Iphone OpenGL不再显示对象

我是OpenGL ES编程新手。我发现一个很好的教程开始，项目显示了一个正方形。然后，我尝试将大部分OpenGL代码从视图控制器移动到一个模型对象，该模型对象将存储顶点、颜色等，然后在视图控制器中，我将调用：

[model update];
[model load];

这样的话，如果我有几个模型可以展示的话，会更实用。由于我这样做了，立方体不再显示在屏幕上。我想我指出了所有模型视图矩阵计算都发生在更新方法中的错误，因为当我注释掉此方法时，将显示多维数据集，但它只填充屏幕

-(void)update: (int)width And:(int)height{
float aspect = (width/height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(
                                      GLKMathDegreesToRadians(65.0f), aspect,
                                      4.0f, 10.0f);
self.effect.transform.projectionMatrix = projectionMatrix;

GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 6.0f);   
rotation += 90;
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix,
                                       GLKMathDegreesToRadians(rotation), 0, 0, 1);
self.effect.transform.modelviewMatrix = modelViewMatrix;
}  

下面是加载方法：

- (void)load{
self.effect = [[GLKBaseEffect alloc] init];

NSDictionary * options = [NSDictionary dictionaryWithObjectsAndKeys:
                          [NSNumber numberWithBool:YES],
                          GLKTextureLoaderOriginBottomLeft, 
                          nil];

NSError * error;    
NSString *path = [[NSBundle mainBundle] pathForResource:@"tile_floor" ofType:@"png"];
GLKTextureInfo * info = [GLKTextureLoader textureWithContentsOfFile:path options:options error:&error];
if (info == nil) {
    NSLog(@"Error loading file: %@", [error localizedDescription]);
}
self.effect.texture2d0.name = info.name;
self.effect.texture2d0.enabled = true;

glGenVertexArraysOES(1, &vertexArray);
glBindVertexArrayOES(vertexArray);

glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);

glGenBuffers(1, &indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);

glEnableVertexAttribArray(GLKVertexAttribPosition);        
glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Position));
glEnableVertexAttribArray(GLKVertexAttribColor);
glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Color));
glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, TexCoord));

glBindVertexArrayOES(0);
}

- (void)render{
[self.effect prepareToDraw];
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);

glBindVertexArrayOES(vertexArray);
glDrawElements(GL_TRIANGLES, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);
}

下面是渲染方法：

- (void)load{
self.effect = [[GLKBaseEffect alloc] init];

NSDictionary * options = [NSDictionary dictionaryWithObjectsAndKeys:
                          [NSNumber numberWithBool:YES],
                          GLKTextureLoaderOriginBottomLeft, 
                          nil];

NSError * error;    
NSString *path = [[NSBundle mainBundle] pathForResource:@"tile_floor" ofType:@"png"];
GLKTextureInfo * info = [GLKTextureLoader textureWithContentsOfFile:path options:options error:&error];
if (info == nil) {
    NSLog(@"Error loading file: %@", [error localizedDescription]);
}
self.effect.texture2d0.name = info.name;
self.effect.texture2d0.enabled = true;

glGenVertexArraysOES(1, &vertexArray);
glBindVertexArrayOES(vertexArray);

glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);

glGenBuffers(1, &indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);

glEnableVertexAttribArray(GLKVertexAttribPosition);        
glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Position));
glEnableVertexAttribArray(GLKVertexAttribColor);
glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, Color));
glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (const GLvoid *) offsetof(Vertex, TexCoord));

glBindVertexArrayOES(0);
}

- (void)render{
[self.effect prepareToDraw];
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);

glBindVertexArrayOES(vertexArray);
glDrawElements(GL_TRIANGLES, sizeof(Indices)/sizeof(Indices[0]), GL_UNSIGNED_BYTE, 0);
}

---

任何帮助都将不胜感激。谢谢

这里没有真正的“错误”。问题是，您没有真正设置投影矩阵和模型视图矩阵，以便它很好地构建模型。没有神奇的解决办法。你应该考虑你正在绘制的模型中的顶点（它们是否上升到100？1000？仅仅是0.5？），并为GLKMatRIX4MaMax透视选择合适的设置，将它们直接放在屏幕上。

-(void)update: (int)width And:(int)height{
float aspect = (width/height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(
                                      GLKMathDegreesToRadians(65.0f), aspect,
                                      4.0f, 10.0f);
self.effect.transform.projectionMatrix = projectionMatrix;

GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 6.0f);   
rotation += 90;
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix,
                                       GLKMathDegreesToRadians(rotation), 0, 0, 1);
self.effect.transform.modelviewMatrix = modelViewMatrix;
}  

作为一条捷径，（因为您说过，如果没有平移和旋转，它将填充整个屏幕），您可以使用缩放命令替换这些变换，以缩小对象的大小

比如：

GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.1f, 0.1f, 0.1f);   

---

作为一般建议，试着单独考虑每个命令的效果。如果您想了解投影/转换概念的介绍，我找到了以下链接：跳到“投影和世界空间”部分。

您能发布[model update]和[model load]吗？另外，不要评论整个更新方法，而是找出问题的原因。是翻译吗？轮换？如果两者都没有，无论如何都要注释掉它们，以使诊断更容易。我试着分别注释平移线和旋转线，但没有成功。屏幕仍然是黑色的。但是当我把它们都注释掉时，对象就被画出来了，但是它填充了屏幕，这不是我想要的。上面的方法是update方法。我需要将视图的宽度和高度传递给它，以便它能够正确地创建透视图。谢谢。我认为你是对的。现在我可以让它出现在屏幕上，而无需注释更新方法。