Publications

Optimizing Draw Call Batching Using Transient Data-Guided Texture Atlases

Master’s thesis, November 24, 2017

Author

Jordy van Dortmont [1,2]

Supervisors

Bas Zalmstra [1], Wishnu Prasetya [2], Jacco Bikker [2]

[1] Abbey Games, [2] Utrecht University

Abstract

Rendering a large number of 2D textures in real-time requires reducing the overhead of a large number of draw calls on the CPU caused by binding different textures when drawing. Texture atlases are used to avoid switching textures by packing textures into one larger texture before rendering. Graphics hardware APIs limit the size of a texture, so textures need to be partitioned into multiple atlases. Unfortunately, composing textures into atlases is performed manually by developers or artists with an educated guess and requires manually checking which texture switch breaks a draw call batch to improve batching. Manual composition of texture atlases is cumbersome, time-consuming and not optimal for large-scale and unpredictable use of textures. We automated the composition of atlases based on previously gathered texture rendering data to remove manual intervention and created transient texture atlases at run-time based on usage to optimize draw call batching. We applied our approach to four simulations and measured the number of draw calls, CPU frame time and GPU frame time. The number of draw calls is similar or less for data-guided texture atlases than for manually composed texture atlases. Transient data-guided texture atlases reduce the number of draw calls significantly for unpredictable use of textures, which leads to performance gains on the CPU.

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Scenarios in virtual learning environments for one-to-one communication skills training

International Journal of Educational Technology in Higher Education, May 11, 2017. Springer Open

Authors

Raja Lala, Johan Jeuring, Jordy van Dortmont, Marcell van Geest

Utrecht University

Abstract

A scenario is a description of a series of interactions between a player and a virtual character for one-to-one communication skills training, where at each step the player is faced with a choice between statements. In this paper, we analyse the characteristics of scenarios and provide a classification to represent such scenarios. The analysis is performed through a literature review and by comparing virtual learning environments for scenario based training. Using this analysis we specify requirements for describing communication scenarios related to their: structure (linear, branching, interleaving), properties (static information stored per scenario like situation, background, which virtual character to show), and parameters (characteristics of a scenario that can be modified per statement like a score on a learning goal and an emotional effect in a virtual character). We define a schema for representing such communication scenarios and present an authoring tool to create a scenario.

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An implementation architecture for scenario-based simulations

In: ITS 2016, 13th International Conference on Intelligent Tutoring Systems, Zagreb, Croatia, June 7-10, 2016. Springer, Lecture Notes in Computer Science 9684

Authors

Raja Lala, Johan Jeuring, Jordy van Dortmont

Utrecht University

Abstract

The past years have witnessed an increased use of applied games for developing and evaluating communication skills. These skills benefit from interpersonal interactions. Providing feedback to students practicing communication skills is difficult in a traditional class setting with one teacher and many students. This logistic challenge may be partly overcome by providing training using a simulation in which a student practices with communication scenarios. A scenario is a description of a series of interactions, where at each step the player is faced with a choice. We have developed a scenario editor that enables teachers to develop scenarios for practicing communication skills. A teacher can develop a scenario without knowledge of the implementation. This paper presents the implementation architecture for such a scenario-based simulation.

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