minecraft-renderObj.py

#www.stuffaboutcode.com
#Raspberry Pi, Minecraft - Create 3D Model from Obj file

#import the minecraft.py module from the minecraft directory
import minecraft.minecraft as minecraft
#import minecraft block module
import minecraft.block as block
#import time, so delays can be used
import time
#import datetime, to get the time!
import datetime

# return maximum of 2 values
def MAX(a,b):
    if a > b: return a
    else: return b

# return step
def ZSGN(a):
    if a < 0: return -1
    elif a > 0: return 1
    elif a == 0: return 0

# draw point
def point3d(mc, x, y, z, blockType):
    mc.setBlock(x,y,z,blockType)

# draw a line in 3d space
def line3d(mc, x1, y1, z1, x2, y2, z2, blockType):

    # if the 2 points are the same, draw a single block
    if (x1 == x2 and y1 == y2 and z1 == z2):
        mc.setBlock(x1, y1, z1, blockType)
    # else draw a line in 3d space
    else:
    
        dx = x2 - x1
        dy = y2 - y1
        dz = z2 - z1

        ax = abs(dx) << 1
        ay = abs(dy) << 1
        az = abs(dz) << 1

        sx = ZSGN(dx)
        sy = ZSGN(dy)
        sz = ZSGN(dz)

        x = x1
        y = y1
        z = z1

        # x dominant
        if (ax >= MAX(ay, az)):
            yd = ay - (ax >> 1)
            zd = az - (ax >> 1)
            loop = True
            while(loop):
                point3d(mc, x, y, z, blockType)
                if (x == x2):
                    loop = False
                if (yd >= 0):
                    y += sy
                    yd -= ax
                if (zd >= 0):
                    z += sz
                    zd -= ax
                x += sx
                yd += ay
                zd += az
        # y dominant
        elif (ay >= MAX(ax, az)):
            xd = ax - (ay >> 1)
            zd = az - (ay >> 1)
            loop = True
            while(loop):
                point3d(mc, x, y, z, blockType)
                if (y == y2):
                    loop=False
                if (xd >= 0):
                    x += sx
                    xd -= ay
                if (zd >= 0):
                    z += sz
                    zd -= ay
                y += sy
                xd += ax
                zd += az
        # z dominant
        elif(az >= MAX(ax, ay)):
            xd = ax - (az >> 1)
            yd = ay - (az >> 1)
            loop = True
            while(loop):
                point3d(mc, x, y, z, blockType)
                if (z == z2):
                    loop=False
                if (xd >= 0):
                    x += sx
                    xd -= az
                if (yd >= 0):
                    y += sy
                    yd -= az
                z += sz
                xd += ax
                yd += ay

# load obj into lists
def load_obj(filename) :
    V = [] #vertex
    T = [] #texcoords
    N = [] #normals
    F = [] #face indexies

    fh = open(filename)
    for line in fh :
        if line[0] == '#' : continue
        line = line.strip().split(' ')
        if line[0] == 'v' : #vertex
            V.append(line[1:])
        elif line[0] == 'vt' : #tex-coord
            T.append(line[1:])
        elif line[0] == 'vn' : #normal vector
            N.append(line[1:])
        elif line[0] == 'f' : #face
            face = line[1:]
            for i in range(0, len(face)) :
                face[i] = face[i].split('/')
                # OBJ indexies are 1 based not 0 based hence the -1
                # convert indexies to integer
                for j in range(0, len(face[i])) :
                    if face[i][j] != "":
                        face[i][j] = int(face[i][j]) - 1
                        
            F.append(face)

    return V, T, N, F

# strips the x,y,z co-ords from a vertex line, scales appropriately, rounds and converts to int
def getVertexXYZ(vertexLine, scale, startCoord, swapYZ):
    # convert, round and scale
    x = int((float(vertexLine[0]) * scale) + 0.5)
    y = int((float(vertexLine[1]) * scale) + 0.5)
    z = int((float(vertexLine[2]) * scale) + 0.5)
    # add startCoord to x,y,z
    x = x + startCoord.x
    y = y + startCoord.y
    z = z + startCoord.z
    # swap y and z coord if needed
    if swapYZ == True:
        swap = y
        y = z
        z = swap
    return x, y, z

# main program
if __name__ == "__main__":

    print datetime.datetime.now()

    #Connect to minecraft by creating the minecraft object
    # - minecraft needs to be running and in a game
    mc = minecraft.Minecraft.create()

    mc.player.setPos(-131,25,98)
    
