Materials in Oolite - Revision history

Cholmondely: Added note about age of page

2021-12-20T09:36:20Z

Added note about age of page

Cholmondely: Link to A_C_'s thread. Added some dates to give context.

2021-05-12T17:58:44Z

Link to A_C_'s thread. Added some dates to give context.

Ahruman at 18:55, 4 May 2013

2013-05-04T18:55:17Z

Svengali: added category Oolite_scripting

2012-02-10T22:07:36Z

added category Oolite_scripting

Ahruman: /* Important concepts */ Linked specular map demo video

2011-07-14T19:58:03Z

‎Important concepts: Linked specular map demo video

Eric Walch: Named colours: corrected lightGrayColor definition

2010-11-13T14:15:21Z

Named colours: corrected lightGrayColor definition

Ahruman: /* Material dictionary example */

2010-06-28T13:15:00Z

‎Material dictionary example

Ahruman: Updated for 1.74.

2010-06-28T13:14:25Z

Updated for 1.74.

Show changes

Ahruman: Partially updated for 1.74.

2010-06-28T11:46:21Z

Partially updated for 1.74.

Show changes

Ahruman: /* Material attributes dictionaries */

2010-04-30T18:22:10Z

‎Material attributes dictionaries

← Older revision		Revision as of 09:36, 20 December 2021
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	Since v.1.87 (August 2018), more advanced options have become available. See [http://www.aegidian.org/bb/viewtopic.php?f=2&t=19881 A Description of the Improved Lighting and Materials System] (2018), the attached update of Oct 2018 and the clarifications of May 2021.		Since v.1.87 (August 2018), more advanced options have become available. See [http://www.aegidian.org/bb/viewtopic.php?f=2&t=19881 A Description of the Improved Lighting and Materials System] (2018), the attached update of Oct 2018 and the clarifications of May 2021.

		+	{{OXPNote\|This page was last properly edited in 2013, well after the introduction of shaders but before [[User:Another commander\|Another commander]]'s work on Oolite introducing specular & gloss maps, the new Oren-Nayar diffuse light model, high-definition graphic resolution ''etc''}}

	Traditionally, the surface appearance of ships in Oolite has been defined entirely by textures specified in the ship’s model file and the ''[[#smooth\|smooth]]'' attribute. Test release 1.67 added support for [[Shaders in Oolite\|shaders]], and test release 1.69 expanded this to a more flexible '''material model'''. Under the new model, the texture file names in model files have been repurposed as '''material keys'''. A material key specifies an entry in the ship’s '''material dictionary''', specified in the ship’s ''[[shipdata.plist]]'' entry. For backwards compatibility, if no material of a given name is found, a material is generated using the material key as a diffuse texture name – providing the same functionality as previous versions of Oolite.		Traditionally, the surface appearance of ships in Oolite has been defined entirely by textures specified in the ship’s model file and the ''[[#smooth\|smooth]]'' attribute. Test release 1.67 added support for [[Shaders in Oolite\|shaders]], and test release 1.69 expanded this to a more flexible '''material model'''. Under the new model, the texture file names in model files have been repurposed as '''material keys'''. A material key specifies an entry in the ship’s '''material dictionary''', specified in the ship’s ''[[shipdata.plist]]'' entry. For backwards compatibility, if no material of a given name is found, a material is generated using the material key as a diffuse texture name – providing the same functionality as previous versions of Oolite.

@@ Line 1: / Line 1: @@
 Traditionally, the surface appearance of ships in Oolite has been defined entirely by textures specified in the ship’s model file and the ''[[#smooth|smooth]]'' attribute. Test release 1.67 added support for [[Shaders in Oolite|shaders]], and test release 1.69 expanded this to a more flexible '''material model'''. Under the new model, the texture file names in model files have been repurposed as '''material keys'''. A material key specifies an entry in the ship’s '''material dictionary''', specified in the ship’s ''[[shipdata.plist]]'' entry. For backwards compatibility, if no material of a given name is found, a material is generated using the material key as a diffuse texture name – providing the same functionality as previous versions of Oolite.
-This page documents the material model as of Oolite test release 1.74, and applies to stable release 1.76 and later.
+This page documents the material model as of Oolite test release 1.74 (2010), and applies to stable release 1.76 (2011) and later.
 == Important concepts ==

@@ Line 1: / Line 1: @@
 Traditionally, the surface appearance of ships in Oolite has been defined entirely by textures specified in the ship’s model file and the ''[[#smooth|smooth]]'' attribute. Test release 1.67 added support for [[Shaders in Oolite|shaders]], and test release 1.69 expanded this to a more flexible '''material model'''. Under the new model, the texture file names in model files have been repurposed as '''material keys'''. A material key specifies an entry in the ship’s '''material dictionary''', specified in the ship’s ''[[shipdata.plist]]'' entry. For backwards compatibility, if no material of a given name is found, a material is generated using the material key as a diffuse texture name – providing the same functionality as previous versions of Oolite.
-This page documents the material model as of Oolite test release 1.74.
+This page documents the material model as of Oolite test release 1.74, and applies to stable release 1.76 and later.
 == Important concepts ==

← Older revision		Revision as of 22:07, 10 February 2012
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	* [[Material Test Suite OXP]] — demonstrates most material properties.		* [[Material Test Suite OXP]] — demonstrates most material properties.

