martinchristen/pyRT

# Example 6: **Matrix, Camera, Triangle**
#
# In this example you learn how 3D transformation works
# In addition to example 5, an animated gif is created using Pillow
# This example requires Pillow, moviepy and its dependencies (esp. numpy) to create an animated gif.

from pyrt.renderer import RGBImage
from pyrt.math import Vec2, Vec3
from pyrt.camera import PerspectiveCamera
from pyrt.geometry import Triangle, Vertex
from PIL import Image
import moviepy.editor as mpy    # pip install moviepy
import numpy as np


def make_frame(t):
    w = 320
    h = 240
    image = RGBImage(w, h)

    # Create a camere with width, height and field of view:
    camera = PerspectiveCamera(w, h, 60)

    posy = -90 + t*25   # move camera along y-axis. t is time in seconds.


    # Set View matrix of camera: define where to look at
    camera.setView(Vec3(0,posy,0), Vec3(0,0,0), Vec3(0,0,1))

    #  Create view-projection matrix (right to left)
    vp =  camera.projection * camera.view

    # Create a triangle
    t = Triangle(Vertex(position=(-5, 1, 0)),
                 Vertex(position=(0, 1, 5)),
                 Vertex(position=(5, 1, 0)))

    # Triangle in normalized device coordinates:
    at = vp * t.a.position
    bt = vp * t.b.position
    ct = vp * t.c.position

    # Triangle in Screen coordinates:
    a_screenpos = Vec2(int(w * 0.5*(at.x + 1.) / at.z), int(h * 0.5*(at.y + 1.)/ at.z))
    b_screenpos = Vec2(int(w * 0.5*(bt.x + 1.) / bt.z), int(h * 0.5*(bt.y + 1.)/ at.z))
    c_screenpos = Vec2(int(w * 0.5*(ct.x + 1.) / ct.z), int(h * 0.5*(ct.y + 1.)/ at.z))

    # Draw the Triangle (wireframe) in image:
    color = Vec3(1,1,1)
    image.drawLine(a_screenpos, c_screenpos, color)
    image.drawLine(c_screenpos, b_screenpos, color)
    image.drawLine(b_screenpos, a_screenpos, color)

    return np.asarray(image.data)


# Create the clipp.

clip = mpy.VideoClip(make_frame, duration=3) # duration 3 seconds
clip.write_gif("06.gif",fps=15)