For the ray traversal order, given that the ray is exactly on a grid line, would we just check the grid cells on both sides or is there something else that can be done?
chenwnicole
I'm not sure what this is doing here: so the circles are our objects in the 3D world, and the grid is our 2D image world? What is the ray doing? (For the pixels shaded in light blue, would they receive shadows or?)
VioIchigo
@chenwnicole I think the "grid" is also in 3D world because the ray is a 3D line. We actually divide the 3D space into uniform 3D voxels. And for the "ray", we want to do testing on it. The algorithm aims to reduce the number of intersection tests we need to enhance the speed we do the test.
VioIchigo
@jeromylui we use 3D DDA in this algorithm, here are some more explanations on it: http://euklid.mi.uni-koeln.de/c/mirror/www.cs.curtin.edu.au/units/cg351-551/notes/lect12p1.html
go-lauren
I think page 7 of this https://web.cs.wpi.edu/~emmanuel/courses/cs543/f13/slides/lecture10_p3.pdf explains 2D DDA very well, and https://www.scratchapixel.com/lessons/advanced-rendering/introduction-acceleration-structure/grid is a nice resource for then understanding 3D DDA
For the ray traversal order, given that the ray is exactly on a grid line, would we just check the grid cells on both sides or is there something else that can be done?
I'm not sure what this is doing here: so the circles are our objects in the 3D world, and the grid is our 2D image world? What is the ray doing? (For the pixels shaded in light blue, would they receive shadows or?)
@chenwnicole I think the "grid" is also in 3D world because the ray is a 3D line. We actually divide the 3D space into uniform 3D voxels. And for the "ray", we want to do testing on it. The algorithm aims to reduce the number of intersection tests we need to enhance the speed we do the test.
@jeromylui we use 3D DDA in this algorithm, here are some more explanations on it: http://euklid.mi.uni-koeln.de/c/mirror/www.cs.curtin.edu.au/units/cg351-551/notes/lect12p1.html
I think page 7 of this https://web.cs.wpi.edu/~emmanuel/courses/cs543/f13/slides/lecture10_p3.pdf explains 2D DDA very well, and https://www.scratchapixel.com/lessons/advanced-rendering/introduction-acceleration-structure/grid is a nice resource for then understanding 3D DDA