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mapping:cawe:lighting [2007-10-28 23:36] Carsten Augmented the text |
mapping:cawe:lighting [2007-11-08 22:23] Carsten Augmented the text |
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| Here is an overview of the available Radiosity light sources and how they are created in a map: | Here is an overview of the available Radiosity light sources and how they are created in a map: | ||
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| ==== Area Light Sources ==== | ==== Area Light Sources ==== | ||
| Any primitive (brush or Bezier patch) surface that you place in a Ca3DE map can be turned into an //area light source//. The key point here is that a surfaces characteristic of being an area light source is //not// :!: directly set in the Ca3DE World Editor CaWE. Rather, being an area light source is a //material// property. | Any primitive (brush or Bezier patch) surface that you place in a Ca3DE map can be turned into an //area light source//. The key point here is that a surfaces characteristic of being an area light source is //not// :!: directly set in the Ca3DE World Editor CaWE. Rather, being an area light source is a //material// property. | ||
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| That means that a surface becomes an area light source when it has a material applied to it which in turn is defined to emit Radiosity light. | That means that a surface becomes an area light source when it has a material applied to it which in turn is defined to emit Radiosity light. | ||
| - | As a mapper, if you want to find out if a material emits area light, its intensity and color, FIXME | + | * In order to place an area light source, use the [[mapping:cawe:editingtools:editfaceprops|Edit Face Properties]] tool to apply an appropriately defined material to the desired brush or Bezier patch surface. You can learn which materials cast Radiosity area light by clicking on them once in the [[mapping:cawe:materialbrowser|Material Browser]]. The bar at the bottom will show "Radiant Exitance" information on the selected material, if any.\\ Tip: Filter for materials with the string "light" in their name. This heightens the chance to find a relevant material quickly. |
| + | * In order to change the definition of a new or existing material to emit light, make sure that the ''meta_radiantExitance'' keyword is employed. Please refer to the Material Systems [[matsys:cmat_manual:keywordreference]] for more details.\\ Note that the effect of changing the definition of an //existing// material is //global//. That is, if the material is used elsewhere (in another map), also the other map will be affected when CaLight is run next. | ||
| ==== Point light sources ==== | ==== Point light sources ==== | ||
| - | Radiosity light can also be emitted from point light sources. | + | You can also place //point light sources// to participate in the Radiosity lighting process. |
| + | This is easily achieved with the [[mapping:cawe:editingtools:newlight|New Light tool]], whose documentation explains the placement and parameter setup in detail. | ||
| ==== Sky Light ==== | ==== Sky Light ==== | ||
| - | [ FIXME TODO: Screenshots!, link to my thesis in See Also section, link to DK project] | + | Adding sun- or moonlight to a map works analogously to adding an area light source: Just apply a "sky" material to any surface, and if the material is defined to emit skylight, everything else will happen automatically: |
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| + | * The [[mapping:cawe:materialbrowser|Material Browser]] browser informs you whenever a material with "Irradiance" values is selected. | ||
| + | * The material definition can be changed according to the Material Systems [[matsys:cmat_manual:keywordreference]], see the ''meta_sunlight'' keyword. | ||
| + | * You may refer to the [[mapping:cawe:yourfirstmap]] tutorial to see an example. It's actually that easy! | ||
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| Dynamic lighting has become popular with the advent of hardware-acceleration for 3D graphics in the recent years. | Dynamic lighting has become popular with the advent of hardware-acceleration for 3D graphics in the recent years. | ||
| - | Its main properties/characteristics are that its computational steps occur //per-pixel// and //per-frame//. | + | It is the preferred and most frequently employed lighting technique in most recent commercial graphics software. |
| - | + | ||
| - | //Per-pixel// means that.. FIXME | + | |
| + | The essential characteristic of dynamic lighting is that its computational steps occur //per-pixel// and //per-frame//. | ||
| + | //Per-pixel// means that the lighting computations occur on the basis of the output pixels of the rendered primitives (triangles). | ||
| //Per-frame// refers to the fact that all lighting computations occur only at runtime, and in fact, they are performed for each rendered frame anew. This allows both light sources and lit objects to move arbitrarily through the scene, with the lights and shadows being updated correctly and instantaneously. | //Per-frame// refers to the fact that all lighting computations occur only at runtime, and in fact, they are performed for each rendered frame anew. This allows both light sources and lit objects to move arbitrarily through the scene, with the lights and shadows being updated correctly and instantaneously. | ||
| - | * hardware accelerated. | + | These properties have many implications for the practical use of dynamic lighting: |
| - | * dynamic light+shadow entities | + | Dynamic lighting is fast, flexible, dynamic, instantaneously, yields good results and is well supported and accelerated in hardware. |
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| + | Even though dynamic lighting looks not quite as real as the Radiosity method, this is often not a problem, because lighting that looks dramatically good is often preferred over the boring natural. Moreover, dynamic lighting avoids the computational complexity that comes with the Radiosity method. Therefore, dynamic lighting is an important component of the Ca3D-Engine. | ||
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| + | ==== Point light sources ==== | ||
| + | ==== Projective lights ==== | ||
| + | ==== Stencil shadows ==== | ||
| + | ==== Shadow-Map shadows ==== | ||
mapping/cawe/lighting.txt · Last modified: 2013-01-07 12:07 (external edit)