the possession of SEGA. If you have not signed such a non-disclosure agreement, please contact
SEGA immediately and return this document to SEGA.
document. SEGA may make improvements and/or changes in the product(s) and/or the
program(s) described in this document at any time.
information about SEGA products must be made to your authorized SEGA Technical Services
representative.
party.
property claims or other problems that may result from applications based on the examples
describe herein.
Such references/information must not be construed to mean that SEGA intends to provide such
SEGA products or services in countries other than Japan. Any reference of a SEGA licensed prod-
uct/program in this document is not intended to state or simply that you can use only SEGA's
licensed products/programs. Any functionally equivalent hardware/software can be used instead.
document. Please address comments to :
150 Shoreline Drive, Redwood City, CA 94065
SEGA may use or distribute whatever information you supply in any way
it believes appropriate without incurring any obligation to you.
Game Development
For more information................................................................................................................ iii
Conventions................................................................................................................................ iii
System Manager and Peripheral Control (SMPC)................................................................ 3
SH-2 CPUs .................................................................................................................................. 4
Cart port...................................................................................................................................... 4
CD-ROM subsystem.................................................................................................................. 4
MPEG decompression chip........................................................................................ 5
Dual frame buffer........................................................................................................ 6
VDP 2 ............................................................................................................................ 6
68EC000 ........................................................................................................................ 7
The display list ........................................................................................................................... 12
Specifying colors........................................................................................................................ 15
Color calculations ...................................................................................................................... 16
Changing and erasing the frame buffer ................................................................................. 16
Rotating the entire frame buffer.............................................................................................. 17
VRAM and the display interval .............................................................................................. 20
Character patterns and scroll planes ...................................................................................... 22
Scroll plane display ................................................................................................................... 23
Priority functions ........................................................................................................ 24
Color processing.......................................................................................................... 24
BRIP............................................................................................................................... 26
SaturnSp_C PhotoShop/Debabelizer module........................................................ 26
SaturnBRIP PhotoShop/Debabelizer module (under development).................. 26
3DS2SAT (under development)................................................................................ 26
The Hitachi E7000 ICEs .............................................................................................. 29
Sherry SH-2 simulator ................................................................................................ 30
Hitachi documentation ............................................................................................... 31
SCU documentation ....................................................................................................31
CD-ROM subsystem documentation........................................................................31
Video subsystem documentation ..............................................................................31
Sound subsystem documentation ............................................................................. 32
subsystem, and summarizes some of the resources available to Saturn game
developers. You should read this document before reading any other Saturn
documentation and before attending your first Saturn training session.
and some of its most important capabilities.
interval, and some of the calculations it can perform as it displays each pixel.
developers.
Documentation" in Chapter 4.
not kilobits (Kbits) and megabits (Mbits). 1 Mbit = 1024 Kbits = 128 KB.
including the following:
calculations such as matrix transformations. Both SH-2s have access to
1.5 MB of synchronous DRAM (labeled Work RAM in Figure 1-1).
into appropriate control signals for the other buses.
video and sound subsystems.
supports 15-bit or 24-bit color. VDP 1 uses a dual frame buffer that allows it
to plot a new frame while the previously plotted frame is being displayed,
permitting display at 60 frames per second or at slower rates that divide
evenly into 60 frames per second.
and can be programmed for 3-D sound and other effects.
achieve simultaneous processing of different kinds of data. For example, Saturn
can play up to 32 sounds while calculating transformations of 3-D models and
displaying the resulting 2-D sprites in real time.
RAM
controller, and a direct memory access (DMA) chip. The bus controller translates
addresses specified by the SH-2 CPU on the system bus into appropriate control
signals for the other buses. This allows the SCU to integrate the A bus and B bus
memory and processors into one large SH-2 memory map.
