Eight Directional Sprite System

EDSS is a system that allows you to display 2-dimensional sprites in the 3D world in the way used in some 3D oldschool FPS games.
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INTRODUCTION

The creators of the first computer games implemented in 3D technology, encountered many problems related to the efficiency of the equipment at the time. The mere rendering of the three-dimensional world of the game absorbed most of the computing power of the computer without leaving it much for the rest of the calculations.

Therefore, to display characters and other models, it was decided to use the so-called sprites (ghosts) or two-dimensional images representing a given character or model. It was so-called 2.5D characters.

The character's animation took place through a fast, continuous replacement of the images of a given sprite. For the character, eight separate animations were prepared - one for each of the eight different directions in which the character could be oriented.

All pictures for a given character or game model (all animations) were stored in one texture - so-called atlas. The clever system of calculating the image number allowed to display the picture appropriate for a given frame of animation and the angle resulting from the direction of camera observation and the direction in which the given model was returned.

Each EDSS actor consists of two separate objects. The main object is responsible for the position and orientation of the actor in the scene. The second, subordinate object is responsible for the graphical representation of the actor.

The Actor Billboard component deals with determining which image from a given animation should be displayed by the Sprite Renderer component and additionally it deals with setting the sprite so that it always faces the camera. Just before rendering by the current camera, the Actor Billboard component will use the current actor vector to determine the image to be displayed.

In order to display the actor on the screen, the Actor Billboard component should be supplied with the animation to play. Animation in EDSS contains a sequence of frames (images) to display in the right order and at the appropriate speed.

In the case of 8-directional sprites, each frame contains a definition of eight pictures (one for each of the 8 directions of the character).

However, in the case of 1-directional sprites, from each frame, only one (the first) image is used. For static actors which do not have any animations, you can create the Actor Animation with only one frame.