lighting in game is NOT hardware lighting... most games only use a single light and thats the Zero Light or Ambient Light.
You have many ways to create light
Lightmap, Vertex, Pixel, Sprite, Volumetric, Stencil, Buffer Overlay
each have thier advantage and disadvantages, most of them are because they're SLOW.
Best is combining the different types for what you particularly need within that scene...
I mean all lights do is react with the textures to brighten or dim them from standard brightness. Really should be accenting them for real lighting effects but hell that would be more expensive too.
Lightmap - you use a premade greyscale image and then blend it with the texture of a face to achieve a light effect.
Vertex - you alter the vertex colour of the vertex point and the engine should blend this automatically with your texture
Pixel - same as vertex only using shaders on the pixel level
Sprite - its how it sounds you uses a sprite light image, as it overlaps ghosted it achieves a similar effect to lightmapping
Volumetric - this is an object that represents a light within the scene, you can either use the plain coloured alpha map
... with this you can also use a texture and it become a 3D sprite
... or you can use the image's alpha as a selection area, you then create a backfacing version and take both the for face and back face versions to calculate depth - then use that depth with the lights colour and blend from origin to targer raster
Stencil - not possible in DBP, but with this you basically project a stencil and use the stencil buffer to fill in the colour - works similar to volumetric only it only affects the intersected surfaces, better for flashlights.
BackBuffer - using a copy of the scenes backbuffer and alpha cuts of the target and origins you then put in a 2D beam trace effectively a clever 2D light variation of volumetric ... cna look odd at times though
[edit-] noticed i'd forgotten projected, but ho hum
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