Hands On DarkBASIC Pro - Digital Skills

� Space within the 3D world is measured in world units. These do not relate to real
world units.
� A point in 3D space is defined by its distance along each of the axes.
� 3D objects have their own local axes.
� 3D objects can be rotated about their own local axes.
� Rotations are measured in degrees.
� Rotation is in a clockwise direction (as viewed from the positive end of the axis
of rotation).
� DarkBASIC Pro provides 3D vector objects in which the coordinates of a point
in 3D space can be stored.
� 3D objects are constructed from polygons.
� The simplest polygon is the triangle.
� The end of a line within a polygon is known as a vertex.
� The line between two vertices is known as an edge.
� More detailed objects require more polygons.
� Increasing the number of polygons used in a scene increases the load on the
computer.
� When faced by a heavy load, the computer will output at a reduced frame rate.
� Images can be used to texture a 3D shape to increase realism.
� Some images can contain alpha channels which effect lightness when the image
is used to texture a surface.
� Virtual cameras determine which parts of the 3D world are shown on the screen.
� Lights can be added to a scene to help create the desired atmosphere.
� The effects of lights on a surface are calculated using surface normals or vertex
normals.
� Every polygon has an associated surface normal.
� A surface normal is a vector at right angles to its polygon.
� Using surface normals to calculate shading can result in a patchy effect.
� Every vertex of a polygon has an associated vertex normal.
� Vertex normals may be used to create smoother shading effects, but at the cost
of more complex calculations.
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754 DarkBASIC Pro: 3D - Concepts and Terminology