User's Manual

Table Of Contents
2D S3C2450X RISC MICROPROCESSOR
19-4
4 RENDERING PIPELINE
The rendering pipeline of 2D is illustrated in Figure 19-3. The functionality and related registers of each stage are
introduced in detail in the rest of this chapter.
Figure 19-3. 2D Rendering Pipeline
4.1 PRIMITIVE DRAWING
Primitive Dra
wing determines the pixels to fill, and pass their coordinates to the next stage for further operations.
2D supports three types of primitive drawing: 1) line/point drawing; 2) bit block transfer; 3) color expansion.
4.1.1 Line/Point Drawing
Line Drawing renders a line between the starting point (sx, sy) and the ending point (ex, ey) specified by the user.
If the distance of these two points along y axis is greater than that along x axis ( |ey - sy| > |ex - sx| ), the Major
Axis should be set to y-axis; otherwise, x-axis. If y-axis is the Major Axis, the y-coordinate of a pixel on the line is
increased or decreased by 1 from its preceding pixel, while the x-coordinate increased or decreased by X-INCR
(smaller than 1). In the same vein, if x-axis is the Major Axis, the x-coordinate is increased or decreased by 1
while the y-coordinate by Y-INCR. Note that X-INCR and Y-INCR should be given in 2’s complement format as
shown below.
Figure 19-4. Data Format