OpenTK：让点显示为圆而不是方块

#version 460 core

layout(location = 0) in vec2 aPosition;  
layout(location = 1) in vec3 aColor;
layout(location = 2) in float aPointSize;

out vec3 ourColor;

uniform mat4 projection;
uniform mat4 model;
uniform float scaleFactor;

void main(void)
{
    gl_Position = projection * model * vec4(aPosition, 0.0, 1.0);
	ourColor = aColor;
    gl_PointSize = aPointSize * scaleFactor;
}

#version 460 core

in vec3 ourColor;

out vec4 outputColor;
const float smoothness = 0.02;

void main()
{
    vec2 center = vec2(0.5, 0.5);
    float distance = distance(gl_PointCoord, center);
    if (distance > 0.5) discard;

    float alpha = 1.0 - smoothstep(0.5 - smoothness, 0.5, distance);    
    outputColor = vec4(ourColor, alpha);
}

GL.Enable(EnableCap.Blend); // 启用混合功能
GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha); // 设置混合函数