Glowing Effect
Orkl	In a game (for example Helbreath or Dungeon Siege) sometimes an Item will "Glow", I was wondering how you could do that? If anyone has any suggestions... Post 'em :[:I]
Eric Coleman	For a glowing effect, you would render a slightly larger copy of the model using special textures and alpha values depending on the normal. To make the model "grow", not the same as scale, you need to add a small percent of a vertex's normal to itself. This makes each piece of geometry grow outward as though its expanding like a balloon. The next step is to take this modified geometry and alter the alpha value per vertex relative to the camera viewport. I think a nice glow would be a cosine curve of the dot product between the "lookat" vector and the vertex normal. Of course, you can use a different curve if you would like. If you do a search for my name at http://www.planetsourcecode.com/ you'll fine a transparency sample that I uploaded. The vertex alpha is the opposite of what you would want. The effect that I was trying to create was a membrane effect, like a jellyfish, where the surface is transparent when you look at it in a straight line, and then becomes less transparent when you look at it from an angle. A glow effect would the opposite I think. I think I use a sin^10 function for the alpha values. You could easily change the sin to cos in the source code to see what I'm talking about. Of course, its been so long since I looked at that code, I may have my sin and cos mixed up. Its either one or the other.
Orkl	ok, i have no idea what: Vector, Vertex or Alpha values mean.. lol or how you would use sine and cosine in programming =S
Eric Coleman	Well, to do any advanced game programming, you'll need to be fairly proficient with math. Also, you never said if this was for a 3D game or for a 2D game. For a 2D game its a bit easier. You would simply use Adobe Photoshop or Gimp or whatever your favorite image editing program might be, and then apply a glow filter/effect to the sprite. Then just blt the "glowing" sprite instead of the normal sprite whenever you want it to glow.
Orkl	ahhh ok, well it was for a 2d Isometric game :D i know I need to be proficient at maths, but hey, only s**t they teach us in year 10 is "Indicies" and "Square Root"... Like i'll EVER need that...
AT	That trig might come in handy ... What do you think you need to use for distance calculations ?
Bonez2044	I just wanted to know if i can make my sprites glow that only i wear?