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| Shield Effect |
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Timorg
Member #2,028
March 2002
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I am working on the shield effect for my psg game. I have come up with this effect.. {"name":"596953","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/b\/6\/b6d840e9400773d426de5d25f5cd1402.gif","w":400,"h":400,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/b\/6\/b6d840e9400773d426de5d25f5cd1402"} It uses the stencil buffer to mask the object. (This is a square, but it would work on any other shape.) Then scales up the polygon and draws the outside. The number of times this is done depends on the shield power, with each one larger than the last. I guess I am looking for other ways to implement shield effects. I am using OpenGL, so there is a lot open to me, I just can't think of any good ideas. A possibly is to use fragment shaders, but I don't even know where to start, or how useful they would be to achieve what I actually want. I really want to generate an outline that increases transparency the further it goes away from the ship. Any thoughts or suggestions on what I have already, what I want to achieve or alternative solutions, that would be great. ____________________________________________________________________________________________ |
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Trent Gamblin
Member #261
April 2000
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You say you want it to increase in transparency the further from the ship, but it looks to me like it already does that. I take it that you are drawing the shape in transparent blue, making it slightly larger each time until maximum. That should have the desired effect. Play with the translucency value until it looks perfect.
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Timorg
Member #2,028
March 2002
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Its not as smooth as I would like, the steps that transparency is done in sort of irks me. It just occurred to me that I could convert the lines to polygons, because I would have a lot more control. I would have to process the 4 points that would make up the polygon, where I have a feeling that this way is a lot cheaper. ____________________________________________________________________________________________ |
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Trent Gamblin
Member #261
April 2000
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I think using less alpha would help. Make it so that the innermost line JUST gets 255 alpha and no more. The way it is now it looks like several lines out are all fully opaque.
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Timorg
Member #2,028
March 2002
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I don't really know which is cheaper, but I came up with a solution that has pretty much the effect I want (It needs a slight tweak where both vertexes are on the same location, they are skipped over, where it needs to generate an appropriate normal from the point.) At the moment the code gives me the following... http://www.allegro.cc/files/attachment/596963 Just for fun I really pumped up the glow size, (The point at the top is skipped, rather than having a vertical line directly up, so it doesn't look right as the ship changes shape. So anywho, with the glow size pumped up it gives me... http://www.allegro.cc/files/attachment/596964 The lines were 0.3f for the alpha, thanks for the suggestion though. ____________________________________________________________________________________________ |
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Thomas Fjellstrom
Member #476
June 2000
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Small suggestion, would it look better if the field followed the lines of the craft? that is if the field is similar in shape to the ship? -- |
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Trent Gamblin
Member #261
April 2000
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Maybe interpolating from one color to another, e.g., (255, 255, 255) to (0, 0, 255) as you move outwards would look cool.
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piccolo
Member #3,163
January 2003
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it looks like 2 objects the blue one is fixed to the red one at the centers. Then the blue one is scaled on the y and x -axes to do the animation. wow |
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Any other thoughts relating to the new effect?