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import math, sys
from PIL import Image
W, H = 640, 480
FILL = (0, 0, 0)
fb = None
def fixed_color(color):
for c in color[:3]:
c = abs(int(c * (1 << 8)))
yield (c & 255) | (255 if (c & (1 << 8)) else 0)
def fixed(p):
pos, color = p
w = pos
pos = tuple(int(c / pos[3] * (1 << 13)) for c in pos[:3])
return (pos, tuple(fixed_color(color)))
def bounding(p0, p1, p2):
minx = max(min(p0[0][0], p1[0][0], p2[0][0]), (-W // 2) << 4)
maxx = min(max(p0[0][0], p1[0][0], p2[0][0]), (W // 2) << 4)
miny = max(min(p0[0][1], p1[0][1], p2[0][1]), (-H // 2) << 4)
maxy = min(max(p0[0][1], p1[0][1], p2[0][1]), (H // 2) << 4)
return (minx, miny, maxx, maxy)
def edge_fn(p, q, sx, sy):
p, q = p[0], q[0]
# https://www.scratchapixel.com/lessons/3d-basic-rendering/rasterization-practical-implementation/rasterization-stage.html
a, b = p[1] - q[1], -(p[0] - q[0])
r = (sx - q[0]) * a + (sy - q[1]) * b
return r, r, a, b
def raster(p0, p1, p2, msaa=False):
global fb
minx, miny, maxx, maxy = bounding(p0, p1, p2)
sx, sy = minx // 16 * 16, miny // 16 * 16
base_x_a, base_y_a, add_x_a, add_y_a = edge_fn(p0, p1, sx, sy)
base_x_b, base_y_b, add_x_b, add_y_b = edge_fn(p1, p2, sx, sy)
base_x_c, base_y_c, add_x_c, add_y_c = edge_fn(p2, p0, sx, sy)
int_x_a = add_x_a << 4
int_x_b = add_x_b << 4
int_x_c = add_x_c << 4
int_y_a = add_y_a << 4
int_y_b = add_y_b << 4
int_y_c = add_y_c << 4
if msaa:
samples = ((-5, 10), (11, 2), (-7, -4))
else:
samples = ((0, 0),)
samples_a = tuple(add_x_a * sx + add_y_a * sy for sx, sy in samples)
samples_b = tuple(add_x_b * sx + add_y_b * sy for sx, sy in samples)
samples_c = tuple(add_x_c * sx + add_y_c * sy for sx, sy in samples)
for x in range(minx // 16 * 16, maxx + 16, 16):
for y in range(miny // 16 * 16, maxy + 16, 16):
count = 0
for a, b, c in zip(samples_a, samples_b, samples_c):
b0 = base_y_a + a
b1 = base_y_b + b
b2 = base_y_c + c
if b0 >= 0 and b1 >= 0 and b2 >= 0:
count += 1
if count > 0:
s = b0 + b1 + b2
b0 /= s
b1 /= s
b2 /= s
yield (x >> 4, y >> 4, b0, b1, b2)
base_y_a += int_y_a
base_y_b += int_y_b
base_y_c += int_y_c
base_x_a += int_x_a
base_x_b += int_x_b
base_x_c += int_x_c
base_y_a = base_x_a
base_y_b = base_x_b
base_y_c = base_x_c
def backend():
tri = (((-5 / 320, -5 / 240, 1.0, 1.0), (0.0, 0.0, 0.0, 1.0)),
((-50/320, -5/240, 1.0, 1.0), (0.0, 1.0, 0.0, 0.0)),
((-20/320, -70/240, 1.0, 1.0), (0.0, 0.0, 1.0, 0.0)))
t = tri
tri = tuple(fixed(p) for p in tri)
for x, y, b0, b1, b2 in raster(*tri):
if -W // 2 <= x < W // 2 and -H // 2 <= y < H // 2:
r = b0 * t[0][1][1] + b1 * t[1][1][1] + b2 * t[2][1][1]
g = b0 * t[0][1][2] + b1 * t[1][1][2] + b2 * t[2][1][2]
b = b0 * t[0][1][3] + b1 * t[1][1][3] + b2 * t[2][1][3]
x += W // 2
y = H // 2 - y - 1
fb[y * W + x] = (int(r * 255), int(g * 255), int(b * 255))
imgs = []
def do_frame():
global fb, imgs
fb = [FILL] * W * H
backend()
image = Image.new('RGB', (W, H))
image.putdata(fb)
imgs.append(image)
for n in range(1):
do_frame()
imgs[0].save('out.gif',
save_all=True,
append_images=imgs[1:],
duration=100,
loop=0)
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