TVP4020
Programmers Reference Manual
Graphics Programming
53
It is recommended that for OpenGL rendering, the ContinueNewLine
command is not used and individual segments are rendered.
5.3.3
Points
P
ERMEDIA
supports a single pixel aliased point primitive. For points larger
than one pixel, trapezoids should be used. The fields in the Render
command register are described in detail later, however, in this case the
PrimitiveType field in the Render command should be set to equal
P
ERMEDIA
_POINT_PRIMITIVE. The pseudocode portion to render an
aliased unity sized point is:
// Set the Rasterizer mode to the default, see
// §5.3.11
RasterizerMode (0)
// Set-up the start values and the deltas.
// Note that the X and Y coordinates are converted to
// 16.16 format
StartXDom (X<<16)
StartY (Y<<16)
// Set-up the render command.
render.PrimitiveType = PERMEDIA_POINT_PRIMITIVE
// Render the point
Render (render)
5.3.4
Rectangles
The rectangle primitive is restricted to integer pixel positions only;
rectangles requiring sub-pixel positioning should use the trapezoid
primitive. The rectangle is defined with two registers, RectangleOrigin
which defines the X and Y start point, and RectangleSize which defines
the width and height. The direction in which the rectangle is filled can be
controlled by the Render command, with separate control of fill direction
in X and Y making the primitive suitable for copy operations.
5.3.5
Spans
Shapes more complex than points, lines or trapezoids may be drawn as
a series of spans. Each span may be drawn as a horizontal line or as a
single pixel high trapezoid. Both are special cases of 5.3.2 and 5.3.3 in
that the loading of certain registers may be omitted e.g. dXDom, dXSub
and dY. However, trapezoids can optionally use block writes for constant
color spans and so may be preferable.
Содержание TVP4020 PERMEDIA 2
Страница 1: ...Texas Instruments TVP4020 PERMEDIA 2 Programmer s Reference Manual Issue 4 ...
Страница 47: ...Memory I O and Organization TVP4020 Programmers Reference Manual 38 Texture address TextureBaseAddress T W S ...
Страница 284: ...TVP4020 Programmers Reference Manual A Gouraud Shaded Triangle 275 ...
Страница 292: ...TVP4020 Programmers Reference Manual Register Tables 283 ...
Страница 314: ...TVP4020 Programmers Reference Manual Index 305 ...
Страница 315: ...Index TVP4020 Programmers Reference Manual 306 Index ...
Страница 323: ...Index TVP4020 Programmers Reference Manual 314 ...