Unexpected behavior of RotationStyle

[nighca]

In Scratch, for a sprite with rotationStyle: left-right:

• heading: [0, 180] is considered facing right
• heading: (-180, 0) is considered facing left

While in spx, the logic is strange:

spx/spgdi.go

Lines 72 to 79 in 72b5b4f

	} else if p.sprite.rotationStyle == LeftRight {
	if math.Abs(p.sprite.direction) > 155 && math.Abs(p.sprite.direction) < 205 {
	geo.Scale(-1, 1)
	}
	if math.Abs(p.sprite.direction) > 0 && math.Abs(p.sprite.direction) < 25 {
	geo.Scale(-1, 1)
	}
	}

I don't understand. But it causes some result that is IMO not expected, for example:

setRotationStyle LeftRight

setHeading float64(Left)  // spx will render the sprite facing right
setHeading float64(Down)  // spx will render the sprite facing left
setHeading float64(Right) // spx will render the sprite facing right
setHeading float64(Up)    // spx will render the sprite facing right

I think it is reasonable to adopt the same logic as Scratch.

As discussed, we should adopt the same logic as Scratch.

[nighca]

fixed by #303