In-Depth Discussion on Teardown and Voxel-Based Rendering with Dennis Gustafsson

Software Engineering Daily hosted an enlightening episode featuring Dennis Gustafsson, the visionary founder of Tuxedo Labs and the creative force behind the acclaimed sandbox puzzle game, Teardown. Engaging in a comprehensive conversation, host Joe Nash delves into Dennis’s extensive 20-year journey in game development, his profound passion for physics in gaming, the intricate mechanics of Teardown, and the future technological ventures on the horizon.

A Journey Rooted in Physics and Game Development

Dennis Gustafsson's foray into game development is deeply intertwined with his fascination for physics rather than rendering. Clarifying misconceptions early in the conversation, Dennis states, "My main interest has always been physics in games and that's also where my main part of my career has been" ([02:24]). This passion was ignited during his university years while studying media technology. Unlike his peers who were captivated by rendering, Dennis found the interactivity of physics more compelling. He reminisces about early inspirations, mentioning games like Carmageddon 2 and a pioneering dinosaur game that allowed object manipulation, which fueled his desire to explore physics-driven gameplay ([02:36]-[03:54]).

Teardown: Redefining Sandbox Gaming with Voxels

At the heart of the discussion is Teardown, a voxel-based sandbox game that centers around executing high-stakes heists. Dennis provides a succinct overview: "Teardown is a voxel sandbox game where the gameplay is based around heists..." ([04:05]). Unlike traditional voxel games such as Minecraft, Teardown distinguishes itself through its highly interactive and fully destructible environments. Dennis emphasizes the unique physics-based destruction mechanics, explaining that "when you remove something and explode something, they actually fly and rotate and behave like actual objects" ([04:53]-[05:21]). This level of realism elevates the gameplay, making every environmental interaction meaningful and strategically significant.

Innovative Engine Development: Voxel-Based Rendering Meets Physics

Dennis’s journey with Teardown involved developing a bespoke engine tailored to harness the power of voxels for both rendering and physics. The inspiration stemmed from MagicAvoxel, a voxel modeling program that showcased stunning visuals, leading Dennis to believe in the potential of voxels for game development: "The idea for the voxels started... it was also kind of perfect for physics..." ([07:02]-[08:19]).

One of the primary technical challenges was implementing efficient ray tracing within a voxel-based framework. Dennis shares, "Getting all that to run in voxel space and make it more correct, that was quite challenging..." ([09:00]-[10:29]). Despite initial concerns, Dennis found that collision detection and physics interactions were more manageable with voxels compared to traditional triangle meshes, although implementing structural integrity—ensuring objects break realistically under stress—remains an ongoing challenge ([10:50]-[12:17]).

Pushing Rendering Boundaries: From OpenGL to Vulkan

Teardown's rendering engine was meticulously crafted using the OpenGL API, allowing Dennis complete control over the voxel-based rendering system. He elaborates, "I wrote the graphics using the OpenGL API... It's very much a handwritten engine in that sense" ([12:39]). However, recognizing the limitations of OpenGL, especially concerning hardware ray tracing, Dennis has embarked on transitioning to Vulkan. This shift aims to leverage hardware-accelerated ray tracing to enhance lighting and performance: "With hardware ray tracing, we don't really need this big bitmap of voxels... we can just operate directly on the objects" ([31:20]-[33:16]).

Dennis discusses the innovative approach of maintaining a voxelized version of each level in memory, represented as a single bit per voxel, which streamlines shadow calculations: "I actually create a voxelized version of the level that is all in memory, where I just represent each voxel as a single bit..." ([14:03]-[16:29]). This method significantly optimizes performance, allowing for real-time updates even as players manipulate the environment extensively.

