glGenTextures有效，但每次都返回相同的纹理名称

我有一个名为Texture的类。这个类负责管理纹理。在程序启动时，OpenGL上下文被正确初始化（这就是为什么这个问题与大多数涉及意外glGenTextures行为的问题不同）。Texture从glGenTextures()获得纹理名称，然后在函数texGLInit()中将图像数据加载并绑定到该纹理名称的存储器中。这是有效的，并且纹理显示完全符合预期。

但是，我也希望我的纹理能够更改当用户单击按钮并从OpenFileDiaglog中的HDD中选择一个按钮时显示的纹理。此函数称为reloadTexture()。此功能尝试从内存中删除旧的图像/像素数据，并用用户选择的文件中的新数据替换。然而，当这种情况发生时，它会使用glDeleteTextures删除纹理名称，然后分配一个新的纹理名称，并使用函数texGLInit()将新的像素数据加载到内存中。但纹理名称在100%的时间内与之前的名称完全相同（通常为"1"）。

发生这种情况后显示的图像很奇怪。它有新的图像尺寸，但仍然有旧的图像像素。简单地说，它将旧图像缩小到新图像的大小。它仍在使用据称已删除的像素数据进行绘制。应该发生的是，屏幕现在在屏幕上显示新的图像文件。我相信这与纹理名称不唯一有关。

代码包含在下面：

Texture::Texture(string filename)//---Constructor loads in the initial image. Works fine!
{
    textureID[0]=0;
    const char* fnPtr = filename.c_str(); //our image loader accepts a ptr to a char, not a string
    //printf(fnPtr);
    lodepng::load_file(buffer, fnPtr);//load the file into a buffer
    unsigned error = lodepng::decode(image,w,h,buffer);//lodepng's decode function will load the pixel data into image vector from the buffer
    //display any errors with the texture
    if(error)
    {
        cout << "ndecoder error " << error << ": " << lodepng_error_text(error) <<endl;
    }
    //execute the code that'll throw exceptions to do with the images size
    checkPOT(w);
    checkPOT(h);

    //image now contains our pixeldata. All ready for OpenGL to do its thing
    //let's get this texture up in the video memory
    texGLInit();
    Draw_From_Corner = CENTER;  
}
void Texture::reloadTexture(string filename)//Reload texture replaces the texture name and image/pixel data bound to this texture
{
    //first and foremost clear the image and buffer vectors back down to nothing so we can start afresh 
    buffer.clear();
    image.clear();
    w = 0;
    h = 0;
    //also delete the texture name we were using before
    glDeleteTextures(1, &textureID[0]);


    const char* fnPtr = filename.c_str(); //our image loader accepts a ptr to a char, not a string
    //printf(fnPtr);
    lodepng::load_file(buffer, fnPtr);//load the file into a buffer
    unsigned error = lodepng::decode(image,w,h,buffer);//lodepng's decode function will load the pixel data into image vector from the buffer
    //display any errors with the texture
    if(error)
    {
        cout << "ndecoder error " << error << ": " << lodepng_error_text(error) <<endl;
    }
    //execute the code that'll throw exceptions to do with the images size
    checkPOT(w);
    checkPOT(h);
    //image now contains our pixeldata. All ready for  to do its thing
    //let's get this texture up in the video memoryOpenGL
    texGLInit();
    Draw_From_Corner = CENTER;
}
void Texture::texGLInit()//Actually gets the new texture name loads the pixeldata into openGL
{
    glGenTextures(1, &textureID[0]);
    ////printf("ntextureID = %u", textureID[0]);
    glBindTexture(GL_TEXTURE_2D, textureID[0]);//evrything we're about to do is about this texture
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    //glDisable(GL_COLOR_MATERIAL);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8,w,h,0, GL_RGBA, GL_UNSIGNED_BYTE, &image[0]);
    //we COULD free the image vectors memory right about now. But we'll do it when there's a need to. At the beginning of the reloadtexture func, makes sure it happens when we need it to.

