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TVP4020
Programmers Reference Manual
Graphics Programming
105
// If software writemasks are to be used then they are
// set appropriately, and the framebuffer set-up to do
// extra read operation
// Disable the Color DDA unit, we do not want to
// associate a color with this fragment.
colorDDAMode.UnitEnable = PERMEDIA_FALSE
ColorDDAMode(colorDDAMode)
// Define the region we wish to copy from.
StartXDom (200<<16)
StartXSub (300<<16)
dXSub (0)
dXDom (0)
StartY (0)
dY (1<<16)
Count (100)
render.PrimitiveType = PERMEDIA_TRAPEZOID
Render (render)
// Start the rasterization
5.11
Color DDA Unit
The Color DDA unit is used to associate a color with a fragment
produced by the Rasterizer. This unit should be enabled for rendering
operations and disabled for pixel rectangle operations (i.e. copies,
uploads and downloads).
5.11.1
RGBA and Color-Index(CI) Modes
Two color modes are supported by P
ERMEDIA
, true color RGBA and
color index (CI).
P
ERMEDIA
's internal color representation is RGBA with 8 bits per
component:
0
8
16
24
31
Blue
Alpha
Green
Red
Figure 5.37
Color Representation
This format is the same for all the different framebuffer configurations
supported. If the number of bits in the framebuffer for a color component
is less than 8 then the color value is left shifted into the most significant
bits of that components field. The unused least significant bits should be
set to zero.
Summary of Contents for TVP4020 PERMEDIA 2
Page 1: ...Texas Instruments TVP4020 PERMEDIA 2 Programmer s Reference Manual Issue 4 ...
Page 284: ...TVP4020 Programmers Reference Manual A Gouraud Shaded Triangle 275 ...
Page 292: ...TVP4020 Programmers Reference Manual Register Tables 283 ...
Page 314: ...TVP4020 Programmers Reference Manual Index 305 ...
Page 315: ...Index TVP4020 Programmers Reference Manual 306 Index ...
Page 323: ...Index TVP4020 Programmers Reference Manual 314 ...