Is simulated by using the OGRE engine architecture, can be more convenient realistic three-dimensional stage lighting environment, virtual technology itself has the presence and interaction can not only as dynamic representation of the design and creation of static transformed, but also can timely grasp and show the designer ideas, creativity and inspiration, a mature and perfect the system of virtual design platform both for lighting designers, performance director, lighting control operator, or the light art teaching and demonstration of lighting effects and is a very professional and practical design tool and a good helper. And real-time interactive features, the system makes the system more real-time and operability. This system provides a real-time interactive operating environment, to meet the needs of users.
First, system architecture
1 logical framework
Both games or virtual reality, in order to show the realistic and the virtual scene are more complex, so the virtual scene create most of the generated by a 3D modeling tool, and then the scene real-time rendering output. Stage lighting design by the 3DMAX to provide the basic scene file, through the DOM (Object Model Document) interface for analysis, and the introduction of resources and the organization of the scene. Eventually entered OGRE
System rendering.
The illumination model is varied, and it is needed to realize their effect in the scene. At the same time, users should be able to perform a variety of operations through the UI interface. System requirements of high complexity, large amount of computation, can be expanded. Need to design and build a data processing and computational efficiency is high, scalable and function modules engage in loose strong cohesion of the overall architecture, as shown in Figure 1, is resource layer, interface layer, render layers.
Resource layer: the 3DMAX + Ofusion plugin is derived, generating the scene organization, material, entity, map, and other system required resources.
Interface layer: responsible for importing these resources into the scene.
Rendering layer: to realize the rendering of the scene and lighting, the management of system resources, and the real-time response of the user interaction.
Two, the system to achieve the key technology research
1 scene organization and formation
The resource files required by the system are derived from Ofusion through the 3DMAX plug-in. The derived scene organization file is a XML format, recording some basic parameters of the stage and the location of each stage entity, and the information from all aspects. The scene node is organized by a tree in the form of each node has the corresponding parent node, so we can through the operation of the parent node, so that more and more sub node at the same time to move and rotate.
2 3D coordinate transformation
To display three-dimensional rendering results to the two-dimensional screen, the need to carry out the conversion from the three-dimensional coordinates to the coordinates of the plane. First of all, it is necessary to establish a three-dimensional coordinate system, we create a 3D oblique double axonometric coordinate system, which X axis direction is horizontal to the left, Z axis is a vertical upward, Y axis direction for a 45 degree angle with the horizontal direction. In this coordinate system, the length of the X axis and the Z axis is taken as the actual length, while the length of the Y axis is half the length.
In the formula, x, y, Z, x, N, y, Z axis deformation coefficient. The following equations can be determined by the transformation of the axis projection:
Where f and D are the coefficients of the axis of the transformation matrix, which can be solved by solving the equation:
In order to make the stereo sense stronger, so that the -0.354 d=f=, can be obtained from the axis to measure the transformation matrix:
Next, you need to convert three-dimensional coordinates of the graphics on the screen of the device coordinate, in the perspective window, screen coordinate origin is located in the upper left corner, right direction for the positive direction of X axis and downward direction for the positive direction of the y-axis.
Assuming that a point (x, y, z) in a 3D space (,), the coordinates in the device coordinates are (XX, YY), the use of the axis projection transformation matrix, you can get the following conversion formula:
The formula of xX and yY is the relative coordinates of the 3D coordinates of the origin in the device coordinate system.
The formula (4) (5), can be drawn into the transformation equation:
3 particle system simulation
Particles are represented by a quadrilateral. It has properties such as length, direction, color, life, quantity, material, weight and rate. The properties of particles are determined by Emitter Particle and Affector Particle. Particle emitter is responsible for the particle emission, particles are given in the launch of some attributes, including velocity, color, and so on; particle effects influence is responsible for particle from launch to before the demise of the particle properties change, can be used to simulate gravity, tension, color decay of special effects. When the particle emitter is constantly sprayed with a large number of particles, the smoke, fire and explosion can be formed.
OGRE provides the particle system scripting language, you can set the various properties of particles in the script.
In this paper, the effect of rain and fog is described by the particle system. Combined with the effect of OGRE, it can achieve more realistic scene particle effect.
4 illumination effect simulation
Lighting is the key factor of the stage effect, and also the core of this design system. The rendering engine provides several common lights, such as point light source, directional light source, and the spotlight. But these are not enough for real stage lighting effects. For some special stage lighting effects, such as volume light, etc., need to be achieved through the programmable rendering pipeline technology (shader). Shader has two kinds, one is the vertex level, known as shader vertex (called ve OpenGL program), to replace the fixed rendering pipeline |
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