java – OpenGL渲染到纹理坐标

我希望能够渲染到纹理(对于着色器,字体),但我有一个问题是正确定位四边形(帧缓冲本身做它应该做的事情).生成的(复制的)纹理在大多数情况下显示左上角,其余的被裁剪.这对于矩形纹理来说更糟糕,对方形纹理几乎没有影响(所以我好几天都没有认识到这种行为)

示例代码：

public Texture copy(final Texture tex) {
    final int tempTex = glGenTextures();
    Draw.bindTexture(tempTex);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
    glTexImage2D(GL_TEXTURE_2D,GL_RGBA,tex.getImageWidth(),tex.getImageHeight(),GL_RGB,GL_UNSIGNED_BYTE,(ByteBuffer)null);

    // Adjust projection matrix
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    glViewport(0,tex.getImageHeight());

    // Change blendmode to ignore the transparent background
    Draw.blendingMode(GL_ONE,GL_ONE_MINUS_SRC_ALPHA);

    // Prepare fbo,add the texture as backend and clear it
    final int fbo = glGenFramebuffers();
    glBindFramebuffer(GL_FRAMEBUFFER,fbo);
    glFramebufferTexture2D(GL_FRAMEBUFFER,GL_COLOR_ATTACHMENT0,GL_TEXTURE_2D,tempTex,0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Finally draw
    Draw.bindTexture(tex.getId());
    glBegin(GL_QUADS);
    {
        glTexCoord2f(0,0);
        glVertex2f(-1,-1);
        glTexCoord2f(1,0);
        glVertex2f(1,1);
        glVertex2f(1,1);
        glTexCoord2f(0,1);
        glVertex2f(-1,1);
    }
    glEnd();

    // Unbind framebuffer
    glBindFramebuffer(GL_FRAMEBUFFER,0);

    // Reset projection matrix
    glViewport(0,1920,1080); // TODO Don't hardcode
    glPopMatrix();

    return new Texture(tempTex,tex.getImageHeight());
}

示例图片：

鞋面是复制版本下方渲染的原始图像

我究竟做错了什么？

更新：现在看起来纹理得到了下采样