    #Post a message to the minecraft chat window 
    mc.postToChat("Hi, Minecraft 3d model maker, www.stuffaboutcode.com")
    
    #Load objfile and set constants

    # COORDSSCALE = factor to scale the co-ords by
    # STARTCOORD = where to start the model, the relative position 0
    # CLEARAREA1/2 = 2 points the program should clear an area in between to put the model in
    # SWAPYZ = True to sway the Y and Z dimension
    # BLOCKTYPE = type of block to build the model in

    # Cube
    #COORDSSCALE = 10
    #STARTCOORD = minecraft.Vec3(0,10,0)
    #BLOCKTYPE = block.STONE
    #SWAPYZ = False
    #vertices,textures,normals,faces = load_obj("cube.obj")

    # Shuttle
    #COORDSSCALE = 4
    #STARTCOORD = minecraft.Vec3(-60,0,20)
    #CLEARAREA1 = minecraft.Vec3(-30, 5, -30)
    #CLEARAREA2 = minecraft.Vec3(-90, 30, 30)
    #BLOCKTYPE = block.WOOL
    #SWAPYZ = True
    #vertices,textures,normals,faces = load_obj("shuttle.obj")

    # Shyscraper
    #COORDSSCALE = 1.4
    #STARTCOORD = minecraft.Vec3(0,10,15)
    #CLEARAREA1 = minecraft.Vec3(-30, -3, -15)
    #CLEARAREA2 = minecraft.Vec3(30, 65, 35)
    #BLOCKTYPE = block.IRON_BLOCK
    #SWAPYZ = False
    #vertices,textures,normals,faces = load_obj("skyscraper.obj")

    # Head
    #COORDSSCALE = 3
    #STARTCOORD = minecraft.Vec3(0,-431,-60)
    #CLEARAREA1 = minecraft.Vec3(-30, -30, -30)
    #CLEARAREA2 = minecraft.Vec3(30, 65, -110)
    #BLOCKTYPE = block.GOLD_BLOCK
    #SWAPYZ = False
    #vertices,textures,normals,faces = load_obj("head.obj")

    # Cessna
    #COORDSSCALE = 2
    #STARTCOORD = minecraft.Vec3(-75, 25, -60)
    #CLEARAREA1 = minecraft.Vec3(-30, 15, -30)
    #CLEARAREA2 = minecraft.Vec3(-100, 65, -90)
    #BLOCKTYPE = block.WOOD_PLANKS
    #SWAPYZ = False
    #vertices,textures,normals,faces = load_obj("cessna.obj")

    # New York
    COORDSSCALE = 0.1
    STARTCOORD = minecraft.Vec3(-185, 0, 135)
    CLEARAREA1 = minecraft.Vec3(-130, 0, -130)
    CLEARAREA2 = minecraft.Vec3(130, 65, 130)
    BLOCKTYPE = block.IRON_BLOCK
    SWAPYZ = False
    vertices,textures,normals,faces = load_obj("NY_LIL.obj")

    print "obj file loaded"
    
    # clear a suitably large area
    mc.setBlocks(CLEARAREA1.x, CLEARAREA1.y, CLEARAREA1.z, CLEARAREA2.x, CLEARAREA2.y, CLEARAREA2.z, block.AIR)
    time.sleep(10)

    # loop through faces
    for face in faces:
        #persist the first vertex of the face
        firstVertex = face[0]
        #get the x,y,z co-ords of the first vertex
        firstVertexX, firstVertexY, firstVertexZ = getVertexXYZ(vertices[firstVertex[0]], COORDSSCALE, STARTCOORD, SWAPYZ)
        #last vertex is current none
        lastVertex = None

        # loop through vertex's in face and draw lines between them
        for vertex in face:
            vertexX, vertexY, vertexZ = getVertexXYZ(vertices[vertex[0]], COORDSSCALE, STARTCOORD, SWAPYZ)
            
            if lastVertex != None:
                # got 2 vertices, draw a line between them
                line3d(mc, lastVertexX, lastVertexY, lastVertexZ, vertexX, vertexY, vertexZ, BLOCKTYPE)

            #persist the last vertex found    
            lastVertex = vertex
            lastVertexX, lastVertexY, lastVertexZ = vertexX, vertexY, vertexZ        

        # draw a line between the last and first vertex's
        line3d(mc, lastVertexX, lastVertexY, lastVertexZ, firstVertexX, firstVertexY, firstVertexZ, BLOCKTYPE)

    mc.postToChat("Model complete, www.stuffaboutcode.com")

    print datetime.datetime.now()