Light Strips in Vulkan Renderer
Entry posted by Josh ·
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It's always fun when I can do something completely new that people have never seen in a game engine. I've had the idea for a while to create a new light type for light strips, and I got to implement this today. The new engine has taken a tremendous amount of effort to get working over two years, but as development continues I think I will become much more responsive to your suggestions since we have a very strong foundation to build on now.
Using this test scene provided by @reepblue you can see how this new light type looks and behaves. They are great for placing along walls, but what really made me interested was the idea to calculate specular lighting not from a single point, but with a different way. I thought if I could figure out the math I would get a realistic reflection on the ground, and it worked!
The reflection on the floor is actually the specular component of the light. We are used to thinking of specular reflections as a little white circle that moves around, but the light doesn't have to be coming from a single point. Some calculations in the shader can be used to determine the closest point to the light strip and use that for reflections. The net effect is that a long bar appears on the floor, matching the length of the light. This is not a screen-space effect or a cubemap. When you look down at the floor the specular component is still there shining back at you. Every surface is using the same exact equation, but it appears very different on the walls, the ceiling, and the floor due to the different angles.
Even a surface facing opposite the light will correctly reflect it back to the camera.
In this image, I created a small green strip light that looks like a laser. There is no visible laser beam, but if there was it would appear above the soft green lighting. The hard line on the ground is actually the specular reflection of the light. You can see it reflecting off the sphere as well.
The new Vulkan renderer also supports box lights, which are a directional light with a defined boundary, and I have an idea for one more type of light.
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