Hellcats Over the Pacific
Encyclopedia
Hellcats Over the Pacific is a flight simulator
computer game for the Apple Macintosh computer written by Parsoft Interactive
and released by Graphic Simulations in 1991. Hellcats was a major release for the Mac platform, one of the first 3D games to be able to drive a 640 x 480 x 8-bit display at reasonable frame rates. The graphics engine was combined with a simple Mac interface, a set of randomized missions and a number of technical features that greatly enhanced the game's playability and made it a lasting favorite into the mid-1990s. The basic Hellcats engine was later adapted to produce a series of games, including A-10 Attack!
, A-10 Cuba, the F-18 Hornet series and early versions of Warbirds.
aircraft in a series of fictional missions during 1943's Guadalcanal Campaign
.
Hellcats focused almost entirely on the flying of the aircraft, with a minimum of setup or in-game controls. After starting the player would find themselves in a minimal interface consisting of a small number of dialog boxes for preferences and selecting missions. The entire interface was based on the Mac's built-in UI, as opposed to hand-rolled elements built out of the game engine itself. This made for a spartan but easy-to-use interface. After the initial setup the user rarely used any of the out-of-game controls except for the mission setup dialog box, where radio buttons allowed the player to select one of the eight missions, along with their fuel load and zero, one or two 500 lb (226.8 kg) bombs. Nothing else was required, and after selecting a mission the game switched to the in-cockpit view.
Due to the simplicity of the game engine, the flight controls were also quite simple, offering basic controls for the engine, rudder, flaps and landing gear. Primary flight control for roll and pitch was normally handled by the mouse, which included a scaler that improved the "feel", although the game was also fairly insensitive to overcontrol. Joysticks could also be used, via the "mouse mapping" that most Mac joysticks used. View controls allowed for a number of different options, including tower views and similar, but also a "slow following" chase mode that slowed down transitions between different flight directions in order to reduce the total amount of movement when correcting for small adjustments in flight path (this is now common to most games). One feature that was lacking from Hellcats was a "snap view" that allows the player to look in different directions and then return to a front view when the key is released. This feature was also lacking from most Parsoft games that followed.
One oft-commented-on feature of Hellcats was its "instant replay" view. The game logged out all actions in the game world to a buffer, and on command could play them back from an external viewpoint. The game would select a viewpoint that kept the "important action" in-frame. For instance, if the player was in the midst of dropping a bomb on a ship, during replay the camera would leave the aircraft and follow the bomb down to impact. On the other hand, if the player was in aerial combat and two planes collided nearby, the replay would instead keep the player's aircraft centered and rotate to show this event relative to the player. The game rarely got it wrong, and the effect was often cinematic.
The game world consisted primarily of the player's Hellcat and enemy aircraft, normally the A6M Zero
. Some missions included "friendly" F6F's, an F4U Corsair
(which used the same flight model as the F6F, however) and a B-17 Flying Fortress. Enemy aircraft also included the Mitsubishi G4M
"Betty" in one mission. Ground targets included AA guns, cruiser
s, battleship
s, aircraft carrier
s, and sometimes static aircraft parked at the airbases. Many of these targets could be destroyed by bombing, which was "eyeballed" by diving on them. Smaller targets could also be destroyed with machine gun fire.
Air-to-air combat was relatively simple, normally degenerating into a turning fight which, unrealistically, the F6F could win by lowering its flaps. Actually shooting down the historically flimsy Zero was difficult in the game, at least at closer ranges, and often ended with the opposing aircraft's engine failing and the aircraft crashing while ditching. Although it was possible to directly "kill" the aircraft, this generally only occurred with hits at long range; at shorter ranges, most bullets simply went right through the aircraft. Another issue with the combat system was sighting distances, which made targets practically invisible at even a few kilometers' range. To address this, the game included an unrealistic "radar" display that showed, without failure, every aircraft above a few hundred feet altitude in a 360-degree view around the player's aircraft.
