子龙山人出了一个系列：基于Cocos2d-x学习OpenGL ES 2.0。弄c++来搞cocos2dx的可以看看。
教程是参考iphone的教程来写的，坑点也有不少，最主要的坑点还是在版本。所以还是弄个cocos2dx 3.2比较好。前两天辉辉说cocos2dx 3.2也很 *** 蛋，.h里声明的返回值在源码实现的时候返回类型竟然变了。不得不吐槽一下~
子龙山人的教程只能教你照葫芦画瓢，什么原理的东西是压根就没涉及，有的还因为cocos2dx的封装过度会产生一些误导。
cocos2dx对opengl es封装的有点让人恶心，如果想学习opengl es是不建议在cocos2dx下进行学习的。
废话少说吧，开始正文。
根据子龙山人的教程，弄出了立方体纹理贴图，但是假如想在同一个面上贴多个纹理呢？该怎么实现？
本文提到两个方法，第一就是获取两个纹理，分别画图贴纹理，意思就是装顶点，装索引，绑定纹理，画图一。装顶点，装纹理，画图二。此时用到的都是GL_TEXTURE0，在frag文件中，只需要一个采样器就ok。
第二中方法就是用两个sampler，装顶点，装索引，绑定纹理一，绑定纹理二，画图。就OK了。
说起来比较简单，真要自己动手做，对于一个新手来说，过程还是有点小郁闷的。
下面就上源码了，对于步骤和方法的含义，此处不作介绍。相信强大的Google和百度可以发挥巨大的作用。
第一种是立方体六个面贴上纹理，其中一个面再次贴上第二个纹理。
所用到的shader文件：
1 attribute vec4 a_position; // 1 2 attribute vec4 a_color; 2 3 attribute vec2 TextureCoord; 4 5 varying vec4 Destinationcolor; 3 6 varying vec2 v_texCoord; 7 8 9 voID main(voID) { 410 Destinationcolor = a_color; 511 v_texCoord = TextureCoord;12 gl_position = CC_MVPMatrix * a_position; 613 }1 varying vec4 Destinationcolor; 2 varying vec2 v_texCoord;3 4 5 6 gl_Fragcolor = Destinationcolor * texture2D(CC_Texture0,v_texCoord) ; 7 }
所用到的两张图
头文件：
#ifndef _CubeTexture_H__#define _CubeTexture_H__#include "cocos2d.h"using namespace cocos2d;class CubeTexture : public cocos2d::Layer{public: there's no 'ID' in cpp,so we recommend returning the class instance pointer static cocos2d::Scene* createScene(); Here's a difference. Method 'init' in cocos2d-x returns bool,instead of returning 'ID' in cocos2d-iphone virtual bool init(); voID draw(Renderer *renderer,const Mat4 &transform,uint32_t transformUpdated) overrIDe; we call our actual opengl commands here voID onDraw(); implement the "static create()" method manually CREATE_FUNC(CubeTexture);private: Mat4 _modelVIEwMV; CustomCommand _customCommand; GLProgram *mShaderProgram; Glint _colorLocation; Glint _positionLocation; Glint _textureLocation; gluint _textureUniform; gluint _textureID; gluint _textureID2; gluint vertexBuffer; gluint indexBuffer; gluint _vertexBuffer2; gluint _indexBuffer2;};#endif __HELLOWORLD_SCENE_H__1 #include CubeTexture.h" 2 namespace GL; 3 4 cocos2d::Scene* CubeTexture::createScene() 5 { 6 auto scene = Scene::create(); 7 auto layer = CubeTexture::create(); 8 scene->addChild(layer); 9 return scene; 10 } 11 12 bool CubeTexture::init() 13 { 14 if ( Layer::init() ) 15 { 16 mShaderProgram = new GLProgram; 17 mShaderProgram->initWithfilenames(myshader.vert",myshader.frag"); 18 mShaderProgram->link(); 19 mShaderProgram->updateUniforms(); 20 21 _textureID = Director::getInstance()->getTextureCache()->addImage( HelloWorld.png" )->getname(); 22 _textureID2 = Director::getInstance()->getTextureCache()->addImage(item_powerup_fish.png")->getname(); 23 glGenBuffers( 1,&vertexBuffer ); 24 glBindBuffer(GL_ARRAY_BUFFER,vertexBuffer ); 25 26 glGenBuffers( indexBuffer ); 27 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,indexBuffer ); 28 29 return true; 30 } 31 false; 32 } 33 34 voID