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OpenGL Re-loading textures fails

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Exhibits:

Exhibit 1: Exhibit 1
Exhibit 2: Exhibit 2
Exhibit 3:
struct rgl_header {
        unsigned long width;
        unsigned long height;
        unsigned long colorkey;

        //signed long xclip;
        //signed long yclip;
        //unsigned long wclip;
        //unsigned long hclip;
    };




Exhibit 4:
void texture::_save_raw(unsigned char *data) {
    std::ofstream output(m_raw_filename.c_str(), std::ios::binary);
    if (output.bad() || output.fail())
        return;
    #ifdef _DEBUG_
    texture_log << "\n{\n\tsaving raw file with filename: " <<
        m_raw_filename << "\n}\n";
    #endif

    rgl_header header;

    header.width = w();
    header.height = h();
    header.colorkey = m_colorkey;

    //header.xclip = m_clip.x;
    //header.yclip = m_clip.y;
    //header.wclip = m_clip.w;
    //header.hclip = m_clip.h;

    #ifdef _DEBUG_
    texture_log << "\nrgl header (write) {\n\t"
        << "header.w " << header.width << "\n\t"
        << "header.h " << header.height << "\n\t"
        << "header.colorkey " << header.colorkey << "\n}\n";//\t"
        //<< "header.xclip " << header.xclip << "\n\t"
        //<< "header.yclip " << header.yclip << "\n\t"
        //<< "header.wclip " << header.wclip << "\n\t"
        //<< "header.hclip " << header.hclip << "\n}\n";
    #endif

    // valid rgl file
    output.write("RGL", 4);
    // header
    output.write((char*)&header, sizeof(rgl_header));
    // actual data
    output.write((char*)data, header.width * header.height * 4);
}

bool texture::_load_raw(const std::string &filename) {
    #ifdef _DEBUG_
    texture_log << "\n{\n\tloading: " << filename << "\n}\n";
    #endif

    std::ifstream input(filename.c_str(), std::ios::binary);
    if (input.bad() || input.fail() || !input.good()) {
        #ifdef _DEBUG_
        texture_log << "\n{\n\tcannot open raw file: " <<
            filename << "\n}\n";
        #endif
        return false;
    }

    char valid[4];
    // is it a valid rgl file
    input.read(valid, 4);
    if (valid[0] != 'R' || valid[1] != 'G' || valid[2] != 'L') {
        #ifdef _DEBUG_
        texture_log << "\n{\n\tinvalid .rgl file header: " <<
            valid << "\n}\n";
        #endif
        return false;
    }

    // unload previous file
    if (m_loaded || m_id) {
        unload();
    }

    // read the header
    rgl_header header = {0, 0, 0};
    input.read((char*)&header, sizeof(rgl_header));

    #ifdef _DEBUG_
    texture_log << "\nrgl header (read) {\n\t"
        << "header.w " << header.width << "\n\t"
        << "header.h " << header.height << "\n\t"
        << "header.colorkey " << header.colorkey << "\n}\n";//\t"
        //<< "header.xclip " << header.xclip << "\n\t"
        //<< "header.yclip " << header.yclip << "\n\t"
        //<< "header.wclip " << header.wclip << "\n\t"
        //<< "header.hclip " << header.hclip << "\n}\n";
    #endif

    // set up
    m_width = header.width;
    m_height = header.height;
    m_colorkey = header.colorkey;

    //m_clip.x = header.xclip;
    //m_clip.y = header.yclip;
    //m_clip.w = header.wclip;
    //m_clip.h = header.hclip;

    // get the actual data
    const unsigned long SIZE = w() * h() * 4;
    unsigned char *data = new unsigned char[SIZE];
    input.read((char*)data, SIZE);

    // reserve id for texture
    glGenTextures(1, &m_id);

    // bind it so we can get to work!
    this->bind();

    // now it's time for some setting
    // set the data onto the texture
    glTexImage2D(
        GL_TEXTURE_2D,
        0, // mip-map level
        GL_RGBA8, // 4 color components, each taking 8 bits (1 byte)
        m_width,
        m_height,
        0, // border
        GL_RGBA, // type of data
        GL_UNSIGNED_BYTE, // each pixel (or, texel) is an unsigned char
        data
    );

    // set up filtering
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, /*GL_NEAREST*/GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, /*GL_NEAREST*/GL_LINEAR);

    m_loaded = true;
    return true;
}



Problem:

Hello all! I'm having a slight OpenGL-related problem. As you can see in Exhibit 1, loading a texture and displaying it works fine. This means that my loading function(s) work(s) correctly. However, in Exhibit 2 you see the same scene, but with a messed up texture. What I do in my image loading function(s) is check too see if there is a file with the filename passed in, but instead of with .bmp with .rgl. If there is, load the .rgl file, otherwise, load the .bmp file and make a .rgl file. The first time I run my program, all is fine because the bitmap loads and the .rgl file is made. But the second time I run it, the program sees the .rgl file and loads it, giving me Exhibit 2. Exhibit 3 and 4 are how I save the .rgl file. I pass _save_raw() in the exact data that I pass in to OpenGL's glTexImage2D(). Then when I load I pass in the .rgl filename to _load_raw() and it's supposed to load it. However, I get the garbled mess displayed in Exhibit 2. Does anyone have an idea as to why? I'm sure OpenGL is set up correctly, as if I load from the bitmap all is fine... Thank you, and have a nice day!

