Shader module. Allows the definition of shader information (code + parameters).
[ShaderTemplate] Code = "// Shader code void main() { // Do stuff }" CodeList = CodeKey1 # ... # CodeKeyN ParamList = Param1 # ... # ParamN ParamFloat = <float> ParamVector = <vector> ParamTexture = path/to/texture UseCustomParam = <bool> KeepInCache = <bool>
Here's a list of the available properties for an orxSHADER
structure:
CodeList
: The values of this list will be used as config keys from this section to reconstruct, in the given order, a multi-part shader. If not defined, Code will be used instead.KeepInCache
: Defines if the shader code should be kept in memory even if no shader of this type is currently in use. This saves time (reading from disk + compiling) but costs memory. Its default value is false
.UseCustomParam
: When set to true, an event will be sent to override params values at runtime as well as the automated “time” value. Defaults to false, ie. no runtime override unless “time” is used for a float param.Here's a simple example of a non-interactive shader as seen in the spawner/shader tutorial.
[Decompose] Code = "void main() { float fRed, fGreen, fBlue; // Computes positions with offsets vec2 vRedPos = vec2(gl_TexCoord[0].x + offset.x, gl_TexCoord[0].y + offset.y); vec2 vGreenPos = vec2(gl_TexCoord[0].x, gl_TexCoord[0].y); vec2 vBluePos = vec2(gl_TexCoord[0].x - offset.x, gl_TexCoord[0].y - offset.y); // Red pixel inside texture? if((vRedPos.x >= 0.0) && (vRedPos.x <= 1.0) && (vRedPos.y >= 0.0) && (vRedPos.y <= 1.0)) { // Gets its value fRed = texture2D(texture, vRedPos).r; } // Green pixel inside texture? if((vGreenPos.x >= 0.0) && (vGreenPos.x <= 1.0) && (vGreenPos.y >= 0.0) && (vGreenPos.y <= 1.0)) { // Gets its value fGreen = texture2D(texture, vGreenPos).g; } // Blue pixel inside texture? if((vBluePos.x >= 0.0) && (vBluePos.x <= 1.0) && (vBluePos.y >= 0.0) && (vBluePos.y <= 1.0)) { // Gets its value fBlue = texture2D(texture, vBluePos).b; } // Outputs the final decomposed pixel gl_FragColor = vec4(fRed, fGreen, fBlue, 1.0); }" ParamList = texture # offset offset = (-0.05, -0.05, 0.0) ~ (0.05, 0.05, 0.0); <= Let's take some random offset
Please see the Shader Tutorials and Shader Examples for more information.
Shader parameters can be defined on the fly if
UseCustomParam = trueis set in your shader. An event of type
orxEVENT_TYPE_SHADER
and ID orxSHADER_EVENT_SET_PARAM
will be fired for all parameters and its payload will contain the name of the param and its default value. Event handler can then modify that value if need be, and it'll get used by the shader.
However, when UseCustomParam is defined to true, those objects can't be batched at rendering, making the rendering phase more expensive. The severity of the processing penalty depends on how many affected objects are displayed. See the test/playground code, orxBounce, for an example on how to set those shader parameters on the fly.
“time” is a keyword recognized by orx: the parameter value will be the object's “age”, in seconds. Example:
ParamList = fTime fTime = time
There is an internal texture called pixel
. It can be used to specify an image of arbitrary size when used with the Scale property of the object:
[Object] Graphic = MyTexture Scale = (16, 16, 1) [MyTexture] Texture = pixel
In the example above, an Object has a Graphic that will span over 16×16 pixels.
Shaders contain implicit parameters containing owner's texture coordinates. For example:
[GameObject] Graphic = @ Texture = ObjectTexture.png TextureOrigin = (16, 16, 0) TextureSize = (8, 8, 0) ShaderList = Shader [Shader] ParamList = MyTexture # ... Code = ...
Then orx will generate extra parameters behind the scene regarding the texture MyTexture. The names follow the pattern:
<NameOfTexture>_top, <NameOfTexture>_left, <NameOfTexture>_bottom, <NameOfTexture>_right
In the above example, the names will then be:
MyTexture_top, MyTexture_left, MyTexture_bottom, MyTexture_right
If MyTexture's dimensions are 32×32, we'd then get:
MyTexture_top = 16 / 32 => 0.5 MyTexture_left = 16 / 32 => 0.5 MyTexture_bottom = (16 + 8) / 32 => 0.75 MyTexture_right = (16 + 8) / 32 => 0.75
We endeavor to keep the config properties on this page up to date as often as possible. For up to the minute config information for the latest version of Orx, check the most recent published at:
Additionally these files can be found under your orx source tree in the orx/code/bin
folder.