−	[[Category: Oolite]]
		+
		+	[[Category: Oolite]] [[Category:Oolite_scripting]]

@@ Line 12: / Line 12: @@
 * '''Normals''': All lighting calculations require a concept of the orientation of a surface relative to a light and, for reflections, relative to the camera. A surface oriented towards the light will be lighter than a surface oriented away from it. The ''normal'' for any given point on a surface is a vector pointing straight out, which for our purposes ''defines'' the concept of “straight out”.<br />By default, Oolite models have constant normals across each face. By setting the <code>smooth</code> attribute in [[shipdata.plist]], normals are instead interpolated across each face, with each vertex having a normal that is a weighted average of surounding faces’ normals, and each point on a surface getting a weighted average of the normals at the corners of the face. Using ''smooth groups'', a model can be divided into regions which are smoothed but have sharp boundaries between them. As of Oolite 1.74, models can also include explicit per-vertex normals instead of having Oolite calculate them – most 3D modellers export this information.<br />When using smoothing, it is important to understand that Oolite does not add any geometry,and will result in each vertex being lit as if it is locally flat. This is generally inappropriate for any sharp corner. If you set <code>smooth</code> on a basic cube, the result will be badly lit.
 * '''Diffuse reflection''': light that is reflected evenly in all directions. A “dull” surface primarily reflects diffusely. Because the light is reflected evenly in all directions, the diffuse term is independent of the camera position; it is a function of the light and the surface normal. The standard diffuse reflection term is the cosine of the angle between the direction to the light and the normal, or zero if this is negative – this is known as the [http://en.wikipedia.org/wiki/Lambertian_reflectance Lambertian reflectance model]. This value is then modulated with the material’s diffuse colour and diffuse map.
-* '''Specular reflection''': light that is reflected in a particular direction, producing a shiny effect. In real life, this is simply a mirror reflection which is generally darkened and blurred, leaving an enlarged, blurry reflection of bright light sources, with other objects being washed out so they aren’t noticeable. In Oolite, a simpler mathematical model called the [http://en.wikipedia.org/wiki/Blinn–Phong_shading_model Blinn-Phong shading model] is used.
+* '''Specular reflection''': light that is reflected in a particular direction, producing a shiny effect. In real life, this is simply a mirror reflection which is generally darkened and blurred, leaving an enlarged, blurry reflection of bright light sources, with other objects being washed out so they aren’t noticeable. In Oolite, a simpler mathematical model called the [http://en.wikipedia.org/wiki/Blinn–Phong_shading_model Blinn-Phong shading model] is used.<br />[http://www.youtube.com/watch?v=76jvMmV1ih0 This video] demonstrates the effects of specular lighting and specular mapping on the built-in scarred alloy model.
 == The material dictionary ==

@@ Line 90: / Line 90: @@
 | darkGrayColor || 1/3, 1/3, 1/3, 1
 |-
-| lightGrayColor || 1/6, 1/6, 1/6, 1
+| lightGrayColor || 2/3, 2/3, 2/3, 1
 |-
 | whiteColor || 1, 1, 1, 1

@@ Line 219: / Line 219: @@
      };
  };
-Here, the “cube-face” material is assigned the diffuse texture “oolite_shader_test_suite_7_diffuse.png” and a combined emission and illumination map (which is a greyscale+alpha texture). The emission and illumination components are then given coloured tints (slightly green and slightly blue, respectively, producing this:
+Here, the “cube-face” material is assigned the diffuse texture “oolite_shader_test_suite_7_diffuse.png” and a combined emission and illumination map (which is a greyscale+alpha texture). The emission and illumination components are then given coloured tints (slightly green and slightly blue, respectively), producing this:
 [[File:Oolite Material Test Suite 7.png|320px]]

@@ Line 41: / Line 41: @@
 | '''illumination_map''' || texture&nbsp;specifier || A texture specifying local illumination colour, which is added to incoming light. (This is useful for things like hull spotlights.) Illumination mapping is available in Oolite 1.70 and later with shaders enabled, for materials with no custom shader.
 |-
-| '''illumination_color ''' || A colour to modify the illumination map with (available in Oolite 1.74 or later).
+| '''illumination_color ''' || colour&nbsp;specifier || A colour to modify the illumination map with (available in Oolite 1.74 or later).
 |-
 | '''fragment_shader''' || file&nbsp;name || name of GLSL fragment program to use.