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In this piece of code i managed to load a image with SDL and then succesfully pass it as a texture. Basically

SDL_RenderClear(renderer);
image[0] = IMG_Load("../../tiles/1.png"); //path origin: framework/bin

if(image[0]!=nullptr) {
    //printf("h %d w %d d %d\n",image[0]->h, image[0]->w,d);
}
else
    std::cerr << "ERROR: image load failed: " << SDL_GetError() << "\n";

image[1] = IMG_Load("../../tiles/2.png"); //path origin: framework/bin


// set texture wrapping to GL_REPEAT (default wrapping method)
glTexParameteri(TexTarget, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(TexTarget, GL_TEXTURE_WRAP_T, GL_REPEAT);
// set texture filtering parameters
glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

if(image[0]->format->BytesPerPixel == 4) {
    MM = GL_RGBA;
}

glTexImage2D(TexTarget, 0, MM, image[0]->w, image[0]->h, 0, MM, GL_UNSIGNED_BYTE, image[0]->pixels);

I would like to join both image[0] and image[1] in a new SDL_surface like image_total. I tried to use

    SDL_BlitSurface(image[0], NULL, image_total, NULL); 
   //somehow also load image[1] into image_total, for example below image[0]?
    glTexImage2D(TexTarget, 0, MM, image_total->w, image_total->h, 0, MM, GL_UNSIGNED_BYTE, image_total->pixels);

but It does not work (also, generates segm. fault). I can't find a proper example on how to use SDL_Blitsurface. How does it works?

If there is a way to join textures directly in openGL it will be also well accepted.

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  • $\begingroup$ How do you want to "join" the textures? Side by side, one above the other, alpha-blending them on top of each other, adding the colours, ...? Do the dimensions match? $\endgroup$ – Dan Hulme Jan 21 at 17:31
  • $\begingroup$ @DanHulme as pointed out in code comment, I want to join the second below the first (or side by side, I assume the technique should be similar. Not blending or other types of composition). All images have 256x256 pixel $\endgroup$ – marcoresk Jan 23 at 10:22

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