}

这里值得一提的是Texture类中的draw函数。

void Texture::draw(point* origin, ANCHOR drawFrom)
{
    //let us set the DFC enum here.
    Draw_From_Corner = drawFrom;
    glEnable(GL_TEXTURE_2D);
    //printf("nDrawing texture at (%f, %f)",centerPoint.x, centerPoint.y);
    glBindTexture(GL_TEXTURE_2D, textureID[0]);//bind the texture
    //create a quick vertex array for the primitive we're going to bind the texture to
    ////printf("TexID = %u",textureID[0]);
    GLfloat vArray[8];
#pragma region anchor switch
    switch (Draw_From_Corner)
    {
    case CENTER:
        vArray[0] = origin->x-(w/2); vArray[1] = origin->y-(h/2);//bottom left i0
        vArray[2] = origin->x-(w/2); vArray[3] = origin->y+(h/2);//top left i1
        vArray[4] = origin->x+(w/2); vArray[5] = origin->y+(h/2);//top right i2
        vArray[6] = origin->x+(w/2); vArray[7] = origin->y-(h/2);//bottom right i3
        break;
    case BOTTOMLEFT:
        vArray[0] = origin->x; vArray[1] = origin->y;//bottom left i0
        vArray[2] = origin->x; vArray[3] = origin->y+h;//top left i1
        vArray[4] = origin->x+w; vArray[5] = origin->y+h;//top right i2
        vArray[6] = origin->x+w; vArray[7] = origin->y;//bottom right i3
        break;
    case TOPLEFT:
        vArray[0] = origin->x; vArray[1] = origin->y-h;//bottom left i0
        vArray[2] = origin->x; vArray[3] = origin->y;//top left i1
        vArray[4] = origin->x+w; vArray[5] = origin->y;//top right i2
        vArray[6] = origin->x+w; vArray[7] = origin->y-h;//bottom right i3
        break;
    case TOPRIGHT:
        vArray[0] = origin->x-w; vArray[1] = origin->y-h;//bottom left i0
        vArray[2] = origin->x-w; vArray[3] = origin->y;//top left i1
        vArray[4] = origin->x; vArray[5] = origin->y;//top right i2
        vArray[6] = origin->x; vArray[7] = origin->y-h;//bottom right i3
        break;
    case BOTTOMRIGHT:
        vArray[0] = origin->x-w; vArray[1] = origin->y;//bottom left i0
        vArray[2] = origin->x-w; vArray[3] = origin->y+h;//top left i1
        vArray[4] = origin->x-h; vArray[5] = origin->y;//top right i2
        vArray[6] = origin->x; vArray[7] = origin->y;//bottom right i3
        break;
    default: //same as center
        vArray[0] = origin->x-(w/2); vArray[1] = origin->y-(h/2);//bottom left i0
        vArray[2] = origin->x-(w/2); vArray[3] = origin->y+(h/2);//top left i1
        vArray[4] = origin->x+(w/2); vArray[5] = origin->y+(h/2);//top right i2
        vArray[6] = origin->x+(w/2); vArray[7] = origin->y-(h/2);//bottom right i3
        break;

    }
#pragma  endregion          
    //create a quick texture array (we COULD create this on the heap rather than creating/destoying every cycle)
    GLfloat tArray[8] = 
    {
        //this has been tinkered with from my normal order. I think LodePNG is bringing the PD upside down. SO A QUICK FIX HERE WAS NECESSARY.
        0.0f,1.0f,//0
        0.0f,0.0f,//1
        1.0f,0.0f,//2
        1.0f,1.0f//3
    };
    //and finally.. the index array...remember, we draw in triangles....(and we'll go CW)
    GLubyte iArray[6] =
    {
        0,1,2,
        0,2,3
    };
    //Activate arrays
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    //Give openGL a pointer to our vArray and tArray
    glVertexPointer(2, GL_FLOAT, 0, &vArray[0]);
    glTexCoordPointer(2, GL_FLOAT, 0, &tArray[0]);
    //Draw it all
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, &iArray[0]);
    //glDrawArrays(GL_TRIANGLES,0,6);
    //Disable the vertex arrays
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisable(GL_TEXTURE_2D);
}

有人能告诉我为什么OpenGL不会从我加载到它的新像素数据中加载和绘制吗？正如我所说，我怀疑这与glGenTextures没有给我一个新的纹理名称有关。