dessin 3D par échantillonnage, premier jet : une paquerette

src/paquerette.py

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+#encoding: utf-8
+
+import math
+import numpy
+
+import Image
+import ImageDraw
+import ImageColor
+
+width = 1000
+perspective = width
+cameraZ = -width
+
+im = Image.new("RGB", (width,width) )
+
+draw = ImageDraw.Draw(im)
+
+zBuffer = {}
+
+
+def sphere(a, b, radius):
+    angle = a * math.pi * 2
+    x0 = radius*2
+    y0 = radius*2
+
+    return {"x":math.cos(angle) * radius * b + x0,
+            "y":math.sin(angle) * radius * b + y0 ,
+            "z": b * radius - radius / 2, 
+            "r": 50 + math.floor((1 - b**2) * 300),
+            "g": 50 + math.floor((1 - b**2) * 200),
+            "b": 0,
+            }
+
+
+def petal(a,b,radius):
+    x = a * radius*2
+    y = b * radius*2
+    x0 = radius
+    y0 = radius
+
+    if ((x - x0) * (x - x0) + (y - y0) * (y - y0) < radius * radius):
+        return {"x": x,
+                "y": y * (1 + b) / 2,
+                "z": b * radius - radius / 2, 
+                "r": 100 + math.floor((1 - b) * 155),
+                "g": 100 + math.floor((1 - b) * 155),
+                "b": 100 + math.floor((1 - b) * 155)
+                }
+    else:
+        return None
+
+
+def cylinder( a,b, radius=100, length=400 ):
+    angle = a * 2*math.pi
+
+    return {"x": math.cos(angle) * radius,
+            "y": math.sin(angle) * radius,
+            # centrage du cylindre
+            "z": b * length - length / 2, 
+            "r": 0,
+            "g": math.floor(b*255),
+            "b": 0 }
+
+
+def if_none( func ):
+    def wrapper( *args, **kwargs ):
+        if args[0]:
+            return func( *args, **kwargs )
+        else:
+            return None
+    return wrapper
+
+
+@if_none
+def rotate_x( d, a ):
+    d["y"] = d["y"] * math.cos(a) - d["z"] * math.sin(a)
+    d["z"] = d["y"] * math.sin(a) + d["z"] * math.cos(a)
+    return d
+
+
+@if_none
+def rotate_y( d, a ):
+    d["z"] = d["z"] * math.cos(a) - d["x"] * math.sin(a)
+    d["x"] = d["z"] * math.sin(a) + d["x"] * math.cos(a)
+    return d
+
+
+@if_none
+def rotate_z( d, a ):
+    d["x"] = d["x"] * math.cos(a) - d["y"] * math.sin(a)
+    d["y"] = d["x"] * math.sin(a) + d["y"] * math.cos(a)
+    return d
+
+
+@if_none
+def move( d, dx, dy, dz ):
+    d["x"] = d["x"] + dx
+    d["y"] = d["y"] + dy
+    d["z"] = d["z"] + dz
+    return d
+
+
+def draw_point( point ):
+    if point:
+        pX = math.floor( (point["x"] * perspective) / (point["z"] - cameraZ) + width/2 )
+        pY = math.floor( (point["y"] * perspective) / (point["z"] - cameraZ) + width/2 )
+        zbi = pY * width + pX
+        if not zBuffer.has_key(zbi) or point["z"] < zBuffer[zbi]:
+            zBuffer[zbi] = point["z"]
+            fill = ( int(point["r"]), int(point["g"]), int(point["b"]) )
+            #fill = ( 10+int(zBuffer[zbi]), ) * 3
+            draw.point( (int(pX),int(pY)), fill )
+
+
+
+import random
+# Nombres de points à dessiner
+for i in range(90000):
+    a = random.random()
+    b = random.random()
+    #     z
+    #    /
+    #   +-- x
+    #   |
+    #   y
+    r_heart = 25
+    r_petal = 50
+    # coeur
+    draw_point( sphere( a, b, r_heart ) )
+    # pétale du haut
+    draw_point( move( petal( a,b, r_petal ), 0, -70, 0 ) )
+    # pétale du bas
+    draw_point( move( rotate_x( petal( a,b, r_petal ), 1.15*math.pi ), -2, 141, -10 ) )
+    # pétale de gauche
+    draw_point( move( rotate_z( rotate_x( petal( a,b, r_petal ), -0.3*math.pi ), math.pi/6 ), -50, 10, 25 ) )
+    # pétale de droite
+    draw_point( move( rotate_z( rotate_x( petal( a,b, r_petal ), -0.3*math.pi ), -math.pi/6 ), 60, 55, 25 ) )
+    # tige
+    draw_point( move( rotate_x( cylinder( a,b, r_heart/4, 400 ), math.pi/2 ), 55, 250, 250 ) )
+
+im.save("paquerette.png", "PNG")
+