Linear Model Analysis of Real-Time Rendering - Real-Time Rendering: Computer Graphics with Control Engineering - page 28

FIGURE 3.3 (See colour insert.) Screenshot of hardware tessellation sample application
from DirectX SDK adapted with Stanford Dragon model in Experiments 1 and 2.
allows a user to set the tessellation segment values interactively to see the effect on
the 3D object and the frame rate. To simulate the rendering quality in practical appli-
cation, we modified the system for this experiment to load an environment map and
apply different shading effects on 3D objects. The application was developed to allow
easy configuration—a feature that makes it applicable for massive model rendering.
We collected two sets of data including the vertex input values and frame rates over
six tessellation segments. The first set of data consisted of inputs between 120,000
and 920,000 vertices and frame rates (outputs) between 122 and 24 FPS over approxi-
mately 3,500 consecutive rendered frames. The second set consisted of 7,000 ren-
dered frames with the same input and output variables. Approximately 5,200 frames
were used to derive the model; the remaining frames were used for validation.
In addition to deploying the modelling framework on this application, we
extended the validation of the framework to a computer game with highly complex
3D rendering. Figure 3.4 is a screenshot of the “Crysis” computer game (© Crytek).
A total of 22,000 frames of input and output data were collected using Microsoft's
PIX performance profiling toolkit. The first 20,000 frames were used to derive the
model and the remaining frames served as validation data.
3.5.2 e xPeRiment 2: m ultiPle -i nPut -s ingle -o utPut (miso) s ystem
Since interactive rendering applications involve complicated processes, we extended
our modelling framework to support multiple inputs in Experiment 2. In contrast to
previous research [20,21,24] that did not focus on shading (an important aspect of
3D rendering), we demonstrated through Experiment 2 that more than one property
may be captured by our framework. In particular, we developed a shader program
that accepts a numeric value between 1 and 6 to control the quality of the surface