static public VFXExpression GetPerspectiveMatrix(VFXExpression fov, VFXExpression aspect, VFXExpression zNear, VFXExpression zFar)
{
var fovHalf = fov / TwoExpression[VFXValueType.Float];
var cotangent = new VFXExpressionCos(fovHalf) / new VFXExpressionSin(fovHalf);
var deltaZ = zNear - zFar;
var zero = ZeroExpression[VFXValueType.Float];
var m0 = new VFXExpressionCombine(cotangent / aspect, zero, zero, zero);
var m1 = new VFXExpressionCombine(zero, cotangent, zero, zero);
var m2 = new VFXExpressionCombine(zero, zero, MinusOneExpression[VFXValueType.Float] * (zFar + zNear) / deltaZ, OneExpression[VFXValueType.Float]);
var m3 = new VFXExpressionCombine(zero, zero, TwoExpression[VFXValueType.Float] * zNear * zFar / deltaZ, zero);
return(new VFXExpressionVector4sToMatrix(m0, m1, m2, m3));
}
static public VFXExpression SequentialCircle(VFXExpression center, VFXExpression radius, VFXExpression normal, VFXExpression up, VFXExpression index, VFXExpression count)
{
VFXExpression dt = new VFXExpressionCastUintToFloat(VFXOperatorUtility.Modulo(index, count));
dt = dt / new VFXExpressionCastUintToFloat(count);
var cos = new VFXExpressionCos(dt * VFXOperatorUtility.TauExpression[VFXValueType.Float]) as VFXExpression;
var sin = new VFXExpressionSin(dt * VFXOperatorUtility.TauExpression[VFXValueType.Float]) as VFXExpression;
var left = VFXOperatorUtility.Normalize(VFXOperatorUtility.Cross(normal, up));
radius = new VFXExpressionCombine(radius, radius, radius);
sin = new VFXExpressionCombine(sin, sin, sin);
cos = new VFXExpressionCombine(cos, cos, cos);
return(center + (cos * up + sin * left) * radius);
}
static public VFXExpression SphericalToRectangular(VFXExpression theta, VFXExpression phi, VFXExpression distance)
{
//x = cos(theta) * cos(phi) * distance
//y = sin(theta) * cos(phi) * distance
//z = sin(phi) * distance
var cosTheta = new VFXExpressionCos(theta);
var cosPhi = new VFXExpressionCos(phi);
var sinTheta = new VFXExpressionSin(theta);
var sinPhi = new VFXExpressionSin(phi);
var x = (cosTheta * cosPhi);
var y = sinPhi;
var z = (sinTheta * cosPhi);
var result = new VFXExpressionCombine(new VFXExpression[] { x, y, z });
return(result * CastFloat(distance, VFXValueType.Float3));
}
static public VFXExpression SequentialCircle(VFXExpression center, VFXExpression radius, VFXExpression normal, VFXExpression up, VFXExpression index, VFXExpression count, SequentialAddressingMode mode)
{
VFXExpression countForAddressing = count;
if (mode == SequentialAddressingMode.Clamp || mode == SequentialAddressingMode.Mirror)
{
//Explicitly close the circle loop, if `index` equals to `count`, adds an extra step.
countForAddressing = count + OneExpression[VFXValueType.Uint32];
}
VFXExpression dt = ApplyAddressingMode(index, countForAddressing, mode);
dt = new VFXExpressionCastUintToFloat(dt);
dt = dt / new VFXExpressionCastUintToFloat(count);
var cos = new VFXExpressionCos(dt * VFXOperatorUtility.TauExpression[VFXValueType.Float]) as VFXExpression;
var sin = new VFXExpressionSin(dt * VFXOperatorUtility.TauExpression[VFXValueType.Float]) as VFXExpression;
var left = VFXOperatorUtility.Normalize(VFXOperatorUtility.Cross(normal, up));
radius = new VFXExpressionCombine(radius, radius, radius);
sin = new VFXExpressionCombine(sin, sin, sin);
cos = new VFXExpressionCombine(cos, cos, cos);
return(center + (cos * up + sin * left) * radius);
}