objective-c – 如果手动生成顶点(malloc然后初始化),为什么我的

最终,我试图通过为每个对象提供不同的纹理坐标来使用单个图像来纹理多个对象(六边形).
使用OpenGL ES 2.0和GLKit我提出了一种方法,只是为了发现由于某种原因,如果我手动malloc并初始化Vertex数组,对象将不会渲染.我特别不明白为什么这是因为静态分配版本的顶点数组工作得很好.

前面这里是我正在使用的结构：

typedef struct {
GLKVector3 position;
GLKVector4 color;
GLKVector2 texCoords;
}Vertex;

因此,如果我在六边形的实现中执行此操作,我可以看到应用了纹理的各种六边形：

Vertex _Vertices[] = {
{{ 0,0},{1,1,{0.50,0.50}},//Z
{{ 1,{1.00,//A
{{ 0.5,-0.866,{0.75,0.00}},//B
{{-0.5,{0.25,//C
{{-1,{0,//D
{{-0.5,0.866,1.00}},//E
{{ 0.5,1.00}} //F
};

但是,如果我注释掉上面的声明并添加一个同名的实例变量(Vertex * Vertices而不是Vertex Vertices [],因为我不能直接malloc到数组)然后执行以下操作,没有任何渲染：

-(void)setVertices{
_Vertices = malloc(sizeof(Vertex) * 7);

//Z
_Vertices[0].position.x = 0;
_Vertices[0].position.y = 0;
_Vertices[0].position.z = 0;
_Vertices[0].color.r = 1;
_Vertices[0].color.g = 1;
_Vertices[0].color.b = 1;
_Vertices[0].color.a = 0;
_Vertices[0].texCoords.x = 0.5;
_Vertices[0].texCoords.y = 0.5;

//A
_Vertices[1].position.x = 1;
_Vertices[1].position.y = 0;
_Vertices[1].position.z = 0;
_Vertices[1].color.r = 1;
_Vertices[1].color.g = 1;
_Vertices[1].color.b = 1;
_Vertices[1].color.a = 0;
_Vertices[1].texCoords.x = 1;
_Vertices[1].texCoords.y = 0.5;


//B
_Vertices[2].position.x = 0.5;
_Vertices[2].position.y = -0.866;
_Vertices[2].position.z = 0;
_Vertices[2].color.r = 1;
_Vertices[2].color.g = 1;
_Vertices[2].color.b = 1;
_Vertices[2].color.a = 0;
_Vertices[2].texCoords.x = 0.75;
_Vertices[2].texCoords.y = 0.00;


//C
_Vertices[3].position.x = -0.5;
_Vertices[3].position.y = -0.866;
_Vertices[3].position.z = 0;
_Vertices[3].color.r = 1;
_Vertices[3].color.g = 1;
_Vertices[3].color.b = 1;
_Vertices[3].color.a = 0;
_Vertices[3].texCoords.x = 0.25;
_Vertices[3].texCoords.y = 0;


//D
_Vertices[4].position.x = -1;
_Vertices[4].position.y = 0;
_Vertices[4].position.z = 0;
_Vertices[4].color.r = 1;
_Vertices[4].color.g = 1;
_Vertices[4].color.b = 1;
_Vertices[4].color.a = 0;
_Vertices[4].texCoords.x = 0;
_Vertices[4].texCoords.y = 0.5;


//E
_Vertices[5].position.x = -0.5;
_Vertices[5].position.y = 0.866;
_Vertices[5].position.z = 0;
_Vertices[5].color.r = 1;
_Vertices[5].color.g = 1;
_Vertices[5].color.b = 1;
_Vertices[5].color.a = 0;
_Vertices[5].texCoords.x = 0.25;
_Vertices[5].texCoords.y = 1;


//F
_Vertices[6].position.x = 0.5;
_Vertices[6].position.y = 0.866;
_Vertices[6].position.z = 0;
_Vertices[6].color.r = 1;
_Vertices[6].color.g = 1;
_Vertices[6].color.b = 1;
_Vertices[6].color.a = 0;
_Vertices[6].texCoords.x = 0.75;
_Vertices[6].texCoords.y = 1;
}

这是我的设置功能：

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

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);
}

这是我的绘图功能：

-(void)draw{
glPushGroupMarkerEXT(0,"drawHex");
_effect.texture2d0.envMode = GLKTextureEnvModeReplace;
_effect.texture2d0.target = GLKTextureTarget2D;
_effect.texture2d0.name = _texture.name;
[self.effect prepareToDraw];
glBindBuffer(GL_ARRAY_BUFFER,_vertexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,_indexBuffer);

glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(GLKVertexAttribPosition,3,GL_FLOAT,GL_FALSE,sizeof(Vertex),(const GLvoid *) offsetof(Vertex,position));

glEnableVertexAttribArray(GLKVertexAttribColor);
glVertexAttribPointer(GLKVertexAttribColor,4,color));

glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
glVertexAttribPointer(GLKVertexAttribTexCoord0,2,texCoords));

//draw
glDrawElements(GL_TRIANGLES,sizeof(_Indices)/sizeof(_Indices[0]),GL_UNSIGNED_BYTE,0);
glPopGroupMarkerEXT();
}

如果重要的话,纹理在对象外部创建一次,然后传入指向它的指针.创建如下纹理：

-(void)setTextureImage:(UIImage *)image {
NSError *error;
_hexTexture = [GLKTextureLoader textureWithCGImage:image.CGImage options:nil error:&error];
if (error) {
    NSLog(@"Error loading texture from image: %@",error);
}}

我是所有这一切的新手,试图找出这里发生的事情变得非常令人沮丧.

在我的广泛搜索中,我看到了一些关于’捕获opengl es frame’的内容,但它似乎没有启用Xcode中的iphone模拟器所以我无法深入研究它:(

我真的很想知道为什么会这样.

如果有帮助,我可以提供更多代码或解释.

有什么想法吗？