Glossary

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Glossary
3D Three-dimensional.
3D driver See drawing engine.
accelerator See graphics accelerator.
aliasing The jagged edges (or staircasing) that result from drawing an image on a raster device such as a computer screen. Compare antialiasing.
alpha channel A color component in some color spaces whose value represents the opacity of the color defined in the other components.
antialiasing The smoothing of jagged edges on a displayed shape by modifying the transparencies of individual pixels along the shape's edge. Compare aliasing.
antialiasing mode A draw context state variable that determines the kind of antialiasing applied to a drawing context.
API See application programming interface.
application programming interface (API) The total set of constants, data structures, routines, and other programming elements that allow developers to use some part of the system software.
area stipple pattern One of 32 patterns that specifies which bits in an area are to be drawn and which are masked out. Compare line stipple pattern.
background color The color that is used when a buffer is cleared by QARenderStart.
bitmap A two-dimensional array of values, each of which represents the state of one pixel. Defined by the TQABitmap data type. See also pixmap.
blend matte A pixel map that defines the blending of the pixels in a source and destination image. The alpha channel value of a pixel in the matte governs the relative intensity of a source pixel when copied to the destination image.
cache See draw context cache.
clamp For a shader effect, to replicate the boundaries of the effect across the portion of the mapped area that lies outside the valid range 0.0 to 1.0. Compare wrap.
clipping region A region to which an application can limit drawing. The initial clipping region of a graphics port is an arbitrarily large rectangle: one that covers the entire QuickDraw coordinate plane. An application can set the clipping region to any arbitrary region, to aid in drawing inside the graphics port.
CLUT See color lookup table.
color lookup table (CLUT) A data structure that maps an index to an actual color.
constant shading A method of shading surfaces in which the incident light color and intensity are calculated for a single point on a polygon and then applied to the entire polygon. Compare Gouraud shading, Phong shading.
constructive solid geometry (CSG) A way of modeling solid objects constructed from the union, intersection, or difference of other solid objects.
CSG See constructive solid geometry.
CSG equation A value that encodes which CSG operations are to be performed on a model's CSG objects.
CSG ID A number, attached to an object as an attribute, that identifies an object for CSG operations.
deep z buffering Z buffering with a resolution of greater than or equal to 24 bits per pixel.
device See hardware device, virtual device.
device structure A data structure that contains basic information about a virtual device. Defined by the TQADevice data type.
diffuse coefficient A measure of an object's level of diffuse reflection.
diffuse color The color of the light of a diffuse reflection.
diffuse reflection The type of reflection that is characteristic of light reflected from a dull, nonshiny surface. Also called Lambertian reflection. Compare specular reflection.
diffuse reflection coefficient See diffuse coefficient.
double buffering A technique that uses two buffers to store images.
draw context A structure that maintains state information and other data associated with a drawing engine and device. A draw context is defined by the TQADrawContext data structure.
draw context cache A draw context whose QAContext_Cache flag is set.
draw context method See private draw context method, public draw context method.
draw context state variable See state variable.
draw context structure A data structure that contains basic information about a draw context. Defined by the TQADrawContext data type.
drawing engine Any software component that supports the low-level rasterization operations required for interactive 3D rendering.
flat shading See constant shading.
GDevice data structure A data structure of type GDevice that holds information about the physical characteristics of a video device or offscreen graphics world.
Gouraud shading A method of shading surfaces in which the incident light color and intensity are calculated for each vertex of a polygon and then interpolated linearly across the entire polygon. Compare constant shading, Phong shading.
Gouraud vertex A vertex used for drawing Gouraud-shaded triangles, and also for drawing points and lines. A Gouraud vertex is defined by the TQAVGouraud data structure. Compare texture vertex.
graphics accelerator Any hardware device used to accelerate rendering.
graphics device A virtual device that represents a video device (such as a plug-in video card or built-in video interface) that controls a screen, or an offscreen graphics world (which allows your application to build complex images off the screen before displaying them). For a video device or an offscreen graphics world, a graphics device is defined by the GDHandle data type. Compare memory device.
hardware device A physical part of a Macintosh computer, or a piece of external equipment, that can exchange information with applications or with the Macintosh Operating System. Compare virtual device.
hidden line removal The process of removing any lines in a model that are hidden by opaque surfaces of objects.
hidden surface removal The process of removing any surfaces in a model that are hidden by opaque surfaces of objects. Compare backface culling.
high-quality texture mapping Texture mapping that uses trilinear interpolation or an equivalent algorithm.
image The two-dimensional product of rendering.
image structure A data structure that defines a bitmap or a pixmap. Defined by the TQAImage data type.
indexed triangle A data structure that defines three vertices and a set of triangle flags. Defined by the TQAIndexedTriangle data type.
interactive renderer A renderer that uses a fast and accurate algorithm for drawing solid, shaded surfaces. See also wireframe renderer.
interpolated shading See Gouraud shading.
Lambertian reflection See diffuse reflection.
