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TVP4020
Programmers Reference Manual
Initialization
133
register would be set to 0; to select the back buffer it would be set to the
Back buffer pixel offset. The localbuffer offset should be added to the
window base offset whenever the LBWindowBase register is updated.
The value loaded into the TextureBaseAddress is a count of the number
of texels from the start of memory. Thus the byte offset should be
modified to be a texel count when used. In practice, some sort of texture
allocation scheme will be needed where textures are allocated starting at
the texture memory offset. The final value loaded into the
TextureBaseAddress register will be the texture memory offset
to the required texture with the final value converted to a texel count
from the start of memory.
P
ERMEDIA
supports a range of localbuffer configurations. During
initialization, fields in the LBWriteFormat and LBReadFormat registers
should be set to appropriate values. For example:
lbReadFormat.DepthWidth = 3 // 15 bit depth buffer
lbReadFormat.StencilWidth = 3 // 1 bit stencil
LBReadFormat(lbReadFormat)
lbWriteFormat.DepthWidth = 3 // 15 bit depth buffer
lbWriteFormat.StencilWidth = 3 // 1 bit stencil
LBWriteMode(lbWriteFormat)
Note it is possible to dynamically change the number of bits allocated to
the depth and stencil buffers, for instance on a per window basis.
Set the framebuffer and localbuffer read units to their default data
sources:
fbReadMode.DataType = PERMEDIA_FBDATA
FBReadMode(fbReadMode)
lbReadMode.DataType = PERMEDIA_LBDEFAULT
LBReadMode(lbReadMode)
The following registers are typically only needed for certain specialized
operations. Normally their offsets will be zero.
FBSourceOffset(0)
FBPixelOffset(0)
LBSourceOffset(0)
6.2.7
Host Out Unit
Under some circumstances it is necessary to synchronize with P
ERMEDIA
.
This is controlled through the Sync command. The host out FIFO should
normally be initialized so as to output the Sync tag and data (they can be
filtered out).
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 ...