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Are you sure that the image you're saving has four channels? BMP files only support three. Can we see your BMP loading code?

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Quote:
Original post by Kalidor
Are you sure that the image you're saving has four channels? BMP files only support three. Can we see your BMP loading code?


100% sure.

I load the image into an SDL surface and then create another 32-bit surface which is "fixed" specially for OpenGL. The "fixed" surface has 32 bits in order RGBA.

Anyways, here is the loading code just in case (it relates to SDL, but I'm sure the problem is more on my & OpenGL's side rather than SDL's):

bool texture::load(const std::string &filename) {
if (m_loaded)
unload();

// does an rgl file exist?
m_raw_filename = filename.substr(0, filename.find(".bmp")) + ".rgl";
std::ifstream check(m_raw_filename.c_str(), std::ios::binary);
if (!check.fail() && !check.bad() && check.is_open() && check.good()) {
check.close();
return _load_raw(m_raw_filename);
} else {
check.close();
}

SDL_Surface *raw, *fixed;

raw = SDL_LoadBMP(filename.c_str());
if (!raw) {
#ifdef _DEBUG_
texture_log << "\n{\n\tfailed at loading texture: " << filename
<< "\n\t(.bmp is the only format supported)\n}\n";
#endif
return false;
}

// opengl's y is inverted, so we must flip the data
flipv(raw);

int width = 1, height = 1;
// optimise for square textures: loop only once
while (width < raw->w || height < raw->h) {
if (width < raw->w) width <<= 1;
if (height < raw->h) height <<= 1;
}

m_clip.x = 0;
m_clip.y = 0;
m_clip.w = width;
m_clip.h = height;

m_width = width;
m_height = height;

fixed = SDL_CreateRGBSurface(
SDL_HWSURFACE, // won't be doing any pixel operations
width, height, 32, // w, h, bpp (bpp == 32, using alpha)
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
0xff000000,
0x00ff0000,
0x0000ff00,
0x000000ff
#else
0x000000ff,
0x0000ff00,
0x00ff0000,
0xff000000
#endif
);

if (!fixed) {
#ifdef _DEBUG_
texture_log << "\n{\n\tcould not generate fixed surface for: " << filename
<< "\n}\n";
#endif
return false;
}

// copy the surface onto the other one
SDL_BlitSurface(raw, NULL, fixed, NULL);
// free the old surface
SDL_FreeSurface(raw);

if (SDL_MUSTLOCK(fixed))
while(SDL_LockSurface(fixed));

// rgl
// save the rgl file
_save_raw((unsigned char*)fixed->pixels);

// reserve id for texture
glGenTextures(1, &m_id);

// bind it so we can get to work!
this->bind();

// now it's time for some setting
// set the data onto the texture
glTexImage2D(
GL_TEXTURE_2D,
0, // mip-map level
GL_RGBA8, // 4 color components, each taking 8 bits (1 byte)
width,
height,
0, // border
GL_RGBA, // type of data
GL_UNSIGNED_BYTE, // each pixel (or, texel) is an unsigned char
(unsigned char*)fixed->pixels
);

if (SDL_MUSTLOCK(fixed))
SDL_UnlockSurface(fixed);

// free the new surface
SDL_FreeSurface(fixed);

// set up filtering
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, /*GL_NEAREST*/GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, /*GL_NEAREST*/GL_LINEAR);

m_loaded = true;

return true;
}

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I'll give a quick *bump* before I have to go...

This is sorta stopping me from coding since I want to optimise stuff.... Anyways, thanks in advance.

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0) don't optimise prematurely.
1) you should glDeleteTexture before trying to reload or you'll have a memory leak in the ICD.
2) to me, it looks as if your texture coordinates are messed up, not your loading code.
3) try changing the last GL_RGBA to GL_RGB

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Quote:
Original post by silvermace
0) don't optimise prematurely.

Got it.
Quote:

1) you should glDeleteTexture before trying to reload or you'll have a memory leak in the ICD.

Affirmative -

bool texture::load(const std::string &filename) {
if (m_loaded)
unload();
[...]
}

Quote:

2) to me, it looks as if your texture coordinates are messed up, not your loading code.

I'm 100% sure they are not. Infact, all I do is set the clip rect to 0, 0, width, height - which includes the whole image.
Quote:

3) try changing the last GL_RGBA to GL_RGB

I'll try it, I can't get to the code right now, but I'll reply when I do.

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Quote:
Original post by silvermace
2) to me, it looks as if your texture coordinates are messed up, not your loading code.


Hmm... I looked into this a little more, and guess what? You're right!!! (Rate++ follows after this post.)

I was loading from my constructor, which sets the clip rect to (0, 0, 1, 1). Since my _load_raw() function does NOT do anything with the clip rect, it was just displaying the first pixel of the texture... [lol]. Anyways, saving the rect along with the data (as I did before, but commented out for no true reason) fixed everything.

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eye of experience - I only wish I had someone to point that out to me the first time I did it :-)

congrats/good luck

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