These can be useful for tasks such as 3-D transformations. For example, you can load
a program into the DSP that performs a coordinate transformation for rotating an
object. When you need to rotate that object, you send the matrix of vertices you want
to multiply through the DMA with a command that runs the program in the DSP for
each vertex. The resulting transformed matrix of vertices ends up wherever the
DMA is sending it, in this case VDP 1's VRAM.
hard-wired programs. Sega provides libraries of programs that perform matrix
calculations and other common tasks.
DMA between any parts of memory without involving the SH-2 CPU. For example,
you can DMA from work RAM to VDP 1's VRAM or from the cartridge port ROM
to VDP 2's RAM. For an overview of the system memory map, see "Memory
Configuration" later in this chapter.
real-time clock and can reset either the entire system or individual microprocessors
(SH-2, SH-1, 68EC000, and SCSP). The SMPC also controls nonmaskable interrupts
sent to the SH-2 and via the SCU to the 68EC000, SCSP, VDP 1, and VDP 2. This
capability permits the SH-2, for example, to interrupt the 68EC000's processing to
request that it play a particular sound. The SMPC runs continuously and is powered
by a battery when the system is off.
SH-2 CPU can access the peripheral directly. In indirect mode, the SMPC regularly
polls for and buffers the latest information from a variety of peripheral devices,
including the eight-button Saturn controller and other devices that use a 4-bit
parallel protocol, three-line handshake devices, serial devices, and Genesis
controllers like the six-button controller, the mouse, and the Genesis team player.
routines or poll the peripherals directly. Instead, your program can check SMPC
registers whenever it needs peripheral data, and you can be sure that they contain
the latest data. The SMPC continually polls for data and buffers whatever it finds in
registers.
and poll the devices as necessary.
SH-2. Both chips run at 28 MHz. Because they are on a single system bus, one has to
wait for the other if they both need to access the work RAM or anything else on the
bus at the same time. However, each SH-2 includes cache RAM that you can
configure either as a 4-KB 4-way write-through unified cache or as a 2-KB 2-way
write-through unified cache plus 2 KB of RAM for use as private work RAM.
cache and the slave SH-2's cache RAM configured as a 2-KB two-way cache with
2 KB of additional RAM.
CartDev system module directly into the cartridge port and perform debugging and
other tasks via a SCSI connection with a personal computer. For more information
about the CartDev system, see "Programming Tools" in Chapter 4.
"2x" CD drive that reads data at 300 KB/sec, and a 512-KB data cache. It reads
CD+G, CD Red book (audio CD), CD Yellow book (CD-ROM), and CDX-A formats.
ROM subsystem. For example, if you are writing a fast-paced game and you want
the title screen to appear as soon as a player's character gets killed, you can send
that it will be ready for immediate display when you need it. This capability avoids
the wait times that occur with most CD drives.
SH-1 directly; you can only request, via the driver, that the SH-1 read or write to the
data cache.
for both sound and audio. If this chip is available, it pipes decompressed video
directly to VDP 2 and decompressed audio directly to the SCSP without having to
use the buses.
backgrounds that it plots and displays the resulting image via the RGB encoder.
example, the SH-2 can perform matrix transformations or other processing at the
same time that VDP 1 is plotting the display list to the inactive frame buffer and
VDP 2 is displaying the contents of the active frame buffer and several backgrounds.
information, see Chapters 2 and 3.
backgrounds displayed by VDP 2. VDP 1 plots parts in the frame buffer one pixel at
a time according to a list of commands, texture bitmaps, and other information in its
VRAM.
polygon with four vertices that's filled with a bitmapped texture. You can specify
the colors for a textured part's pixels as 15-bit RGB codes (from a total of 32,768
possible colors), palette offsets (from up to 256 entries) from a base address in
VDP 2's color RAM, or entries in a 16-color color lookup table (CLUT). A
nontextured part is a polygon (interior filled), a polyline (outline colored, interior
empty), or a line. VDP 1 can apply a single RGB or paletted color to a nontextured
part.
for any part. If you specify the color for a part using RGB values, VDP 1 can also
perform color calculations on the part's pixels when it plots them to the frame
buffer, including Gouraud shading, shadowing, half luminance, and half
transparency.
