c++ - Why doesn't glCopyTexSubImage2D copy my square correctly?

here is the output: http://i43.tinypic.com/9a5zyx.png

if things were working the way i wanted, the colors in the left square would match the colors in the right square. thanks for any help regarding the subject

#include 

const char* title="test";
GLuint img;
unsigned int w=64,h=64;
int screenwidth,screenheight;

void enable2d()

{
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();

    glViewport(0,0,screenwidth,screenheight);
    glOrtho(0,screenwidth,screenheight,0,-1,1);

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();

    glLoadIdentity();

    glPushAttrib(GL_DEPTH_BUFFER_BIT|GL_LIGHTING_BIT);
    glDisable(GL_DEPTH_TEST);
    glDisable(GL_LIGHTING);

    glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
}

void drawmytex()

{
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D,img);
    glBegin(GL_QUADS);
    glTexCoord2i(0,0);
    glVertex2i(0,0);
    glTexCoord2i(1,0);
    glVertex2i(w,0);
    glTexCoord2i(1,1);
    glVertex2i(w,h);

    glTexCoord2i(0,1);
    glVertex2i(0,h);
    glEnd();
    glDisable(GL_TEXTURE_2D);
}

void drawquad(int x,int y)
{
    glBegin(GL_QUADS);
    glColor3f(0.0f,1.0f,0.0f);

    glVertex2i(x,y);
    glColor3f(1.0f,0.0f,1.0f);
    glVertex2i(x+w,y);
    glColor3f(0.0f,1.0f,1.0f);
    glVertex2i(x+w,y+h);
    glColor3f(0.0f,0.0f,1.0f);
    glVertex2i(x,y+h);
    glEnd();
}


void texcopy()
{
    if (!glIsTexture(img))
        glDeleteTextures(1,&img);
    glGenTextures(1,&img);
    glBindTexture(GL_TEXTURE_2D,img);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,w,h,0,GL_RGBA,GL_UNSIGNED_BYTE,0);


    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0,w,h,0,-1,1);
    glViewport(0,0,w,h);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    drawquad(0,0);


    glBindTexture(GL_TEXTURE_2D,img);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    //glCopyTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,0,0,w,h,0);
    glCopyTexSubImage2D(GL_TEXTURE_2D,0,0,0,0,0,w,h);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0,screenwidth,screenheight,0,-1,1);
    glViewport(0,0,screenwidth,screenheight);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

int main()
{
    int running;

    glfwInit();


    running=glfwOpenWindow(640,480,0,0,0,0,0,0,GLFW_WINDOW);
    if (!running)
    {
        glfwTerminate();
        return 0;
    }


    glfwSetWindowTitle(title);
    glfwEnable(GLFW_STICKY_KEYS);

    glfwGetWindowSize(&screenwidth,&screenheight);

    enable2d();
    texcopy();

    do
    {
        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        glLoadIdentity();


        drawquad(64,0);
        drawmytex();

        glfwSwapBuffers();
        running=!glfwGetKey(GLFW_KEY_ESC)&&glfwGetWindowParam(GLFW_OPENED);
        GLenum error=glGetError();
        if (error!=GL_NO_ERROR)running=error;
        glfwSleep(.017);
    }
    while (running==1);


    glDeleteTextures(1,&img);

    glfwTerminate();
    return running;
}

Answer

Try adding 'glColor3f(1,1,1);' in your 'drawmytex' function. I suspect that your texture is modulated (multiplied) with the current color, if so, the problem is not the texture copy but the way you display it.