Although the damage modeling was simplistic, the game did track damage to the pilot and would "kill" them in certain circumstances. This could be avoided in many cases by quickly exiting the mission before crashing, although this did not help in the case of a direct hit on the pilot or a mid-air explosion. The pilot could also be lost in action after bailing out of a stricken aircraft. This was a bone of contention among players, as the system for deciding whether or not the pilot was lost was completely random; even landing in the middle of a friendly airbase would often result in a dialog stating the search and rescue
teams could not find you, leaving that pilot MIA
. The game had no built-in method of reviving dead or missing pilots, but there were 3rd party programs that were available to do this.
The game manual was typically sparse. Instructions for the UI and basic flight were included, the later being copied from an FAA manual that often disagreed with the basic flight model in the game. The manual also included a complete copy of the original F6F flight manual, useful for historical purposes only.
The key to Hellcatss long life was the overall simplicity of the game as a whole. Starting the game and entering a mission could be completed in a few seconds, and the in-game action demanded more situational awareness than outright flying skill. The lack of complex weapons also helped make the control system quite "thin." This resulted in a game that was much more approachable than its more complex follow-ons, and Hellcats was widely enjoyed by players that would not normally play flight simulators.
. The SPARCstation allowed the memory of the graphics card to be mapped into main memory, the CPU placed data in those locations they would automatically be copied over the SBus
to a frame buffer that the graphics card drew to the screen. This method of access allowed the card to continually update the screen independently of the CPU; if the two shared the memory directly
it can lead to contention issues that will slow overall performance. However, the path between the main memory and the frame buffer was relatively slow, so while both the CPU and the frame buffer could move memory quickly within their own private memory, they could not easily communicate those changes. Specifically, the CPU could create 40 MB/s of data in main memory, but this could only be copied to the frame buffer at 5 MB/s. The SPARCstation had a resolution of 1000 x 1000 x 8 bits per pixel, about 1 MB per frame, so at best the display could run at about 5 frame/s at full resolution if each frame was being generated by the CPU and sent over the bus.
Parker came up with the idea of using the CPU to compress the images, allowing them to be moved over the bus more quickly. However, display cards of the era had no "smarts", so whatever technique was used it would have to run entirely within the CPU – an actual compression system like ZIP would not work because the card had no way to decompress the image. His solution was to implement a page flipping system in main memory. The CPU was place in charge of two complete frames, one holding the image currently being displayed by the frame buffer, and the other used by the 3D engine to draw the "next" frame into. When the 3D engine finished its work drawing into the offscreen buffer, a compositor system compared the two frames and only copied the changes into the memory seen by the frame buffer. Since the frame buffer also copied only the changes over the bus, this system greatly reduced bus use. His first experiment drew a flat-shaded rotating cube, and was able to reach 120 frames per second.
This method only works well if the image as a whole is not changing. For instance, this technique eliminates the possibility of using a fully texture mapped display, because in that case even minor changes in camera angle or position would require any portion covered by a texture to be re-drawn. This limited the engine to polygon-based flat-shaded graphics
, but at the time this was not uncommon, and with this engine many more polys could be drawn per-frame, greatly increasing visual fidelity.
Additionally, the engine was much less affected by changes in resolution than traditional engines, as the number of pixels changing at a higher resolution was not necessarily much larger than on a lower one, at least not in direct relation to the change in resolution. This allowed the game to be run at any resolution the Mac could support, including the then-extremely-high 1024 x 768 that was common on 21" monitors which could be found on some Macs of the era. In addition to having higher resolution than contemporary PC's, it was not uncommon to see more than one monitor attached to a Mac, especially in the desktop publishing
market. The Parsoft engine was able to take advantage of this as well, allowing the user to put the game on up to three of monitors to allow for side or rear views.
. The game is focussed on the battle between the F6F Hellcat
and A6M Zero
that first took place over these islands, whose outcome changed the balance of air power in the Pacific war. A map of a large portion of the island chain was created, along with airbases and other fixed locations.
