Difference between revisions of "3D Fundamentals Tutorial 6"
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The tutorial video is on YouTube [https://www.youtube.com/watch?v=h_Aqol0oTs4 here]. | The tutorial video is on YouTube [https://www.youtube.com/watch?v=h_Aqol0oTs4 here]. | ||
| − | * Recap of our problem: | + | * Recap of our problem: triangles are always drawn in the same order [https://youtu.be/h_Aqol0oTs4?t=0m20s 0:20] |
| + | * Solution: Back face culling [https://youtu.be/h_Aqol0oTs4?t=2m02s 2:02] | ||
| + | :* Poor solution: painter's algoritm (sort the triangles back to front, draw front ones last) | ||
| + | :* Better solution: never draw back facing triangles. For convex single objects front facing triangles will never overlap | ||
| + | * Using a triangle's surface normal to determine its orientation [https://youtu.be/h_Aqol0oTs4?t=5m15s 5:15] | ||
| + | :* Just the z-component of the face normal is not good enough | ||
| + | :* Correct approach: take the viewing vector (v1) and the face normal direction (v2) | ||
| + | :* (viewing vector: vector from focal point to any point on the triangle in world space) | ||
| + | :* If their dot product is negative (opposide directions), the triangle's face is towards the focal point | ||
== Downloads == | == Downloads == | ||
Revision as of 23:33, 11 May 2020
Get rid of those dirty back-facers, we don't serve their kind here. Also, learn the new sex move that is taking New England by storm: the Bridgeport Shocker.
Video
The tutorial video is on YouTube here.
- Recap of our problem: triangles are always drawn in the same order 0:20
- Solution: Back face culling 2:02
- Poor solution: painter's algoritm (sort the triangles back to front, draw front ones last)
- Better solution: never draw back facing triangles. For convex single objects front facing triangles will never overlap
- Using a triangle's surface normal to determine its orientation 5:15
- Just the z-component of the face normal is not good enough
- Correct approach: take the viewing vector (v1) and the face normal direction (v2)
- (viewing vector: vector from focal point to any point on the triangle in world space)
- If their dot product is negative (opposide directions), the triangle's face is towards the focal point
Downloads
The GitHub repository for the tutorial code is here.
