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136 lines
7.2 KiB
HTML
136 lines
7.2 KiB
HTML
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
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<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
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<meta name="ProgId" content="FrontPage.Editor.Document">
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<title>Lighting the Terrain</title>
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</head>
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<body background="../pics/background.jpg" text="#FFFFFF" link="#FFFFFF" vlink="#FFFFFF" alink="#FFFFFF">
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<b><font SIZE="5">
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<p align="center">Lighting the Terrain</p>
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<div align="right">
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<table border="1" cellspacing="1" width="100%" bordercolor="#808080" bgcolor="#000000" cellpadding="10">
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<tr>
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<td width="100%"><font FACE="Times New Roman">
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<p> Terrain maps also require some rethinking about the way you light maps.</p>
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</font><b><i><font SIZE="4">
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<p>Vertex Only</p>
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</font></i></b><font FACE="Times New Roman">
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<p> If you are making a large terrain map, you should plan on making your terrain
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textures be lit by vertex lighting only. Lightmaps can quickly become far too
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large for the game to handle.</p>
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<p>Make sure your large terrain textures contain the following parameters:</p>
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<b>
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<p>Surfaceparm nolightmap</b> //signifies vertex lighting only.</p>
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<b>
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<p>Q3map_novertexshadows</b> //this is what keeps those caulk vis blockers from
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causing ugly shadows to form on your terrain.</p>
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<p> If you are using q3map_sun in your sky <20></p>
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<b>
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<p>Q3map_forcesunlight</b> //this makes the light emitted by a q3map_sun
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parameter affect the vertex lit surface.</p>
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</font><b><i><font SIZE="4">
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<p>Light Sources</p>
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</font></i></b><font FACE="Times New Roman">
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<p> For outdoor maps, the obvious source of lighting ought to be the sky. The
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skies in the mpterra maps began with skies used in more conventional Team Arena
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maps, but were modified to better suit the needs of the terrain worlds.</p>
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<blockquote>
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<blockquote>
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</font><font FACE="Symbol" SIZE="2">
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<p><EFBFBD> </font><b><font FACE="Times New Roman">Slow Down Those Clouds.</font></b><font FACE="Times New Roman">
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One thing to consider is slowing down the rate of cloud movement. What looks
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OK in smaller maps looks wrong in vast panoramas.</p>
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</font><b><font FACE="Symbol" SIZE="2">
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<p><EFBFBD> </font><font FACE="Times New Roman" color="#FFFFFF">Strong Sunlight is
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Good.</font></b><font FACE="Times New Roman" color="#FFFFFF"> For team maps,
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you want to try and keep the light relatively the same in both base areas, so
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if you have mountains or large base structures, having the light come in at a
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nearly vertical angle is good, but less dramatic.
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</font></p>
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<b><font FACE="Symbol" SIZE="2">
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<p><font color="#FFFFFF"><EFBFBD> </font> </font><font FACE="Times New Roman">Ambient Light is Not
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So Bad.</font></b><font FACE="Times New Roman" color="#FFFFFF"> Since the
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beginning of Q3A map development we<77>ve said things like <20>Ambient Lighting
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is bad<61>. Well, the problems caused by ambient lighting are still there
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(flattening of shadows and colors), but with the distance of the play areas
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from the sky surface (in some maps), adding an ambient really helps bring up
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the overall light value in the map. Start low, maybe around an ambient value
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of 5 and creep upwards until the map looks right. It is VERY IMPORTANT that
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you give your ambient light a color. If you leave it white, you get ugly pink
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light instead of white. Even specifying white makes it look wrong. Best
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suggestion is to sample the sky texture color and translate that into an rgb
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formula for your ambient. One warning
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though <20> if you include <20>interior spaces<65> in your maps, the ambient
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light will affect those areas too. You will not get the deep dark shadows you
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may want in there.
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</font></p>
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<font FACE="Symbol" SIZE="2">
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<p><font color="#FFFFFF"><EFBFBD> </font> </font><font color="#FFFFFF"><b><font FACE="Times New Roman">Sky Shader Trick #1: Lose the
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Backsplash</font></b></font><font FACE="Times New Roman"><font color="#FFFFFF">. The attributes of the sky
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shader can have a significan</font>t effect on the amount of time it takes to perform
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a light compile on a map. You have to think of the sky as a huge area light.
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However, unlike light emitting textures (like your average light fixture), the
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sky doesn<73>t need to be illuminated itself. Therefore, you can eliminate the
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backsplash light feature which is the default status of the q3map_surfacelight
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parameter. Your sky shader should have the parameter q3map_backsplash with a
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value of -1. Removing backsplash light doesn<73>t affect the appearance of the
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sky, but does remove a significant amount of compiling overhead when the
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-light algorithm is used (the normal way you light things).</p>
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</font><font FACE="Symbol" SIZE="2">
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<p><EFBFBD> </font><b><font FACE="Times New Roman">Sky Shader Trick#2: Big
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Subdivisions.</font></b><font FACE="Times New Roman"> Q3Map automatically
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subdivides the sky into triangle quads. The more triangle quads, the more
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light emitting surfaces you have on your sky (if q3map_surfacelight is used).
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The light compile calculates for every one of these light emitting surfaces.
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Increase the size of the subdivision and you get less light emitters and a
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faster compile.</p>
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</font><font FACE="Symbol" SIZE="2">
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<p><EFBFBD> </font><b><font FACE="Times New Roman">Sky Shader Trick #3: -V-light.</font></b><font FACE="Times New Roman">
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This is a fast lighting algorithm. It<49>s especially fast for calculating sky
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lighting. It loses a little precision, but it can greatly speed up the time it
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takes to light a map. Even if you decide to use a normal light operation for
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your final map, using -vlight for interim compiles can mean a lot less time
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spent waiting on the compiler to see your results.</p>
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<b>
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<p> </p>
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</blockquote>
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</blockquote>
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</b></font><b><i><font SIZE="4">
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<p>The Light Grid</p>
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</font></i></b><font FACE="Times New Roman">
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<p> This is discussed in detail under terrain-related Worldspawn features. One of
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the things that can add enough memory complexity to a large terrain map, enough
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to make it unplayable (read crash the game), is the light grid. Think of the
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light grid as a map for determining how to light entities in the world. It<49>s
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what makes player models appear to move in and out of shadows as they move
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through the world. It<49>s a nice effect, but costly in memory terms. For the
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largest maps in Q3:TA, we <20>traded down<77> to a less detailed light grid.
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Increasing the size of grid subdivisions from 32 units to 256 units did this. We
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experimented with smaller and larger grids and settled on 256 x 256 x 256 as the
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best size. Smaller and the grid became large and unwieldy. Larger (especially on
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the z dimension) and not enough light reached some of the entities.</p>
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<p> The details of this feature are noted below under Terrain-Related WorldSpawn
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Features.</p>
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</font>
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<p align="center"><a href="the_meta_shader.html">Back</a> - <a href="table_of_contents.html">Table
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of Contents</a> - <a href="terrain_related_worldspawn_features.html">Terrain
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Worldspawn Features</a></p>
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<p> </td>
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</tr>
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</table>
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</div>
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</font></b>
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<p> </p>
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<p> </p>
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<p align="center">-22-</p>
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</body>
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</html>
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