The low CPU cost of the graphics engine left the CPU with ample free time. To fill it up, the game included a number of live objects that other games generally lacked. For instance, airbases often had a number of AA guns arranged around the field, and they would track and follow the aircraft as it flew around. These objects were placed throughout the very large map area, so the player could ignore the mission and fly off to distant islands and still find operational airfields. It added a depth that few other games of the era offered; for instance, the Red Baron map was "dead" with the exception of the hand-placed objects in the mission.
With a basic environment in place, Hellcats was fleshed out with the addition of the physics engine
. The engine used a formulaic approach to calculate the forces on the aircraft, whereas most contemporary games used a lookup table approach. The latter has the disadvantage of showing easily visible changes in performance; for instance, an aircraft might climb at 90 mi/h at an angle of 20 degrees, but when the nose is raised even slightly, to 21 degrees, it suddenly slows to 80 mi/h. In contrast, the Hellcats engine was completely fluid throughout the entire flight regime. While by no means high fidelity in terms of matching real-world aircraft performance, Hellcats was nevertheless a major advance in terms of flight quality. Most complaints about the performance were aimed at the too-soft response at the edges of the envelope; stalls were difficult, spins impossible.
The engine also lacked a number of features that reduced the realism. For one, the engine did not model gee-induced blackouts or redouts, which allowed unrealistic maneuvers. Additionally, the only structural limits the game checked on were the landing gear
or direct impact, so for instance the flaps would not be damaged by lowering them at high speed. This led to a number of behaviors that would be impossible otherwise, notably dive bombing at hundreds of miles an hour followed by dropping the flaps to allow a multi-tens-of-gee pullout. More detailed structural limits were relatively common in other games of the era.
One of the last things added to the game was the missions themselves, which were coded up in a two week period immediately prior to shipping. This is one area where Hellcats was significantly behind the technology curve compared to contemporary games. It included only eight pre-rolled missions, one of which was training, and no ability to edit or add your own. One advantage to the system is that it allowed direct programming of the behavior of the objects in the game, allowing for the addition of bombers and kamikaze
behavior. The missions also incorporated some degree of randomness, enough to make each play different, sometimes significantly. They also varied widely in difficulty, from simple missions against one or two other targets, to The Duel with about a dozen aircraft and five ships. However the long term appeal of the game was affected by the mission system's limitations. In comparison, games like Red Baron had hundreds of missions, and while they played exactly the same every time, there were so many of them there was less of a problem with lack of novelty.
Hellcats was released to huge acclaim, although the Mac gaming market was small. It is still listed at the No. 7 most influential Mac game of all time, according to Inside Mac Games. It also won many "comparison" articles when judged for realism, although most articles included a caveat about the graphics.
These upgrades were released a year later as Hellcats: Missions at Leyte Gulf. Although it was marketed as an upgrade pack, it was actually an entirely new game with its own runnable application. The new version included dramatically improved detail at the airbases, added jeeps and trucks, more detailed ships, the P-38 Lightning
and the Ki-84 "Frank"
, and rockets and torpedoes in addition to the bombs and machine guns.
The rest of the game remained otherwise similar to Hellcats. Both the physics engine and missions system were largely unchanged. The new game included another eight missions, this time with no training. Although they all had considerably more detail and a greater number of in-game targets, they had the same lack of user editability as the original.
Parsoft, on the other hand, moved on to a completely new system. Aware that the major problems in the original engine were the lack of realistic structural physics and pilot effects, Parsoft's new A-10 Attack!
included a complete rigid-body simulator in addition to a re-written flight dynamics engine. The result was one of the most realistic flight simulations of the era. Another addition to the new engine was the "Virtual Battlefield Environment" (VBE), a plug-in system that allowed new vehicles and weapons to be added to the engine by dropping them into a directory. Although the game did not include a flexible mission editor, it did, in theory, allow missions to be added through the VBE system, missions that could include computer code to increase the customization. Unfortunately the VBE specifications were never published, and no 3rd party plug-ins were ever made. The VBE system was used by Parsoft to produce A-10 Cuba, a new mission set taking place at and around Guantanamo Bay. This was initially released as a stand-alone game on both the Mac and PC, and was later re-released on the Mac as a true VBE plug-in.