being displayed by VDP 2. VDP 2 integrates each frame with the current
backgrounds, taking account of priority settings to determine how to display
overlapping pixels.
the way individual frames are erased and switched, which in turn determines how
many frames are displayed per second. Display at 60 frames per second makes for
smoother animation and a clearer image, but slower rates allow you to display more
parts in a single frame.
pattern tables, and other information in its VRAM. It can access four 128-KB banks
of VRAM simultaneously during the four- or eight-cycle display interval after it
displays one pixel and before it displays the next. You have complete control, via
registers, of the way VDP 2 uses the cycles available in the display interval to access
each bank of VRAM.
VDP 1 and VDP 2. You can use either 15-bit or 24-bit color for palette entries.
a scroll plane is larger than the TV display area and consists of tiled character
patterns or a single bitmap image with an RGB color assigned to each pixel. Pixels
specified with RGB colors may be 15-bit or 24-bit.
planes. A normal scroll plane supports vertical and horizontal scrolling and can
rotate around the z axis only. A rotation scroll plane supports two-axis rotation and
scaling as well as vertical and horizontal scrolling. VDP 2 can display four normal
scroll planes, or two normal scroll planes and one rotation scroll plane, or two
rotation scroll planes.
other backgrounds are transparent. The back plane can display a single RGB color or
a different RGB color for each line, but can't display paletted colors.
source for either frequency modulation (FM) sounds or pulse-code modulation
(PCM) sounds. Musicians can compose music or generate sound effects using
standard MIDI programs on a personal computer. To play those sounds in a game,
you load tone bank data, AIFF files, MIDI sequence data, DSP programs, and
commands into the appropriate parts of the sound memory map and trigger the
commands when necessary. The system can handle 8- or 16-bit samples.
a sound wave editor, and a sound compiler that creates sound banks and patch
banks. These tools are described in the sound documentation listed under
"Documentation" in Chapter 4. Sega also provides a library of general MIDI sounds.
(PCM/FM) slots, a sound-exclusive 128-step DSP, and a digital mixer. The SCSP also
acts as a DRAM controller for the 68EC000.
frequency of each sample to the DSP sampling frequency of 44.1 KHz. You can use
the 128-step program area in the DSP to apply various effects to all 32 channels,
including reverberation, early reflection, echo, pitch shifting, surround sound, voice
canceling, distortion, filters, panning, and parametric EQ. Sega provides tools that
allow you to construct programs for the DSP on a Macintosh and to generate code
you can download to the DSP from your program.
of the mixer's slots can accept more than one channel's output.
on a time-sharing basis with the SCSP, the 68EC000 runs at half this speed when the
SCSP is running at full specification.
commands and, like any MIDI sequencer, takes care of playing the sounds with the
specified instrument, controller information, and so on. In most cases you don't
need to provide your own sound driver, although you can if you want to.
memory map. The SH-2 doesn't need to process additional instructions to access the
multiplexed B bus. Instead, the SCU translates signals as necessary to provide
transparent access to the entire system. You can access all memory and devices via
the SH-2 memory map.
four 32-MB areas shown in Figure 1-2. These four areas represent the entire SH-2
memory map. The IPL ROM occupies a small portion of CS0, the SCU uses CS1 and
CS2, and CS3 is SDRAM.
addresses as cache addresses. If you use these addresses, SH-2 looks first in its RAM
cache for the specified address and uses it via the cache. Alternatively, if you use a
cache through address to refer to the same location in the memory map, SH-2 looks
directly in external memory without checking the cache first, even if the cache
controller is turned on.
memory maps, see the documentation for each component.
0x05900000
0x06000000
0x5900000 or from the SH-2 at 0x06000000. If you use the SCU address, you can
perform a DMA, for example, from work RAM directly through to VDP 1. In this
case the SCU generates an address for the work RAM, gets the data, puts it in the
work RAM at that address, generates an address for VDP 1, and passes the data
directly to VDP 1. This is faster than having the SH-2 perform the same task.
and other information in its VRAM. While VDP 1 is plotting parts to the inactive
buffer, VDP 2 integrates the active frame buffer with the backgrounds defined by its
VRAM and displays the result. The frame buffers then switch roles and the process
is repeated. Figure 2-1 shows the relationship between VDP 1, the frame buffers, and
VDP 2.
