lecture 15

Question 1

a primitive in visual rendering is formed by what

Answer 1

one or more vertices

Question 2

vertices are not

Answer 2

grid aligned

Question 3

all primitives are merged to produce what

Answer 3

2d pixels on the display

Question 4

what two things does the rendering process user

Answer 4

visibility problem and shading combined

Question 5

what two things are involved with the visibility problem

Answer 5

recasting and rasterization

Question 6

what is raytracing

Answer 6

image order rendering: loops over pixels, then over triangles (grid in front of the triangle that a ray angles to/ doesnt scale , needs very fast rendering),

Question 7

different shading models (2)

Answer 7

lambert and blinnphong

Question 8

what is rasterization

Answer 8

object order rendering: loops over triangles and then over pixels, asks if the pixels lies in the triangle (it projects vertices onto grid and thenloops over the pixels

Question 9

painters algorithm

Answer 9

inefficient for large numbers of objects (object, foreground, trees, image by image rather than which is in a pixle)

Question 10

zbuffer

Answer 10

looks at two different objects, in the zbuffer depth buffer and in a 3d scene evaluates which objects are in front and then for the projection plane, only renders what is seen from front

Question 11

texture mapping

Answer 11

render traingles, then base color, then individually pixelate?

Question 12

bump mappping

Answer 12

alters the surface normal, takes a ball and places a texture on top of it to create an orange like texture

Question 13

aliasing

Answer 13

not a huge problem fro mdoern displays ~>300ppi, but it is for vr because eyes are so close to the screen

Question 14

counteract aliasing

Answer 14

hardware line then prefiltering box then prefiltering gaussian which blurs the edges

Question 15

mipmapping

Answer 15

takes a texture and renders it at different sizes and places them at different depths to give illusion

Question 16

3 types of culling

Answer 16

view frustrum, occlusion, back face

Question 17

view frustrum culling

Answer 17

see images in periphery

Question 18

occlusion culling

Answer 18

they are behind the images in front

Question 19

back face

Answer 19

they only have one side rendered, point away, can also be front face and point towards

Question 20

3 vr rasterization probems

Answer 20

aliasing problem because vr displays dont have high pixel density and provide mistmatch movement, magnified by setero perception, stereovision makes texutre mapping look fake

Question 21

correct distortions

Answer 21

barrel/pincushion distortion, correct using fresnel lens because more accuratley bends lights

Question 22

latency diagram with 6 steps

Answer 22

input, usb, engine, write display, pixel switching, new images

Question 23

high latency causes what 3 problesm

Answer 23

reduce presence, cause vr sickness, inefficient interaction

Question 24

6 remedies for high latency

Answer 24

lower complextiy, improve rendering pipeline performance, remove pipleine delays, user prediction to estimate future viewpoints, shift/disort rendered image to compesnate for missig frames, faster phones, image warping

Question 25

video and photo on vr is a form of what

Answer 25

texture mapping

Question 26

what are the mispmatch framerates with projection

Answer 26

24 fps versus 60-90

Question 27

panoramic phtoo is called what

Answer 27

photospehre

Question 28

panoramic video is called what

Answer 28

videosphere