The ultimate evolution of the Hellcats concepts was Fighter Squadron:Screamin' Demons Over Europe, which replaced the now-dated polygonal shading graphics engine with a texture-mapped engine running on modern graphics cards, and further improved the editability of the engine. VBE was replaced by a much simpler system, OpenPlane, that allowed all of the customization to be carried out in resource files with no coding or compiling required.
Flight simulator
A flight simulator is a device that artificially re-creates aircraft flight and various aspects of the flight environment. This includes the equations that govern how aircraft fly, how they react to applications of their controls and other aircraft systems, and how they react to the external...
computer game for the Apple Macintosh computer written by Parsoft Interactive
Parsoft Interactive
Parsoft Interactive, or simply Parsoft, is a former computer game company known for their series of technically advanced flight simulators. Their first release was Hellcats Over the Pacific on the Apple Macintosh in 1991, which they followed in 1992 with Missions at Leyte Gulf, an expansion pack...
and released by Graphic Simulations in 1991. Hellcats was a major release for the Mac platform, one of the first 3D games to be able to drive a 640 x 480 x 8-bit display at reasonable frame rates. The graphics engine was combined with a simple Mac interface, a set of randomized missions and a number of technical features that greatly enhanced the game's playability and made it a lasting favorite into the mid-1990s. The basic Hellcats engine was later adapted to produce a series of games, including A-10 Attack!
A-10 Attack!
A-10 Attack! is a combat flight simulator for the Apple Macintosh computer released by Parsoft Interactive in 1995. The game features an A-10 Thunderbolt II aircraft that takes part in a variety of missions in West Germany during a hypothetical limited conventional attack by the Warsaw Pact...
, A-10 Cuba, the F-18 Hornet series and early versions of Warbirds.
Description
Hellcats is a combat simulation of the F6F HellcatF6F Hellcat
The Grumman F6F Hellcat was a carrier-based fighter aircraft developed to replace the earlier F4F Wildcat in United States Navy service. Although the F6F resembled the Wildcat, it was a completely new design powered by a 2,000 hp Pratt & Whitney R-2800. Some tagged it as the "Wildcat's big...
aircraft in a series of fictional missions during 1943's Guadalcanal Campaign
Guadalcanal campaign
The Guadalcanal Campaign, also known as the Battle of Guadalcanal and codenamed Operation Watchtower by Allied forces, was a military campaign fought between August 7, 1942 and February 9, 1943 on and around the island of Guadalcanal in the Pacific theatre of World War II...
.
Due to the simplicity of the game engine, the flight controls were also quite simple, offering basic controls for the engine, rudder, flaps and landing gear. Primary flight control for roll and pitch was normally handled by the mouse, which included a scaler that improved the "feel", although the game was also fairly insensitive to overcontrol. Joysticks could also be used, via the "mouse mapping" that most Mac joysticks used. View controls allowed for a number of different options, including tower views and similar, but also a "slow following" chase mode that slowed down transitions between different flight directions in order to reduce the total amount of movement when correcting for small adjustments in flight path (this is now common to most games). One feature that was lacking from Hellcats was a "snap view" that allows the player to look in different directions and then return to a front view when the key is released. This feature was also lacking from most Parsoft games that followed.
One oft-commented-on feature of Hellcats was its "instant replay" view. The game logged out all actions in the game world to a buffer, and on command could play them back from an external viewpoint. The game would select a viewpoint that kept the "important action" in-frame. For instance, if the player was in the midst of dropping a bomb on a ship, during replay the camera would leave the aircraft and follow the bomb down to impact. On the other hand, if the player was in aerial combat and two planes collided nearby, the replay would instead keep the player's aircraft centered and rotate to show this event relative to the player. The game rarely got it wrong, and the effect was often cinematic.
The game world consisted primarily of the player's Hellcat and enemy aircraft, normally the A6M Zero
A6M Zero
The Mitsubishi A6M Zero was a long-range fighter aircraft operated by the Imperial Japanese Navy Air Service from 1940 to 1945. The A6M was designated as the , and also designated as the Mitsubishi A6M Rei-sen and Mitsubishi Navy 12-shi Carrier Fighter. The A6M was usually referred to by the...
