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using System.Reflection;
using UnityEngine;
namespace UnityEditor.ShaderGraph
{
[Title("Procedural", "Shape", "Rounded Polygon")]
class RoundedPolygonNode : CodeFunctionNode
{
public RoundedPolygonNode()
{
name = "Rounded Polygon";
synonyms = new string[] { "shape" };
}
protected override MethodInfo GetFunctionToConvert()
{
return GetType().GetMethod("RoundedPolygon_Func", BindingFlags.Static | BindingFlags.NonPublic);
}
static string RoundedPolygon_Func(
[Slot(0, Binding.MeshUV0)] Vector2 UV,
[Slot(1, Binding.None, 0.5f, 0, 0, 0)] Vector1 Width,
[Slot(2, Binding.None, 0.5f, 0, 0, 0)] Vector1 Height,
[Slot(3, Binding.None, 5f, 0, 0, 0)] Vector1 Sides,
[Slot(4, Binding.None, 0.3f, 0, 0, 0)] Vector1 Roundness,
[Slot(5, Binding.None)] out Vector1 Out)
{
return
@"
{
UV = UV * 2. + $precision2(-1.,-1.);
$precision epsilon = 1e-6;
UV.x = UV.x / ( Width + (Width==0)*epsilon);
UV.y = UV.y / ( Height + (Height==0)*epsilon);
Roundness = clamp(Roundness, 1e-6, 1.);
$precision i_sides = floor( abs( Sides ) );
$precision fullAngle = 2. * PI / i_sides;
$precision halfAngle = fullAngle / 2.;
$precision opositeAngle = HALF_PI - halfAngle;
$precision diagonal = 1. / cos( halfAngle );
// Chamfer values
$precision chamferAngle = Roundness * halfAngle; // Angle taken by the chamfer
$precision remainingAngle = halfAngle - chamferAngle; // Angle that remains
$precision ratio = tan(remainingAngle) / tan(halfAngle); // This is the ratio between the length of the polygon's triangle and the distance of the chamfer center to the polygon center
// Center of the chamfer arc
$precision2 chamferCenter = $precision2(
cos(halfAngle) ,
sin(halfAngle)
)* ratio * diagonal;
// starting of the chamfer arc
$precision2 chamferOrigin = $precision2(
1.,
tan(remainingAngle)
);
// Using Al Kashi algebra, we determine:
// The distance distance of the center of the chamfer to the center of the polygon (side A)
$precision distA = length(chamferCenter);
// The radius of the chamfer (side B)
$precision distB = 1. - chamferCenter.x;
// The refence length of side C, which is the distance to the chamfer start
$precision distCref = length(chamferOrigin);
// This will rescale the chamfered polygon to fit the uv space
// diagonal = length(chamferCenter) + distB;
$precision uvScale = diagonal;
UV *= uvScale;
$precision2 polaruv = $precision2 (
atan2( UV.y, UV.x ),
length(UV)
);
polaruv.x += HALF_PI + 2*PI;
polaruv.x = fmod( polaruv.x + halfAngle, fullAngle );
polaruv.x = abs(polaruv.x - halfAngle);
UV = $precision2( cos(polaruv.x), sin(polaruv.x) ) * polaruv.y;
// Calculate the angle needed for the Al Kashi algebra
$precision angleRatio = 1. - (polaruv.x-remainingAngle) / chamferAngle;
// Calculate the distance of the polygon center to the chamfer extremity
$precision distC = sqrt( distA*distA + distB*distB - 2.*distA*distB*cos( PI - halfAngle * angleRatio ) );
Out = UV.x;
float chamferZone = ( halfAngle - polaruv.x ) < chamferAngle;
Out = lerp( UV.x, polaruv.y / distC, chamferZone );
// Output this to have the shape mask instead of the distance field
#if defined(SHADER_STAGE_RAY_TRACING)
Out = saturate((1 - Out) * 1e7);
#else
Out = saturate((1 - Out) / fwidth(Out));
#endif
}
";
}
}
}