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# dcousens/heightmap.py

Last active Jun 9, 2017
Prototype of the midpoint displacement algorithm, also known as the diamond square algorithm.heightmap.py creates a triangular mesh represented as a list vertices and indices from a 2d normalized array of values and some parameters. Commonly used as a heightmap.
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 import itertools def get_verts_indices_for_heightmap(heightmap, stepx, stepy, minz, maxz): """ heightmap assumed to be normalized (values between 0 and 1) """ height = len(heightmap) width = len(heightmap[0]) spanz = maxz - minz # n_heightmap = width * height # n_tris = n_heightmap * 2 # n_indices = n_tris * 3 indices = [] verts = [] # the indices # embarassingly parallel for i, j in itertools.product(range(width - 1), range(height - 1)) idx = (i * width) + j # 4 points of a grid cell a = idx b = idx + 1 c = idx + width d = idx + width + 1 t1 = (a, c, b) t2 = (b, c, d) indices.extend(t1) indices.extend(t2) # the vertices # embarassingly parallel for i, j in itertools.product(range(width), range(height)) x = j * stepx y = i * stepy z = minz + (normalized_map[i][j] * spanz) vert = (x, y, z)) verts.append(vert) return verts, indices
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 import random def mdp(base, r): # Calculate new dimensions n = len(base) * 2 - 1 assert(n > 2) # Allocate copy = [[0 for _ in range(n)] for _ in range(n)] # Resize # 1 0 1 # 0 0 0 # 1 0 1 for i in range(0, n, 2): for j in range(0, n, 2): copy[i][j] = base[i // 2][j // 2] # Diamond algorithm # 0 0 0 # 0 1 0 # 0 0 0 for i in range(1, n, 2): for j in range(1, n, 2): # get surrounding values a = copy[i - 1][j - 1] b = copy[i - 1][j + 1] c = copy[i + 1][j - 1] d = copy[i + 1][j + 1] # average value = (a + b + c + d) // 4 # random value += random.randint(-r, r) # clamp value = max(value, 0) value = min(value, 255) # store copy[i][j] = value # Square algorithm # 0 1 0 # 1 0 1 # 0 1 0 for i in range(n): for j in range(i % 2 == 0, n, 2): a = 0 b = 0 c = 0 d = 0 # get surrounding values and account for edge cases if (i > 0): a = copy[i - 1][j] if (j > 0): b = copy[i][j - 1] if (i + 1 < n): c = copy[i + 1][j] if (j + 1 < n): d = copy[i][j + 1] # average value = a + b + c + d if (i == 0) or (j == 0) or (i + 1 == n) or (j + 1 == n): value //= 3 else: value //= 4 # random value += random.randint(-r, r) # clamp value = max(value, 0) value = min(value, 255) # store copy[i][j] = value return copy def create_noise(n): return [[random.randint(0, 255) for _ in range(n)] for _ in range(n)] def smoothen(base): n = len(base) for i in range(1, n - 1): for j in range(1, n - 1): base[i][j] = ( base[i - 1][j - 1] + base[i - 1][j] + base[i - 1][j + 1] + base[i + 0][j - 1] + base[i + 0][j] + base[i + 0][j + 1] + base[i + 1][j + 1] + base[i + 1][j] + base[i + 1][j - 1] ) // 9 def toPPM(pixels): height = len(pixels) width = len(pixels[0]) buf = [] buf.append("P3") buf.append("%i %i\n%i" % (width, height, 255)) for row in pixels: for pixel in row: r = (pixel >> 16) & 0xFF g = (pixel >> 8) & 0xFF b = pixel & 0xFF buf.append("%i %i %i" % (r, g, b)) return "\n".join(buf) def fromPPM(text): lines = text.splitlines() width, height, _ = (int(x) for x in lines[1].split()) pixels = [[0 for _ in range(width)] for _ in range(height)] lines = reverse(lines) for row in pixels: for i, pixel in enumerate(row) r, g, b = (int(x) for x in lines.pop().split()) row[i] = (r << 16) & (g << 8) & b return pixels import json def save(noise, name): js = json.dumps(noise) with open(name + ".json", "w") as fh: fh.write(js) ppm = toPPM(noise) with open(name + ".ppm", "w") as fh: fh.write(ppm) if (__name__ == "__main__"): noi = create_noise(32) save(noi, "0") for i in range(1, 6): onoi = noi noi = mdp(noi, 64 // i) save(noi, str(i))
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 import random def createColoredGrid(width, height, padding, nboxes, padding_color, colors): box_len = width // nboxes columns = (width // box_len) + 1 row_colors = [colors[x % len(colors)] for x in range(columns)] pixels = [] for y in range(height): if (y % box_len == 0): random.shuffle(row_colors) row = [padding_color] * width y_offset = y % box_len if (y_offset >= padding and y_offset <= box_len): for x in range(len(row)): x_offset = x % box_len if (x_offset < padding or x_offset > box_len): continue row[x] = row_colors[x // box_len] pixels.append(row) return pixels def toPPM(pixels): height = len(pixels) width = len(pixels[0]) buf = [] buf.append("P3") buf.append("%i %i\n%i" % (width, height, 255)) for row in pixels: for pixel in row: r = (pixel >> 16) & 0xFF g = (pixel >> 8) & 0xFF b = pixel & 0xFF buf.append("%i %i %i" % (r, g, b)) return "\n".join(buf) if (__name__ == "__main__"): colors = [0xffa70f, 0xff4948, 0x700090, 0x878787, 0x8f3900] filler = 0x000000 pixels = createColoredGrid(1600, 1000, 5, 50, filler, colors) ppm = toPPM(pixels) with open("output.ppm", "w") as fh: fh.write(ppm)