. Some missions included "friendly" F6F's, an F4U Corsair
F4U Corsair
The Vought F4U Corsair was a carrier-capable fighter aircraft that saw service primarily in World War II and the Korean War. Demand for the aircraft soon overwhelmed Vought's manufacturing capability, resulting in production by Goodyear and Brewster: Goodyear-built Corsairs were designated FG and...
(which used the same flight model as the F6F, however) and a B-17 Flying Fortress. Enemy aircraft also included the Mitsubishi G4M
Mitsubishi G4M
The Mitsubishi G4M 一式陸上攻撃機, 一式陸攻 Isshiki rikujō kōgeki ki, Isshikirikkō was the main twin-engine, land-based bomber used by the Imperial Japanese Navy Air Service in World War II. The Allies gave the G4M the reporting name Betty...
"Betty" in one mission. Ground targets included AA guns, cruiser
Cruiser
A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...
s, battleship
Battleship
A battleship is a large armored warship with a main battery consisting of heavy caliber guns. Battleships were larger, better armed and armored than cruisers and destroyers. As the largest armed ships in a fleet, battleships were used to attain command of the sea and represented the apex of a...
s, aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
s, and sometimes static aircraft parked at the airbases. Many of these targets could be destroyed by bombing, which was "eyeballed" by diving on them. Smaller targets could also be destroyed with machine gun fire.
Air-to-air combat was relatively simple, normally degenerating into a turning fight which, unrealistically, the F6F could win by lowering its flaps. Actually shooting down the historically flimsy Zero was difficult in the game, at least at closer ranges, and often ended with the opposing aircraft's engine failing and the aircraft crashing while ditching. Although it was possible to directly "kill" the aircraft, this generally only occurred with hits at long range; at shorter ranges, most bullets simply went right through the aircraft. Another issue with the combat system was sighting distances, which made targets practically invisible at even a few kilometers' range. To address this, the game included an unrealistic "radar" display that showed, without failure, every aircraft above a few hundred feet altitude in a 360-degree view around the player's aircraft.
Although the damage modeling was simplistic, the game did track damage to the pilot and would "kill" them in certain circumstances. This could be avoided in many cases by quickly exiting the mission before crashing, although this did not help in the case of a direct hit on the pilot or a mid-air explosion. The pilot could also be lost in action after bailing out of a stricken aircraft. This was a bone of contention among players, as the system for deciding whether or not the pilot was lost was completely random; even landing in the middle of a friendly airbase would often result in a dialog stating the search and rescue
Search and rescue
Search and rescue is the search for and provision of aid to people who are in distress or imminent danger.The general field of search and rescue includes many specialty sub-fields, mostly based upon terrain considerations...
teams could not find you, leaving that pilot MIA
Missing in action
Missing in action is a casualty Category assigned under the Status of Missing to armed services personnel who are reported missing during active service. They may have been killed, wounded, become a prisoner of war, or deserted. If deceased, neither their remains nor grave can be positively...
. The game had no built-in method of reviving dead or missing pilots, but there were 3rd party programs that were available to do this.
The game manual was typically sparse. Instructions for the UI and basic flight were included, the later being copied from an FAA manual that often disagreed with the basic flight model in the game. The manual also included a complete copy of the original F6F flight manual, useful for historical purposes only.
The key to Hellcatss long life was the overall simplicity of the game as a whole. Starting the game and entering a mission could be completed in a few seconds, and the in-game action demanded more situational awareness than outright flying skill. The lack of complex weapons also helped make the control system quite "thin." This resulted in a game that was much more approachable than its more complex follow-ons, and Hellcats was widely enjoyed by players that would not normally play flight simulators.
Incremental update
The Hellcats engine was based on an idea Eric Parker formulated while studying the SPARCstation 1SPARCstation 1
The SPARCstation 1, or Sun 4/60, is the first of the SPARCstation series of SPARC-based computer workstations sold by Sun Microsystems. It had a distinctive slim enclosure and was first sold in April 1989, with Sun's support for it ending in 1995.Based around a LSI Logic RISC CPU running at...
