Systems and methods for rendering visual effects that are a function of depth

In a rendering system for rendering an image on an output device, a method for rendering the image having a first object that is transparent or translucent and generally contains a second object and a visibility-reducing effect, wherein the visibility-reducing effect at least partially obscures the second object, the method comprising the acts of:

• identifying a first depth value representing a distance a between a viewpoint and the second object;
• identifying a second depth value representing a distance between said viewpoint and the first object;
• generating a first visibility value by applying said first depth value to a first visibility function;
• generating a second visibility value by applying said second depth value to a second visibility function;
• generating an adjusted visibility value based on a difference between said second visibility value and said first visibility value;
• and
• applying said adjusted visibility value to the second object prior to compositing image data associated with the second object in a buffer, wherein said adjusted visibility value at least partially obscures the second object.

In a rendering system that includes an output device, a method for rendering on the output device an image that includes a generally contained visibility-reducing effect, the method comprising the acts of:

• using a first pipeline to perform the acts of:
• identifying a first depth value representing a distance between a viewpoint and a distal end of a segment of the visibility-reducing effect;
• and
• generating a first visibility value by applying said first depth value to a first visibility function;
• using a second pipeline to perform the acts of:
• identifying a second depth value representing a distance between a viewpoint and a proximal end of said segment of the visibility-reducing effect;
• and
• generating a second visibility value by applying said second depth value to a second visibility function;
• generating an adjusted visibility value based on a difference between said second visibility value and said first visibility value;
• and
• applying said adjusted visibility value to image data that represents the image that is rendered on the output device.

A computer program product for implementing in a computer system a method for applying to an object a segment of a visibility-reducing effect positioned between the object and a viewpoint of an image that is to be rendered on a display screen of the computer system, the computer program product comprising:

• a computer readable medium carrying executable code that, when executed by the computer system, implements the acts of:
• identifying:
• a first depth value representing a distance between the viewpoint and an object located, with respect to said viewpoint, at a distal end of the segment of the visibility-reducing effect that at least partially obscures said object;
• and
• a second depth value representing a distance between a proximal end of the segment and said viewpoint;
• generating a first visibility value by applying said first depth value to a visibility function;
• generating a second visibility value by applying said second depth value to said visibility function;
• generating an adjusted visibility value based on a difference between said second visibility value and said first visibility value;
• and
• applying said adjusted visibility value to said object prior to compositing image data associated with the object in a buffer.