Differences

This shows you the differences between two versions of the page.

--- engine:worldlayout [2017/01/31 04:59] – created stohrendorf
+++ engine:worldlayout [2017/06/04 21:34] (current) – zdimension
@@ Line 1: / Line 1: @@
 ====== World Layout ======
+===== Coordinate System =====
+The engine uses a right-handed coordinate system, with $X$ to the right, $Y$ down, and $Z$ forward.
+The mapping between OpenGL and the engine's coordinate system is $(x, y, z)_\mathrm{gl} = (x, -y, -z)$.
+==== Units ====
+The most important "metering" in the engine is the //sector size//, which defines a length of $1024$ units,
+and approximately equals two meters in the real world.
+Another significant, but less important, metering is the //click//, which is a quarter sector size ($256$ units).
+It is used to define floor and ceiling slants, and is also a "rule of thumb"
+==== Sectors ====
+The whole engine world is divided into //sectors//.  A sector (which defines a $1024 \times 1024$ rectangular area)
+defines
+  * ceiling and floor layout,
+  * behaviour, and
+  * the adjoining room for that sector.
 ===== Angles =====
-{{:engine:angle.png?nolink|}}
+{{:engine:angle.png?nolink |}}
+"AU" is short for "Angular Unit". $1$ AU equals the $2^{16}$th of a full circle and ranges from $-2^{15}$ ($-32768$) to
+$2^{15}-1$ ($32767$), representing the interval $[-180^°; 180^°[$.
+The conversion functions are:
+\\
+$\varphi_{\mathrm{rad}} = \varphi_{\mathrm{deg}} \cdot \pi / 180 = \varphi_{\mathrm{AU}} \cdot \pi / 2^{15}$
+\\
+$\varphi_{\mathrm{deg}} = \varphi_{\mathrm{rad}} \cdot 180 / \pi = \varphi_{\mathrm{AU}} \cdot 180 / 2^{15}$
+\\
+$\varphi_{\mathrm{AU}} = \varphi_{\mathrm{deg}} \cdot 2^{15} / 180 = \varphi_{\mathrm{rad}} \cdot 2^{15} / \pi$
+==== YPR Rotation ====
+The engine uses Euler angles to express rotations, and applies them in ZXY order.
+===== Rooms & Portals =====
+The world is divided into so-called //rooms//, which are basically subdivisions of the whole level.
+A room may be physically incomplete, i.e. a large physical room may be artificially split into two engine rooms.
+Each room is connected to its direct neighbors through //portals//.  The engine uses these visibility portals
+to determine which room should be rendered and which not.
+See https://en.wikipedia.org/wiki/Portal_rendering for a more in-depth explanation.

engine/worldlayout.1485838758.txt.gz · Last modified: 2017/01/31 04:59 (external edit)

Back to top