效果图
- 准备工作：主要是变量的定义及界面设置
- viewDidLoad函数：创建图层并渲染图形
2.1 setupContext函数:新建图层
2.2 render函数:渲染图形 - GLKViewDelegate代理方法：使用索引绘制图形
- update函数：图形的旋转变换
- 按钮点击事件：判断图形是否围绕该轴旋转
1. 准备工作
主要是变量的定义及界面设置
- 1.1 新建工程,设置ViewController继承自GLKViewController,导入GLKit框架文件,并在storyboard中设置ViewController的class类型为GLKViewController
#import
#import
@interface ViewController : GLKViewController
@end
image.png
-
1.2 设置controller.view的class类型为GLKView
设置controller.view的class类型为GLKView -
1.3 导入一张图片资源
导入一张图片资源 - 1.3 ViewController定义属性
@interface ViewController()
//上下文
@property(nonatomic,strong)EAGLContext *mContext;
//着色器
@property(nonatomic,strong)GLKBaseEffect *mEffect;
//顶点个数
@property(nonatomic,assign)int count;
//旋转的度数
@property(nonatomic,assign)float XDegree;
@property(nonatomic,assign)float YDegree;
@property(nonatomic,assign)float ZDegree;
//是否旋转X,Y,Z
@property(nonatomic,assign) BOOL XB;
@property(nonatomic,assign) BOOL YB;
@property(nonatomic,assign) BOOL ZB;
@end
@implementation ViewController
{
//定时器
dispatch_source_t timer;
}
@end
2. viewDidLoad函数
主要创建图层并渲染图形
viewDidLoad函数
- 2.1 新建图层
//1.新建图层
-(void)setupContext
{
//1.新建OpenGL ES上下文
self.mContext = [[EAGLContext alloc]initWithAPI:kEAGLRenderingAPIOpenGLES2];
//设置GLKView对象
GLKView *view = (GLKView *)self.view;
//GLKView指定context
view.context = self.mContext;
//GLKView颜色格式
view.drawableColorFormat = GLKViewDrawableColorFormatRGBA8888;
//GLKView深度格式
view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
//设置上下文
[EAGLContext setCurrentContext:self.mContext];
//开启深度测试
glEnable(GL_DEPTH_TEST);
}
- 2.2 渲染图形
//2.渲染图形
-(void)render
{
//1.顶点数据
//前3个元素，是顶点数据；后面3个元素，是顶点颜色值，
GLfloat attrArr[] =
{
-0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f, //左上
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 1.0f, //右上
-0.5f, -0.5f, 0.0f, 1.0f, 1.0f, 1.0f, //左下
0.5f, -0.5f, 0.0f, 1.0f, 1.0f, 1.0f, //右下
0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, //顶点
};
//2.绘图索引数组
GLuint indices[] =
{
0, 3, 2,
0, 1, 3,
0, 2, 4,
0, 4, 1,
2, 3, 4,
1, 4, 3,
};
//计算顶点个数
self.count = sizeof(indices) /sizeof(GLuint);
//将顶点数组放入数组缓冲区中 GL_ARRAY_BUFFER
GLuint buffer;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(attrArr), attrArr, GL_STATIC_DRAW);
//将索引数组存储到索引缓冲区 GL_ELEMENT_ARRAY_BUFFER
GLuint index;
glGenBuffers(1, &index);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
//使用顶点数据
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 6, NULL);
//使用颜色数据
glEnableVertexAttribArray(GLKVertexAttribColor);
glVertexAttribPointer(GLKVertexAttribColor, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 6, (GLfloat *)NULL + 3);
//创建着色器effct
self.mEffect = [[GLKBaseEffect alloc]init];
//创建投影矩阵,并赋值给effct中的projectionMatrix
CGSize size = self.view.bounds.size;
float aspect = fabs(size.width / size.height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(90.0), aspect, 0.1f, 100.0);
projectionMatrix = GLKMatrix4Scale(projectionMatrix, 1.0f, 1.0f, 1.0f);
self.mEffect.transform.projectionMatrix = projectionMatrix;
//创建模型视图矩阵,并且平移2.0
GLKMatrix4 modelViewMatrix = GLKMatrix4Translate(GLKMatrix4Identity, 0.0f, 0.0f, -2.0f);
//赋值给effct中的modelviewMatrix
self.mEffect.transform.modelviewMatrix = modelViewMatrix;
//设置定时器,开启回调
double seconds = 0.1;
timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_main_queue());
dispatch_source_set_timer(timer, DISPATCH_TIME_NOW, seconds * NSEC_PER_SEC, 0.0);
dispatch_source_set_event_handler(timer, ^{
self.XDegree += 0.1f * self.XB;
self.YDegree += 0.1f * self.YB;
self.ZDegree += 0.1f * self.ZB ;
});
dispatch_resume(timer);
}
- 2.3 viewDidLoad调用函数
-(void)viewDidLoad
{
[super viewDidLoad];
//1.新建图层
[self setupContext];
//2.渲染图形
[self render];
}
3. GLKViewDelegate代理方法
主要使用索引绘制图形
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//准备绘制
[self.mEffect prepareToDraw];
//使用索引绘制图形
glDrawElements(GL_TRIANGLES, self.count, GL_UNSIGNED_INT, 0);
}
4. update函数
主要图形的旋转变换
update函数的功能就等同于GLKViewControllerDelegate中的代理方法glkViewControllerUpdate，苹果官方文档针对这部分有详细说明：当你没有实现glkViewControllerUpdate时，可以通过update来实现，也是一样的道理
苹果官方文档介绍glkViewControllerUpdate
//图形的旋转变换
-(void)update
{
GLKMatrix4 modelViewMatrix = GLKMatrix4Translate(GLKMatrix4Identity, 0.0f, 0.0f, -2.5);
modelViewMatrix = GLKMatrix4RotateX(modelViewMatrix, self.XDegree);
modelViewMatrix = GLKMatrix4RotateY(modelViewMatrix, self.YDegree);
modelViewMatrix = GLKMatrix4RotateZ(modelViewMatrix, self.ZDegree);
self.mEffect.transform.modelviewMatrix = modelViewMatrix;
}
5. 按钮点击事件
-
5.1 在页面上添加 x,y,z按钮
添加x,y,z按钮 - 5.2 设置按钮点击事件
#pragma mark -XYZClick
- (IBAction)XClick:(id)sender {
_XB = !_XB;
}
- (IBAction)YClick:(id)sender {
_YB = !_YB;
}
- (IBAction)ZClick:(id)sender {
_ZB = !_ZB;
}