VRAM when it plots parts to the frame buffer, and some of its most important
capabilities. For detailed information about VDP 1, see the VDP 1 Manual.
polygon with four vertices that's filled with a texture bitmap. VDP 1 can plot three
kinds of textured parts:
for displaying 2-D transformations of 3-D objects.
or offsets within palettes in VDP 2's color RAM. If you specify RGB colors for a
sprite, you can also apply Gouraud shading and other color calculations to it.
single palette color. VDP 1 can plot three kinds of nontextured parts:
for each of its vertices. VDP 1 can then interpolate intervening color offsets across all
the part's pixels. For example, if you specify color offsets for the vertices of a
polygon that's part of a three-dimensional object, VDP 1 can interpolate the
intervening color offsets across the polygon's pixels and shade the color smoothly as
if the polygon were reflecting light from a nearby source.
commands that tell VDP 1 what to plot for a single frame. Each command in the
display list is specified by a command table, a 32-byte block that also indicates
which command to execute next and other information VDP requires to execute the
command successfully. For sprites, this information includes coordinates within
which to plot and the address of a sprite bitmap elsewhere in VRAM. Depending on
the command, a command table may also specify the address of a color lookup table
or a Gouraud shading table.
Figure 2-2 shows a simplified example.
information in the SH-2's work RAM and replace the relevant parts of VRAM with a
copy of the shadow during the VBL interrupt. VDP 1 then plots the sprites defined
by the revised display list to the inactive frame buffer while VDP 2 is displaying the
contents of the active frame buffer. Both byte access and word access are possible
from the SH-2 or by DMA. All access to VRAM and the frame buffers occurs using
burst transfer.
commands:
whether or not to clip and if so whether to clip inside or outside the currently
defined boundaries.
list by specifying a jump mode for each command. Jump modes instruct VDP to
jump (after processing the current table) or skip (without processing the current
table) to the next command table or to another command table elsewhere in the list.
You can also use jump modes to specify another command as a subroutine of the
current one, so that VDP 1 returns, after processing the subroutine, to the original
command table or the one that follows it. Thus, if you want to keep a group of
related commands that plot a particular object in one place in VRAM, you can move
them in and out of the display list by manipulating jump modes.
command should be performed inside or outside of the area defined by the
clipping coordinates. If clipping is disabled, VDP 1 ignores any previously
processed Set User Clipping Coordinates command when it processes the
part.
between the end codes. End codes make it possible to display sprites with
nonrectangular shapes much faster than would otherwise be possible.
plotted underneath those pixels (that is, with a lower priority) will be visible.
If see-through pixels are disabled, see-through color codes in the sprite
bitmap are plotted like other color codes and make those pixels opaque.
described in the next sections.
a single palette or CLUT while it plots the part. Any RGB color may be altered by the
color calculations described in the next section while VDP 1 is plotting individual
pixels to the frame buffer.
frame buffer. Depending on a color mode set in the command table, VDP 1
interprets the sprite bitmap data as 4-bit offsets into a CLUT, 4- to 8-bit offsets into a
color palette, or 16-bit RGB values.
pixels. For RGB data, this involves simply copying the pixel data from VRAM. In
this case, the high bit of each pixel descriptor is set to 1, and the remaining 15 bits
specify an RGB value. For CLUT or palette data, VDP combines bits set in the color
control word of the command table with the 4- to 8-bit offsets specified in the
bitmap to obtain the values for all 16 bits. In this case, the high bit of the color
control word (and thus of the pixel descriptors that VDP I plots to the frame buffer)
should be set to 0. Figure 2-3 shows these two basic formats for pixel descriptors.
