ModdingSupport/Red Alert 3/Shaders/Random.fxh

//////////////////////////////////////////////////////////////////////////////
// ©2006 Electronic Arts Inc
//
// A simple random number generator
//////////////////////////////////////////////////////////////////////////////

#ifndef _RANDOM_FXH_
#define _RANDOM_FXH_

//
// Random number generator
//

#define MAX_RANDOM_VALUES 16

// $note (WSK) - PS3 is having trouble dealing with the longer decimals so trimming it to 8 decimal points
#if defined(EA_PLATFORM_PS3)

STATICARRAY const float4 RandomValues[MAX_RANDOM_VALUES] = // random values in range 0..1
{
	// To generate this table, use excel with rows of this formula: =CONCATENATE("float4(",RAND(),", ",RAND(),", ", RAND(),", ", RAND(), "),")
	float4(0.95789700, 0.37887052, 0.36357189, 0.32876090),
	float4(0.17623724, 0.91457511, 0.43609350, 0.34762842),
	float4(0.74321894, 0.44256111, 0.99745457, 0.36221379),
	float4(0.48966265, 0.66642329, 0.83056984, 0.97425771),
	float4(0.89476745, 0.82362151, 0.93097054, 0.05219847),
	float4(0.14110073, 0.65270023, 0.00845252, 0.64305738),
	float4(0.22979899, 0.89799901, 0.75382196, 0.13165037),
	float4(0.58153839, 0.28369165, 0.09156471, 0.40748094),
	float4(0.27060439, 0.72281806, 0.16943672, 0.14690524),
	float4(0.59955557, 0.09645330, 0.87639832, 0.11722288),
	float4(0.51017107, 0.94215719, 0.19578879, 0.91675649),
	float4(0.03546792, 0.53400940, 0.16732177, 0.55767641),
	float4(0.86156402, 0.22516010, 0.08233199, 0.87900387),
	float4(0.17308658, 0.89351880, 0.01392405, 0.17873812),
	float4(0.82693834, 0.77181436, 0.43953593, 0.49396301),
	float4(0.54236134, 0.72186167, 0.76973142, 0.58785667),
};	

#else // #if defined(EA_PLATFORM_PS3)

STATICARRAY const float4 RandomValues[MAX_RANDOM_VALUES] = // random values in range 0..1
{
	// To generate this table, use excel with rows of this formula: =CONCATENATE("float4(",RAND(),", ",RAND(),", ", RAND(),", ", RAND(), "),")
	float4(0.957897000503582, 0.378870525347763, 0.363571890095615, 0.328760908964182),
	float4(0.176237249178937, 0.914575110140635, 0.436093504459558, 0.347628420779846),
	float4(0.74321894178331, 0.442561117711613, 0.997454573448046, 0.362213792964882),
	float4(0.489662653412263, 0.666423292057291, 0.830569846431306, 0.974257713027646),
	float4(0.894767456143942, 0.823621517393205, 0.930970549797899, 0.0521984733736147),
	float4(0.141100733280401, 0.652700235943417, 0.00845252291957532, 0.643057387894008),
	float4(0.22979899343149, 0.897999019438672, 0.753821963794792, 0.131650373484698),
	float4(0.581538391481718, 0.283691652574809, 0.0915647105845903, 0.407480940983646),
	float4(0.270604393931209, 0.72281806272639, 0.16943672558123, 0.146905246115598),
	float4(0.599555574957733, 0.096453300376983, 0.876398320463974, 0.117222883790552),
	float4(0.510171077745377, 0.942157193101133, 0.195788791440078, 0.916756497322788),
	float4(0.0354679287382584, 0.534009408848821, 0.167321778635773, 0.557676417292525),
	float4(0.861564026888471, 0.225160105115149, 0.0823319997715926, 0.87900387469963),
	float4(0.173086589845635, 0.89351880243715, 0.0139240580314164, 0.178738120005564),
	float4(0.826938346482238, 0.771814362160947, 0.439535939575699, 0.49396301649165),
	float4(0.542361347073796, 0.721861671956157, 0.769731420798597, 0.587856677976187),
};	

#endif // #if defined(EA_PLATFORM_PS3)

// Get a random value in a specific range. Range has minimum in x and spread (= max - min) in y
float GetRandomFloatValue(float2 range, float index, float seed)
{
	float fraction = frac(seed * 11.0f/MAX_RANDOM_VALUES + index * 3.0f / MAX_RANDOM_VALUES); 
	return (range.x + RandomValues[fraction * MAX_RANDOM_VALUES].x * range.y);
}

float2 GetRandomFloatValues(float2 minimum, float2 range, float index, float seed)
{
	float fraction = frac(seed * 11.0f/MAX_RANDOM_VALUES + index * 3.0f / MAX_RANDOM_VALUES);
	return minimum + RandomValues[fraction * MAX_RANDOM_VALUES].xy * range;
}

float3 GetRandomFloatValues(float3 minimum, float3 range, float index, float seed)
{
	float fraction = frac(seed * 11.0f/MAX_RANDOM_VALUES + index * 3.0f / MAX_RANDOM_VALUES);
	return minimum + RandomValues[fraction * MAX_RANDOM_VALUES].xyz * range;
}

float4 GetRandomFloatValues(float4 minimum, float4 range, float index, float seed)
{
	float fraction = frac(seed * 11.0f/MAX_RANDOM_VALUES + index * 3.0f / MAX_RANDOM_VALUES);
	return minimum + RandomValues[fraction * MAX_RANDOM_VALUES] * range;
}

#endif // _RANDOM_FXH_