nicer point render

cosets/src/shaders/main.fs.glsl

@@ -3,9 +3,12 @@
 uniform vec4 color;
 
 in vec4 v;
+in vec4 screen;
 
 out vec4 fcolor;
 
+const float scale = .2;
+
 vec3 hsv2rgb(vec3 c) {
     vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
     vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
@@ -14,4 +17,5 @@ vec3 hsv2rgb(vec3 c) {
 
 void main(){
     fcolor = color;
+    fcolor.xyz *= smoothstep(scale, -scale, screen.z);
 }

cosets/src/shaders/main.vs.glsl

@@ -4,11 +4,12 @@ uniform mat4 proj;
 
 in vec4 pos;
 out vec4 v;
+out vec4 screen;
 
 void main(){
   v = pos;
 
   /* stereographic projection */
   vec4 vert = vec4(pos.xyz / (1 - pos.w), 1);
-  gl_Position = proj * vert;
+  screen = gl_Position = proj * vert;
 }