{"id":3284,"date":"2016-07-24T03:53:25","date_gmt":"2016-07-24T02:53:25","guid":{"rendered":"http:\/\/phoenixgamedevelopment.com\/blog\/?p=3284"},"modified":"2016-07-24T03:53:25","modified_gmt":"2016-07-24T02:53:25","slug":"p-152-virtual-world-concept-update-140-planet-sized-terrain-part-19-lods-tier-2","status":"publish","type":"post","link":"https:\/\/phoenixgamedevelopment.com\/blog\/p-152-virtual-world-concept-update-140-planet-sized-terrain-part-19-lods-tier-2\/","title":{"rendered":"P-152: Virtual World Concept Update 140: Planet-sized Terrain: Part 19: LOD’s (Tier 2)"},"content":{"rendered":"

It has turned out to be a lot more difficult than I thought to implement the additional Levels of Detail for viewing at close range.<\/p>\n

I have tried various techniques, involving duplicating the existing LOD code (which is messy) and modifying it.<\/p>\n

The main issue that I am having is in bridging the gap between \u00a064-bit space (which deals with real world distances) and 32 bit space which deals with coordinates within the 10,000 unit limit, as defined by the floating origin system.<\/p>\n

I have tried implementing all LOD’s using 64-bit numbers, but with these extremely high values, it seems that the border between all LOD’s is greatly exaggerated:<\/p>\n

\"P152_DEBUG<\/a>
P152_DEBUG
23\/07\/2016 , 01:21:17 AM
Torque 3D MIT – P152<\/figcaption><\/figure>\n

\"P152_DEBUG<\/a><\/p>\n

P152_DEBUG
\n23\/07\/2016 , 12:54:16 AM
\nTorque 3D MIT – P152<\/p>\n

This obviously does not work. It does further prove that the high-level subdivision (which I am calling “Tier 1”) is working, since adding further subdivision levels results in a terrain with vast features, ie, very high peaks, very deep valleys.<\/p>\n

\"P152_DEBUG<\/a>
P152_DEBUG
23\/07\/2016 , 01:00:44 AM
Torque 3D MIT – P152<\/figcaption><\/figure>\n

Subdividing based on the 64-bit numbers should produce this, due to their high values. However, what I want to do is nodes which are within 32-bit space, and subdivide only those nodes, in 32-bit space, to produce a smooth terrain. When the player stands on, essentially the “North Pole” of the planet, these 10K nodes form a very neat shape, which makes visualising the subdivision a lot easier:<\/p>\n

\"P152_DEBUG<\/a>
P152_DEBUG
22\/07\/2016 , 08:26:02 PM
Torque 3D MIT – P152<\/figcaption><\/figure>\n

I believe I am making progress with this. I have had to duplicate the subdivision code, which is not efficient, but my main goal now is getting the code to work, I can optimise it later. I have implemented partial “Tier 2” subdivision, but as the below images show, there are problems with nodes not rendering:<\/p>\n

\"P152_DEBUG<\/a>
P152_DEBUG
22\/07\/2016 , 09:13:23 PM
Torque 3D MIT – P152<\/figcaption><\/figure>\n
\"P152_DEBUG<\/a>
P152_DEBUG
22\/07\/2016 , 09:06:40 PM
Torque 3D MIT – P152<\/figcaption><\/figure>\n
\"P152_DEBUG<\/a>
P152_DEBUG
23\/07\/2016 , 12:27:51 AM
Torque 3D MIT – P152<\/figcaption><\/figure>\n

I may actually be closer to a solution than these images portray, however.<\/p>\n

It seems clear now that I will need to add another objective to my objectives list for MS2, which is to translate the 64-bit space node positions to 32-bit. Currently, the culling and Tier 1 subdivisions are being done in 64-bit space. I am then grabbing all nodes with a 10k distance of the player, however, these nodes are being rendered with their 64-bit positions, This is causing some z-fighting issues, and will need to be fixed. I have devised an algorithm to fix this on paper, but I haven’t implemented it yet.<\/p>\n

I may also need to combine the 64-bit and 32-bit space positions of the player together, which would be another objective for MS2. Currently, the players position in 64-bit space is used to cull any nodes outside of 10,000 units, and the players 32-bit position is used to subdivide those nodes further to produce a smooth terrain. I may be able to handle the two position separately, I am not sure yet.<\/p>\n","protected":false},"excerpt":{"rendered":"

It has turned out to be a lot more difficult than I thought to implement the additional Levels of Detail for viewing at close range. I have tried various techniques, involving duplicating the existing LOD code (which is messy) and modifying it. The main issue that I am having is in bridging the gap between […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,17,10,11],"tags":[],"class_list":["post-3284","post","type-post","status-publish","format-standard","hentry","category-astral-realms","category-p-0","category-software-and-games","category-spiritus-astrum","has-post-title","has-post-date","has-post-category","has-post-tag","has-post-comment","has-post-author",""],"aioseo_notices":[],"builder_content":"","_links":{"self":[{"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/posts\/3284"}],"collection":[{"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/comments?post=3284"}],"version-history":[{"count":6,"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/posts\/3284\/revisions"}],"predecessor-version":[{"id":3297,"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/posts\/3284\/revisions\/3297"}],"wp:attachment":[{"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/media?parent=3284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/categories?post=3284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/phoenixgamedevelopment.com\/blog\/wp-json\/wp\/v2\/tags?post=3284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}