HI all,
following this tutorial and code here:
, i am attempting to make my own meta ball shader. However im trying to put a twist on this standard meta ball shader, which is the metaballs are only made up of 2 colors, either blue or red. the two meta balls need to blend colors with each other. So when a blue meta ball is next to a red meta ball, the middle part where they join should be a blended color between red and blue. Any ideas on how one can proceed?
The basic metaball shader looks like this:
Shader "Unlit/HeatmapShader"
{
Properties
{
_MainTex("Texture", 2D) = "white" {}
_Color0("Color 0",Color) = (0,0,0,1)
_Color1("Color 1",Color) = (0,.9,.2,1)
_Color2("Color 2",Color) = (.9,1,.3,1)
_Color3("Color 3",Color) = (.9,.7,.1,1)
_Color4("Color 4",Color) = (1,0,0,1)
_Range0("Range 0",Range(0,1)) = 0.
_Range1("Range 1",Range(0,1)) = 0.25
_Range2("Range 2",Range(0,1)) = 0.5
_Range3("Range 3",Range(0,1)) = 0.75
_Range4("Range 4",Range(0,1)) = 1
_Diameter("Diameter",Range(0,1)) = 1.0
_Strength("Strength",Range(.1,4)) = 1.0
_PulseSpeed("Pulse Speed",Range(0,5)) = 0
}
SubShader
{
Tags { "RenderType" = "Opaque" }
LOD 100
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
float4 _MainTex_ST;
float4 _Color0;
float4 _Color1;
float4 _Color2;
float4 _Color3;
float4 _Color4;
float _Range0;
float _Range1;
float _Range2;
float _Range3;
float _Range4;
float _Diameter;
float _Strength;
float _PulseSpeed;
v2f vert(appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
UNITY_TRANSFER_FOG(o,o.vertex);
return o;
}
//----
float3 colors[5]; //colors for point ranges
float pointranges[5]; //ranges of values used to determine color values
float _Hits[3 * 32]; //passed in array of pointranges 3floats/point, x,y,intensity
int _HitCount = 0;
void initalize()
{
colors[0] = _Color0;
colors[1] = _Color1;
colors[2] = _Color2;
colors[3] = _Color3;
colors[4] = _Color4;
pointranges[0] = _Range0;
pointranges[1] = _Range1;
pointranges[2] = _Range2;
pointranges[3] = _Range3;
pointranges[4] = _Range4;
}
float3 getHeatForPixel(float weight)
{
if (weight <= pointranges[0])
{
return colors[0];
}
if (weight >= pointranges[4])
{
return colors[4];
}
for (int i = 1; i < 5; i++)
{
if (weight < pointranges[i]) //if weight is between this point and the point before its range
{
float dist_from_lower_point = weight - pointranges[i - 1];
float size_of_point_range = pointranges[i] - pointranges[i - 1];
float ratio_over_lower_point = dist_from_lower_point / size_of_point_range;
//now with ratio or percentage (0-1) into the point range, multiply color ranges to get color
float3 color_range = colors[i] - colors[i - 1];
float3 color_contribution = color_range * ratio_over_lower_point;
float3 new_color = colors[i - 1] + color_contribution;
return new_color;
}
}
return colors[0];
}
//Note: if distance is > 1.0, zero contribution, 1.0 is 1/2 of the 2x2 uv size
float distsq(float2 a, float2 b)
{
float area_of_effect_size = _Diameter;
return pow(max(0.0, 1.0 - distance(a, b) / area_of_effect_size), 2.0);
}
fixed4 frag(v2f i) : SV_Target
{
fixed4 col = tex2D(_MainTex, i.uv);
initalize();
float2 uv = i.uv;
uv = uv * 4.0 - float2(2.0,2.0); //our texture uv range is -2 to 2
float totalWeight = 0.0;
for (float i = 0.0; i < _HitCount; i++)
{
float2 work_pt = float2(_Hits[i * 3], _Hits[i * 3 + 1]);
float pt_intensity = _Hits[i * 3 + 2];
totalWeight += 0.5 * distsq(uv, work_pt) * pt_intensity * _Strength * (1 + sin(_Time.y * _PulseSpeed));
}
return col + float4(getHeatForPixel(totalWeight), .5);
}
ENDCG
}
}
}