Issue link: https://digital.copcomm.com/i/10832
n n n n Gaming light sources, depending on the shader—vertex- shaded point lights, pixel-shaded point lights, and directional lights, for instance. Visceral Games thought it necessary to judge the quality of the geometry in-game, says Christmann, so lighters had two dual- CPU or quad-core Xeon workstations with 4gb of RAM, allowing them to set up and iter- ate on two scenes simultaneously—polishing the one scene while the other baked. Despite these steps, the game’s 60-fps render cycle remained an obstacle. Lighters were careful as to where they spent their cycles; lighters and environmental artists made trade-offs so that they could adhere to the budget. In many cases, the crew was able to use low-res shaders in the backgrounds, says Christmann. Te game, for the most part, is forward- lit, with Dane’s cross being the only per-pixel point light. “It’s always stuck on the hero, so the player will always be moving per-pixel de- tail around the gameplay, says Christmann. “For the in-game characters, this light was sto- len to improve lighting quality.” Te directional shadow-casting light affect- ed the character and environmental shaders differently. Tis lighting method was used for depth-map shadow, while character shaders also received diffuse and specular illumination from this source. Meanwhile, environmental shaders received only specular illumination, as their diffuse lighting was already pre-rendered in Turtle. Tis added some per-pixel illumina- tion detail without washing out or over-bright- ening the scene. Specular cube maps also pro- vided another source of per-pixel detail. Meanwhile, many of the things that people assumed were lighting elements—light beams, glows, fire, and so forth—were done by the VFX artists during their passes through the world, Christmann notes, and not by illumi- nation methods. An Effect on the Game Inferno is packed with visual effects from the beginning to the end. Te title has many tradi- tional environmental effects: water, fire, wind, fog, lighting, and weather. In addition, Hell has many specific effects, such as boiling skies, the dead plunging on fire from the heavens, a tor- nado of tormented souls, or sinners boiling in rivers of blood or lava. “For the first time, we had characters made completely of fire and smoke that were made entirely of effects,” says Kuipers. Other notable character effects include Phlegyas, a 50-foot-high molten giant who breathes fire and goes on a rampage demol- ishing buildings in Hell’s city of Dis in the Anger circle. In addition, Dante has dozens of 28 May 2010 Visual effects, most of which were created with Alchemy, Visceral’s proprietary VFX system, are commonplace within the environments, adding to their overall complexity. VFX-intensive magical attacks, and each boss battle with Minos, Cerberus, and Lucifer was packed with its own unique effects. VFX were even used to do final color tuning from level to level and other postproduction touches, like bloom, depth of field, and motion blur. To generate the effects, the team used Al- chemy, the studio’s proprietary VFX system, as well as an in-house materials and shader system, Maya, and Photoshop. Alchemy, though, did the heavy lifting, accounting for 95 percent of the work, while the in-house materials system enabled the artists to create custom shaders for specific uses, such as water or tornados. Maya, meanwhile, helped build mesh particles, do fluid and dynamic simulations, and generate textures for animated fire, smoke, and blood, for instance. Photoshop enabled the artists to hand-paint various particle textures. Kuipers describes Visceral’s particle system as “feature-rich,” allowing for a great deal of flexibility. “We have a concept of ‘smart’ ver- sus ‘dumb’ particles,” he explains. “Dumb particles are extremely cheap, and we can put thousands of them on screen at the same time because they use pre-calculated data. Smart particles can be interacted with dynamically, using forces, wind, normal mapping, or col- lision. Tey are more expensive, but when we need that extra control or interactivity, they are invaluable.” Te team also used meta particles, mesh particles, stretched particles, and distor- tion particles to achieve the desired outcomes. As Kuipers explains, Alchemy is so much more than a particle system; it is a sophisticat- ed VFX sequencer. “Te particle system is just one small part of what Alchemy is,” says Kui- pers. He explains: “Tink of it as a real-time compositing package, wherein each VFX is made up of multiple layers, and each layer can be a variety of different types, called ‘modules.’ Some of the modules the VFX artists have at their disposal include particles, procedural ge- ometry, trails, distortion, dynamic lights, opti- cal effects, light beams, decals, motion, forces, shape emitters, post FX, masking, messaging, and even sound.” Lest we forget, this is Hell, so fire was an absolute necessity. To create that effect digi- tally, the group used a combination of various elements, including procedural geometry, par- ticles, animated textures, and dynamic lights. Maya Fluid Effects provided specific looks for the animated fire texture sequences. “We had to make the fire look believable and perform well at 60 fps,” says Kuipers. “Normally, we layer many elements to keep the fire looking as random as possible. However, with our perfor- mance constraints, we had to be careful with overlapping elements because the fill rate was our big performance killer.” Another challenging effect involved the Smoke Lucifer, which had to be a reasonable in-game match to the prerendered treatment given the character in the cut-scenes. Te prerendered version consists of fluid-dynam- ics-driven smoke and millions of particles. Te in-game version, meanwhile, had to approxi- mate that look in real time and maintain the frame rate. “Tis was no small task to pull off. Maintaining 60 fps was our biggest challenge across the game, especially when there were a lot of effects on screen combined with lots of combat,” Kuipers points out. By confronting potential digital imagery demons from the beginning, the artists at Visceral Games were able to avoid falling into a hellish nightmare during the title’s two-year development period. Tis allowed the team to accomplish its goal of sending players to Hell, a visit—in this instance—they welcomed. But at the end of their journey through the Nine Circles of Hell, players receive a divine reward: Purgatory, which is also the next can- tiche (main part) in “Te Divine Comedy,” thus opening the gate wide for a sequel to the game. n Karen Moltenbrey is the chief editor for Computer Graphics World.