Fostering a Thriving Modding Community

Teardown's flexibility and robust modding support have cultivated a vibrant community of creators. Dennis reveals that while modding wasn't the initial focus, the team's foresight led to comprehensive support for modders from the outset: "We did have this idea that we wanted to support modding properly already from the start" ([25:15]-[27:29]). This dedication is reflected in the game's scripting API, enabling players to craft intricate modifications. Dennis highlights a standout mod where players implemented a portal gun, showcasing the community's ingenuity: "Someone obviously implemented the portal gun in Teardown... they were using the UI API to draw big rectangles and... put them in the world using sprites" ([27:20]-[28:16]).

The ability to modify and extend the game’s mechanics not only enriches the player experience but also perpetuates the game's longevity and relevance in the gaming landscape.

Navigating Company Evolution and Future Endeavors

The conversation transitions to the business side of Tuxedo Labs, where Dennis discusses the company's acquisition by Sabre Interactive and the subsequent transition to Embracer. Despite the changes, Dennis notes that the transition has been relatively smooth, granting the team greater autonomy: "We do have a little bit more control now, which is good, but it's been relatively smooth" ([28:28]-[30:09]).

Looking ahead, Dennis has shifted his focus away from active development on Teardown, entrusting updates and maintenance to a dedicated team. This strategic move allows him to delve into new technological explorations, particularly in rendering and physics simulations: "I've spent most of this year actually researching new technologies and new types of rendering..." ([29:23]-[34:02]). Among his interests are fluid and soft body simulations, which promise to push the boundaries of interactive environments in future projects.

Embracing New Technologies and Continued Innovation

Dennis's foray into Vulkan marks a significant step in advancing Teardown’s rendering capabilities. Although he admits that Vulkan's low-level nature presents a steeper learning curve, the benefits of hardware ray tracing are undeniable: "It's actually really useful... you can do proper path tracing and you get much better lighting and performance..." ([31:20]-[33:16]). This transition not only enhances visual fidelity but also removes previous constraints, such as the voxel grid size limitation imposed by OpenGL.

Furthermore, Dennis is exploring avenues to integrate more sophisticated physics simulations, aiming to enrich the gameplay experience with more dynamic and realistic interactions: "I've been looking into fluid simulation, for instance, a little bit, and also soft body simulation..." ([33:26]-[34:02]). These innovations hint at exciting developments both within Teardown and potentially in future titles from Tuxedo Labs.

Closing Thoughts

The episode wraps up with a reflection on the successes and challenges faced throughout Teardown’s development. Dennis expresses immense satisfaction with the game's reception and the creativity of its modding community. He remains optimistic about the future, eager to apply his technical expertise to new projects and continue pushing the envelope in game development: "I've been wanting to write that up for some time... It's been a lot of fun to get back to more tech research" ([09:00], [29:23]-[34:02]).

Dennis Gustafsson’s insights offer a compelling glimpse into the intersection of physics, rendering technology, and interactive gameplay. His dedication to innovation and community engagement underscores the enduring appeal and technical prowess of Teardown, solidifying its place as a standout title in the realm of voxel-based sandbox games.

Notable Quotes:

• Dennis Gustafsson ([02:24]): "My main interest has always been physics in games and that's also where my main part of my career has been."

• Dennis Gustafsson ([05:21]): "They're still on a grid, but each object is on its own grid. And then the whole grid can rotate in the world and move around freely."

• Dennis Gustafsson ([10:50]): "There is one clear candidate for this question and that is the structural integrity."

• Dennis Gustafsson ([14:54]): "So since I have not been so interested in rendering previously, I kind of missed that whole train of learning all these tricks that you have to do in rendering."

• Dennis Gustafsson ([27:20]): "Someone obviously implemented the portal gun in Teardown and that... they were using the UI API to draw big rectangles and they just did lots of them."

• Dennis Gustafsson ([31:20]): "It's actually really useful... you can do proper path tracing and you get much better lighting and performance is awesome."

This comprehensive summary encapsulates the depth and breadth of Dennis Gustafsson’s conversation on Software Engineering Daily, providing valuable insights into the technical marvels and creative vision that underpin Teardown’s success.