CubeTexture::draw( Renderer *renderer,255);line-height:1.5;">const Mat4 &transform,uint32_t transformUpdated ) 35 { 36 Layer::draw(renderer,transform,transformUpdated); 37 38 _customCommand.init(_globalZOrder); 39 _customCommand.func = CC_CALLBACK_0(CubeTexture::onDraw,255);line-height:1.5;">this); 40 renderer->addCommand(&_customCommand); 41 } 42 43 voID CubeTexture::onDraw() 44 { 45 Director::getInstance()->pushmatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW); 46 Director::getInstance()->loadIDentityMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW); 47 Director::getInstance()->pushmatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION); 48 Director::getInstance()->loadIDentityMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION); 49 50 Mat4 modelVIEwMatrix; 51 Mat4::createLookAt(Vec3(0,128);line-height:1.5;">5),Vec3(0),-modelVIEwMatrix); 52 modelVIEwMatrix.translate(0 ); 53 54 static float rotation = 20; 55 modelVIEwMatrix.rotate(Vec3(0),CC_degrees_TO_radians(rotation)); 56 57 Mat4 projectionMatrix; 58 Mat4::createPerspective(60,128);line-height:1.5;">480/320,128);line-height:1.5;">1.0,128);line-height:1.5;">42,&projectionMatrix); 59 Director::getInstance()->multiplyMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION,projectionMatrix); 60 Director::getInstance()->multiplyMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW,modelVIEwMatrix); 61 62 typedef struct { 63 float position[3]; 64 float color[4]; 65 float TexCoord[2]; 66 } Vertex; 67 #define TEX_COORD_MAX 1 68 69 Vertex Vertices[] = { 70 Front 71 {{0},{1},{TEX_COORD_MAX,128);line-height:1.5;">0}}, 72 {{1},TEX_COORD_MAX}},128);line-height:1.5;"> 73 {{-0,128);line-height:1.5;"> 74 {{- 75 Back 76 {{2},128);line-height:1.5;"> 77 {{- 78 {{ 79 {{- 80 left 81 {{- 82 {{- 83 {{- 84 {{- 85 Right 86 {{ 87 {{ 88 {{ 89 {{ 90 top 91 {{ 92 {{ 93 {{- 94 {{- 95 Bottom 96 {{ 97 {{ 98 {{- 99 {{-0}}100 };101 int vertexCount = sizeof(Vertices) / sizeof(Vertices[0]);102 103 glubyte Indices[] = {104 105 2,128);line-height:1.5;">106 2,128);line-height:1.5;">3,128);line-height:1.5;">107 108 4,128);line-height:1.5;">5,128);line-height:1.5;">6,128);line-height:1.5;">109 7,128);line-height:1.5;">110 111 8,128);line-height:1.5;">9,128);line-height:1.5;">10,128);line-height:1.5;">112 10,128);line-height:1.5;">11,128);line-height:1.5;">8,128);line-height:1.5;">113 114 12,128);line-height:1.5;">13,128);line-height:1.5;">14,128);line-height:1.5;">115 14,128);line-height:1.5;">15,128);line-height:1.5;">12,128);line-height:1.5;">116 117 16,128);line-height:1.5;">17,128);line-height:1.5;">18,128);line-height:1.5;">118 18,128);line-height:1.5;">19,128);line-height:1.5;">16,128);line-height:1.5;">119 120 20,128);line-height:1.5;">21,128);line-height:1.5;">22,128);line-height:1.5;">121 22,128);line-height:1.5;">23,128);line-height:1.5;">20122 };123 124 1) Add to top of file125 const Vertex Vertices2[] = {126 {{0.5,128);line-height:1.5;">0.01},128);line-height:1.5;">1}},128);line-height:1.5;">127 {{128 {{-129 {{-130 };131 132 const glubyte Indices2[] = {133 3134 };135 136 glBindBuffer(GL_ARRAY_BUFFER,vertexBuffer);137 glBufferData(GL_ARRAY_BUFFER,255);line-height:1.5;">sizeof(Vertices),Vertices,GL_STATIC_DRAW);138 139 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,indexBuffer);140 glBufferData(GL_ELEMENT_ARRAY_BUFFER,255);line-height:1.5;">sizeof(Indices),Indices,128);line-height:1.5;">141 142 143 _positionLocation = glGetAttribLocation(mShaderProgram->getProgram(),0);line-height:1.5;">a_position144 _colorLocation = glGetAttribLocation(mShaderProgram->getProgram(),0);line-height:1.5;">a_color145 146 _textureLocation = glGetAttribLocation(mShaderProgram->getProgram(),0);line-height:1.5;">TextureCoord147 _textureUniform = glGetUniformlocation(mShaderProgram->getProgram(),0);line-height:1.5;">CC_Texture0148 149 mShaderProgram->use();150 mShaderProgram->setUniformsForBuiltins();151 152 glEnabLevertexAttribarray(_positionLocation);153 glEnabLevertexAttribarray(_colorLocation);154 glEnabLevertexAttribarray(_textureLocation);155 156 glVertexAttribPointer(_positionLocation,GL_float,GL_FALSE,255);line-height:1.5;">sizeof(Vertex),(GLvoID*)offsetof(Vertex,position));157 158 glVertexAttribPointer(_colorLocation,color));159 160 glVertexAttribPointer(_textureLocation,255);line-height:1.5;">sizeof(Vertex),128);line-height:1.5;">161 (GLvoID*)offsetof(Vertex,TexCoord));162 //163 ////set sampler164 GL::bindTexture2DN(165 glActiveTexture( GL_TEXTURE0 );166 glBindTexture(GL_TEXTURE_2D,_textureID);167 glBlendFunc(GL_ONE,GL_ONE_MINUS_SRC_Alpha);168 glEnable(GL_BLEND);169 glEnable(GL_DEPTH_TEST);170 glDrawElements(GL_TRIANGLES,128);line-height:1.5;">36,GL_UNSIGNED_BYTE,128);line-height:1.5;">0);171 gluniform1i(_textureUniform,128);line-height:1.5;">0); unnecc in practice172 173 glGenBuffers(_vertexBuffer2);174 glBindBuffer(GL_ARRAY_BUFFER,_vertexBuffer2);175 glBufferData(GL_ARRAY_BUFFER,255);line-height:1.5;">sizeof(Vertices2),Vertices2,128);line-height:1.5;">176 177 glGenBuffers(_indexBuffer2);178 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,_indexBuffer2);179 glBufferData(GL_ELEMENT_ARRAY_BUFFER,255);line-height:1.5;">sizeof(Indices2),Indices2,128);line-height:1.5;">180 181 glBindBuffer(GL_ARRAY_BUFFER,128);line-height:1.5;">182 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,128);line-height:1.5;">183 184 GL::bindTexture2DN(185 gluniform1i(_textureUniform,128);line-height:1.5;">186 187 glVertexAttribPointer(_positionLocation,128);line-height:1.5;">188 glVertexAttribPointer(_colorLocation,(GLvoID*) (sizeof(float) * 3));189 glVertexAttribPointer(_textureLocation,128);line-height:1.5;">7));190 191 glDrawElements(GL_TRIANGLE_STRIP,255);line-height:1.5;">sizeof(Indices2)/sizeof(Indices2[0]),128);line-height:1.5;">192 193 CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1,vertexCount);194 195 CHECK_GL_ERROR_DEBUG();196 gldisable(GL_DEPTH_TEST);197 198 Director::getInstance()->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);199 Director::getInstance()->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);200 }
