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195 lines
4.9 KiB
195 lines
4.9 KiB
2 years ago
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//Star Nest algorithm by Pablo Román Andrioli
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//Unity 5.x shader by Jonathan Cohen
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//This content is under the MIT License.
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//
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//Original Shader:
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//https://www.shadertoy.com/view/XlfGRj
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//
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//This shader uses the same algorithm in 3d space to render a skybox.
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Shader "FX/Galaxy" {
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Properties {
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_MainTex ("Texture Sampler (UV Only)", 2D) = "grey" {}
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//2D: Zoom level
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_Zoom ("Zoom", Float) = 800
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_Color ("Main Color", Color) = (1,1,1,1)
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[Toggle(CLAMPOUT)] _CLAMPOUT("Clamp Output with Main Color", Float) = 0
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//Scrolls in this direction over time. Set 'w' to zero to stop scrolling.
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_Scroll ("Scrolling direction (x,y,z) * w * time", Vector) = (3, 1, .6, .01)
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//Center position in space and time.
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_Center ("Center Position (x, y, z, time)", Vector) = (1, .3, .5, 0)
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//Rotation angles
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_Rotation ("Rotation (x,y,z)*w angles", Vector) = (35, 25, 75, .1)
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//Iterations of inner loop.
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//The higher this is, the more distant objects get rendered.
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_Iterations ("Iterations", Range(1, 30)) = 17
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//Volumetric rendering steps. Each 'step' renders more objects at all distances.
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//This has a higher performance hit than iterations.
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_Volsteps ("Volumetric Steps", Range(1,40)) = 20
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//Magic number. Best values are around 400-600.
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_Formuparam ("Formuparam", Float) = 530
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//How much farther each volumestep goes
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_StepSize ("Step Size", Float) = 130
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//Fractal repeating rate
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//Low numbers are busy and give lots of repititio
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//High numbers are very sparce
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_Tile ("Tile", Float) = 700
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//Brightness scale.
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_Brightness ("Brightness", Float) = 2
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//Abundance of Dark matter (in the distance).
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//Visible with Volsteps >= 8 (at 7 its really, really hard to see)
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_Darkmatter ("Dark Matter", Float) = 25
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//Brightness of distant objects (or dim) are distant objects
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//Ironically, Also affets brightness of 'darkmatter'
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_Distfading ("Distance Fading", Float) = 68
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//How much color is present?
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_Saturation ("Saturation", Float) = 85
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}
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SubShader {
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Tags { "Queue"="Geometry" "RenderType"="Opaque" }
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Cull Off
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CGPROGRAM
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#pragma surface surf Lambert
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#pragma multi_compile __ CLAMPOUT
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#include "UnityCG.cginc"
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fixed4 _Color;
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int _Volsteps;
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int _Iterations;
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sampler2D _MainTex;
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float4 _Scroll;
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float4 _Center;
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float _CamScroll;
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float4 _Rotation;
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float _Formuparam;
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float _StepSize;
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float _Zoom;
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float _Tile;
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float _Brightness;
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float _Darkmatter;
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float _Distfading;
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float _Saturation;
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struct Input {
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float2 uv_MainTex;
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};
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void surf (Input IN, inout SurfaceOutput o) {
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half3 col = half3(0, 0, 0);
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float zoom = _Zoom / 1000;
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float2 uv = IN.uv_MainTex;
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uv -= .5;
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half3 dir = float3(uv * zoom, 1);
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float time = _Center.w + _Time.x;
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//Un-scale parameters (source parameters for these are mostly in 0...1 range)
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//Scaling them up makes it much easier to fine-tune shader in the inspector.
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float brightness = _Brightness / 1000;
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float stepSize = _StepSize / 1000;
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float3 tile = abs(float3(_Tile, _Tile, _Tile)) / 1000;
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float formparam = _Formuparam / 1000;
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float darkmatter = _Darkmatter / 100;
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float distFade = _Distfading / 100;
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float3 from = _Center.xyz;
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//scroll over time
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from += _Scroll.xyz * _Scroll.w * time;
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//scroll from camera position
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//from += _WorldSpaceCameraPos * _CamScroll * .00001;
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//Apply rotation if enabled
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float3 rot = _Rotation.xyz * _Rotation.w;
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if (length(rot) > 0) {
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float2x2 rx = float2x2(cos(rot.x), sin(rot.x), -sin(rot.x), cos(rot.x));
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float2x2 ry = float2x2(cos(rot.y), sin(rot.y), -sin(rot.y), cos(rot.y));
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float2x2 rz = float2x2(cos(rot.z), sin(rot.z), -sin(rot.z), cos(rot.z));
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dir.xy = mul(rz, dir.xy);
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dir.xz = mul(ry, dir.xz);
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dir.yz = mul(rx, dir.yz);
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from.xy = mul(rz, from.xy);
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from.xz = mul(ry, from.xz);
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from.yz = mul(rx, from.yz);
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}
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//volumetric rendering
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float s = 0.1, fade = 1.0;
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float3 v = float3(0, 0, 0);
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for (int r = 0; r < _Volsteps; r++) {
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float3 p = abs(from + s * dir * .5);
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p = abs(float3(tile - fmod(p, tile*2)));
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float pa,a = pa = 0.;
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for (int i = 0; i < _Iterations; i++) {
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p = abs(p) / dot(p, p) - formparam;
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a += abs(length(p) - pa);
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pa = length(p);
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}
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//Dark matter
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float dm = max(0., darkmatter - a * a * .001);
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if (r > 6) { fade *= 1. - dm; } // Render distant darkmatter
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a *= a * a; //add contrast
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v += fade;
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// coloring based on distance
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v += float3(s, s*s, s*s*s*s) * a * brightness * fade;
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// distance fading
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fade *= distFade;
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s += stepSize;
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}
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float len = length(v);
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//Quick color saturate
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v = lerp(float3(len, len, len), v, _Saturation / 100);
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v.xyz *= _Color.xyz * .01;
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#ifdef CLAMPOUT
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v = clamp(v, float3(0,0,0), _Color.xyz);
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#endif
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o.Emission = float3(v * .01);
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}
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ENDCG
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}
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Fallback Off
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}
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