Add manual section on subdividing patches

doc/manual.adoc

@@ -807,3 +807,25 @@ Portion of an arch covering a 90 degree angle. This may be placed along room
 edges to give a curved appearance.
 
 |===
+
+==== Controlling patch subdivision
+
+Although patches are defined by Bezier curves, they are subdivided into flat
+polygons for rendering. By default, the number of polygons to create is
+determined dynamically by the game engine, based on the shape of the patch.
+However, you can also use the *Patch Inspector* to explicitly set the level of
+subdivision required, which can be useful when optimising a map by reducing
+on-screen polygon counts.
+
+.Default (automatic) subdivision, 2x2 subdivision, 3x3 subdivision, 3x10 subdivision
+image::PatchSubdivision.png[align="center"]
+
+To subdivide a patch:
+
+. Select *Patch Inspector* in the *View* menu to make the inspector widget
+visible.
+. With the patch selected, enable the *Fixed Subdivisions* checkbox.
+. Use the *Horizontal* and *Vertical* numeric spinboxes to set the number of
+polygons to divide the patch into. The value can range from *1*, making the
+patch completely flat regardless of control point positions, up to a maximum of
+*32*. Each dimension can have a different subdivision level, if required.

doc/manual.html

@@ -471,6 +471,7 @@ <h1>DarkRadiant User Guide</h1>
 <li><a href="#_creating_a_simple_patch">Creating a simple patch</a></li>
 <li><a href="#_manipulating_control_points">Manipulating control points</a></li>
 <li><a href="#_more_complex_patch_shapes">More complex patch shapes</a></li>
+<li><a href="#_controlling_patch_subdivision">Controlling patch subdivision</a></li>
 </ul>
 </li>
 </ul>
@@ -1728,8 +1729,8 @@ <h4 id="_more_complex_patch_shapes">More complex patch shapes</h4>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><span class="image"><img src="img/PatchEndCap.png" alt="PatchEndCap"></span></p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><strong>End cap</strong>
 </p><p class="tableblock">An arch or half-cylinder covering a 180 degree angle, aligned with the 2D view
-axis. The curved part of the arch will be at the top if created in front or side
-views, making this useful for curved ceilings and the like.</p></td>
+axis. The peak of the arch will be at the top if created in front or side views,
+making this useful for curved ceilings and the like.</p></td>
 </tr>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock"><span class="image"><img src="img/PatchBevel.png" alt="PatchBevel"></span></p></td>
@@ -1740,13 +1741,50 @@ <h4 id="_more_complex_patch_shapes">More complex patch shapes</h4>
 </tbody>
 </table>
 </div>
+<div class="sect3">
+<h4 id="_controlling_patch_subdivision">Controlling patch subdivision</h4>
+<div class="paragraph">
+<p>Although patches are defined by Bezier curves, they are subdivided into flat
+polygons for rendering. By default, the number of polygons to create is
+determined dynamically by the game engine, based on the shape of the patch.
+However, you can also use the <strong>Patch Inspector</strong> to explicitly set the level of
+subdivision required, which can be useful when optimising a map by reducing
+on-screen polygon counts.</p>
+</div>
+<div class="imageblock" style="text-align: center">
+<div class="content">
+<img src="img/PatchSubdivision.png" alt="PatchSubdivision">
+</div>
+<div class="title">Figure 7. Default (automatic) subdivision, 2x2 subdivision, 3x3 subdivision, 3x10 subdivision</div>
+</div>
+<div class="paragraph">
+<p>To subdivide a patch:</p>
+</div>
+<div class="olist arabic">
+<ol class="arabic">
+<li>
+<p>Select <strong>Patch Inspector</strong> in the <strong>View</strong> menu to make the inspector widget
+visible.</p>
+</li>
+<li>
+<p>With the patch selected, enable the <strong>Fixed Subdivisions</strong> checkbox.</p>
+</li>
+<li>
+<p>Use the <strong>Horizontal</strong> and <strong>Vertical</strong> numeric spinboxes to set the number of
+polygons to divide the patch into. The value can range from <strong>1</strong>, making the
+patch completely flat regardless of control point positions, up to a maximum of
+<strong>32</strong>. Each dimension can have a different subdivision level, if required.</p>
+</li>
+</ol>
+</div>
+</div>
 </div>
 </div>
 </div>
 </div>
 <div id="footer">
 <div id="footer-text">
-Last updated 2018-09-19 21:22:42 BST
+Last updated 2018-09-25 20:46:21 BST
 </div>
 </div>
 </body>