高手出招！linux下，利用OpenGL把原始图片（各种格式的如JPG，PNG）加载到程序里面并用OpenGl显示出来，急急急！

[xuehlxs]

linux下，利用OpenGL把原始图片（各种格式的如JPG，PNG）加载到程序里面并用OpenGl显示出来，实现方法，最好是代码，急急急！

[牛晨光]

从我的代码中扣出几个函数，希望对你有帮助。

1、读取png图片

int jnImage::loadFromFile(string filename)
{
    clear();
    
    FILE *fp = fopen(filename.c_str(), "rb");
    if (NULL == fp)
    {
        LogFatal(LOG_FILE, "No such File: %s", filename.c_str());
        return -1;
    }

    png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
    png_infop info_ptr = png_create_info_struct(png_ptr);
    setjmp(png_jmpbuf(png_ptr));
    png_init_io(png_ptr, fp);
    png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_EXPAND, 0);
    fclose(fp);

    width = png_get_image_width(png_ptr, info_ptr);
    height = png_get_image_height(png_ptr, info_ptr);
    int color_type = png_get_color_type(png_ptr, info_ptr);
    
    int bys = 0;
    switch (color_type)
    {
    case PNG_COLOR_TYPE_RGB:
        alpha = 0;
        bys = 3;
        break;

    case PNG_COLOR_TYPE_RGB_ALPHA:
        alpha = 1;
        bys = 4;
        break;

    default:
        png_destroy_read_struct(&png_ptr, &info_ptr, 0);
        LogFatal(LOG_FILE, "Not support this color type. %s:%d",
            filename.c_str(), color_type);
        return -2;
    }

    int size = width * height * bys;
    data = (unsigned char*) malloc(size);

    png_bytep* row_pointers = png_get_rows(png_ptr, info_ptr);
    int pos = 0;
    int i,j;
    for(i=0; i<height; i++)
    {
       for(j=0; j<(bys*width); j+=bys)
       {
            data[pos++] = row_pointers[i][j];
            data[pos++] = row_pointers[i][j+1];
            data[pos++] = row_pointers[i][j+2];
            if (bys == 4)
                data[pos++] = row_pointers[i][j+3];
       }
    }

    png_destroy_read_struct(&png_ptr, &info_ptr, 0);

    return 0;
}

2、绑定给texture

void jnTexture::addFromFile(string filename)
{
    jnImage image;

    if (image.loadFromFile(filename) != 0)
        return;

    glBindTexture(GL_TEXTURE_2D, _array[_count]);

    if (image.alpha == 1)
    {
        _blend = 1;
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width,
            image.height, 0, GL_RGBA, GL_UNSIGNED_BYTE,
            image.data);
    }
    else
    {
        _blend = 0;
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, image.width,
            image.height, 0, GL_RGB, GL_UNSIGNED_BYTE,
            image.data);

    }

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

    _count++;
}

3、绘制
[code=C/C++]
void jnRenderable::render(int index)
{
    if (_visible == false)
        return;

    glPushMatrix();
    glTranslatef(_position.x, _position.y, 0.0f);
    //glRotatef(_rotation, 0, 0, 1);

    //glColor4f(sprite->color.r, sprite->color.g, sprite->color.b, sprite->color.a);

    _texture->blendBegin();
    glEnable(GL_TEXTURE_2D);

    GLuint tex = _texture->getTexture(index);
    //if (tex == 0)
    //{
    //    LogFatal(LOG_FILE, "tex error ! tex = %d", tex);
    //    return;
    //}

    glBindTexture(GL_TEXTURE_2D, tex);

    glBegin(GL_QUADS);
    {
        _texture->render(TEXTURE_LEFT_TOP);
        glVertex2i(_size.w/-2, _size.h/2);

        _texture->render(TEXTURE_LEFT_BOTTOM);
        glVertex2i(_size.w/-2, _size.h/-2);

        _texture->render(TEXTURE_RIGHT_BOTTOM);
        glVertex2i(_size.w/2, _size.h/-2);

        _texture->render(TEXTURE_RIGHT_TOP);
        glVertex2i(_size.w/2, _size.h/2);
    }
    glEnd();

    glDisable(GL_TEXTURE_2D);
    _texture->blendEnd();

    glPopMatrix();
}

[/code]

[爱情黑白猫]

你想要的资源在这儿
http://download.csdn.net/source/3462434