# OpenGL ES 案例 - 实现一个有纹理的立方体
2020-07-28 本文已影响0人
DSMars
效果如下图
旋转效果.gif
1.定义一个结构体
typedef struct {
GLKVector3 positionCoord; //顶点坐标
GLKVector2 textureCoord; //纹理坐标
GLKVector3 normal; //法线
} CCVertex;
2.相关属性设置
@property (nonatomic, strong) GLKView *glkView;
@property (nonatomic, strong) GLKBaseEffect *baseEffect;
@property (nonatomic, assign) CCVertex *vertices;
@property (nonatomic, strong) CADisplayLink *displayLink;
@property (nonatomic, assign) NSInteger angle;
@property (nonatomic, assign) GLuint vertexBuffer;
3. OpenGL ES 相关初始化
- (void) commonInit{
// 1、创建context
EAGLContext *context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES3];
[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、使用深度测试
self.glkView.drawableDepthFormat = GLKViewDrawableDepthFormat24;
glDepthRangef(1, 0);
// 4、将glkView加入到view上
[self.view addSubview:self.glkView];
// 5、获取纹理图片
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"timg" ofType:@"jpeg"];
UIImage *image = [UIImage imageWithContentsOfFile:filePath];
// 6、设置纹理参数
NSDictionary *options = @{GLKTextureLoaderOriginBottomLeft: @(YES)};
GLKTextureInfo *textureInfo = [GLKTextureLoader textureWithCGImage:[image CGImage] options:options error:NULL];
// 7、使用effect
self.baseEffect = [[GLKBaseEffect alloc] init];
self.baseEffect.texture2d0.name = textureInfo.name;
self.baseEffect.texture2d0.target = textureInfo.target;
// 光照
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);
}
4.加载顶点/纹理坐标数据
- (void)setupVertex{
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}};
// 开辟缓存区
glGenBuffers(1, &_vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(CCVertex)*kCoordCount, 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));
// 光照
glEnableVertexAttribArray(GLKVertexAttribNormal);
glVertexAttribPointer(GLKVertexAttribNormal, 3, GL_FLOAT, GL_FALSE, sizeof(CCVertex), NULL+offsetof(CCVertex, normal));
}
- (void)addCADisplayLink{
self.angle = 0;
self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(update)];
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
5. GLKViewDelegate
-(void)glkView:(GLKView *)view drawInRect:(CGRect)rect{
// 开启深度测试
glEnable(GL_DEPTH_TEST);
// 清除缓存区
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// 准备绘制
[self.baseEffect prepareToDraw];
// 绘图（数组绘制）
glDrawArrays(GL_TRIANGLES, 0, kCoordCount);
}
6.添加定时器
- (void)addCADisplayLink{
self.angle = 0;
self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(update)];
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
- (void) update{
//计算旋转度数
self.angle = (self.angle +5) % 360;
// 修改baseEffect.transform.modelviewMatrix
self.baseEffect.transform.modelviewMatrix = GLKMatrix4MakeRotation(GLKMathDegreesToRadians(self.angle), 0.3, 1, 0.7);
// 重新渲染
[self.glkView display];
}
