Chaoscope Manual

There are currently five different rendering modes available in Chaoscope, from Gas, which is a very simple monochrome accumulation render, to Solid, a ray-tracing like render that includes shadows and specular highlights. Some attractors will look better rendered in one mode than another, depending on their fractal dimension.

The Gas rendering method, as well as the next three rendering modes, is based on pixel accumulation : after each iteration, the pixel value corresponding to the current orbit position is increased (the pixel becomes brighter with the default gradient) very much like a crystal on a photographic film being hit by a photon. When the image is updated, all the pixel values are normalized, mapped to the gradient (black to white by default) according to the Contrast and finally Gamma is applied.
The higher the number of iterations, the sharper the attractor rendering will be. With the default 640 by 480 image size, 1,000,000 iterations will be necessary to get a clear idea of the attractor features. Subsequent iterations will reduce chaos induced noise and will enhance details.

Once the image is rendered, two parameters can be adjusted to improve the rendering quality of the attractor. These parameters are:

Monitors, especially old CRTs, don't display brightness intensities linearly. For instance, a mid-gray at 50% of absolute luminosity will appear darker than it should on a screen (i.e. 40% of apparent luminosity). As a result, the dim features of an attractor would be hardly noticeable if the Gamma correction wasn't applied to the rendered image. It also helps brightening areas of the attractor with low orbit hits. As a side effect, colors tend to lose their saturation when the Gamma value is high. The default Gamma value is 2.5 for Gas and Liquid methods, 2 for Light and Plasma, 1 for Solid. The Gamma parameter is common to all rendering methods.

Similar to the brightness setting of a monitor, it's a linear multiplication factor. The default value is 2. It may need to be lowered for attractors with a high fractal dimension. The Contrast parameter is common to Gas and Liquid rendering methods and is similar to Brightness for Light and Plasma.

Gas is the fastest rendering mode. It can be used as an improved preview, before going for a more complex rendering method.

As the basic accumulation algorithm the way it was implemented in Chaoscope lacks of natural visual clues like haze and perspective, it can be difficult at times to "read" the shape of a static convoluted attractor. To make it easier, the Liquid rendering method adds depth and opacity to the Gas rendering through the use of a z-buffer.

The Light rendering mode is similar to the Gas mode, with the difference that a color is given to each point (each position of the orbit) rather than each pixel. The colour is obtained by adding two different gradients.
The first gradient, a light spectrum by default, depends on the distance between two successive orbit positions, or what can be called the "orbit speed". A reddish tint denotes a slow orbit and is usually located in the center of the attractor. Purple shades denote a fast orbit and are usually located at the periphery of the attractor.
The second gradient, which goes from black to gray by default, is based on the angle formed between three successive orbit positions. The sharper the angle is the lighter the pixel will be.
Different gradients may be loaded, as described in the Interface chapter. Three examples of the gradient arithmetic are shown below. The result obtained will be hard to predict at first, so it is a good idea to start experimenting with simple two-colors gradients, like those provided with the program.
Brightness replaces Contrast in Light and Plasma modes, but has a the same purpose.

The Plasma rendering mode is similar to Light rendering with added opacity.

The Solid mode uses the same tools as the Liquid mode, an accumulation buffer and a z-buffer, but renders them differently. The accumulation buffer is used for transparency and the z-buffer is rendered using a ray-tracing-like lighting method which includes specular highlights and shadows. Once the image is rendered, seven parameters specific to the Solid method can be adjusted. These parameters are :

Opacity : This is the transparency level of the attractor and shadows. The default value is 8.

Roughness : This parameter sets the size of the specular highlights on the attractor. The default value is 0.008.

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