运行结果：
方法二，所需要的shader文件：
1 attribute vec4 a_position; 2 attribute vec2 a_texCoord;4 varying vec2 v_texCoord; 6 voID) {7 gl_position = CC_MVPMatrix * a_position; 8 v_texCoord = a_texCoord;9 } 1 precision mediump float; 2 varying vec2 v_texCoord; 3 uniform sampler2D s_lightmap; 4 uniform sampler2D s_baseMap; 5 6 7 8 vec4 basecolor; 9 vec4 lightcolor;10 basecolor = texture2D( s_baseMap,v_texCoord);11 lightcolor = texture2D( s_lightmap,v_texCoord );12 basecolor = texture2D( CC_Texture0,128);line-height:1.5;">13 lightcolor = texture2D( CC_Texture1,v_texCoord ); 14 gl_Fragcolor = basecolor * ( lightcolor + 0.25 ); 15 }所需要的图
头文件
MultiTexture.h源文件
MultiTexture.h 2 3 cocos2d::Scene* MultiTexture::createScene() 4 { 5 auto scene = Scene::create(); 6 auto layer = MultiTexture::create(); 7 scene->addChild(layer); 8 9 } 10 11 bool MultiTexture::init() 12 { 13 14 { 15 mShaderProgram = 16 mShaderProgram->initWithfilenames(multiTexture.vertmultiTexture.frag 17 mShaderProgram->link(); 18 mShaderProgram->updateUniforms(); 19 20 _baseMapTexID = Director::getInstance()->getTextureCache()->addImage( 21 _lightmapTexID = Director::getInstance()->getTextureCache()->addImage(crate.jpg 22 glGenVertexArrays(VAO); 23 glBindVertexArray(VAO); 24 25 glGenBuffers( 26 glBindBuffer(GL_ARRAY_BUFFER,128);line-height:1.5;"> 27 28 glGenBuffers( 29 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,128);line-height:1.5;"> 30 31 32 } 33 34 } 35 36 voID MultiTexture::draw( Renderer *renderer,128);line-height:1.5;"> 37 { 38 Layer::draw(renderer,128);line-height:1.5;"> 39 40 _customCommand.init(_globalZOrder); 41 _customCommand.func = CC_CALLBACK_0(MultiTexture::onDraw,128);line-height:1.5;"> 42 renderer->addCommand(&_customCommand); 43 } 44 45 voID MultiTexture::onDraw() 46 { 47 Director::getInstance()->pushmatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW); 48 Director::getInstance()->loadIDentityMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW); 49 Director::getInstance()->pushmatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION); 50 Director::getInstance()->loadIDentityMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION); 51 52 typedef 53 54 55 } Vertex; 56 57 58 Vertex Vertices[] = { 59 60 {{- 61 {{- 62 {{0},{ TEX_COORD_MAX,128);line-height:1.5;"> 63 {{ 64 65 }; 66 67 68 glubyte Indices[] = { 69 70 71 }; 72 73 glBindBuffer(GL_ARRAY_BUFFER,128);line-height:1.5;"> 74 glBufferData(GL_ARRAY_BUFFER,128);line-height:1.5;"> 75 76 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,128);line-height:1.5;"> 77 glBufferData(GL_ELEMENT_ARRAY_BUFFER,128);line-height:1.5;"> 78 79 _positionLoc = glGetAttribLocation(mShaderProgram->getProgram(),128);line-height:1.5;"> 80 _texCoordLoc = glGetAttribLocation(mShaderProgram->getProgram(),0);line-height:1.5;">a_texCoord 81 _baseMapLoc = glGetUniformlocation(mShaderProgram->getProgram(),"s_baseMap"); 82 _lightmapLoc = glGetUniformlocation(mShaderProgram->getProgram(),"s_lightmap"); 83 _baseMapLoc = glGetUniformlocation(mShaderProgram->getProgram(),128);line-height:1.5;"> 84 _lightmapLoc = glGetUniformlocation(mShaderProgram->getProgram(),0);line-height:1.5;">CC_Texture1 85 86 glEnabLevertexAttribarray(_positionLoc); 87 glEnabLevertexAttribarray(_texCoordLoc); 88 89 glVertexAttribPointer(_positionLoc,128);line-height:1.5;"> 90 glVertexAttribPointer(_texCoordLoc,128);line-height:1.5;"> 91 (GLvoID*)offsetof(Vertex,128);line-height:1.5;"> 92 93 mShaderProgram->use(); 94 mShaderProgram->setUniformsForBuiltins(); 95 96 glEnable(GL_DEPTH_TEST); 97 glBindVertexArray(VAO); 98 99 GL::bindTexture2DN(100 gluniform1i(_lightmapLoc,128);line-height:1.5;">0 ); 101 102 GL::bindTexture2DN(103 gluniform1i(_baseMapLoc,128);line-height:1.5;">1); 104 105 glDrawElements(GL_TRIANGLES,128);line-height:1.5;">6,128);line-height:1.5;">106 107 glBindVertexArray(108 CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(6);109 110 CHECK_GL_ERROR_DEBUG();111 gldisable(GL_DEPTH_TEST);112 113 Director::getInstance()->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);114 Director::getInstance()->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);115 }运行效果：
第二种方法中，
cpp内的：
//_baseMapLoc =glGetUniformlocation(mShaderProgram->getProgram(),"s_baseMap");
//_lightmapLoc = glGetUniformlocation(mShaderProgram->getProgram(),"s_lightmap");
_baseMapLoc = glGetUniformlocation(mShaderProgram->getProgram(),"CC_Texture0");
_lightmapLoc = glGetUniformlocation(mShaderProgram->getProgram(),"CC_Texture1");
和shader内的
//basecolor = texture2D( s_baseMap,v_texCoord);
//lightcolor = texture2D( s_lightmap,v_texCoord );
basecolor = texture2D( CC_Texture0,v_texCoord);
lightcolor = texture2D( CC_Texture1,v_texCoord );
将注释解开，把下面两行注掉。同样可以。这说明了，cocos2dx在进行编译shader的时候内置了多个uniform值。大家可以看一下，其中就包括CC_Texture0系列。
其实用起来不算方便了，而不注意的人，可能会声明和内置变量相同的名字，此时，咳咳咳咳咳~ shader编译的时候就会出错了。不知道为啥cocos2dx要多次一举。
还有一点：
////set sampler
GL::bindTexture2DN(0,_textureID);
//glActiveTexture( GL_TEXTURE0 );
//glBindTexture(GL_TEXTURE_2D,_textureID);
我使用了GL::bindTexture2DN 方法，而并没有使用opengl es原装的 glActiveTexture 和glBindTexture这两个方法。其实GL::bindTexture2DN 内部就调用了后面的两个方法，那为何不直接用后面的两个方法呢？
原因是，直接用opengl es的方法，会出错！！！尼玛 这才是坑点。跟踪后发现，cocos2dx给GL相关的东西添加了一个StateCache的东西，当activeTexture时，需要更改cache内的东西。直接调用glActiveTexture的方法，就略去了往cache内塞东西的步骤，这样就出错了。
猜测是cocos2dx进行渲染的时候，调用了cache内的什么东西。尼玛，你还能封装的再恶心一点么？
所以说，不喜欢cocos2dx这种处理问题的方法的，可以完全抛开cocos2dx了。
(原文：https://www.cnblogs.com/slysky/p/3981210.HTML） 总结以上是内存溢出为你收集整理的基于Cocos2d-x学习OpenGL ES 2.0之多纹理全部内容，希望文章能够帮你解决基于Cocos2d-x学习OpenGL ES 2.0之多纹理所遇到的程序开发问题。
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