美文网首页
9-4.GLKit案例-绘制立方体并旋转

9-4.GLKit案例-绘制立方体并旋转

作者: Pufus | 来源:发表于2020-10-26 22:28 被阅读0次
效果展示

  • 流程分析


    流程图

  • 准备工作

首先新建一个工程，在CubeViewController(ViewController改名为CubeViewController)里面导入 <GLKit/GLKit.h>库，并且需要在工程中导入一张图片，将图片渲染到正方形表面上。

#import <GLKit/GLKit.h>
  1. 首先定义一个枚举类型的结构体，用来表示正方体的顶点坐标(类型为GLKVector3三维坐标)，纹理坐标(类型为GLKVector2二维坐标)，法线(类型为GLKVector3三维类型)，并且定义一个正方体的顶点数量的常量 kCoordCount 
typedef struct {
    GLKVector3 positionGoord; //顶点坐标
    GLKVector2 textureCoord; //纹理坐标
    GLKVector3 normal;  //法线
} CSVertex;

//顶点数量, 正方体有6个面，每个面有2个三角形，每个三角形有3个顶点
static NSInteger const kCoordCount = 36;
  1. 实现GLKViewDelegate
@interface CubeViewController () <GLKViewDelegate>

@end
  1. 定义几个全局变量用来保存当前状态
@interface CubeViewController () <GLKViewDelegate>
//定义GLKView对象glkView
@property (nonatomic, strong) GLKView *glkView;
//定义GLKBaseEffect对象 baseEffect
@property (nonatomic, strong) GLKBaseEffect *baseEffect;
//定义数据结构体数组 vertices
@property (nonatomic, assign) CCVertex *vertices;
//定义定时器对象 displayLink
@property (nonatomic, strong) CADisplayLink *displayLink;
//记录旋转角度变量 angle
@property (nonatomic, assign) NSInteger angle;
//顶点缓冲区ID vertexBuffer
@property (nonatomic, assign) GLuint vertexBuffer;
@end
  1. OpenGL ES相关初始化commonInit函数

commonInit这个方法里面主要是OpenGL ES相关的初始化工作，先设置当前content上下文，创建glkView并添加代理方法GLKViewDelegate, 要开启深度缓存后将glkView添加到当前控制器的view中,接下来获取纹理图片并设置参数

- (void)commonInit {
   
    //1.创建context
     EAGLContext *context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
    //设置当前context
    [EAGLContext setCurrentContext:context];
    
    //2.创建GLKView并设置代理
    CGRect frame = CGRectMake(0, 100, self.view.frame.size.width, self.view.frame.size.width);
    self.glkView = [[GLKView alloc] initWithFrame:frame context:context];
    self.glkView.backgroundColor = [UIColor clearColor];
    self.glkView.delegate = self;
    
    //3.使用深度缓存
    self.glkView.drawableDepthFormat = GLKViewDrawableDepthFormat24;
    //默认是(0, 1)，这里用于翻转 z 轴，使正方形朝屏幕外
    glDepthRangef(1, 0);
    
    //4.将GLKView 添加self.view 上
    [self.view addSubview:self.glkView];

    //5.获取纹理图片
    NSString *imagePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"kunkun.jpg"];
    UIImage *image = [UIImage imageWithContentsOfFile:imagePath];
    
    //6.设置纹理参数
    NSDictionary *options = @{GLKTextureLoaderOriginBottomLeft : @(YES)};
    GLKTextureInfo *textureInfo = [GLKTextureLoader textureWithCGImage:[image CGImage]
                                                               options:options
                                                                 error:NULL];
    //7.使用baseEffect
    self.baseEffect = [[GLKBaseEffect alloc] init];
    self.baseEffect.texture2d0.name = textureInfo.name;
    self.baseEffect.texture2d0.target = textureInfo.target;
    //开启光照效果
    self.baseEffect.light0.enabled = YES;
    //漫反射颜色
    self.baseEffect.light0.diffuseColor = GLKVector4Make(1, 1, 1, 1);
    //光源位置
    self.baseEffect.light0.position = GLKVector4Make(-0.5, -0.5, 5, 1);
    
    /*
     解释一下:
     这里我们不复用顶点，使用每 3 个点画一个三角形的方式，需要 12 个三角形，则需要 36 个顶点
     以下的数据用来绘制以（0，0，0）为中心，边长为 1 的立方体
     */
    
    //8. 开辟顶点数据空间(数据结构SenceVertex 大小 * 顶点个数kCoordCount)
    self.vertices = malloc(sizeof(CCVertex) * kCoordCount);
    
