1. Introduction

The assignment will involve using modern OpenGL to render a scene-this means a programmable pipeline must be used. Scene graphs are required in the modelling process and animation controls are required for hierarchical models.

2. Learning outcomes

After completing this assignment, you will be able to:

● Use data structures and mathematics in representing and manipulating 3D objects

● Produce interactive software that makes use of a graphics API

3. Requirements

Figure 1 shows a scene which contains three menhir-like statues (each made of a different material and each with a face), a security spotlight that can point its beam of light in any direction, and a bee that flies around the statues. The scene is set in a 'backdrop' - see below.

You must use either the Phong or Blinn-Phong approach for the fragment shader. You must use only standard diffuse, specular and emission maps for the texture mapping. Do not consider normal maps or other advanced texturing approaches. Whilst this may limit the appearance of some objects, it will help in controlling the amount of time spent on the practical work.

You must satisfy all the following requirements.

3.1 The backdrop

● The backdrop could be a sculpture park or a scuare in a city centre or a building quadrangle (like Regent Court), or you could choose another backdrop.

● The backdrop needs to be textured to look like the backdrop you have chosen. For example, if you have chosen a park, should there be grass on the ground and trees in :he background? If you have chosen a city square, should there be buildings (i.e. pictures of buildings) around the square and what is the ground made of (possible stcnes or concrete)?

● Think about the detail of the backdrop. Would layers heip help improve the look? Would a skytox give a full environment feel? How does the backdrop look when the camera moves?

● The backdrcp should change in some way, e.g. different times of the day or different weather or the clouds moving across the sky. You choose.

● The quality of what you produce for this part of the scene will be part of the marking. Some alternatives indicated above are more advanced than others and will attract higher marks. You must choose what to try to implement.

3.2 The statues

● Each statue is a single scaled sphere. In Figure 1, the base of the sphere is on the ground. Instead, vou could allow it to penetrate the ground if that looks better-this will not lose marks.

● Each statue must be made of a different material. One must be a stone appearance (e.g. limestone, sandstone, marble), one must be a metal appearance (e.g. brushed steel) and one must be a kind of wood. You must source the texture maps to use for the texture mapping.

● Each statue should also use texture mapping for a unique face. This could be a separate texture map blended with the base material texture map during rendering, or could be mixed into the base material texture map when you make that.

● Each statue's face should change its expression when the bee flies nearby. This will require a proximity test for each statue. Each statue should have its own reaction to the bee, e.g. one statue might be scared and another might be surprised and ancther might be angry.

● The faces should be cartoon in appearance.

● Figure 1 shows the statues in a simple triangular arrangement. You could choose a line if you prefer or the statues could face each other or two could stare at one. It is your choice.

3.3 The bee

● This is a hierarchical model made of different shaped spheres. The hierarchy and associated transformations are the important aspect. I want you to demonstrate that you understand transformations and a scene graph hierarchy

● The bee should have a body, two wings, a tail, two eyes and two antenna (where an antenna is made of two spheres). Extra pieces could also be added. The design is your chance to show a bit of creativity.

● The wings should flap when the bee is flying

● The bee can fly to any part of the scene and is especially interested in the statues.

● Aspects of the bee might change when a statue makes a facial reaction to the bee (e.g. the bee's eyes might grow larger).

● Exaggerated cartoon effects for the bee's movements and poses (e.g. cartoons often have exaggerated eye effects) would show extra creativity and attract higher marks.

3.4 The security spotlight

● This can be modelled using spheres. Consider a scene graph.

● The spotlight mechanism should be static until initiated by a button on the interface. This is the switch to switch it on when it gets dark.

● Once switched on, the spotlight will continually sweep the area containing the statues, i.e. move in a circular pattern that covers each statue in turn.

3.5 General illumination

● The scene should be illuminated with at least one general world light which can be positioned anywhere in the world. Two world lights would show extra complexity.

● These general world lights will illuminate all parts of the scene and help visualise the scene during development and tes:ing.

● When you switch off the general light(s) (using an interface option-see next section), to simulate nighttime, the effects of the spotlight will be much clearer on the rest of the scene.

● You de NOT have to do shadows. Do not worry about shadow effects. (The general world light(s) will illuminate all polygons with a normal pointing towards it (them) and the spotligit will illuminate all objects in the direction it is pointing in which are inside its spotlignt area as there are no shadow effects to show light not reaching particular points.)

3.8 User interface

● A user-controlled camera should be positioned in the scene. Use the camera that was given in one of the exercise sheets - the mouse can be used to change the direction the camera is pointing in and the keys can be used to move about. Do not change the key mappings from the one on the exercise sheet. If you change the key mappings it will make it difficult to mark.

● It should be possible to turn the general light(s) on and off (or, more creatively, dim, i.e. reduce the intensity) from the interface.

● It should be possible to turn the spotlight movement on and off and also to turn the light on and off (or, more creatively, dim it, i.e. reduce the intensity) from the interface.

● There should be a button to switch between continuous and pose modes in the interface.

● In pose mode, there should be buttons to move the bee to be in specific key positions in front of each statue so the proximity test for the statue car be shown. This would require three buttons, one for each statue. The bee should immediately jump to each new position. This is an immediate movement to the new position the bee disappears in one position and reappears in the rew position.

● In continuous mode, the bee will just fly between five key positions in the scene. Three of these positions are in front of the statues (to trigger the proximity test) and the other two can be somewhere else in the scene. You chopse.

3.9 Animation

● This requirement is advanced and you may decide not to do this part, although you would not be able to get full marks.

● The bee can be in pose mode, where buttons in the interface are used to jump from position to position immediately or it can be in continuous movement mode, where the bee should animate between the positions in its path in a smooth way. Creativity in the continuous movement will attract higher marks. Consider exaggerated movements as the bee flies, as well as speed of movement.

● It is perfectly acceptable to animate the Euler angles to achieve movement of the hierarchy. Do not consider using quaternions, as this is beyond the requirements for this assignment.