![]() ImpostorRenderVector = set(HemiOct.x, HemiOct.y, 0) Vector2 HemiOct = set(CoordModify.x + CoordModify.y, CoordModify.x - CoordModify.y) Note that for textures in games it is recommended to use 1:1 aspect ratio with a power of two resolution.įloat fx = fit(x, -1, 1, 0, 1) * float(xy_size) įloat fy = (1 - fit(y, -1, 1, 1, 0)) * float(xy_size) įloat floorx = clamp(float(xy_size) - trunc(fx) - 1.0, 0, xy_size-1) įloat floory = clamp(float(xy_size) - trunc(fy) - 1.0, 0, xy_size-1) įloat fracx = (frac(fx) * 2.0 - 1) * camera_width įloat fracy = (frac(fy) * 2.0 - 1) * camera_width Those two vectors will also get the same transformations applied like our camera. So they will always be the same relative to our camera regardless of where we move or rotate our camera to. The definition tells us those two are defined in camera space. Vector I – Ray direction for pixel in camera space Vector P – Ray origin for pixel in camera space Those two things are defined with variables in our Lens Shader. In what direction will my ray for the current pixel go?Ī Lens Shader is responsible for computing primary rays from screen coordinates, and is a flexible way to define new kinds of camera projections that can’t be modeled as perspective or orthographic projections. Where will I be casting my ray for the current pixel from? 2. That’s what our Lens Shader will be defining: 1. To give the pixels on our image a value, we will need to cast a ray from those pixel positions into a specific direction. ![]() That’s what is being visualized in the image above. Imagine we took a blank canvas with the desired resolution we would like to be rendering (ex 1920x1080px), and aligned that with the camera near clipping plane. The main examples used in this article revolve around Game Development, but are applicable to anyone doing rendering. There isn’t a lot of documentation on Lens Shaders in Houdini, so this will help you get a good understanding. Lens Shaders can be pretty complex, but they can also be a lot of fun. Due to the scope of the article it will not explain every single piece of code in detail, but should get you far enough to kickstart your own experiments. In this article I’d like to teach you about Lens Shaders and some of the things you can do with them. Which is exactly what I am currently doing at my job at SideFX with Houdini – including creating tutorials, giving live lectures, attending events and presenting custom workshops to customers. ![]() While there, I found my passion in helping others create amazing things in a better, faster and more flexible way. I studied International Game Architecture and Design at NHTV University of Applied Sciences in Breda, Netherlands. Hi there! My name is Paul Ambrosiussen and I’m a 3D Technical Artist focusing on Tool Development to support effective art pipelines, and optimize tool and workflow quality for the artists around the world I’m working with. ![]()
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