MoonShading.compute

#pragma kernel CSMain

#include "../../Includes/FractalNoise.cginc"
#include "../../Includes/Math.cginc"
//
StructuredBuffer<float3> vertices;
RWStructuredBuffer<float4> shadingData;
uint numVertices;

StructuredBuffer<float4> points;
int numRandomPoints;

float4 noiseParams_biomeWarp[3];
float4 noiseParams_detailWarp[3];
float4 noiseParams_detail[3];

float4 params;

StructuredBuffer<float4> ejectaCraters;
int numEjectaCraters;

float calcSphereNoise(float3 pos) {
	float sphereNoise = 3.402823466e+38F;
	for (int i = 0; i < numRandomPoints; i ++) {
		float3 sphereCentre = points[i].xyz;
		float sphereRadius = points[i].w;
		float dst = length(pos - sphereCentre);
		float t = dst / sphereRadius;
		sphereNoise = min(sphereNoise, t);
	}
	return sphereNoise;
}

[numthreads(512,1,1)]
void CSMain (uint id : SV_DispatchThreadID)
{
	if (id >= numVertices) { return; }

	float3 pos = vertices[id];

	float3 domainWarp = 0;
	domainWarp.x = simpleNoise(pos, noiseParams_biomeWarp);
	domainWarp.y = simpleNoise(pos + 100, noiseParams_biomeWarp);
	domainWarp.z = simpleNoise(pos - 100, noiseParams_biomeWarp);

	float3 detailWarp = 0;
	detailWarp.x = simpleNoise(pos, noiseParams_detailWarp);
	detailWarp.y = simpleNoise(pos + 100, noiseParams_detailWarp);
	detailWarp.z = simpleNoise(pos - 100, noiseParams_detailWarp);

	float domainWarp2 = simpleNoise(pos, noiseParams_detailWarp);

	// Sphere noise
	float3 warpedPos = pos + (domainWarp) * 0.1;
	float sphereNoise = calcSphereNoise(warpedPos);

	float detailNoise = simpleNoise(pos + domainWarp2 * 0.1, noiseParams_detail);

	// Calculate uv coords for crater 'ejecta ray' texture to be projected onto the surface around select craters
	float2 ejectaUV = 1;
	float minDst = 999;
	for (int craterIndex = 0; craterIndex < numEjectaCraters; craterIndex ++) {
		float3 craterCentre = ejectaCraters[craterIndex].xyz;
		float dst = length(craterCentre - pos);
		float scaledDst = dst / ejectaCraters[craterIndex].w;

		if (scaledDst < minDst) {
			minDst = scaledDst;

			float3 craterUp = craterCentre;
			float3 craterForward = normalize(cross(craterUp, float3(0,1,0)));
			float3 forward = normalize(cross(pos, craterUp));

			float cross_x = forward.y * craterForward.z - forward.z * craterForward.y;
			float cross_y = forward.z * craterForward.x - forward.x * craterForward.z;
			float cross_z = forward.x * craterForward.y - forward.y * craterForward.x;
			float angleSign = sign(craterUp.x * cross_x + craterUp.y * cross_y + craterUp.z * cross_z);

			float angle = acos(dot(craterForward, forward)) * angleSign;
			//float estBiomeVal = Blend(7 * 0.8, 0.8, calcSphereNoise(craterCentre));
			//float biomeSign = (estBiomeVal < 0.5)?-1:1;
			ejectaUV = float2 (angle, scaledDst);
		}
	}
	
	shadingData[id] = float4(ejectaUV.xy, detailNoise, sphereNoise);
}