Raymarching Shader Generator in Unity
uRaymarching is a raymarching shader templates using uShaderTemplate. The following functions are implemented:
The following shapes are rendered inside a 12-polygon cube.
Check more examples here:
https://github.com/hecomi/uShaderTemplate.git#upm
https://github.com/hecomi/uRaymarching.git#upm
https://registry.npmjs.com
com.hecomi
Generator
.Please also see uShaderTemplate to learn the detail of shader generation function.
The UI is generated by uShaderTemplate automatically from template files located in the Assets/uRaymarching/Editor/Resources/ShaderTemplates.
Universal Render Pipelin/Lit
shader.Universal Render Pipelin/Unlit
shader.The items in Conditions and Variables are different depending on the selected template. Please see each page for further details:
This block is inserted into a Property
section in a shader.
[Header(Additional Parameters)]
_Grid("Grid", 2D) = "" {}
Write a distance function here. The following code is the one generating the example of morphing sphere in Screenshots section in this document.
inline float DistanceFunction(float3 pos)
{
float r = abs(sin(2 * PI * _Time.y / 2.0));
float d1 = RoundBox(Repeat(pos, float3(6, 6, 6)), 1 - r, r);
float d2 = Sphere(pos, 3.0);
float d3 = Plane(pos - float3(0, -3, 0), float3(0, 1, 0));
return SmoothMin(SmoothMin(d1, d2, 1.0), d3, 1.0);
}
Math.cginc and Primitives.cginc are included in the generated shader, so in this example some functions like RoundBox()
and Repeat()
come from these include files (of cource you can write them by yourself).
Post Effect is similar to a surface function in a surface shader. The following code is used in the hexagon-tile example in Screenshots section.
float4 _TopColor;
inline void PostEffect(RaymarchInfo ray, inout PostEffectOutput o)
{
float3 localPos = ToLocal(ray.endPos);
o.Emission += smoothstep(0.48, 0.50, localPos.y) * _TopColor;
o.Occlusion *= 1.0 - 1.0 * ray.loop / ray.maxLoop;
}
RaymarchInfo
is the input and the output of a raymarching calculation and this is defined in Struct.cginc.
struct RaymarchInfo
{
// Input
float3 startPos; // start position of ray
float3 rayDir; // ray direction
float3 projPos; // ComputeScreenPos-applied position
float3 polyNormal; // normal on polygon surface
float minDistance; // minimum ray distance (comes from material setting)
float maxDistance; // maximum ray distance (changes by the raymarching setting)
int maxLoop; // maximum number of loop (comes from material setting)
// Output
int loop; // total number of loop of the calculation (<= maxLoop)
float3 endPos; // last position (= surface of the distance function)
float lastDistance; // the final distance of the raymarching
float totalLength; // total ray length
float depth; // depth (encoded)
float3 normal; // normal (encoded)
};
So ray.loop / ray.maxLoop
is a normalized value and becomes close to 0.0 on the position where a ray reaches easily and becomes close to 1.0 when hard. So you can use it as a factor of a rechability or 1.0 - ray.loop / ray.maxLoop
as an simple and a light-weight occlusion factor.
PostEffectOutput
is defferent depending on the selected shader template. For example, it is an alias of SurfaceOutputStandard
in Standard template. Please see the following pages for more details.
Please see each template file by clicking Edit button on the right side of the Shader Template drop-down list for more details.
Press Export button or Ctrl + R to export shader. Then, press Create Material button to generate a material which uses the shader (or create a material manually from the Project pane).