Unit 6: Apply 2D Game Design

Unit 6: Apply 2D Game Design Perspective, Scene Design and Basic Animation

In this Unit You will learn: • To recognize a basic 2D game engine interface and the associated terminologies. • To illustrate 2D game sprites, actions, events and sounds. • To execute 2D games that represent different genres. • To illustrate 2D game levels.

Game Engine Interface • A game engine is a software system designed for the creation and development of 2D or 3D video games. • The game content such as animations, sounds, artificial intelligence, and physics are called “assets”. http://ivanleben.blogspot.com/2010/12/over-last-few-years-while-studying.html

2D Games • 2D games: • use graphics that are created in 2D graphic software • usually produced by an X and Y array of pixels • have a flat appearance • can have an illusion of depth through shading techniques or assets using layers.

Types of 2D Games • Illusion of depth can be created using: • Parallel projection (axonometric) allows developers to create large complex gameworlds with few art asset by dividing the art into sprites or tiles and reusing them repeatedly. • Top down perspective (bird’s eye view, overhead view or helicopter view) refers to a cameras angle that shows the player and the area around them from above. Was once common in 2D RPGs, Wargames, Simulation games as well as in action and action-adventure games such as Legend of Zelda and Grand Theft Auto. • Side Scrolling Game is where the viewpoint is taken from the side. Characters generally move from the left side of the screen to the right. Examples are Sonic the hedgehog, Double Dragon. • Billboarding-objects are represented by 2-dimensional images applied to a single polygon which is typically kept perpendicular to the line of sight. • Parallax Scrolling is when 2D graphics move independently of each other creating an illusion of depth. Such as background scrolling from right to left while the character is in front of the background.

2.5D Games • Use 2D graphics that are drawn from a 2-point perspective • Sometimes called pseudo-3D graphics, ¾ perspective. These are informal terms used to describe graphical projections and techniques that try to "fake” three dimensionally by using some form of parallel projection, where the point of view if from a fixed perspective, but reveals multiple facets of a object. • Player’s movement is restricted to a 2-dimensional level in an otherwise.

Orthographic Projection

Types of Drawings for game design • Perspective -Perspective drawing is used for both technical work as well as artistic. These drawings give the illusion of space and distance by using a vanishing point. Perspective drawings are much like a person sees the world. These drawings are not done to scale and are used mostly for rendering or mock-ups of a finished project.

Types of Drawings for game design • Oblique-An oblique drawing usually shows the front of object but also one side and the top. These drawings are not done to scale and are drawn with vertical and horizontal lines that are drawn 45 degrees to the horizontal. The main difference in oblique drawings compared to others like isometric or orthographic is that the measurements on the 45-degree lines are drawn at half their true length.

Types of Drawings for game design • Isometric- Isometric drawings show all three planes of an item in a single drawing. They are often used to create plans for piping grids. The lines in an isometric drawing are vertical and depth is achieved by using angles that are 30 degrees to the horizontal. • These 3-D drawings are drawn to scale and represent a realistic view of an object.

Types of Drawings for game design • Orthographic-These types of drawings are two-dimensional and are a projection of the outline of an object. They usually show the top, front and right side views of an object. Orthographic drawings are either full-size or drawn to scale and the dimensions of the object are included along each line. The MIT website suggests imagining an item in a clear box and each surface of the box would represent an orthographic projection or drawing.

Skyboxes • Example is Half-Life 3, used in many 3D games to represent distant background objects that are not worth rendering in real time.

Parallax Scrolling • Examples are Sonic the Hedgehog and Street Fighter

Types of perspective • http://glasnost.itcarlow.ie/~powerk/GeneralGraphicsNotes/projection/projection_viewing.html • In addition, 3D graphical techniques such as bump mapping (technique used in 3D for simulating bumps and wrinkles on an object) and parallax mapping are often used to extend the illusion of three-dimensionality without substantially increasing the resulting computational overhead introduced by increasing the polygon count. • http://www.explore-drawing-and-painting.com/perspective-drawing.html

Isometric/axonometric projection: Examples of games are The Sims, Diablo and Zaxxon

Oblique Projection Oblique projection: Examples are Ultima VII and Paperboy

First Person Perspective • Graphical representation rendered from the viewpoint of the player character, ie the viewpoint from the cockpit of a vehicle. • The most notable genre to make use of this device is the first person shooter genre. Adventure games to Flight Simulations have made use of this device as well. • These type games are usually avatar based, where the game displays what the avatar would see with the avatar’s own eyes. This viewpoint also is used to represent the driver of a vehicle.

Third Person Perspective • Graphical representation rendered from a view that is some distance away usually behind a character. • Allows players to see a more strongly characterized avatar. An example of this would be Super Mario 64 and Tomb Raider series.

Perspective • Straight lines in a perspective projection do not appear straight in a fisheye projection.

Parallel projection • Depth is shown by parallel projection, flat planes and drop shadows.

Difference between Orthographic and Perspective Views

Difference between Orthographic drawings and Isometric Drawings • Orthographic drawings are 2D representations of the different views of an object(s). Take for instance the layout of a bedroom. Each wall would be drawn to scale with all the details of the windows, doors, trim etc. None of this would have shading, but may have color added to it to define the different aspects of what you are viewing. • Isometric drawings are meant to depict a 3D image of an object that is to be designed with the exception that this type of drawing is not truly done in perspective. All vertical lines are parallel to one another, as are the 30 degree lines drawn diagonally up to the right and the 160 degree lines to the left. When drawn on a drafting board a 30/60/90 degree triangle is used. Notice how all the degrees add up to 180.

What projection is this?

Basic Concepts • The horizon line is a theoretical line that represents the eye level of the observer. The horizon line is the same as the horizon (the edge of the land against the sky) only on a large flat plane like the ocean. Most of the time geographic features (hills) and other objects (trees and buildings) make the horizon above the horizon line.

Look at the three sketches below. The same telephone pole is in the same position in all of the formats. The horizon (line) is different. Can you tell where you are in relationship to the poles?

Vanishing Points • Vanishing points (usually) on the horizon line where receding lines (planes) converge. The vanishing point (v.p.) is on the horizon line when an objects has horizontal planes that are parallel to the ground. When the object's planes are inclined the vanishing points can be above or below the horizon line.

Objects that are placed parallel to one another use the same vanishing points. Objects set at different angles each have their own vanishing points.

ONE-POINT PERSPECTIVE One-point perspective is what you see when you look straight at the side of an object. It uses only one vanishing point, hence its name.

The line of sight in one-point perspective is perpendicular (at a right angle to) the side of the cube in these examples. That means you see the near side in plane view (actual shape undistorted by perspective).

Two Point Perspective • Two-point perspective is used when you look at or into the corner of an object. There are two vanishing points since the two sets of sides are receding in two different directions.

Rendering • Process of generating an image from a model by means of computer programs. • Rendering is one of the major sub-topics of 3D computer graphics. In the graphic pipeline it is the last major step, giving the final appearance to the models and animation. • Rendering has use in architecture, video games, simulators, movie or TV visual effects and design visualization where each employs a different balance of features and techniques. • There are a variety of renderers available, some are integrated into modeling and animation packages and some are stand alone. On the inside a renderer is an engineered program related to light physics, visual perception, mathematics and software development.

Unit 6: Apply 2D Game Design