descriptor's format and, depending on the format, the pixel's priority and
information related to color calculation. The bits in a CLUT descriptor specify the
CLUT's base address, which VDP 1 adds to the 4-bit offset in the sprite bitmap to
locate an entry in that CLUT. The entry in the CLUT can be either a 16-bit RGB
descriptor or a complete palette descriptor. If it is a palette descriptor in a format
that permits priority settings, a CLUT entry may be used to specify the priority of an
individual pixel as well as its color.
paletted colors. All sprites whose pixels are defined with RGB values have the same
priority, which is determined by a register set in VDP 2. A sprite whose bitmap is
defined using paletted colors can have its own priority as determined by the color
control word in its command table. If you want to set the priorities for a single
backgrounds, use paletted colors. Priority has no effect between parts; to place parts
in front of other parts, you must draw them in sequence, backmost part first.
specified with RGB color:
as bright.
data by two, adds the results, and plots the sum, producing a semitransparent
effect.
VRAM. VDP 1 interpolates the intervening color offsets across the part to
produce a smooth gradation.
mode, plot trigger mode, fill data for erasing, and the frame buffer change mode.
The frame buffer change mode determines the way VDP 1 changes and erases the
frame buffers, which in turn determines how many frames are displayed per second.
pixel in the active frame buffer after it is displayed and switches the frame buffers
every 1/60 of a second for a display rate of 60 frames per second. Because the
number of parts that VDP 1 can plot to a single frame is limited by the size and
scaling of each part, the way colors are specified, the color calculations applied, and
other factors, it may sometimes be necessary to plot more than once to the same
frame buffer to display a large number of parts. You can do this by setting the frame
buffer change mode register during the VBL interrupt to one of three manual modes
(valid only for the next frame):
buffers.
buffers.
frame buffers.
frame (for display at 30 frames per second), you can set the frame buffer change
mode as follows:
during next VBL
automatic 1-cycle mode, which only needs to be set once, or the Erase & Change
manual mode, which needs to be reset for each cycle.
diagonally, in effect rotating the entire frame buffer. Pixels that lie beyond the frame
buffer coordinates are treated as transparent. Clipping areas remain fixed with
respect to the frame buffer, so they are also rotated.
mode is set to high resolution or HDTV.
patterns, and other information in its VRAM. VDP 2 also includes 4 KB of color
RAM that defines color data for use by both VDP 1 and VDP 2. Figure 3-1 shows the
configuration of VDP 2.
provides for accessing VRAM during the display interval, and some of the
calculations it can perform as it displays each pixel. For detailed information about
VDP 2, see the VDP 2 User's Manual.
planes. The picture in a scroll plane is larger than the TV display area and consists
either of tiled cells or a single bitmap image with an RGB color assigned to each
pixel. A cell for a scroll plane consists of the color data for an 8-by-8-pixel area,
defined either as palette offsets or as RGB colors.
horizontal flipping of cells. You can also display the contents of two pattern
name tables in different windows within a single rotation scroll plane.
scrolled. It is visible only when all other backgrounds are transparent. The back
plane can display a single RGB color or a different RGB color for each line, but can't
display paletted colors.
buffer, scroll plane data it reads from VRAM, priority settings for backgrounds and
sprites, any color calculations to be performed, and various settings in its registers.
When the TV screen is in normal mode, VDP 2 has an eight-cycle display interval:
that is, it has eight clock cycles after the display of each pixel to get the scroll plane
data it needs from VRAM to display the next pixel. When the TV screen is in high-
resolution mode, VDP 2 has a four-cycle display interval.
interval. VDP 2's VRAM consists of two 256-KB banks labeled VRAM-A and
VRAM-B. You can optionally divide each of these into two 128-KB banks, for a
total of four banks, each of which has a corresponding cycle pattern register as
shown in Figure 3-2.
VRAM-A1
VRAM-B0
VRAM-B1
by one square) determines
access to the corresponding
bank of VRAM during a
single clock cycle.
interval. Four eight-slot cycle pattern registers determine how VDP 2 uses the cycles
it has available. You can set each slot in each register to specify that VDP 2 read a
specific table in the corresponding bank of VRAM, provide read and write access to
that bank from the SH-2 CPU, or not allow access the bank at all during that cycle.
