Shapes Shader

A simple shader that outputs 3 shapes : A quadrilateral( square/rect ), A Circle, A Polygon (Triangle to Infinitygon).

This shader can be used in fast level designing such as the shapes available on unity. The cover image is an example of a scene i designed with this shader, it took 5 minutes.

The parameters are :

Shape – (0, 1, 2) – 0 is Circle, 1 is Rect, 2 is Polygon

Poly Count – (3 – inf) – 3 is Triangle, 4 is Square, 5 is Pentagon and so on. (Only works if shape is a Polygon)

(Ignore the fog in the cover photo :/)

Shader code

shader_type canvas_item;

uniform int shape = 0;
uniform float poly_count = 3.0;

const float PI =  3.14159265359;
const float TWO_PI =  6.28318530718;

float Circle(vec2 st)
{
	vec2 center = vec2(0.5) - st;
	return step(length(center), 0.5);
}

float Square(vec2 st)
{
	return 1.0;
}

float Triangle(vec2 st, float width)
{
	st = st * 2.0 - 1.0;
	
	if (poly_count > 2.0)
	{
		if (poly_count < 4.0)
		{
			st.y += 0.25;
		}
	}
	
	float angle = atan(st.x, st.y) + radians(180.0);
	float radius = TWO_PI / float(poly_count);
	
	float dist = cos(floor(0.5 + angle / radius) * radius - angle) * length(st);
	float poly = step(width, dist);
	return 1.0 - poly;
}

void fragment()
{
	vec2 st = UV;
	st.y = 1.0 - st.y;
	
	float sh;
	
	if (shape == 0)
	{
		sh = Circle(st);
	}
	else if (shape == 1)
	{
		sh = Square(st);
	}
	else if (shape == 2)
	{
		sh = Triangle(st, 0.5);
	}
	
	vec3 color = vec3(sh);
	
	color = 1.0 - color;
	float alpha = 1.0 - color.r;
	color = 1.0 - color;
	
	COLOR = vec4(color, alpha);
}

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