    // 前面
    self.vertices[0] = (CCVertex){{-0.5, 0.5, 0.5}, {0, 1}, {0, 0, 1}};
    self.vertices[1] = (CCVertex){{-0.5, -0.5, 0.5}, {0, 0}, {0, 0, 1}};
    self.vertices[2] = (CCVertex){{0.5, 0.5, 0.5}, {1, 1}, {0, 0, 1}};
    self.vertices[3] = (CCVertex){{-0.5, -0.5, 0.5}, {0, 0}, {0, 0, 1}};
    self.vertices[4] = (CCVertex){{0.5, 0.5, 0.5}, {1, 1}, {0, 0, 1}};
    self.vertices[5] = (CCVertex){{0.5, -0.5, 0.5}, {1, 0}, {0, 0, 1}};
    
    // 上面
    self.vertices[6] = (CCVertex){{0.5, 0.5, 0.5}, {1, 1}, {0, 1, 0}};
    self.vertices[7] = (CCVertex){{-0.5, 0.5, 0.5}, {0, 1}, {0, 1, 0}};
    self.vertices[8] = (CCVertex){{0.5, 0.5, -0.5}, {1, 0}, {0, 1, 0}};
    self.vertices[9] = (CCVertex){{-0.5, 0.5, 0.5}, {0, 1}, {0, 1, 0}};
    self.vertices[10] = (CCVertex){{0.5, 0.5, -0.5}, {1, 0}, {0, 1, 0}};
    self.vertices[11] = (CCVertex){{-0.5, 0.5, -0.5}, {0, 0}, {0, 1, 0}};
    
    // 下面
    self.vertices[12] = (CCVertex){{0.5, -0.5, 0.5}, {1, 1}, {0, -1, 0}};
    self.vertices[13] = (CCVertex){{-0.5, -0.5, 0.5}, {0, 1}, {0, -1, 0}};
    self.vertices[14] = (CCVertex){{0.5, -0.5, -0.5}, {1, 0}, {0, -1, 0}};
    self.vertices[15] = (CCVertex){{-0.5, -0.5, 0.5}, {0, 1}, {0, -1, 0}};
    self.vertices[16] = (CCVertex){{0.5, -0.5, -0.5}, {1, 0}, {0, -1, 0}};
    self.vertices[17] = (CCVertex){{-0.5, -0.5, -0.5}, {0, 0}, {0, -1, 0}};
    
    // 左面
    self.vertices[18] = (CCVertex){{-0.5, 0.5, 0.5}, {1, 1}, {-1, 0, 0}};
    self.vertices[19] = (CCVertex){{-0.5, -0.5, 0.5}, {0, 1}, {-1, 0, 0}};
    self.vertices[20] = (CCVertex){{-0.5, 0.5, -0.5}, {1, 0}, {-1, 0, 0}};
    self.vertices[21] = (CCVertex){{-0.5, -0.5, 0.5}, {0, 1}, {-1, 0, 0}};
    self.vertices[22] = (CCVertex){{-0.5, 0.5, -0.5}, {1, 0}, {-1, 0, 0}};
    self.vertices[23] = (CCVertex){{-0.5, -0.5, -0.5}, {0, 0}, {-1, 0, 0}};
    
    // 右面
    self.vertices[24] = (CCVertex){{0.5, 0.5, 0.5}, {1, 1}, {1, 0, 0}};
    self.vertices[25] = (CCVertex){{0.5, -0.5, 0.5}, {0, 1}, {1, 0, 0}};
    self.vertices[26] = (CCVertex){{0.5, 0.5, -0.5}, {1, 0}, {1, 0, 0}};
    self.vertices[27] = (CCVertex){{0.5, -0.5, 0.5}, {0, 1}, {1, 0, 0}};
    self.vertices[28] = (CCVertex){{0.5, 0.5, -0.5}, {1, 0}, {1, 0, 0}};
    self.vertices[29] = (CCVertex){{0.5, -0.5, -0.5}, {0, 0}, {1, 0, 0}};
    
    // 后面
    self.vertices[30] = (CCVertex){{-0.5, 0.5, -0.5}, {0, 1}, {0, 0, -1}};
    self.vertices[31] = (CCVertex){{-0.5, -0.5, -0.5}, {0, 0}, {0, 0, -1}};
    self.vertices[32] = (CCVertex){{0.5, 0.5, -0.5}, {1, 1}, {0, 0, -1}};
    self.vertices[33] = (CCVertex){{-0.5, -0.5, -0.5}, {0, 0}, {0, 0, -1}};
    self.vertices[34] = (CCVertex){{0.5, 0.5, -0.5}, {1, 1}, {0, 0, -1}};
    self.vertices[35] = (CCVertex){{0.5, -0.5, -0.5}, {1, 0}, {0, 0, -1}};
    