This means, for example, that you can calculate line scrolling for a single scroll plane
without having to calculate it for all scroll planes.
User's Manual. For example, certain kinds of accesses must be performed at or before
specific cycles in the display interval. If you are trying to do something complex,
you may find that you need to use two VRAM banks and split up the accesses across
two different cycle pattern registers. Similarly, because of the additional data and
accesses required for a rotation scroll plane, you need to use two 128-KB banks and
two cycle pattern registers to plot each pixel in the plane.
VRAM bank consists, at a minimum, of a pattern name table, a character pattern
table, and character patterns. If you define a scroll plane using RGB colors, the data
in VRAM consists, at a minimum, of the bitmap data. In addition, a bank of VRAM
may also include the following tables, depending on the kind of scroll plane and
what you want to do with it:
edge of the rotation plane, matrix parameters that specify the degree of
rotation is observed, and center coordinates that determine the point around
which the plane rotates.
example, if the horizontal coefficient is 0.1, VDP II stretches out each pixel
horizontally to occupy ten times it's normal width. You can use coefficient
tables to stretch or squeeze the plotting of one or more pixels vertically or
horizontally to produce scaling, bowing, and other effects.
2048 palette entries or from 32,768 or 16,777,216 RGB colors. The amount of RAM
required to specify each of a cell's pixels varies from 4 bits to 32 bits, depending on
the number of colors. Cells are referenced through several levels of indirection from
tables in VRAM that identify character patterns and collections of character patterns
to be displayed as a scroll plane.
table, for a square made of either one or four cells. Each character pattern is
referenced from a pattern name table, which references all the characters for a 32-
by-32- or 64-by-64-character page. References to pages can be grouped in planes,
and references to planes can be grouped in a map that defines a single scroll plane.
You can combine these references in various ways to build up a scroll plane as large
as 8192 by 8192 pixels from just a few character patterns occupying a small portion
of VRAM.
character pattern table. Depending on the way the character pattern's colors are
specified, the pattern name table may also identify the address of a palette in color
RAM and additional information about horizontal or vertical flipping and priority
and color calculations.
values. If you use 15-bit color, each palette entry occupies 16 bits and you can
specify a total of 2048 entries. If you use 24-bit color, each palette entry occupies a
using 24-bit color wastes 1 byte of RAM per palette entry and restricts the total
number of entries to 1024.
registers, and set the cycle pattern registers as necessary during each display
interval. Initialization includes setting the scroll rotation matrix parameters, the
color mode register (for either 15-bit or 24-bit color), and the priority registers and
clearing the color calculation and color offset registers.
the starting point within the pattern name table for display of the upper-left corner
of the plane on screen. For continuous scrolling, you should reset these values
during each VBL interrupt.
the portion that fits and then replace it with another portion that is shifted in the
appropriate direction through the original table.
to a pattern name table and a character pattern table. The coefficient table
determines the rate at which VDP II steps through the original pattern name table as
it plots each pixel, thus allowing for vertical or horizontal scaling and special effects.
Each coefficient is a 4-byte representation of a decimal value and applies to a line,
groups of pixels, or (potentially) a single pixel.
displays one frame. Because VDP 2 needs continuous access to the k coefficients to
display a rotation scroll plane accurately, you should normally load new k
coefficients during the VBL interrupt, either just before or just after you swap frame
buffers. It's also possible to load new coefficients during the HBL interrupt.
parameters set in VDP 2's registers. These include the following:
axis, or on the y and z axis, but not on the x axis and y axis simultaneously.
priority settings for each part that uses paletted colors, a single priority setting for all
parts that use RGB colors, and a single priority setting associated with each
background. For example, if you are displaying a sprite and two backgrounds, one
showing trees in front of a main background showing a landscape, you can set
priority bits for the sprite's pixels so that Saturn displays the trees in front of the
main background and the sprite between the backgrounds. You can then bring the
sprite to the foreground by changing the priority settings for all its pixels.