Lambert illumination A method of calculating the illumination of a point on a surface based on diffuse reflection. Compare Phong illumination.
line stipple pattern A pattern that specifies which bits in a line are to be drawn and which are masked out. Compare area stipple pattern.
matte See blend matte.
memory device A virtual device that represents an area of memory. A memory device is defined by a structure of type TQAMemoryDevice. Compare graphics device.
memory device structure A data structure that contains basic information about a memory device. Defined by the TQAMemoryDevice data type.
method selector A value that indicates of which method a drawing engine should return the address.
mipmapping A method of storing texture maps in an array of pixel images of varying pixel depths. The first element in the array must be the mipmap page having the highest resolution, with a width and height that are even powers of 2. Each subsequent pixel image in the array should have a width and height that are half those of the previous image.
notice method An application-defined method that is called asynchronously at certain specified times during the operations of QuickDraw 3D RAVE.
OpenGL A graphics library developed by Silicon Graphics that you can use to create, configure, render, and interact with models of three-dimensional objects.
Phong illumination A method of calculating the illumination of a point on a surface based on both diffuse reflection and specular reflection. Compare Lambert illumination.
Phong shading A method of shading surfaces in which the incident light color and intensity are calculated for a series of points along each edge of a polygon and then interpolated across the entire polygon. Compare constant shading, Gouraud shading.
pixel image See pixmap.
pixel map See pixmap.
pixmap A two-dimensional array of values, each of which represents the color of one pixel. Defined by the TQAPixmap data type. See also bitmap.
plug-in See drawing engine.
private draw context method A draw context method that is called only by QuickDraw 3D RAVE. Compare public draw context method.
public draw context method A method to which a pointer is contained in one of the method fields of a draw context structure. Compare private draw context method.
QuickDraw A collection of system software routines on Macintosh computers that perform two-dimensional drawing on the user's screen.
QuickDraw 3D A graphics library developed by Apple Computer, Inc., that you can use to create, configure, render, and interact with models of three-dimensional objects. You can also use QuickDraw 3D to read and write 3D data.
QuickDraw 3D Acceleration Layer The hardware abstraction layer that is comprised of QuickDraw 3D RAVE and all registered drawing engines.
QuickDraw 3D Renderer Acceleration Virtual Engine (RAVE) The part of the Macintosh system software that controls 3D drawing engines.
rasterization The process of determining values for the pixels in a rendered image. Also called scan conversion.
RAVE See QuickDraw 3D Renderer Acceleration Virtual Engine.
rectangle structure A data structure that defines the area into which a drawing engine is to draw. Defined by the TQARect data type.
render To create an image (on the screen or some other medium) of a model.
renderer The software or hardware that renders an image of a model. See also interactive renderer, wireframe renderer.
rendering The process of creating an image (on the screen or some other medium) of a model. See also rasterization.
scan conversion See rasterization.
scene cache See draw context cache.
scissor box A rectangle that determines which pixels can be modified by drawing commands.
smooth shading See Gouraud shading, Phong shading.
specular coefficient A measure of an object's level of specular reflection.
specular color The color of the light of a specular reflection.
specular control See specular reflection exponent.
specular exponent See specular reflection exponent.
specular highlight A bright area on an object's surface caused by specular reflection.
specular reflection The type of reflection that is characteristic of light reflected from a shiny surface. Compare diffuse reflection.
specular reflection coefficient See specular coefficient.
specular reflection exponent A value that determines how quickly the specular reflection diminishes as the viewing direction moves away from the direction of reflection.
state variable A variable associated with a draw context that maintains state information about the draw context. See also state value, tag.
state value The value of a state variable.
tag A unique identifier associated with a state variable.
texture magnification function A function that is called when a pixel being textured maps to an area that is less than or equal to one texture element. See also texture minifying function.
texture mapping A technique wherein a predefined image (the texture) is mapped onto the surface of an object in a model. See also high-quality texture mapping.
texture mapping filter mode A state variable that determines how a drawing engine performs texture mapping filtering.
texture mapping operation A state variable that determines how a drawing engine performs texture mapping.
texture minifying function A function that is called when a pixel being textured maps to an area that is greater than one texture element. See also texture magnification function.
texture mode A value that determines certain features of a texture map.
texture vertex A vertex used for drawing triangles to which a texture is to be mapped. A texture vertex is defined by the TQAVTexture data structure. Compare Gouraud vertex.
transparency The ability of an object to allow light to pass through it.
transparency blending function A function that determines the kind of transparency blending applied to a drawing context when combining new pixels (the "source" pixels) with the pixels already in a frame buffer (the "destination" pixels).
triangle mode A value that determines how a drawing engine draws a triangle.
triangle mesh A mesh composed entirely of triangles.
trimesh See triangle mesh.
uv clamping See clamp.
uv wrapping See wrap.
vertex A dimensionless position in three-dimensional space at which two or more lines (for instance, edges) intersect. Defined by the TQAVGouraud and TQAVTexture data types. See also Gouraud vertex, texture vertex.
vertex mode A value that determines how a drawing engine interprets and draws an array of vertices.
virtual device A representation of a hardware device that is the destination for a drawing engine. A virtual device is defined by a structure of type TQADevice. Compare hardware device. See also graphics device, memory device.
visual line determination See hidden line removal.
visual surface determination See hidden surface removal.
wireframe renderer A renderer that creates line drawings of models. See also interactive renderer.
wrap For a shader effect, to replicate the entire effect across the mapped area. Compare clamp.
z perspective control A state variable that determines whether the z or the invW field of a vertex (of type TQAVGouraud or TQAVTexture) is to be used for hidden surface removal.
z sorting function A function that determines which surfaces are to be removed during hidden surface removal.
z test mode See z sorting function.