Teapots in the Sea
The final image is made up of three major components.
- A grass bush
- Water surface
- Three teapots
The following rendering techniques were implemented in order to render the above objects:
- Anti-aliasing to give the grass blades a soft touch
- Bump mapping to create the ocean surface
- Mix of bump and texture mapping to implement the land
- Glossy reflection for one of the teapots
- Refraction with Beers law and Fresnel reflection for the refractive teapot.
- Soft shadows with disk lights
In addition, code for Depth of field was added but isnŐt shown in the final image. ItŐs addition lead to an exponential increase in render time while not contributing to enhance the overall look of the image.
The Grass Bush
The grass bush was implemented as a sequence of repeating triangles. The bottom two vertices of each triangle were repeated at regular intervals. The x-coordinates of the top vertice of each triangle was varied as a sine function of the x-axis with a little random value added to give it a natural look. However, uncontrolled application of sine function caused the grass blades at the right edge to appear long and unnatural. The best way around this problem was to ŇtrimÓ the grass blades as they curved towards the ground.
The grass bush rendered his way had sharp jagged edges displaying a classic case of aliasing. Anti-aliasing was implemented to give the grass blades a soft smooth look. The following is an image of the bush with and without aliasing.
Fig 1: Grass bush without anti-aliasing. Note the broken edges as the grass blade tapers
Fig 2: Grass bus with anti-aliasing. Note the smoothing of the tapering edges (ignore the first attempts at adding flowers to the bush)
The Water Surface
The water surface is implemented as a turbulence function with 6 octaves of (F1 – F0) of Worley noise. The frequency controlled if the water surface would have clam ripples or rough waves.
Fig 3: Lower frequency F-F Worley noise turbulence
Fig 4: Higher frequency F-F Worley noise turbulence
The three teapots are each made up of a different material. The rightmost teapot gives a frosty look realized with the help of glossy reflection. The second teapot is made up of a purely reflective material. The third teapot is made of a purely refractive material incorporating both Beers law and Fresnel reflection. Some interesting teapot scenes are shown in the following figures.
Fig 5: Teapot with glossy reflection
Fig 6: Teapot made of refractive material, implementing Beers law and Fresnel reflection
The land was implemented by bump mapping a triangle using Perlin noise to give it the granular look. Texture mapping, again with Perlin noise was used to achieve the slight variation in colour.
There is more that could have been added to the final image were time not a constraint. The following are some ideas:
- A hazy night sky with a misty moon and twinkling stars
- Shadow of the moon on the water surface
- Smoother transition from land to water with maybe a curving water front
- Pebbles on the land to give it a more natural feel
- Refraction in water and a water bottom to give a water a more realistic feel