1. import GLKit/GLKit.h

ViewContrllor 继承自 GLKViewController

storyboard view  类 GLKView

2、 

//1. OpenGLES上下文

{

self.mContext= [[EAGLContextalloc]initWithAPI:kEAGLRenderingAPIOpenGLES2];

GLKView* view = (GLKView*)self.view;//Storybord里设置view类glkview

view.context=self.mContext;

view.drawableColorFormat=GLKViewDrawableColorFormatRGBA8888;//颜色缓冲器格式

//view.drawableDepthFormat = GLKViewDrawableDepthFormat24; //模板缓冲区格式

[EAGLContextsetCurrentContext:self.mContext];

}

//2.

//顶点数据，前三个是顶点坐标，后面两个是纹理坐标，每行一个顶点

//顶点坐标xyz,中心- 0,0, 0,OpenGLES的世界坐标系是[-1, 1]，

//纹理坐标左下角0，0

GLfloatsquareVertexData[] = {

0.5, -0.5,0.0f,1.0f,0.0f,//右下

-0.5,0.25,0.0f,0.0f,1.0f,//左上

-0.5, -0.35,0.0f,0.0f,0.0f,//左下

0.5,0.5, -0.0f,1.0f,1.0f,//右上

};

//顶点索引

//索引数组是顶点数组的索引，把squareVertexData数组看成4个顶点，每个顶点会有5个GLfloat数据，索引从0开始。

GLuintindices[] = {

0,1,2,

1,3,0

};

self.mCount=sizeof(indices) /sizeof(GLuint);

//3、顶点数据缓存

/**

glGenBuffers申请一个标识符

glBindBuffer把标识符绑定到GL_ARRAY_BUFFER上

glBufferData把顶点数据从cpu内存复制到gpu内存

glEnableVertexAttribArray是开启对应的顶点属性

glVertexAttribPointer设置合适的格式从buffer里面读取数据

*/

//-(void)vertexBuffer

{

//定点数据缓存

GLuintbuffer;

glGenBuffers(1, &buffer);

glBindBuffer(GL_ARRAY_BUFFER, buffer);

glBufferData(GL_ARRAY_BUFFER,sizeof(squareVertexData), squareVertexData,GL_STATIC_DRAW);

GLuintindex;

glGenBuffers(1, &index);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index);

glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(indices), indices,GL_STATIC_DRAW);

glEnableVertexAttribArray(GLKVertexAttribPosition);//顶点数据缓存

glVertexAttribPointer(GLKVertexAttribPosition,3,GL_FLOAT,GL_FALSE,sizeof(GLfloat) *5, (GLfloat*)NULL+0);

glEnableVertexAttribArray(GLKVertexAttribTexCoord0);//纹理

glVertexAttribPointer(GLKVertexAttribTexCoord0,2,GL_FLOAT,GL_FALSE,sizeof(GLfloat) *5, (GLfloat*)NULL+3);

}

//4、纹理贴图

/**

GLKTextureLoader读取图片，创建纹理GLKTextureInfo

创建着色器GLKBaseEffect，把纹理赋值给着色器

*/

//- (void)textureLoader

{

NSString* filePath = [[NSBundlemainBundle]pathForResource:@"Untitled"ofType:@"png"];

NSDictionary* options = [NSDictionarydictionaryWithObjectsAndKeys:@(1),GLKTextureLoaderOriginBottomLeft,nil];

////GLKTextureLoaderOriginBottomLeft纹理坐标系是相反的

GLKTextureInfo* textureInfo = [GLKTextureLoadertextureWithContentsOfFile:filePathoptions:optionserror:nil];

//着色器

self.mEffect= [[GLKBaseEffectalloc]init];

self.mEffect.texture2d0.enabled=GL_TRUE;

self.mEffect.texture2d0.name= textureInfo.name;

}

/**  5

*  渲染场景代码

*/

- (void)glkView:(GLKView*)view drawInRect:(CGRect)rect

{

glClearColor(.5f, 0.6f, .50f, 1.0f);

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

//启动着色器

[self.mEffect prepareToDraw];

glDrawElements(GL_TRIANGLES, self.mCount, GL_UNSIGNED_INT, 0);

}

/**

*  场景数据变化

*/

- (void)update

{

}