Scene simulator

Claim 1

In a training apparatus in which an operator can gain experience in the performance of a predetermined task without the cost and without the risk that is inherent in the performance of the task in the real world, the training apparatus including a computer generated video visual display of a predetermined scene composed of features, lines and surfaces, and some of the surfaces may occult other features in the scene, the image generator comprising: general purpose computer means including a central processing unit and a data base for containing information on every feature to be displayed; general processor means including a perspective transformation means to convert isometric coordinates to perspective coordinates connected at the output of said computer means; image generator means connected to receive an output signal from said perspective transformation means and including a texture generator, an occulting system, and a display interface means; said occulting system including data buffer means, a line memory circuit, and a separate surface memory circuit; said line memory circuit having sufficient locations to store data at locations relating to the maximum number of lines occurring in all occulting surfaces; said surface memory circuit having one memory location for each surface, each memory location storing horizontal start and end points of said surface, maximum value to observer, and maximum value of top points of said surface; and means for comparing data of each incoming feature successively with data stored in surface memory locations to determine whether the possibility of occulting is indicated, so that said data of an incoming feature is connected into said data buffer means, when no occulting is indicated, for connection to said display interface means.