How to draw a circle

Draw a circle in a fragment shader without vertices.

data

Vertice Index x y
0 0 0 0
1 1 512 0
2 2 0 288
3 3 0 288
4 4 512 288
5 5 512 0

pixel

r
0
g
0
b
0
a
0
x
0
y
0

Fragment Shader

precision mediump float;uniform vec2 u_resolution;void main() { vec2 uv = gl_FragCoord.xy; vec2 center = u_resolution * 0.5; if (distance(uv, center) < 25.) { gl_FragColor = vec4(0.027, 0.988, 0.341, 1.); }}

Vertex Shader

precision mediump float;attribute vec2 a_position;uniform vec2 u_resolution;void main() { vec2 pos = a_position / u_resolution * 2.0 - 1.0; gl_Position = vec4(pos.x, -pos.y, 0.0, 1.0);}