Specific design aims for the engine included increases in workflow efficiency by reducing iteration time for modifications to gameplay and game design.[2] Additionally, the engine introduced improved physical modeling of fluids and emphasis on global illumination rendering.[2] Development of a new engine began in summer 2011. Features of the new development engine included: in-engine management of shader (GPU) programs; an engine virtual machine allowing game scripting to be written initially in C#; changes in organization of the workflow/content meant that backwards compatibility with the MT Framework engine was lost.[3] The engine corresponds to DirectX 11 level of technology.[4]
The initial game to be developed with Panta Rhei was Deep Down,[1] whose team provided feedback on the engine development;[2] development of the game and engine were carried out in parallel.[5] A trailer for Deep Down and the Panta Rhei engine were publicly demonstrated by Yoshinori Ono at the PlayStation 4 unveiling event in February 2013.,[6][7] the Deep Down technology demo used ~3GB of textures, with 30 shaders, running at approximately 30 frames per second. Graphics techniques used in the Deep Down demo included tessellation (actors cloak); with deferred rendering implementing dynamic lightsources; and surfaces rendered including diffuse and specular light reflections with surface roughness implemented by the Oren–Nayar reflectance model; global illumination calculations (such as light from a dragon's fiery breath) were estimated using the 'voxel cone tracing' method (with 1 specular 'ray' and an approximation to 12 dodecahedrally situated 'rays', sampled at a lower resolution, for diffuse reflectance); moving light sources including flames were modeled using a 64x64x64 voxel (voxel cube size ~0.5m) implemented as 3D textures stored in a Mipmap like structure.[8]
Further technology demos showcasing fluid simulations of fire and smoke in the Panta Rhei engine were released in August 2013.[9] The tech demo demonstrated the engine's use of volume-based simulations of fire (also used in the February 2013 Deep Down video), as opposed to less functional 2D "billboarded" (see Sprite) based depictions. The demos used a volume (voxel) based physical simulation of the fluid, with fixed voxel size. The simulation of fluid flow used a semi-Lagrangian method for approximations to the solution of the advection equation - specifically vorticity confinement simulations with the MacCormack method used to obtain solutions.[10] The voxel representation of the fluid required a 'ray marching' graphics rendering process (see Volume ray casting); self-shadowing of fluids, and scattering were also implemented in the engine demos.[11]
Further details of the game engine were discussed at a talk at CEDEC (CESA Developers Conference) 2014 given by Hitoshi Mishima (三嶋 仁) and Haruna Akuzawa (阿久澤陽菜). In common with other PS4/Xbox One generation rendering engines the Panta Rhei engine used physically based rendering methods for calculating lighting reflectance; demonstrations based around the Deep Down Panta Rhei development videogame used an Oren-Nayar model for diffuse reflectance, Cook-Torrance model for specular highlights (replacing a Blinn–Phong shading model used in earlier demonstrations). Demonstrations used tile-based deferred rendering generally, with forward rendering also applied for simulations of translucent skin effects, and other transparent objects. Indirect lighting was demonstrated again, using a 128x128x128 voxel grid representing local light intensity, and voxel cone tracing along 12 directions (dodecahedral). Specific demonstrations at CEDEC were a pre-integrated skin shader for simulation of light through (human/animal) skin effects, and a 'liquid' shader; surface reflections were modelled using a screen space reflection technique originally developed by Crytek, utilising parallax-corrected environmental maps; a hair modelling effect using runtime compute shader generation of hair positions, in conjunction with tessellation.[12]
In November 2014 at AMD's "Future of Compute" Singapore conference Masaru Ijuin of Capcom announced that AMD's Mantle API technology was being incorporated into the game engine.[13]