. The SPARCstation allowed the memory of the graphics card to be mapped into main memory, the CPU placed data in those locations they would automatically be copied over the SBus
SBus
SBus is a computer bus system that was used in most SPARC-based computers from Sun Microsystems and others during the 1990s...
to a frame buffer that the graphics card drew to the screen. This method of access allowed the card to continually update the screen independently of the CPU; if the two shared the memory directly
Shared Memory Architecture
In computer architecture, Shared Memory Architecture refers to a design where the graphics chip does not have its own dedicated memory, and instead shares the main system RAM with the CPU and other components....
it can lead to contention issues that will slow overall performance. However, the path between the main memory and the frame buffer was relatively slow, so while both the CPU and the frame buffer could move memory quickly within their own private memory, they could not easily communicate those changes. Specifically, the CPU could create 40 MB/s of data in main memory, but this could only be copied to the frame buffer at 5 MB/s. The SPARCstation had a resolution of 1000 x 1000 x 8 bits per pixel, about 1 MB per frame, so at best the display could run at about 5 frame/s at full resolution if each frame was being generated by the CPU and sent over the bus.
Parker came up with the idea of using the CPU to compress the images, allowing them to be moved over the bus more quickly. However, display cards of the era had no "smarts", so whatever technique was used it would have to run entirely within the CPU – an actual compression system like ZIP would not work because the card had no way to decompress the image. His solution was to implement a page flipping system in main memory. The CPU was place in charge of two complete frames, one holding the image currently being displayed by the frame buffer, and the other used by the 3D engine to draw the "next" frame into. When the 3D engine finished its work drawing into the offscreen buffer, a compositor system compared the two frames and only copied the changes into the memory seen by the frame buffer. Since the frame buffer also copied only the changes over the bus, this system greatly reduced bus use. His first experiment drew a flat-shaded rotating cube, and was able to reach 120 frames per second.
This method only works well if the image as a whole is not changing. For instance, this technique eliminates the possibility of using a fully texture mapped display, because in that case even minor changes in camera angle or position would require any portion covered by a texture to be re-drawn. This limited the engine to polygon-based flat-shaded graphics
Gouraud shading
Gouraud shading, named after Henri Gouraud, is an interpolation method used in computer graphics to produce continuous shading of surfaces represented by polygon meshes...
, but at the time this was not uncommon, and with this engine many more polys could be drawn per-frame, greatly increasing visual fidelity.
Producing a game
Parker had always been interested in flight simulators, and started adapting the basic graphics engine as the core of a new game. Working at home at nights after his "day job", he began the process of converting the workstation engine to a PC platform in his new company, Parsoft. The choice to target the Mac was technical, as it was the only machine on the mass market at the time that commonly featured the ability to run at reasonably high resolutions, at that time 640 x 480 or higher. At lower resolutions the amount of data that had to move over the bus was limited, so the "brute force" approach of drawing every frame to the buffer would work fine, and did for contemporary games like Red Baron. Only on the Mac's higher resolution would the engine provide a real advantage.Additionally, the engine was much less affected by changes in resolution than traditional engines, as the number of pixels changing at a higher resolution was not necessarily much larger than on a lower one, at least not in direct relation to the change in resolution. This allowed the game to be run at any resolution the Mac could support, including the then-extremely-high 1024 x 768 that was common on 21" monitors which could be found on some Macs of the era. In addition to having higher resolution than contemporary PC's, it was not uncommon to see more than one monitor attached to a Mac, especially in the desktop publishing
Desktop publishing
Desktop publishing is the creation of documents using page layout software on a personal computer.The term has been used for publishing at all levels, from small-circulation documents such as local newsletters to books, magazines and newspapers...
market. The Parsoft engine was able to take advantage of this as well, allowing the user to put the game on up to three of monitors to allow for side or rear views.