    //开辟顶点缓存区
    glGenBuffers(1, &_vertexBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
    GLsizeiptr bufferSizeBytes = sizeof(CCVertex) * kCoordCount;
    glBufferData(GL_ARRAY_BUFFER, bufferSizeBytes, self.vertices, GL_STATIC_DRAW);
    
    //顶点数据
    glEnableVertexAttribArray(GLKVertexAttribPosition);
    glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, sizeof(CCVertex), NULL + offsetof(CCVertex, positionCoord));
    
    //纹理数据
    glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
    glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(CCVertex), NULL + offsetof(CCVertex, textureCoord));
    
    //法线数据
    glEnableVertexAttribArray(GLKVertexAttribNormal);
    glVertexAttribPointer(GLKVertexAttribNormal, 3, GL_FLOAT, GL_FALSE, sizeof(CCVertex), NULL + offsetof(CCVertex, normal)); 
}
  1. addCADisplayLink定时器函数

addCADisplayLink方法里面主要是添加一个周期性调用的定时器，我们使用的是CADisplayLink来计时,这个计时器属于QuartzCore.framework中, 具体可以参考该篇博客 (https://www.cnblogs.com/panyangjun/p/4421904.html)

- (void)addCADisplayLink {
    //定时器提供一个周期性调用
    self.angle = 0;
    self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(update)];
    [self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
  1. 定时器计时update

定时器计时的方法实现update,主要是根据时间变化，实时改变正方体旋转角度

- (void)update {
   
    //1.计算旋转度数   除以360是为了防止度数超过360度
    self.angle = (self.angle + 5) % 360;
    //2.修改baseEffect.transform.modelviewMatrix
    self.baseEffect.transform.modelviewMatrix = GLKMatrix4MakeRotation(GLKMathDegreesToRadians(self.angle), 0.3, 1, 0.7);
    //3.重新渲染
    [self.glkView display];
}
  1. GLKViewDelegate代理方法

GLKViewDelegate代理方法，这里主要是根据旋转度数实时绘制图形

- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
    //1.开启深度测试
    glEnable(GL_DEPTH_TEST);
    //2.清除颜色缓存区和深度缓存区
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    //3.准备绘制
    [self.baseEffect prepareToDraw];
    //4.绘图
    glDrawArrays(GL_TRIANGLES, 0, kCoordCount);
}
  1. viewDidLoad调用commonInit, addCADisplayLink函数
- (void)viewDidLoad {
    [super viewDidLoad];
    //1.View背景色
    self.view.backgroundColor = [UIColor blackColor];
   
    //2. OpenGL ES 相关初始化
    [self commonInit];
    
    //3. 添加CADisplayLink
    [self addCADisplayLink];  
}
  1. 在 dealloc函数里面释放顶点缓存区，计时器要失效处理
- (void)dealloc {
    
    if ([EAGLContext currentContext] == self.glkView.context) {
        [EAGLContext setCurrentContext:nil];
    }
    if (_vertices) {
        free(_vertices);
        _vertices = nil;
    }
    
    if (_vertexBuffer) {
        glDeleteBuffers(1, &_vertexBuffer);
        _vertexBuffer = 0;
    }
    
    //displayLink 失效
    [self.displayLink invalidate];
}

运行代码,得到旋转的立方体

效果展示

相关文章

网友评论

      本文标题：9-4.GLKit案例-绘制立方体并旋转

      本文链接：https://www.haomeiwen.com/subject/ozrfmktx.html

      延伸阅读

      深度阅读

      • 您也可以注册成为美文阅读网的作者，发表您的原创作品、分享您的心情！

      栏目导航

      热点阅读

      关于我们|服务条款|联系我们|9-4.GLKit案例-绘制立方体并旋转|投稿指南|网站地图|RSS订阅|排版工具|手机版

      提供经典美文摘抄,优美散文欣赏,现代诗歌精选,短篇小说,心情随笔,表白情书范文,故事会在线阅读欣赏

      Copyright © 2014-2023 Haomeiwen.com All Rights Reserved. 好美文阅读网 版权所有

      备案信息：桂公网安备 45052102000051号 · 桂ICP备13007215号-3

      本站所收录作品、热点评论等信息部分来源互联网，目的只是为了系统归纳学习和传递资讯

      所有作品版权归原创作者所有，与本站立场无关，如不慎侵犯了你的权益，请联系我们告知，我们将做删除处理！