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  • 基于Cocos2d-x学习OpenGL ES 2.0之多纹理

    没想到原文出了那么多错别字,实在对不起观众了。介绍opengl es 2.0的不多。相信介绍基于Cocos2d-x学习OpenGL ES 2.0之多纹理的,我是独此一家吧。~~

    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也很操蛋,.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) { // 4
    10     DestinationColor = a_color; // 5
    11     v_texCoord = TextureCoord;
    12     gl_Position = CC_MVPMatrix * a_position; // 6
    13 }
    myshader.vert
    1 varying  vec4 DestinationColor; // 1
    2 varying vec2 v_texCoord;
    3 
    4 void main(void) { // 2
    5 
    6     gl_FragColor = DestinationColor * texture2D(CC_Texture0, v_texCoord) ; // 3
    7 }
    myshader.frag

    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();  
    
        virtual 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__
    CubeTexture.h
      1 #include "CubeTexture.h"
      2 using 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( 1, &indexBuffer );
     27         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer );
     28 
     29         return true;
     30     }
     31     return false;
     32 }
     33 
     34 void CubeTexture::draw( Renderer *renderer, 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,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(0,0,5), Vec3(0,0,0), Vec3(0,-1,0), &modelViewMatrix);
     52     modelViewMatrix.translate(0, 0,0 );
     53 
     54     static float rotation = 20;
     55     modelViewMatrix.rotate(Vec3(0,1,0),CC_DEGREES_TO_RADIANS(rotation));
     56 
     57     Mat4 projectionMatrix;
     58     Mat4::createPerspective(60, 480/320, 1.0, 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         {{1, -1, 0}, {1, 0, 0, 1}, {TEX_COORD_MAX, 0}},
     72         {{1, 1, 0}, {0, 1, 0, 1}, {TEX_COORD_MAX, TEX_COORD_MAX}},
     73         {{-1, 1, 0}, {0, 0, 1, 1}, {0, TEX_COORD_MAX}},
     74         {{-1, -1, 0}, {0, 0, 0, 1}, {0, 0}},
     75         // Back
     76         {{1, 1, -2}, {1, 0, 0, 1}, {TEX_COORD_MAX, 0}},
     77         {{-1, -1, -2}, {0, 1, 0, 1}, {TEX_COORD_MAX, TEX_COORD_MAX}},
     78         {{1, -1, -2}, {0, 0, 1, 1}, {0, TEX_COORD_MAX}},
     79         {{-1, 1, -2}, {0, 0, 0, 1}, {0, 0}},
     80         // Left
     81         {{-1, -1, 0}, {1, 0, 0, 1}, {TEX_COORD_MAX, 0}},
     82         {{-1, 1, 0}, {0, 1, 0, 1}, {TEX_COORD_MAX, TEX_COORD_MAX}},
     83         {{-1, 1, -2}, {0, 0, 1, 1}, {0, TEX_COORD_MAX}},
     84         {{-1, -1, -2}, {0, 0, 0, 1}, {0, 0}},
     85         // Right
     86         {{1, -1, -2}, {1, 0, 0, 1}, {TEX_COORD_MAX, 0}},
     87         {{1, 1, -2}, {0, 1, 0, 1}, {TEX_COORD_MAX, TEX_COORD_MAX}},
     88         {{1, 1, 0}, {0, 0, 1, 1}, {0, TEX_COORD_MAX}},
     89         {{1, -1, 0}, {0, 0, 0, 1}, {0, 0}},
     90         // Top
     91         {{1, 1, 0}, {1, 0, 0, 1}, {TEX_COORD_MAX, 0}},
     92         {{1, 1, -2}, {0, 1, 0, 1}, {TEX_COORD_MAX, TEX_COORD_MAX}},
     93         {{-1, 1, -2}, {0, 0, 1, 1}, {0, TEX_COORD_MAX}},
     94         {{-1, 1, 0}, {0, 0, 0, 1}, {0, 0}},
     95         // Bottom
     96         {{1, -1, -2}, {1, 0, 0, 1}, {TEX_COORD_MAX, 0}},
     97         {{1, -1, 0}, {0, 1, 0, 1}, {TEX_COORD_MAX, TEX_COORD_MAX}},
     98         {{-1, -1, 0}, {0, 0, 1, 1}, {0, TEX_COORD_MAX}}, 
     99         {{-1, -1, -2}, {0, 0, 0, 1}, {0, 0}}
    100     };
    101     int vertexCount = sizeof(Vertices) / sizeof(Vertices[0]);
    102 
    103     GLubyte Indices[] = {
    104         // Front
    105         0, 1, 2,
    106         2, 3, 0,
    107         // Back
    108         4, 5, 6,
    109         4, 5, 7,
    110         // Left
    111         8, 9, 10,
    112         10, 11, 8,
    113         // Right
    114         12, 13, 14,
    115         14, 15, 12,
    116         // Top
    117         16, 17, 18,
    118         18, 19, 16,
    119         // Bottom
    120         20, 21, 22,
    121         22, 23, 20
    122     };
    123 
    124     // 1) Add to top of file
    125     const Vertex Vertices2[] = {
    126         {{0.5, -0.5, 0.01}, {1, 1, 1, 1}, {1, 1}},
    127         {{0.5, 0.5, 0.01}, {1, 1, 1, 1}, {1, 0}},
    128         {{-0.5, 0.5, 0.01}, {1, 1, 1, 1}, {0, 0}},
    129         {{-0.5, -0.5, 0.01}, {1, 1, 1, 1}, {0, 1}},
    130     };
    131 
    132     const GLubyte Indices2[] = {
    133         1, 0, 2, 3
    134     };
    135 
    136     glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    137     glBufferData(GL_ARRAY_BUFFER,sizeof(Vertices),Vertices, GL_STATIC_DRAW);
    138 
    139     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
    140     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices),Indices,GL_STATIC_DRAW);
    141 
    142 
    143     _positionLocation = glGetAttribLocation(mShaderProgram->getProgram(), "a_position");
    144     _colorLocation = glGetAttribLocation(mShaderProgram->getProgram(), "a_color");
    145 
    146     _textureLocation = glGetAttribLocation(mShaderProgram->getProgram(), "TextureCoord");
    147     _textureUniform = glGetUniformLocation(mShaderProgram->getProgram(), "CC_Texture0");
    148 
    149     mShaderProgram->use();
    150     mShaderProgram->setUniformsForBuiltins();
    151 
    152     glEnableVertexAttribArray(_positionLocation);
    153     glEnableVertexAttribArray(_colorLocation);
    154     glEnableVertexAttribArray(_textureLocation);
    155 
    156     glVertexAttribPointer(_positionLocation, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, Position));
    157 
    158     glVertexAttribPointer(_colorLocation, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex),(GLvoid*)offsetof(Vertex, Color));
    159 
    160     glVertexAttribPointer(_textureLocation, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
    161         (GLvoid*)offsetof(Vertex, TexCoord));
    162     //
    163     ////set sampler
    164      GL::bindTexture2DN(0, _textureID);
    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,  36, GL_UNSIGNED_BYTE, 0);
    171     glUniform1i(_textureUniform, 0); // unnecc in practice
    172 
    173     glGenBuffers(1, &_vertexBuffer2);
    174     glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer2);
    175     glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices2), Vertices2, GL_STATIC_DRAW);
    176 
    177     glGenBuffers(1, &_indexBuffer2);
    178     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer2);
    179     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices2), Indices2, GL_STATIC_DRAW);
    180 
    181     glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer2);
    182     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer2);
    183 
    184     GL::bindTexture2DN(0, _textureID2);
    185     glUniform1i(_textureUniform, 0); // unnecc in practice
    186 
    187     glVertexAttribPointer(_positionLocation, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0);
    188     glVertexAttribPointer(_colorLocation, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*) (sizeof(float) * 3));
    189     glVertexAttribPointer(_textureLocation, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*) (sizeof(float) * 7));
    190 
    191     glDrawElements(GL_TRIANGLE_STRIP, sizeof(Indices2)/sizeof(Indices2[0]), GL_UNSIGNED_BYTE, 0);
    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 }
    CubeTexture

