UNIT IV RENDERING

1. What is meant by Rendering?

In 3D graphics rendering means the calculation of the final image from the scene that includes models, textures, lights, special effects and cameras. The final image will be 2D image made of pixels. Utilizing materials, lighting techniques, and renderer’s settings one can render multitude of different images from a single 3D scene.

2. Types of Rendering?

 Realistic rendering Clay Rendering Wire Rendering

3. Purpose of Wire Rendering.

The purpose of wire rendering is to reveal the polygon structure of the model. Wire rendering displays only edges of the polygons. Wire render and clay render are often combined.

4. Write the syntax of smooth shading.

Syntax:

glshadeModel(GL_smooth);

It calculates the color at each vertex.

It produces much better image.

It computes during scan conversion.

5. List out the drawbacks of shadow mapping.

• Aliasing especially when using small shadow maps.

• The scene geometry must be rendered once per light inorder to generate the shadow map for a spot light.

6. What are the two types of textures.

Two types of textures are:

Bitmap

Procedural

7. What are the stages of rendering?

Loading the shadow buffer

Rendering the scene

8. Write the function of bitmap textures.

The function texture (s,t) accesses in the code:

color3 texture(Float s,Float t)

{

return txtr[(int)(s*c)][(int)(t*R)]

}

where colr3 holds an RGB tuple.

9. List the advantages of phong shading.

In Phong shading the direction of normal vector varies smoothly from point to point and more closely approximates that of an underlying smooth surface. More realistic rendering are produced. The production of specular highlights is much more faithful than with Gouraud shding.

10.Define Texture mapping?

One of the most important tool in computer graphics is texture mapping.Texture mapping applies an image to a surface.It allows a simple polygon to appear to have a complex surface texture.