initial commit

geo2d.nim

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+import mmath/smatrix
+import mmath/svector
+from nwo/utils import `...`
+from math import sin, cos
+
+type
+    X2d* = SquareSMatrix[3, float32]
+    P2d* = SVector[3, float32]
+    Rect2d* = object
+        tl*, br* : P2d
+
+proc newP2d*(x, y : float32) : P2d =
+    P2d(buildSVector[3, float32](x,y,1f32))
+
+proc x*(p : P2d) : float32 = p[0]
+proc y*(p : P2d) : float32 = p[1]
+
+proc newRect2d*(x, y, width, height : float32) : Rect2d = Rect2d(tl: newP2d(x,y), br: newP2d(x + width, y + height))
+proc top*(rect : Rect2d) : float32 = rect.tl.y
+proc bottom*(rect : Rect2d) : float32 = rect.br.y
+proc left*(rect : Rect2d) : float32 = rect.tl.x
+proc right*(rect : Rect2d) : float32 = rect.br.x
+proc width*(rect : Rect2d) : float32 = rect.br.x - rect.tl.x
+proc height*(rect : Rect2d) : float32 = rect.br.y - rect.tl.y
+proc `*`*(rect : Rect2d, xform : X2d) : Rect2d = Rect2d(tl: rect.tl * xform, br: rect.br * xform) 
+
+proc rot*(alpha: float32) : X2d = 
+    result = identity[3,float32]()
+    let ca = cos(alpha)
+    let sa = sin(alpha)
+    result[0,0] = ca
+    result[1,1] = ca
+    result[0,1] = sa
+    result[1,0] = -sa
+
+proc scale*(x, y: float32) : X2d = 
+    result = identity[3,float32]()
+    result[0,0] = x
+    result[1,1] = y  
+
+proc xlate*(x, y: float32) : X2d =
+    result = identity[3,float32]()
+    result[2,0] = x
+    result[2,1] = y
+
+proc scale*(center : P2d, x, y : float32) : X2d = xlate(-center.x, -center.y) * scale(x,y) * xlate(center.x, center.y)
+proc rot*(center : P2d, angle : float32) : X2d = xlate(-center.x, -center.y) * rot(angle) * xlate(center.x, center.y)
+
+    
+