Building out the system
With the graphics engine in place, what was left was to take the engine and use it to produce a game. ParSoft chose to model the area surrounding the successful U.S. campaign in and around the Solomon IslandsSolomon Islands
Solomon Islands is a sovereign state in Oceania, east of Papua New Guinea, consisting of nearly one thousand islands. It covers a land mass of . The capital, Honiara, is located on the island of Guadalcanal...
. The game is focussed on the battle between the F6F Hellcat
F6F Hellcat
The Grumman F6F Hellcat was a carrier-based fighter aircraft developed to replace the earlier F4F Wildcat in United States Navy service. Although the F6F resembled the Wildcat, it was a completely new design powered by a 2,000 hp Pratt & Whitney R-2800. Some tagged it as the "Wildcat's big...
and A6M Zero
A6M Zero
The Mitsubishi A6M Zero was a long-range fighter aircraft operated by the Imperial Japanese Navy Air Service from 1940 to 1945. The A6M was designated as the , and also designated as the Mitsubishi A6M Rei-sen and Mitsubishi Navy 12-shi Carrier Fighter. The A6M was usually referred to by the...
that first took place over these islands, whose outcome changed the balance of air power in the Pacific war. A map of a large portion of the island chain was created, along with airbases and other fixed locations.
The low CPU cost of the graphics engine left the CPU with ample free time. To fill it up, the game included a number of live objects that other games generally lacked. For instance, airbases often had a number of AA guns arranged around the field, and they would track and follow the aircraft as it flew around. These objects were placed throughout the very large map area, so the player could ignore the mission and fly off to distant islands and still find operational airfields. It added a depth that few other games of the era offered; for instance, the Red Baron map was "dead" with the exception of the hand-placed objects in the mission.
With a basic environment in place, Hellcats was fleshed out with the addition of the physics engine
Physics engine
A physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics , soft body dynamics, and fluid dynamics, of use in the domains of computer graphics, video games and film. Their main uses are in video games , in which case the...
. The engine used a formulaic approach to calculate the forces on the aircraft, whereas most contemporary games used a lookup table approach. The latter has the disadvantage of showing easily visible changes in performance; for instance, an aircraft might climb at 90 mi/h at an angle of 20 degrees, but when the nose is raised even slightly, to 21 degrees, it suddenly slows to 80 mi/h. In contrast, the Hellcats engine was completely fluid throughout the entire flight regime. While by no means high fidelity in terms of matching real-world aircraft performance, Hellcats was nevertheless a major advance in terms of flight quality. Most complaints about the performance were aimed at the too-soft response at the edges of the envelope; stalls were difficult, spins impossible.
The engine also lacked a number of features that reduced the realism. For one, the engine did not model gee-induced blackouts or redouts, which allowed unrealistic maneuvers. Additionally, the only structural limits the game checked on were the landing gear
Landing Gear
Landing Gear is Devin the Dude's fifth studio album. It was released on October 7, 2008. It was his first studio album since signing with the label Razor & Tie. It features a high-profile guest appearance from Snoop Dogg. As of October 30, 2008, the album has sold 18,906 copies.-Track...
or direct impact, so for instance the flaps would not be damaged by lowering them at high speed. This led to a number of behaviors that would be impossible otherwise, notably dive bombing at hundreds of miles an hour followed by dropping the flaps to allow a multi-tens-of-gee pullout. More detailed structural limits were relatively common in other games of the era.
And then, a game
The game engine was placed within a shell using the basic Mac UI, in contrast to most games that have their own UI built inside the game engine. Missions were selected in a dialog box with radio buttons and a slider to select the fuel load. Settings for sound and graphics were likewise accessed entirely though the standard Mac menu and dialog system. A relatively large manual was included anyway, although the majority of this was "boilerplate text" taken from a reprint of the original F6F pilot's manual or a FAA flight training manual.One of the last things added to the game was the missions themselves, which were coded up in a two week period immediately prior to shipping. This is one area where Hellcats was significantly behind the technology curve compared to contemporary games. It included only eight pre-rolled missions, one of which was training, and no ability to edit or add your own. One advantage to the system is that it allowed direct programming of the behavior of the objects in the game, allowing for the addition of bombers and kamikaze
Kamikaze
The were suicide attacks by military aviators from the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, designed to destroy as many warships as possible....
