Opengl纹理映射和图像资源

Question

我正在使用opengl和纹理映射。 问题是，当应用的纹理是512×32像素，每个东西都工作正常，但是当它是128×128时，纹理不能正确应用。

纹理不能正确重复，它应用到对象的开始处，而其余的部分没有任何纹理。

在代码

：长度参数是约100。

LoadTexture：一个功能读取.bmp文件并返回质地指数。

这是我正在使用的代码。

int LoadTexture(char *filename,int alpha) 
{ 
    using namespace std; 
    int i, j=0; //Index variables 
    static int num_texture; 
    ifstream l_file(filename); 
    unsigned char *l_texture; //The pointer to the memory zone in which we will load the texture 

    // windows.h gives us these types to work with the Bitmap files 
    BITMAPFILEHEADER fileheader; 
    BITMAPINFOHEADER infoheader; 
    RGBTRIPLE rgb; 

    num_texture++; // The counter of the current texture is increased 

    if(!l_file) return (-1); // Open the file for reading 

    l_file.read(reinterpret_cast<char *>(&fileheader), sizeof(fileheader)); // Read the fileheader 

    //fseek(l_file, sizeof(fileheader), SEEK_SET); // Jump the fileheader 
    l_file.read(reinterpret_cast<char *>(&infoheader), sizeof(infoheader)); // and read the infoheader 

    // Now we need to allocate the memory for our image (width * height * color deep) 
    l_texture = new byte [infoheader.biWidth * infoheader.biHeight * 4]; 
    // And fill it with zeros 
    memset(l_texture, 0, infoheader.biWidth * infoheader.biHeight * 4); 

    // At this point we can read every pixel of the image 
    for (i=0; i < infoheader.biWidth*infoheader.biHeight; i++) 
    {    
      // We load an RGB value from the file 
      l_file.read(reinterpret_cast<char *>(&rgb), sizeof(rgb)); 

      // And store it 
      l_texture[j+0] = rgb.rgbtRed; // Red component 
      l_texture[j+1] = rgb.rgbtGreen; // Green component 
      l_texture[j+2] = rgb.rgbtBlue; // Blue component 
      l_texture[j+3] = alpha; // Alpha value 
      j += 4; // Go to the next position 
    } 

    l_file.close(); // Closes the file stream 

    glBindTexture(GL_TEXTURE_2D, num_texture); // Bind the ID texture specified by the 2nd parameter 

    // The next commands sets the texture parameters 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // If the u,v coordinates overflow the range 0,1 the image is repeated 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // The magnification function ("linear" produces better results) 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); //The minifying function 

    // Finally we define the 2d texture 
    glTexImage2D(GL_TEXTURE_2D, 0, 4, infoheader.biWidth, infoheader.biHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, l_texture); 

    // And create 2d mipmaps for the minifying function 
    gluBuild2DMipmaps(GL_TEXTURE_2D, 4, infoheader.biWidth, infoheader.biHeight, GL_RGBA, GL_UNSIGNED_BYTE, l_texture); 

    delete [] l_texture; // Free the memory we used to load the texture 

    return num_texture; // Returns the current texture OpenGL ID 
} 

和这里就是我怎么做的贴图坐标

void drawStreetStraight(Vector2d & point1,Vector2d & point2,Vector2d & point3,Vector2d & point4,double length) 
{ 
    glEnable(GL_TEXTURE_2D); 
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECR); 
    glBindTexture(GL_TEXTURE_2D,streetTexture); 
    glBegin(GL_QUADS); 
    glTexCoord2f(0,0); 
    glVertex3d(point1.x,0,point1.y); 
    glTexCoord2f(1,0); 
    glVertex3d(point2.x,0,point2.y); 
    glTexCoord2f(1,length/2.0); 
    glVertex3d(point3.x,0,point3.y); 
    glTexCoord2f(0,length/2.0); 
    glVertex3d(point4.x,0,point4.y); 
    glEnd(); 
    glDisable(GL_TEXTURE_2D); 
} 

Answer 1

我不知道，如果这是您例如修复，但现在看来，您不使用glGenTextures任何地方。

这是有原因吗？

我预习纹理像这样：坐标

glGenTextures(1, &texPlane); 
glBindTexture(GL_TEXTURE_2D, texPlane); 
glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); 
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR); 
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); 
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT); 
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT); 
glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); 
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, texPlanes);