Add the whole ass shader

it has begun

shaders/world1/lib/stars.glsl

@@ -0,0 +1,48 @@
+//Original star code : https://www.shadertoy.com/view/Md2SR3 , optimised
+
+
+
+// Return random noise in the range [0.0, 1.0], as a function of x.
+float hash12(vec2 p)
+{
+	vec3 p3  = fract(vec3(p.xyx) * 0.1031);
+    p3 += dot(p3, p3.yzx + 19.19);
+    return fract((p3.x + p3.y) * p3.z);
+}
+// Convert Noise2d() into a "star field" by stomping everthing below fThreshhold to zero.
+float NoisyStarField( in vec2 vSamplePos, float fThreshhold )
+{
+    float StarVal = hash12( vSamplePos );
+        StarVal = clamp(StarVal/(1.0 - fThreshhold) - fThreshhold/(1.0 - fThreshhold),0.0,1.0);
+
+    return StarVal;
+}
+
+// Stabilize NoisyStarField() by only sampling at integer values.
+float StableStarField( in vec2 vSamplePos, float fThreshhold )
+{
+    // Linear interpolation between four samples.
+    // Note: This approach has some visual artifacts.
+    // There must be a better way to "anti alias" the star field.
+    float fractX = fract( vSamplePos.x );
+    float fractY = fract( vSamplePos.y );
+    vec2 floorSample = floor( vSamplePos );
+    float v1 = NoisyStarField( floorSample, fThreshhold );
+    float v2 = NoisyStarField( floorSample + vec2( 0.0, 1.0 ), fThreshhold );
+    float v3 = NoisyStarField( floorSample + vec2( 1.0, 0.0 ), fThreshhold );
+    float v4 = NoisyStarField( floorSample + vec2( 1.0, 1.0 ), fThreshhold );
+
+    float StarVal =   v1 * ( 1.0 - fractX ) * ( 1.0 - fractY )
+        			+ v2 * ( 1.0 - fractX ) * fractY
+        			+ v3 * fractX * ( 1.0 - fractY )
+        			+ v4 * fractX * fractY;
+	return StarVal;
+}
+
+float stars(vec3 fragpos){
+
+	float elevation = clamp(fragpos.y,0.,1.);
+	vec2 uv = fragpos.xz/(1.+elevation);
+
+	return StableStarField(uv*700.,0.999)/4.*(0.3-0.3*rainStrength);
+}