behavior. The missions also incorporated some degree of randomness, enough to make each play different, sometimes significantly. They also varied widely in difficulty, from simple missions against one or two other targets, to The Duel with about a dozen aircraft and five ships. However the long term appeal of the game was affected by the mission system's limitations. In comparison, games like Red Baron had hundreds of missions, and while they played exactly the same every time, there were so many of them there was less of a problem with lack of novelty.
Hellcats was released to huge acclaim, although the Mac gaming market was small. It is still listed at the No. 7 most influential Mac game of all time, according to Inside Mac Games. It also won many "comparison" articles when judged for realism, although most articles included a caveat about the graphics.
Leyte Gulf
After Hellcats shipped the Parsoft team started work on improving the engine. Tweaks to the graphics engine provided even better performance, allowing more cycles to be spent on other tasks.These upgrades were released a year later as Hellcats: Missions at Leyte Gulf. Although it was marketed as an upgrade pack, it was actually an entirely new game with its own runnable application. The new version included dramatically improved detail at the airbases, added jeeps and trucks, more detailed ships, the P-38 Lightning
P-38 Lightning
The Lockheed P-38 Lightning was a World War II American fighter aircraft built by Lockheed. Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms and a single, central nacelle containing the cockpit and armament...
and the Ki-84 "Frank"
Nakajima Ki-84
The Nakajima Ki-84 was a single-seat fighter used by the Imperial Japanese Army Air Force in World War II. The Allied reporting name was "Frank"; the Japanese Army designation was . Featuring excellent performance and high maneuverability, the Ki-84 was considered to be the best Japanese fighter...
, and rockets and torpedoes in addition to the bombs and machine guns.
The rest of the game remained otherwise similar to Hellcats. Both the physics engine and missions system were largely unchanged. The new game included another eight missions, this time with no training. Although they all had considerably more detail and a greater number of in-game targets, they had the same lack of user editability as the original.
Moving on
Parsoft moved on to new projects after the release of Leyte Gulf. At some point during this time Parsoft and Graphics Simulations had a disagreement and the two companies went their own ways. GraphSim hired a new team and used the existing Hellcats code to produce a new game in 1994 as F-18 Hornet. GraphSim also retained the rights to the version of the software they had at the time, and later licensed it Warbirds.Parsoft, on the other hand, moved on to a completely new system. Aware that the major problems in the original engine were the lack of realistic structural physics and pilot effects, Parsoft's new A-10 Attack!
A-10 Attack!
A-10 Attack! is a combat flight simulator for the Apple Macintosh computer released by Parsoft Interactive in 1995. The game features an A-10 Thunderbolt II aircraft that takes part in a variety of missions in West Germany during a hypothetical limited conventional attack by the Warsaw Pact...
included a complete rigid-body simulator in addition to a re-written flight dynamics engine. The result was one of the most realistic flight simulations of the era. Another addition to the new engine was the "Virtual Battlefield Environment" (VBE), a plug-in system that allowed new vehicles and weapons to be added to the engine by dropping them into a directory. Although the game did not include a flexible mission editor, it did, in theory, allow missions to be added through the VBE system, missions that could include computer code to increase the customization. Unfortunately the VBE specifications were never published, and no 3rd party plug-ins were ever made. The VBE system was used by Parsoft to produce A-10 Cuba, a new mission set taking place at and around Guantanamo Bay. This was initially released as a stand-alone game on both the Mac and PC, and was later re-released on the Mac as a true VBE plug-in.
The ultimate evolution of the Hellcats concepts was Fighter Squadron:Screamin' Demons Over Europe, which replaced the now-dated polygonal shading graphics engine with a texture-mapped engine running on modern graphics cards, and further improved the editability of the engine. VBE was replaced by a much simpler system, OpenPlane, that allowed all of the customization to be carried out in resource files with no coding or compiling required.