openGL iphone sdk中的网格创建

我正在使用它作为我的基础，并试图根据我的要求更改代码。我已经包含了以下代码来在图像上创建网格

-（void）populateMesh{

verticalDivisions = kVerticalDivisions;
horizontalDivisions = kHorisontalDivisions; 
unsigned int verticesArrsize = (kVerticalDivisions * ((2 + kHorisontalDivisions * 2) * 3));
unsigned int textureCoordsArraySize = kVerticalDivisions * ((2 + kHorisontalDivisions * 2) * 2);
verticesArr = (GLfloat *)malloc(verticesArrsize * sizeof(GLfloat));
textureCoordsArr = (GLfloat*)malloc(textureCoordsArraySize * sizeof(GLfloat));
if (verticesArr == NULL) {
    NSLog(@"verticesArr = NULL!");
}   
float height = kWindowHeight/verticalDivisions;
float width = kWindowWidth/horizontalDivisions;
int i,j, count;
count = 0;
for (j=0; j<verticalDivisions; j++) {
    for (i=0; i<=horizontalDivisions; i++, count+=6) { //2 vertices each time...
        float currX = i * width;
        float currY = j * height;
        verticesArr[count] = currX;
        verticesArr[count+1] = currY + height;
        verticesArr[count+2] = 0.0f;            
        verticesArr[count+3] = currX;
        verticesArr[count+4] = currY;
        verticesArr[count+5] = 0.0f;
    } 
}
float xIncrease = 1.0f/horizontalDivisions;
float yIncrease = 1.0f/verticalDivisions;   
int x,y;
//int elements;
count = 0;  
for (y=0; y<verticalDivisions; y++) {
    for (x=0; x<horizontalDivisions+1; x++, count+=4) {
        float currX = x *xIncrease; 
        float currY = y * yIncrease;
        textureCoordsArr[count] = (float)currX;
        textureCoordsArr[count+1] = (float)currY + yIncrease;
        textureCoordsArr[count+2] = (float)currX;
        textureCoordsArr[count+3] = (float)currY;
    }
}
//  int cnt;
//  int cnt = 0;
    NSLog(@"expected %i vertices, and %i vertices were done",(verticalDivisions * ((2 + horizontalDivisions*2 ) * 2) ) , count );
}

编辑这是我得到的输出。而预期的是常规网格。。。

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猜测网格是用zNear值剪切的。尝试将z值更改为-2

verticesArr[count+2] = -2.0f; 
verticesArr[count+5] = -2.0f;

默认情况下，相机位于原点，指向负z轴，上方向向量为（0，1，0）

请注意，您的网格不在视锥（棱锥体）中。请在OpenGL红皮书中查看：

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是一个关于在3D中绘制网格的很棒的教程。它应该有必要的代码来帮助您。我不确定您是在3D还是2D中工作，但即使是2D，也应该很容易适应您的需要。希望有帮助！

由于顶点的排列方式，网格不是规则的。您确定GL_TRIANGLE_STRIP是理想的选择。也许，GL_三角形就是你需要的

我建议使用索引数组来实现更简单的解决方案。例如，在初始化代码中，按正常顺序为网格创建顶点和纹理数组，如下所示：

0 1 2
3 4 5
6 7 8

更新：

- (void) setup
{
  vertices = (GLfloat*)malloc(rows*colums*3*sizeof(GLfloat));
  texCoords = (GLfloat*)malloc(rows*columns*2*sizeof(GLfloat));
  indices = (GLubyte*)malloc((rows-1)*(columns-1)*6*sizeof(GLubyte));

  float xDelta = horizontalDivisions/columns;
  float yDelta = verticalDivisions/rows;

  for (int i=0;i<columns;i++) {
    for(int j=0;j<rows; j++) {
      int index = j*columns+i;
      vertices[3*index+0] = i*xDelta; //x
      vertices[3*index+1] = j*yDelta; //y
      vertices[3*index+2] = -10; //z

      texCoords[2*index+0] = i/(float)(columns-1); //x texture coordinate
      texCoords[2*index+1] = j/(float)(rows-1); //y tex coordinate
    }
  }

  for (int i=0;i<columns-1;i++) {
   for(int j=0;j<rows-1; j++) {

     indices[6*(j*columns+i)+0] = j*columns+i;
     indices[6*(j*columns+i)+1] = j*columns+i+1;
     indices[6*(j*columns+i)+2] = (j+1)*columns+i;

     indices[6*(j*columns+i)+3] = j*columns+i+1;
     indices[6*(j*columns+i)+4] = (j+1)*columns+i+1;
     indices[6*(j*columns+i)+5] = (j+1)*columns+i;
   }
 }
}

- (void) dealloc {
  free(vertices); free(texCoords); free(indices);
}

在“渲染方法”中，请使用以下行：

glVertexPointer(3, GL_FLOAT, 0, vertices);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glDrawElements(GL_TRIANGLES, 6*(columns-1)*(rows-1), GL_UNSIGNED_BYTE, indices);

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希望这会有所帮助。

您是否正确设置了模型和投影视图矩阵？您能否提供矩阵初始设置的代码？确保您的图像的像素大小可以表示为2的幂。例如，512x512我包含了设置视图代码。在实现populateMesh功能之前，我能够显示im年龄…感谢回复…在编辑您的更改和评论GLFRUSUMF（）之后声明我得到了上面的观点。它与我以前的观点没有太大的区别。但是还有一些地方出了问题…你能找出吗？？？添加了微小的更新。不需要循环来绘制元素。更简单的解决方案。我没有测试代码，我从头开始编写，所以它可能包含一些错误，但概念是明确的。

- (void) setup
{
  vertices = (GLfloat*)malloc(rows*colums*3*sizeof(GLfloat));
  texCoords = (GLfloat*)malloc(rows*columns*2*sizeof(GLfloat));
  indices = (GLubyte*)malloc((rows-1)*(columns-1)*6*sizeof(GLubyte));

  float xDelta = horizontalDivisions/columns;
  float yDelta = verticalDivisions/rows;

  for (int i=0;i<columns;i++) {
    for(int j=0;j<rows; j++) {
      int index = j*columns+i;
      vertices[3*index+0] = i*xDelta; //x
      vertices[3*index+1] = j*yDelta; //y
      vertices[3*index+2] = -10; //z

      texCoords[2*index+0] = i/(float)(columns-1); //x texture coordinate
      texCoords[2*index+1] = j/(float)(rows-1); //y tex coordinate
    }
  }

  for (int i=0;i<columns-1;i++) {
   for(int j=0;j<rows-1; j++) {

     indices[6*(j*columns+i)+0] = j*columns+i;
     indices[6*(j*columns+i)+1] = j*columns+i+1;
     indices[6*(j*columns+i)+2] = (j+1)*columns+i;

     indices[6*(j*columns+i)+3] = j*columns+i+1;
     indices[6*(j*columns+i)+4] = (j+1)*columns+i+1;
     indices[6*(j*columns+i)+5] = (j+1)*columns+i;
   }
 }
}

- (void) dealloc {
  free(vertices); free(texCoords); free(indices);
}

(013)(143)(124)(254)(346)(476)... and so on.

glVertexPointer(3, GL_FLOAT, 0, vertices);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glDrawElements(GL_TRIANGLES, 6*(columns-1)*(rows-1), GL_UNSIGNED_BYTE, indices);