• 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
redcoding

How to color a grayscale texture removing the alpha channel?

3 posts in this topic

Hello,

I need some help understanding what I am doing wrong.

I am drawing text into a texture and then render this texture to the screen. The texture used is a grayscale texture. Why? Because the tutorial I have the code from says it saves memory. OK, so I have white text that I need to color. That means I want to color my grayscale texture when I am drawing it. But the result turns out to be unsatisfying.

I am drawing the texture with a quad, each vertex getting the color red and full alpha (1,0,0,1);

Result 1:
bildschirmfoto20121230un.png
I use this code for blending:

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

The red is as expected (full red), but the alpha channel is opaque.




Result 2:
bildschirmfoto20121230ub.png

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR);

With this code, I can remove the black background, but the red is rather pale.

Which settings could I use to remove the black background and keep the full red color? Or is this not possible and I should use an RGBA texture in the first place? I could then color the text when rendering it to the texture. Anyway, I want to understand what is going on, before I decide to spend more memory.

Edited by redcoding
0

Share this post


Link to post
Share on other sites

Hi :)

 

I don't know if it will work, but try this (I've used it somewhere)

glEnable(GL_BLEND);
glBlendFunc(GL_DST_COLOR, GL_ONE_MINUS_DST_ALPHA);

:)

0

Share this post


Link to post
Share on other sites

One option might be to remove your vertex colours, then colour your text using GL_CONSTANT_COLOR/glBlendColor but this is not a good solution as it means you can't combine different coloured text into a single draw call.

 

Your better bet is to get your texture information into your alpha channel somehow, I think the easiest way to achieve this is to use the GL_INTENSITY format instead of the GL_LUMINANCE or GL_RGB format that I assume you're using at the moment.

0

Share this post


Link to post
Share on other sites

I don't get why it doesn't work either... Make sure that when setting the modulation color you don't mess with the alpha channel somehow, though no idea how it could be affected (would need to know more about how your program works).

 

Also are you sure the red is more pale in the second pic? That looks more like an optical illusion because the background is brighter than black. Also, why do you need separate color and alpha? Black outline? Because if you just want a single color like in the second pic you could ditch the alpha altogether and stick to the single color channel (and halve memory usage, as a bonus).

 

EDIT: I think I know why it may not be working, is the texture in decal mode, by any chance? (wild guess here)

Edited by Sik_the_hedgehog
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