1.) How is it done?
2.) Is it hard to do?
3.) Does the bended part have to be black?
4.) Could you link me to some good tutorials on it?
Alpha Bending? Never heard of it. Oh… you probably mean Alpha Blending.
- Instead of standard RGB colors, you can have an additional Alpha component to make RGBA colors. This fourth component is then used in some way to blend multiple colors together. One of the most common ways this is done, is by using the alpha to specify a sort of “level of transparency.” In OpenGL, to do blending you typically use glEnable(GL_BLEND) and glBlendFunc with the parameters to specify the type of blending you want to do. (e.g. glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA). Read up on these functions for more details.
2.) It’s not hard to do if you understand what you are doing.
3.) No the blended part can be any color you want.
4.) I’m pretty sure http://nehe.gamedev.net has some tutorials on blending.