underneath it by specifying 0 as the color for those pixels.
draw them in sequence, backmost part first.
ratios and make use of the priority settings for the sprite or background pixels
involved. VDP 2 color calculations are useful for making sprites and
backgrounds appear or disappear gradually.
and dividing the RGB values of the sprite or background below it in half.
development that are currently available or will soon be available. Other tools, not
discussed here, will also be available later in 1994.
your program. Three tools are currently available:
specify a sprite.
specify a background.
SAT3 file for your program.
a PICT or PCX file and converts it to an array of 15-bit RGB values in the form of a C
header file you can compile directly into your program. The header file defines an
array of 16-bit pixels. When necessary at run time, your program copies the array to
an address in VDP 1's VRAM so that you can specify it as a sprite bitmap.
PCX file and converts it to a C header file you can compile directly into your
program. In the process, BRIP eliminates duplicate character patterns, including
vertical or horizontal mirror images. The PCX file can specify either paletted colors
or up to 256 RGB values. Unlike SCONVERT, BRIP outputs three arrays: an array of
8-bit character patterns (a character pattern table), an array of references to those
character patterns (a pattern name table), and an array that defines a single palette
used by the character patterns. (BRIP doesn't yet support back screens or enforce the
nested references to cells, pages, and planes described in Chapter 3.)
PhotoShop or Debabelizer file to a C header file that you can compile directly into
your program as a sprite bitmap. The file to be converted can specify either RGB
color or paletted color. If the file specifies RGB color, SaturnSP_C outputs an array
of 16-bit RGB color values. If the file specifies paletted color, SaturnSP_C outputs
two arrays: an array of 8-bit indices into the palette and an array that defines a 256-
entry palette.
or Debabelizer file to a C header file you can compile directly into your program.
The file to be converted must specify paletted color. SaturnBRIP outputs three
arrays: an array of character patterns (a character pattern table), an array that defines
an array of references to those character patterns (a pattern name table), and an
array that defines the palette used by the character patterns.
3-D software tools such as 3D Studio and use that model to export a series of
bitmapped images. You then display the bitmapped images in a series of frames to
create the illusion of movement in three dimensions. Each bitmapped image takes
up a lot of memory and you must be able to predict all potential movements of an
object in order to provide the appropriate bitmaps.
model to the SAT3 format, the standard Saturn file format for 3-D information. For
example, suppose you want to display a rotating cube. The 3-D model consists of six
four-sided polygons, each of which is filled with a bitmapped image. When you
transformations for the vertices of the six polygons in 2-D space, distort the bitmaps
for each polygon accordingly, and display the resulting image on the screen--all at
run time at 30 or 60 frames per second. Thus, instead of limiting potential motion to
preselected views of a 3-D model, you can orient it any way you want and update
each frame at run time.
object, an array that defines the object's faces by specifying their vertices, and a
variety of other information such as vertex normals used in Gouraud shading. This
arrangement allows you to perform a matrix transformation on the vertex
coordinates before associating those vertexes with specific faces, thus avoiding
repeated calculations for shared points.
the information provided by the SAT3 file format. For example, if you don't intend
to apply Gouraud shading to an object, you don't need to include that information
in your program. In most cases you should create a third file from the SAT3 file that
includes only the information you need for your program.
SH-2 CPU. GNU supports registerized parameters--that is, it allows you to refer to
up to four registers directly; other parameters are on the stack.
can use to compile and link assembly and C files. You can also use other third-party
assemblers to compile and link assembly files. Typically, these assemblers provide a
debugger, a linker, and a command-line DOS interface that requires a DOS extender.
and other parts in assembly language using a third-party assembler, then link both
the GNU C modules and the assembly files and output C files in the COFF file
format.
debuggers with the CartDev to debug your program, as shown in Figure 4-1.