    运行结果:

       

    方法二,所需要的shader文件:

    1 attribute vec4 a_position; 
    2 attribute vec2 a_texCoord;
    3 
    4 varying vec2 v_texCoord; 
    5 
    6 void main(void) {
    7     gl_Position = CC_MVPMatrix * a_position; 
    8     v_texCoord = a_texCoord;
    9 }
    multiTexture.vert
     1 precision mediump float;
     2 varying vec2 v_texCoord;
     3 //uniform sampler2D s_lightMap;
     4 //uniform sampler2D s_baseMap;
     5 
     6 
     7 void main(void) {
     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, v_texCoord);
    13     lightColor = texture2D( CC_Texture1, v_texCoord );    
    14     gl_FragColor = baseColor * ( lightColor + 0.25 ); 
    15 }
    multiTexture

    所需要的图

      

    头文件

     1 #ifndef _MultiTexture_H__
     2 #define _MultiTexture_H__
     3 
     4 #include "cocos2d.h"
     5 
     6 using namespace cocos2d;
     7 
     8 class MultiTexture : public cocos2d::Layer
     9 {
    10 public:
    11     // there's no 'id' in cpp, so we recommend returning the class instance pointer
    12     static cocos2d::Scene* createScene();
    13 
    14     // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
    15     virtual bool init();  
    16 
    17     virtual void draw(Renderer *renderer, const Mat4 &transform, uint32_t transformUpdated) override;
    18     //we call our actual opengl commands here
    19     void onDraw();
    20 
    21     // implement the "static create()" method manually
    22     CREATE_FUNC(MultiTexture);
    23 
    24 private:
    25     Mat4 _modelViewMV;
    26     CustomCommand _customCommand;
    27 
    28     GLProgram *mShaderProgram;
    29     // attribute locations 
    30     GLint _positionLoc;
    31     GLint _texCoordLoc;
    32 
    33     // sampler locations 
    34     GLuint _baseMapLoc;
    35     GLuint _lightMapLoc;
    36     // Texture handle 
    37     GLuint _baseMapTexId;
    38     GLuint _lightMapTexId;
    39     
    40     GLuint VAO;
    41     GLuint vertexBuffer;
    42     GLuint indexBuffer;
    43 
    44 };
    45 
    46 #endif // __HELLOWORLD_SCENE_H__
    MultiTexture.h

