ShaderCalculationHelper.cginc

// fit a value in a specific range to another specific range
float fitRange(float value, float inMin, float inMax, float outMin, float outMax)
{
	float lerpFactor = lerp(0, 1, (clamp(value, inMin, inMax) - inMin) / (inMax - inMin));
	return lerp(outMin, outMax, lerpFactor);
}

// get reflection vector for box projection 
float3 boxProjection(half3 worldRefl, float3 worldPos, float3 cubemapCenter, float3 boxMin, float3 boxMax)
{
	// normalize reflection vector
	half3 normalizedDir = normalize(worldRefl);

	// get magnitude of a vector from world position to the closest surface of a box
	half3 magnitudeMax = (boxMax - worldPos) / normalizedDir;
	half3 magnitudeMin = (boxMin - worldPos) / normalizedDir;

	half3 magnitude = (normalizedDir > 0) ? magnitudeMax : magnitudeMin;
	half smallestMagnitude = min(min(magnitude.x, magnitude.y), magnitude.z);

	// adjust reflection vector considering position offset of world position from cubemap center
	return (worldPos - cubemapCenter) + normalizedDir * smallestMagnitude;
}