaderSprite::create(constchar*pszFileName)
{
ShaderSprite*pRet=newShaderSprite();
if(pRet&&pRet->initWithFile(pszFileName)){
pRet->autorelease();
returnpRet;
}
else
{
deletepRet;
pRet=NULL;
returnNULL;
}
boolShaderSprite::initWithTexture(CCTexture2D*pTexture,constCCRect&rect)
do{
//CCLog("overrideinitWithTexture!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
CC_BREAK_IF(!CCSprite::initWithTexture(pTexture,rect));
//加载顶点着色器和片元着色器
m_pShaderProgram=newCCGLProgram();
m_pShaderProgram->initWithVertexShaderByteArray(ccPositionTextureA8Color_vert,transparentshader);
CHECK_GL_ERROR_DEBUG();
//启用顶点着色器的attribute变量，坐标、纹理坐标、颜色
m_pShaderProgram->addAttribute(kCCAttributeNamePosition,kCCVertexAttrib_Position);
m_pShaderProgram->addAttribute(kCCAttributeNameColor,kCCVertexAttrib_Color);
m_pShaderProgram->addAttribute(kCCAttributeNameTexCoord,kCCVertexAttrib_TexCoords);
CHECK_GL_ERROR_DEBUG();
//自定义着色器链接
m_pShaderProgram->link();
//设置移动、缩放、旋转矩阵
m_pShaderProgram->updateUniforms();
returntrue;
}while(0);
returnfalse;
voidShaderSprite::draw(void)
//CCLog("overridedraw!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
CC_PROFILER_START_CATEGORY(kCCProfilerCategorySprite,"CCSprite-draw");
CCAssert(!m_pobBatchNode,"IfCCSpriteisbeingrenderedbyCCSpriteBatchNode,CCSprite#drawSHOULDNOTbecalled");
CC_NODE_DRAW_SETUP();
//
//启用attributes变量输入，顶点坐标，纹理坐标，颜色
ccGLEnableVertexAttribs(kCCVertexAttribFlag_PosColorTex);
ccGLBlendFunc(m_sBlendFunc.src,m_sBlendFunc.dst);
m_pShaderProgram->use();
m_pShaderProgram->setUniformsForBuiltins();
//绑定纹理到纹理槽0
ccGLBindTexture2D(m_pobTexture->getName());
#definekQuadSizesizeof(m_sQuad.bl)
longoffset=(long)&m_sQuad;
//vertex
intdiff=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,2,0); background-color:inherit">//color
glVertexAttribPointer(kCCVertexAttrib_Color,4,GL_UNSIGNED_BYTE,GL_TRUE,153); list-style:decimal-leading-zero outside; color:inherit; line-height:20px; margin:0px!important; padding:0px 3px 0px 10px!important"> glDrawArrays(GL_TRIANGLE_STRIP,4);
CC_INCREMENT_GL_DRAWS(1);
CC_PROFILER_STOP_CATEGORY(kCCProfilerCategorySprite,"CCSprite-draw");
}

片段着色器代码

tansparentshader.h

?

"\n\

#ifdefGL_ES\n\
precisionlowpfloat;\n\
#endif\n\
varyingvec4v_fragmentColor;\n\
varyingvec2v_texCoord;\n\
uniformsampler2Du_texture;\n\
voidmain()\n\
{\n\
floatratio=0.0;\n\
vec4texColor=texture2D(u_texture,v_texCoord);\n\
ratio=texColor[0]>texColor[1]?(texColor[0]>texColor[2]?texColor[0]:texColor[2]):(texColor[1]>texColor[2]?texColor[1]:texColor[2]);\n\
if(ratio!=0.0)\n\
{\n\
texColor[0]=texColor[0]/ratio;\n\
texColor[1]=texColor[1]/ratio;\n\
texColor[2]=texColor[2]/ratio;\n\
texColor[3]=ratio;\n\
}\n\
else\n\
texColor[3]=0.0;\n\
gl_FragColor=v_fragmentColor*texColor;\n\
}";