VS Manual: 13. Glossary | Table of Contents |
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[From “The Klk’k guide to one’s interstellar locale” 12th ed. Ivan Kltakln tr. J. Valthorpe catalogued Andolian central distribution, 3263]
Space: n.“Vertex Arrays” - Vertex (drawing) data is stored in an array (record). OpenGL only needs to call on the array, not execute every command in the array. In effect, OpenGL draws a starship each time one is needed (e.g. need five, draw it five times).
“Compiled Vertex Arrays” - Vertex data in an array can be locked down when it is expected to be used multiple times. In effect, OpenGL does not recompute the locked array data until all surfaces using that data have been drawn. OpenGL copies a starship only when the vertex array is compiled. If more than one ship is on screen, then it will only need to download it to the card the first time.
“Display Lists” - This setting takes vertex commands and stores them for later execution. That is, it defines your drawing for multiple, later executions. While vertex arrays can do this with a lesser amount of memory, display lists can operate faster. Graphics hardware may store display lists in dedicated memory, thereby increasing speed and efficiency, and offsetting the need for extra memory. So, with this setting a starship will be downloaded to the video card only when the starship is drawn. This is faster than copying it each time it is drawn. Note: it is recommended that you not use this setting if you do not have high-powered graphics hardware.
“Separate Specular Color Vertex Lighting” - This setting identifies the bright specular highlights that occur when light hits an object’s surface, and projects them onto the reflectivity analysis of that surface. In effect, you get a shine effect on an object that changes, depending on where both the viewer and the light source are.
“Per Pixel Lighting” - This setting offers the ability to calculate lighting effects at the pixel level, greatly increasing precision and realism in a scene. This setting, in effect, makes the lighting effects sharper and more defined. Per-pixel specular lighting is best, when used in conjunction with a pixel shader. It’s not truly necessary, but you suffer a big performance hit, otherwise. GeForce3, Radeon 8500 and later video cards all have such a shader. If game performance is slow, or you have an older generation card, do not select this option.
“Reflection” - An environment map is a picture of the background surrounding an object. When the visual mesh is declared to be specular, this map is projected onto the reflectivity analysis of a surface (e.g. your view of the surface). One result is, that objects become capable of reflecting light and behaving as a mirror.
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