(ICE) as a debugging system. Unlike software debuggers used with the CartDev,
ICEs provide a history display and can deal with more esoteric problems such as
interrupts or anything that requires strict tracing of code. In some cases it may be
desirable to use both the CartDev and an ICE at the same time for different
purposes.
architecture, you can load files into the Sherry simulator, an SH-2 simulation
program that runs on a PC.
Sherry simulator in more detail.
port. It has its own controller that handles all communication. A SCSI (SCSI 2)
interface permits communication with the CartDev from an IBM PC, a Macintosh, or
other hosts, such as SGI workstations. The CartDev communicates with Saturn
through dual port RAM. It also includes dual-access emulation RAM (RAM that can
be read or written to from either the CartDev or from Saturn) that includes 64 KB of
static RAM, with room for up to 8 MB of optional DRAM.
one in-and-out high-speed parallel port for an auxiliary interface. Currently, the
auxiliary interface consists of a sound adapter with a digital audio interface and two
sets of in, out, and through MIDI ports that can handle up to 32 voices. Other
auxiliary interfaces may be developed in the future.
and, when used with appropriate debugging software, allows you to set software
breakpoints, single step through code, and read and write to memory.
to download or upload art or sound files. In general, downloads with the CartDev
are ten or twenty times faster than downloads with the E7000 ICEs. The CartDev has
an open interface that allows third parties to use its communication capabilities for
additional game development tools.
similar hardware debugging capabilities and can emulate the SH-2 processor. Each
version of the E7000 ICE knows about all internal workings of the processor on a
cycle-per-cycle basis (including pipelining), and maintains a history of previous
instructions.
from a host with telnet capabilities.
interface card.
proprietary parallel interface card used with the E7000PC.
same time as the CartDev. The E7000 ICEs can be helpful with low-level problems
such as interrupts or crashes that corrupt the system, or with any problem that you
can't isolate using a software debugger.
program you can run on a PC without any connection to Saturn or any other
hardware. If you load an S record into the Sherry program, it allows you to set
breakpoints and single step through code using a memory map that emulates the
SH-2 memory map. This is especially valuable for observing clock cycle counts for
pipelined RISC instructions and for learning how new instructions and the ordering
of instructions affect the pipeline.
only uses as much of the PC's memory as your program requires, even if you are
addressing a larger memory space. It doesn't simulate the cache.
programs. Because the SH-2 chips are RISC, assembly-language programming for
Saturn can be more complex than for other game machines. For example, you must
deal with pipelining if you write in assembly language. This means development in
assembly language may take longer than development in a high-level language.
some circumstances than an assembler, it takes care of many of the complexities of
RISC programming, such as pipelining, automatically. Hand-crafted assembly code
can be useful in situations where slight performance improvements are significant,
but compiled C code works just as well for many tasks.
programs for Saturn.
Saturn Stream System, ST-098
transparent.
values.
patterns for a scroll plane.
plotted is "clipped."
for a part or information that VDP 1 combines with the offsets specified in a sprite
bitmap to obtain a pixel descriptor.
jump mode, and other information VDP 1 requires to execute the command.
cycles in the display interval to access its VRAM.
and before it displays the next. You have complete control, via the cycle pattern
registers, of the way VDP 2 uses the cycles available in the display interval to access
its VRAM.
frame.
rotated and distorted by specifying the coordinates of four corner points.
color.
that simulates transparency.
vertical scrolling of cells, vertical and horizontal flipping of cells, and line zooming
from 256x to 0.25x of normal size.
the high bit is set to 1, the remaining 15 bits specify an RGB value. If the high bit is
set to 0, the pixel descriptor consists of information from the color control word
combined with an offset in the sprite bitmap, and it specifies either an entry in a
color lookup table or a palette entry in VDP 2's color RAM.
single color.
it encloses) can be drawn with a single color.
well as horizontal line scrolling, vertical scrolling of cells, and horizontal and vertical
flipping of cells.
magnified or reduced horizontally, vertically, or both horizontally and vertically.
with a bitmapped image; also called a sprite.