Updated README.effects with full documentation for texture-unit. Further documentation required.
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Stuart Buchanan
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1 changed files with 53 additions and 29 deletions
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@ -19,7 +19,7 @@ parameters for shader programs. The names of properties in the
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parameter section can be whatever the effects author chooses, although
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some standard parameters are set by FlightGear itself. On the other
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hand, the properties in the techniques section are all defined by the
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FlightGear.
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FlightGear.
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Techniques
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----------
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@ -35,7 +35,7 @@ and, or, equal, less, less-equal
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glversion - returns the version number of OpenGL
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extension-supported - returns true if an OpenGL extension is supported
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property - returns the boolean value of a property
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float-property - returns the float value of a property, useful inside equal, less
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float-property - returns the float value of a property, useful inside equal, less
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or less-equal nodes
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shader-language - returns the version of GLSL supported, or 0 if there is none.
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@ -50,7 +50,7 @@ The proper way to test whether to enable a shader-based technique is:
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</and>
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</predicate>
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There is also a property set by the user to indicate what is the level
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There is also a property set by the user to indicate what is the level
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of quality desired. This level of quality can be checked in the predicate
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like this :
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<predicate>
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@ -63,7 +63,7 @@ like this :
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<!-- other predicate conditions -->
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</and>
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</predicate>
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The range of /sim/rendering/quality-level is [0..5]
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* 2.0 is the threshold for relief mapping effects,
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* 4.0 is the threshold for geometry shader usage.
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@ -143,8 +143,8 @@ The following attributes are currently implemented in techiques:
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alpha-test - children: active, comparison, reference
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Valid values for comparision:
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never, less, equal, lequal, greater, notequal, gequal,
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always
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always
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alpha-to-coverage - true, false
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blend - children: active, source, destination, source-rgb,
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@ -176,7 +176,7 @@ program
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attribute
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geometry-vertices-out - integer, max number of vertices emitted by geometry
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shader
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geometry-input-type - points, lines, lines-adjacency, triangles,
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geometry-input-type - points, lines, lines-adjacency, triangles,
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triangles-adjacency
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geometry-output-type - points, line-strip, triangle-strip
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@ -188,21 +188,45 @@ shade-model - flat, smooth
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texture-unit - has several child properties:
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unit - The number of an OpenGL texture unit
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type - This is either an OpenGL texture type or the name of a
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point-sprite - true, false - Whether this should rendered as a point-sprite
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type - This is either an OpenGL texture type or the name of a
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builtin texture. Currently supported OpenGL types are 1d, 2d,
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3d which have the following common parameters:
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image (file name)
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filter
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mag-filter
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wrap-s
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wrap-t
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wrap-r
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image (file name)
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filter - nearest, linear, [nearest|linear]-mipmap-[nearest|linear]
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mag-filter - nearest, linear, [nearest|linear]-mipmap-[nearest|linear]
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wrap-s - clamp, clamp-to-border, clamp-to-edge, mirror, repeat
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wrap-t - clamp, clamp-to-border, clamp-to-edge, mirror, repeat
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wrap-r - clamp, clamp-to-border, clamp-to-edge, mirror, repeat
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mipmap-control - control the mipmap on a per-channel basis. Children:
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function-r - auto, average, sum, product, min, max
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function-g - auto, average, sum, product, min, max
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function-b - auto, average, sum, product, min, max
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function-a - auto, average, sum, product, min, max
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The following built-in types are supported:
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white - 1 pixel white texture
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noise - a 3d noise texture
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environment
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mode
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color
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noise - a 3d noise texture. (size parameter defines size of texture)
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light-sprite - a procedurally generated sprite suitable for point lights
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cubemap - build a cube-map. Children:
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images - build from 6 images. Children: [positive|negative]-[x|y|z]
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image - build from a single cross-image
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environment
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mode - add, blend, decal, modulate, replace
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color
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texenv-combine
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combine-[rgb|alpha] - replace, modulate, add, add-signed, interpolate, subtract, dot3-rgb, dot3-rgba
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source[0|1|2]-[rgb|alpha] - constant, primary_color, previous, texture, texture[0-7]
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operand[0|1|2]-[rgb|alpha] -src-color, one-minus-src-color, src-alpha, one-minus-src-alpha
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scale-[rgb|alpha]
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constant-color
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texgen
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mode - object-linear, eye-linear, sphere-map, normal-map, reflection-map
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planes - s, t, r, q
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uniform
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name
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type - float, float-vec3, float-vec4, sampler-1d, sampler-2d,
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@ -240,10 +264,10 @@ parameters section.
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Generate
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--------
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Often shader effects need tangent vectors to work properly. These
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tangent vectors, usually called tangent and binormal, are computed
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on the CPU and given to the shader as vertex attributes. These
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vectors are computed on demand on the geometry using the effect if
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Often shader effects need tangent vectors to work properly. These
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tangent vectors, usually called tangent and binormal, are computed
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on the CPU and given to the shader as vertex attributes. These
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vectors are computed on demand on the geometry using the effect if
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the 'generate' clause is present in the effect file. Exemple :
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<generate>
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@ -253,12 +277,12 @@ the 'generate' clause is present in the effect file. Exemple :
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</generate>
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Valid subnodes of 'generate' are 'tangent', 'binormal' or 'normal'.
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The integer value of these subnode is the index of the attribute
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The integer value of these subnode is the index of the attribute
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that will hold the value of the vec3 vector.
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The generate clause is located under PropertyList in the xml file.
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In order to be available for the vertex shader, these data should
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In order to be available for the vertex shader, these data should
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be bound to an attribute in the program clause, like this :
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<program>
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@ -273,9 +297,9 @@ be bound to an attribute in the program clause, like this :
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</attribute>
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</program>
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attribute names are whatever the shader use. The index is the one
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declared in the 'generate' clause. So because generate/tangent has
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value 6 and my_tangent_attribute has index 6, my_tangent_attribute
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attribute names are whatever the shader use. The index is the one
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declared in the 'generate' clause. So because generate/tangent has
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value 6 and my_tangent_attribute has index 6, my_tangent_attribute
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holds the tangent value for the vertex.
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Default Effects in Terrain Materials and Models
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@ -297,7 +321,7 @@ with parameters extracted from OSG objects; this effect inherits, by
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default, from Effects/model-default.eff. A larger set of parameters is
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created for model effects than for terrain because there is more
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variation possible from the OSG model loaders than from the terrain
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system. The parameters created are:
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system. The parameters created are:
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* material active, ambient, diffuse, specular, emissive,
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shininess, color mode
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@ -343,7 +367,7 @@ apply. The effect does not need the file extension.
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NOTE:
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Chrome, although now implemented as an effect, still retains the old method of
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Chrome, although now implemented as an effect, still retains the old method of
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application:
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<animation>
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