RedSDK Spot Light Luminance
About Spot LightFrom the help file - "The spot light source is a centric light. It produces an isotropic lighting in all directions issued from the spot cone apex. The lighting emitted by the spot light decreases at the spot cone borders"
Basically there are two cones to be set, brighter inner cone, and a maximum cone, in this 'additional' cone area the light diminishes from the bight area to no light.
- Intensity decay â€“ Set the rate at which the lights power diminishes.
See separate RedSDK intensity Decay page.
- Diffuse color â€“ Sets the diffuse color of the light.
- Diffuse affect â€“ Sets the relative intensity (power) of the diffused light.
Diffues affect is a bit like a dimmer switch moving the slider to the left lowers the intensity, towards the right increases the intensity, Note, moving either the diffuse colour or the diffuse affect towards the left (black or 0 can mean virtually eliminating the light .
- Specular color â€“ Sets the specular color of the light.
- Specular affect â€“ Sets the relative intensity (power) of the Specular light.
The specular colour reacts with the object colour, which means the actual colour at render time may not be the same as the specular colour applied, in the same way colour varies in a paint program when using multiply, add, etc.
- Pos â€“ This Sets the X,Y,Z position of the light relative to the objects being used as the luminance source, it sets the source position where 0,0,0 = the centre of extents of the object, this needs to be remembered if the source object is a box, sphere etc. it becomes important when shadows is turned on.
in the images below the sphere is 160 units radius.
- Dir â€“ Sets the X,Y,Z direction of the light relative to the position.
To force the light at an angle other that the normal x,y,z axes, one adds a figure in a second column, for example 1,0,1
- Top â€“ Defines a second axis which is perpendicular to the direction used for the rotation if the lights display is not circular.
- Spot Angle
- Additional Spot Angle
- Radial Intensity Decay
- Shadows â€“ Sets whether the light will generate shadows or not.
- Shadow Color â€“ Specifies the color of shadows created by the light.
Unfortunately shadows are not working correctly on my computer at present, therefore no images of its use have been included..
- Shadow Map â€“ Shadow maps are generated by testing whether or not each specific pixel is visible from the light source. This accomplished by comparing each pixel to a depth image (z-buffer) of the light source's view, stored in the form of a texture file. Shadow maps can accelerate the rendering of shadows, but usually as the cost of some quality.
- Shadow Map Resolution â€“ Sets the resolution of the shadow map. Values must be a multiples of 2.
- Shadow Map Blur â€“ Sets a blur factor on the shadow map, reducing jagged edges and transitions.
Because shadow map compares depth map pixels rather than computing each pixel from the light source at render time, shadow maps can be faster that other render modes, however the resolution of the depth map plays an important part in how the shadows appear, if the shadow resolution is too low the shadow can be pixelated, however increasing the resolution too high can be a little slower to render
- Intensity Decay
The final setting for the Spot light is Intensity / intensity decay, this is accessed by clicking the '+' sign against the light within the render manager, the properties differ depending on which intensity decay is set in the main section, if No Decay is set it is used to increasing / decrease the intensity, i.e. the brightness of the light, when set to a decay equation, it adjusts the decay.
See RedSDK Intensity Decay page for options.
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RedSDK Luminance Reference