• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Sunsharior

Create new white texture from existing SDL_Texture.

7 posts in this topic

Hello everyone,

 

I'm trying to accomplish something in SDL and i'm wondering if it can be done easily.

 

What i want to do it this:

 

First i create a new texture from a PNG file with this code. No problem so far.

bool CTextureInfo::Unserialize(std::ifstream &_inputfilestream)
{
    //png
    int pngsize = 0;
    _inputfilestream.read(reinterpret_cast<char *>(&pngsize), sizeof(int) );
    char *textureBinaries = new char[pngsize];
    _inputfilestream.read(reinterpret_cast<char *>(textureBinaries), pngsize);
	
    // Create texture
    SDL_RWops *img = SDL_RWFromConstMem(textureBinaries, pngsize);
	
    // This part is building the texture through SDL_image
    SDL_Texture *texture = IMG_LoadTexture_RW(CSDL_Setup::GetInstance()->GetRenderer(), img, 0);
}

After this i want to create another texture that will be a copy of the first one, but instead all pixels that are not transparent become white.

See attached image for example of what texture 1 and texture 2 should look like.

 

However, i am failing really hard to figure how to do this.

I thank you in advance.

 

 

0

Share this post


Link to post
Share on other sites

The most direct approach would be to use color modulation (SDL_SetTextureColorMod) to something really high (like 255) and then using a RenderCopy to the new texture. It would work if none of your rgb values are 0. 

 

But, given this limitation, you have a second option. You go and read the first texture pixel per pixel and, if it is not magic-pink, render a white pixel on the other texture with the same coordinates. You could also compute the "biggest non-invisible rectangle" and draw it, reducing significantly the drawing calls.

 

It is important to tell, Textures are really awesome for rendering, super fast and all. But you'll have a hard time trying to edit them. This type of editions in SDL2 is usually done using surfaces.

 

PS: Assuming you're using SDL2 (what you should, SDL1 is LGPL).

Edited by dejaime
1

Share this post


Link to post
Share on other sites

Color modulation is the first thing i tried to do, but i noticed setting it to 255, 255, 255 don't change the color.

I attached an image of what i tried to do earlier today.

 

First image is a colorModulation with the normal weapon.

Second image is a colorModulation with a white image (White shadow) of the weapon.

 

IMO it look so much better in the second image. Note that i would actually change the white blade for the actual blade if i manage to find something that work smile.png

 

Right now, i'm trying to do the second thing you said, dejaime. I'm trying to convert the texture to a surface and change all pixel to white.

Oh boy, google is really not helping me on this one, maybe i'm trying to do something very easy in a very complicated way, ahah.

 

Edit: Yes, i'm using SDL2. I also know texture are way faster than surface, this is why i'm trying to avoid using surfaces altogether.

Edited by Sunsharior
2

Share this post


Link to post
Share on other sites

Dejaime! Thank you so much! This has solved my problem exactly how i described it. If i could vote you up one thousand time, i would!

 

0

Share this post


Link to post
Share on other sites

Another way would be to do this pre-process -- actually creating both versions of the image and loading both files.

 

It shouldn't be too difficult to do this with e.g. Photoshop and using a batch/macro. This could also allow you to add various effects (e.g. blur or something) to the image, and potentially manually adjust specific images if needed.

 

That said, this would also mean more files and larger disk footprint, which is something to keep in mind.

1

Share this post


Link to post
Share on other sites

I'm taking the liberty to update this topic in case anyone else is trying to do the same thing i did earlier this month.

 

I have found that dejaime's solution work perfectly fine for 32-bits images, but i got error as soon as i switched to 24-bits.

 

To solve this, refer to this documentation http://sdl.beuc.net/sdl.wiki/Pixel_Access

 

Have a good day!

0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0