I need to know how to draw explosions that look good on any background. I already know how to make good explosions on a black background, but when I try to cut them out a very ugly black border remains.

An explosion most often only lightens the background on which it is rendered upon, to achieve this you should use additive blending when you draw your explosion (I assume you are using an graphics API, OpenGL or DirectX). In OpenGL you would use:

glEnable(GL_BLEND);
glBlendFunc(GL_ONE,GL_ONE);
// Draw your explosion

If you use this method you should not have to worry about the border if your background is black.

If you like to test additive blending right in Photoshop you should use the "screen" blend mode instead of "normal" in the layers window.

My own explosions done this way:



[edited by - Herr_O on July 9, 2003 1:14:27 PM]

I don''t use an API (directly), I use Game Maker (www.gamemaker.nl). I draw explosions in Photoshop and import them as sprites. This is how I draw them: I create a black background layer. Then I add a new layer, set the colors to red and yellow, draw a selection and apply the clouds filter. Next, I apply gaussian blur to the layer to soften the edges. Finally, I add another layer, reset the colors, apply clouds and set the layer style to color dodge. This looks pretty good but a black background is required.

your one flaw is that youre blurring out your sprite from a transparent layer. When you blur like this for the purpose of sprites, you are now depending on the current background color to be the one color which your background will be compatable with. One of the key aspects of creating good sprites of any kind is to be able to make then visible against any sort of background... the answer to this problem can be either 1 of 2 things (that ive come across, there may be other methods but i find these two to work the best. The first solution is the most common and is evident in most hand pixelled sprites these days. Outlines. They may be black outlines, or just dark colored outlines. Ever since the early arcade days theyve been doing this, because of its visibility advantages, but at the same time, realistic games wanted to keep this visibility without making their outlines as obvious. THeir inintial answer to try to help remove the obviousness is to blend the internal contents of the sprite into the outline, to make it smoother in appearance and less obvious, but still jsut as effective. Its usually a blend of light interior to a darker perimiter outline (as opposed to using a gaussian blur on a transparent layer which adds alpha value pixels, causing them to become lighter and more transparent around the perimiter). As the idea of cel shading became more nad more popular, fighting games like garou and CvS started realising the importance of color and saturation. They were able to effectively remove outlining altogether in certain areas where highlight colors were evident because they were so bright and pure, that they would easilyu stand out from any background element (because naturally, any good background scene , just as in nature itself, should only have medium intensity and color at best). Id pull up examples, but i think you can do some searching since im too lazy... search for "metal slug sprite rips" on google or something like that , and search for some of their explosion effects. theyre easily some of the best pixelled explosions ever created , and they will give you great ideas as to how to pursue your explosions as 2d sprites. hope that helps, goodluck!