$25
1. Write down a Python program to draw a transformed triangle and its local frame in a 3D space. A. Set the window title to your student ID and the window size to (480,480).
B. Use the following drawFrame() and drawTriangle() to draw the frame and triangle:
def drawFrame():
glBegin(GL_LINES)
glColor3ub(255, 0, 0)
glVertex2fv(np.array([0.,0.])) glVertex2fv(np.array([1.,0.]))
glColor3ub(0, 255, 0)
glVertex2fv(np.array([0.,0.])) glVertex2fv(np.array([0.,1.]))
glEnd()
def drawTriangle():
glBegin(GL_TRIANGLES)
glVertex2fv(np.array([0.,.5])) glVertex2fv(np.array([0.,0.])) glVertex2fv(np.array([.5,0.]))
glEnd()
C. First draw an untransformed white triangle and a global frame.
D. Then draw a transformed blue triangle and its local frame. The triangle should be first rotated by 30 degrees and then translated by (0.6, 0, 0) w.r.t. the global frame. E. Expected result:
i.
F. Files to submit: A Python source file (Name the file whatever you want (in English). Extension should be .py)
2. Write down a Python program to draw a transformed triangle in a 3D space.
A. Set the window title to your student ID and the window size to (480,480).
B. Use the following code snippet:
gCamAng = 0
gComposedM = np.identity(4)
def render(M, camAng):
# enable depth test (we'll see details later) glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) glEnable(GL_DEPTH_TEST)
glLoadIdentity()
# use orthogonal projection (we'll see details later) glOrtho(-1,1, -1,1, -1,1)
# rotate "camera" position to see this 3D space better (we'll see details later)
gluLookAt(.1*np.sin(camAng),.1, .1*np.cos(camAng), 0,0,0, 0,1,0)
# draw coordinate: x in red, y in green, z in blue glBegin(GL_LINES) glColor3ub(255, 0, 0) glVertex3fv(np.array([0.,0.,0.])) glVertex3fv(np.array([1.,0.,0.])) glColor3ub(0, 255, 0) glVertex3fv(np.array([0.,0.,0.])) glVertex3fv(np.array([0.,1.,0.])) glColor3ub(0, 0, 255) glVertex3fv(np.array([0.,0.,0])) glVertex3fv(np.array([0.,0.,1.])) glEnd()
# draw triangle glBegin(GL_TRIANGLES) glColor3ub(255, 255, 255) glVertex3fv((M @ np.array([.0,.5,0.,1.]))[:-1]) glVertex3fv((M @ np.array([.0,.0,0.,1.]))[:-1]) glVertex3fv((M @ np.array([.5,.0,0.,1.]))[:-1]) glEnd()
def key_callback(window, key, scancode, action, mods):
global gCamAng, gComposedM if action==glfw.PRESS or action==glfw.REPEAT:
if key==glfw.KEY_1:
gCamAng += np.radians(-10) elif key==glfw.KEY_3: gCamAng += np.radians(10)
C. If you press or repeat a key, the triangle should be transformed as shown in the Table.
Note that key 1 and 3 are already implemented in the above code snippet.
Key Transformation
Q Translate by -0.1 in x direction w.r.t global coordinate
E Translate by 0.1 in x direction w.r.t global coordinate
A Rotate about y axis by -10 degrees w.r.t local coordinate
D Rotate about y axis by +10 degrees w.r.t local coordinate
W Rotate about x axis by -10 degrees w.r.t local coordinate
S Rotate about x axis by +10 degrees w.r.t local coordinate
1
Rotate camera -10 degree
3
Rotate camera 10 degree
D. Transformations should be accumulated (composed with previous one).
i. You’ll need two global variables to store current accumulated transformation and current camera angle.