Question

Is there a way to create a plasma effect in SFML that doesn t slow my framerate to a crawl?

Answer 1

1) Manipulate the image bits directly in memory as a byte (or int/whatever depending on your target colour depth) array. Don t use anything which GetsPixel() from an image each time.

2) Minimise your maths. For plasma effects you ll usually be using a lot of trig functions which are fairly slow when you re doing them (heightwidthframerate) times per second. Either use a fast dedicated maths library for your calucations or, better yet, cache the calculations at the start and use a look-up table during the effect to cut the math out of each frame entirely.

3) One of the things which made old-school plasma effects run so fast was palette cycling. I m not aware of any way to replicate this (or palettes in general) with SFML directly but you can use GLSL shaders to get the same kind of result without a big performance hit. Something like this:

float4 PS_ColorShift(float2 Tex : TEXCOORD0) : COLOR0 
{ 
    float4 color = tex2D(colorMap, Tex);

    color.r = color.r+sin(colorshift_timer+0.01f);
    color.g = color.g+sin(colorshift_timer+0.02f);
    color.b = color.b+sin(colorshift_timer+0.03f);
    color.a = 1.0f;

    saturate(color);

    return color;
}

Answer 2

Can you just make your plasma effect in RAM, then place it on a texture and upload it? It s not a shader effect, but it will give you a plasma effect.

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