CSS552: Programming Assignment #4

Texture Mapping and Triangle

Due Time: Refer to the course web-site.

Objective

The goals of this programming assignment are for us to implement, experience, and understand integrating a primitive into the ray tracing system and with texture mapping procedures: explicit image file texture, and implicit procedural texture.

Approach

Please refer to my solution. Here are the command files (with sample rendered images). You should download and unzip both of these files, then double click on the exe to run the sample program. In this assignment, you are to implement the math for position to UV mapping for the sphere, and implement checker, sine, ramp, and compute the implementation of the triangle geometry. Please download this starter project and unzip the source code.

The RayTracer Project

By now, we should all be quite familiar with this project from our mp1 experience. In mp1 you spent time implementing the visibility computation in the RTCore_Compute.cs file. In mp2, we will implement the Phong illumination model in the ComputeShading() function in the RTCore_Shade.cs file. The ComputeShading() function is invoked once to compute for the color of each visible sample from the ComputeImage() function.

In this version of the ray tracer, we want to pay attention to:

RTCore::ComputeShading(): notice we access every single shading parameters via the RTMaterial class now!! For example, instead of access the normal vector at the visible position from the IntersectionRecord, in this latest version we call RTMaterial.GetNormal(). This indirection allows RTMaterial to map and lookup a modified version of the normal vector! This is how bump map is implemented. We will see example implementation of bump mapping in class.
RTMaterial: Notice the TexturableAttribute<> class. Notice many of the elements in the material class are "texturable" now! Including transparency!
RTTextureType: Pay attention to the RTTextureType hierarchy. You must modify each of the texture types (Sine, Checker, Ramp). The number of lines required is very small, but you must understand what you are doing.
RTSphere: You must support the math for 3D position to UV mapping for the sphere.
RTTriangle: You must complete the parsing, response to UI support (for interactive showing), intersection routine, and the 3D position to UV mapping.

Credit Distribution

Here is how the credits are distributed in this assignment:

20%: Sphere: Position to UV mapping to support image file texture mapping
30%: Triangle: parsing + support UI showing

(5%) Correct parsing of triangle (note, the StartProject will crash if you try to parse command files that has a triangle!).
(5%) Correct response to GetVertices()
(15%) Correct intersection for visibility support
(10%) Correct UV mapping support

15%: Checker Texture:

(10%) Respect UV repeat
(5%) Respect color1/color2

15%: Sine Texture:

(5%) Respect period
(8%) Respect direction
(2%) Proper and smooth changing between the two colors

10%: Ramp Texture

(6%) Proper repeat
(4%) Smooth color transition

10%: Proper submission and efficiency

(5%) no useless files
(5%) no useless computations in texture implementation

Extra Credits

5pt: Support texture mapping of light source color (think, how you can have a spot light that shoots illumination according to a check texture, where checker regions are either illuminated or dark).
5pt: Support texture placement, instead of UV covering the entire rectangle, allow user to specify a sub-region in the rectangle for texture mapping.

This programming assignment will count 12% towards your final grade for this class.