    源文件

      1 #include "MultiTexture.h"
      2 
      3 cocos2d::Scene* MultiTexture::createScene()
      4 {
      5     auto scene = Scene::create();
      6     auto layer = MultiTexture::create();
      7     scene->addChild(layer);
      8     return scene;
      9 }
     10 
     11 bool MultiTexture::init()
     12 {
     13     if ( Layer::init() )
     14     {
     15         mShaderProgram = new GLProgram;
     16         mShaderProgram->initWithFilenames("multiTexture.vert","multiTexture.frag");
     17         mShaderProgram->link();
     18         mShaderProgram->updateUniforms();
     19 
     20         _baseMapTexId = Director::getInstance()->getTextureCache()->addImage( "HelloWorld.png" )->getName();
     21         _lightMapTexId = Director::getInstance()->getTextureCache()->addImage("crate.jpg")->getName();
     22         glGenVertexArrays(1, &VAO);
     23         glBindVertexArray(VAO);
     24 
     25         glGenBuffers( 1, &vertexBuffer );
     26         glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer );
     27 
     28         glGenBuffers( 1, &indexBuffer );
     29         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer );
     30 
     31         return true;
     32     }
     33     return false;
     34 }
     35 
     36 void MultiTexture::draw( Renderer *renderer, const Mat4 &transform, uint32_t transformUpdated )
     37 {
     38     Layer::draw(renderer, transform, transformUpdated);
     39 
     40     _customCommand.init(_globalZOrder);
     41     _customCommand.func = CC_CALLBACK_0(MultiTexture::onDraw,this);
     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 struct {
     53         float Position[3];
     54         float TexCoord[2];
     55     } Vertex;
     56 #define TEX_COORD_MAX   1
     57 
     58     Vertex Vertices[] = {
     59 
     60         {{-0.5, 0.5, 0}, {0, 0}},
     61         {{-0.5, -0.5, 0}, {0, TEX_COORD_MAX}},
     62         {{0.5, -0.5, 0}, { TEX_COORD_MAX,TEX_COORD_MAX}},
     63         {{0.5, 0.5, 0}, {TEX_COORD_MAX, 0}},
     64 
     65     };
     66     int vertexCount = sizeof(Vertices) / sizeof(Vertices[0]);
     67 
     68     GLubyte Indices[] = {
     69         0, 1, 2,
     70         2, 3, 0,
     71     };
     72 
     73     glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
     74     glBufferData(GL_ARRAY_BUFFER,sizeof(Vertices),Vertices, GL_STATIC_DRAW);
     75 
     76     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
     77     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices),Indices,GL_STATIC_DRAW);
     78 
     79     _positionLoc = glGetAttribLocation(mShaderProgram->getProgram(), "a_position");
     80     _texCoordLoc = glGetAttribLocation(mShaderProgram->getProgram(), "a_texCoord");
     81     //_baseMapLoc = glGetUniformLocation(mShaderProgram->getProgram(), "s_baseMap");
     82     //_lightMapLoc = glGetUniformLocation(mShaderProgram->getProgram(), "s_lightMap");
     83     _baseMapLoc = glGetUniformLocation(mShaderProgram->getProgram(), "CC_Texture0");
     84     _lightMapLoc = glGetUniformLocation(mShaderProgram->getProgram(), "CC_Texture1");
     85 
     86     glEnableVertexAttribArray(_positionLoc);
     87     glEnableVertexAttribArray(_texCoordLoc);
     88 
     89     glVertexAttribPointer(_positionLoc, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, Position));
     90     glVertexAttribPointer(_texCoordLoc, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
     91         (GLvoid*)offsetof(Vertex, TexCoord));
     92 
     93     mShaderProgram->use();
     94     mShaderProgram->setUniformsForBuiltins();
     95     
     96     glEnable(GL_DEPTH_TEST);
     97     glBindVertexArray(VAO);
     98 
     99     GL::bindTexture2DN(0, _lightMapTexId);
    100     glUniform1i(_lightMapLoc, 0 ); // unnecc in practice
    101 
    102     GL::bindTexture2DN(1, _baseMapTexId);
    103     glUniform1i(_baseMapLoc, 1); // unnecc in practice
    104 
    105     glDrawElements(GL_TRIANGLES,6, GL_UNSIGNED_BYTE, 0 );
    106 
    107     glBindVertexArray(0);
    108     CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1,6);
    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 }
    MultiTexture

    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。

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  • 原文地址:https://www.cnblogs.com/slysky/p/3981210.html
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