Ray Tracer

Output Comparison

Run the program with the specified .ini file to compare your output (it should automatically save to the correct path).

If your program can’t find certain files or you aren’t seeing your output images appear, make sure to:

1. Set your working directory to the project directory
2. Set the command-line argument in Qt Creator to template_inis/illuminate/<ini_file_name>.ini
3. Clone the scenefiles submodule. If you forgot to do this when initially cloning this repository, run git submodule update --init --recursive in the project directory

Note: once all images are filled in, the images will be the same size in the expected and student outputs.

File/Method To Produce Output	Expected Output	Your Output
point_light_1.ini
point_light_2.ini
spot_light_1.ini
spot_light_2.ini
simple_shadow.ini
shadow_test.ini
shadow_special_case.ini
reflections_basic.ini
reflections_complex.ini
texture_cone.ini
texture_cone2.ini
texture_cube.ini
texture_cube2.ini
texture_cyl.ini
texture_cyl2.ini
texture_sphere.ini
texture_sphere2.ini

Design Choices

Texture

Calculate the diffuse value using blending and pass it to the light to calculate the final effect.

Texture Bilinear Filtering

Find the four nearest pixels in the four corners around the intersected point and use the bilinear interpolation similar to lab7.

Refraction

Use the following formula to calculate the refracted direction and a similar code as reflection to recursively calculate the refraction effect.

$\vec{\omega_o} = \sqrt{1 - \frac{1}{\mu^2} [1 - (\vec{n} \cdot \vec{\omega_i})^2]} + \frac{1}{\mu}[-\vec{\omega_i} + (\vec{n} \cdot \vec{\omega_i})\vec{n}]$

Soft Shadow

Use a new type of light LightType::LIGHT_SOFT with a finite area length x length. Sample a random location on the light source for soft-samples times and use the average value to be the color of the shadow.

Collaboration/References

N/A

Known Bugs

• Refraction does not achieve the expected result for refract2.png

• When the sample number of the soft shadow is large (i.e. set a large soft-samples in the .ini file), the speed of the ray tracer is slow.

Extra Credit

Texture Bilinear Filtering

Set bi-filtering = true inside the .ini file.

Use the following two command line arguments to compare the output.

template_inis/illuminate/extra_credit/bilinear.ini

template_inis/illuminate/extra_credit/bilinear_off.ini

Refraction

light.cpp -> refraction

Set refract = true inside the .ini file.

Use the following two command line arguments to see the output.

template_inis/illuminate/extra_credit/refract1.ini

template_inis/illuminate/extra_credit/refract2.ini

The output for refract1 is similar to the expected output.

but the output for refract2 does not achieve the expected results.

Soft Shadow

light.cpp and sceneparser.cpp

• Add a new type of light LightType::LIGHT_SOFT with a new parameter length that specifies the side length for the light, and reuse other parameters and code for LightType::LIGHT_SPOT.

• Example usage for .json file to create LightType::LIGHT_SOFT

"lights": [
        {
          "type": "soft",
          "color": [1.0, 1.0, 1.0],
          "direction": [0.0, -1.0, 0.0],
          "angle": 30.0,
          "penumbra": 20.0,
          "attenuationCoeff": [0.8, 0.05, 0.0],
	 	  "length": 0.3
        }
    ]

• Set soft-samples = 50 inside the .ini file to specify sample points.

• Use the following two command line arguments to compare the output.

  template_inis/illuminate/extra_credit/softshadow.ini

  template_inis/illuminate/extra_credit/softshadow_off.ini

  

• Use the following two command line arguments to compare the output.

  template_inis/illuminate/extra_credit/softshadow2.ini

  template_inis/illuminate/extra_credit/softshadow2_off.ini

  

Output Comparison

Run the program with the specified .ini file to compare your output (it should automatically save to the correct path).

If your program can’t find certain files or you aren’t seeing your output images appear, make sure to:

1. Set your working directory to the project directory
2. Set the command-line argument in Qt Creator to template_inis/intersect/<ini_file_name>.ini
3. Clone the scenefiles submodule. If you forgot to do this when initially cloning this repository, run git submodule update --init --recursive in the project directory

Note: once all images are filled in, the images will be the same size in the expected and student outputs.

File/Method To Produce Output	Expected Output	Your Output
unit_cone.ini
unit_cone_cap.ini
unit_cube.ini
unit_cylinder.ini
unit_sphere.ini
parse_matrix.ini
ambient_total.ini
diffuse_total.ini
specular_total.ini
phong_total.ini
directional_light_1.ini
directional_light_2.ini

Design Choices

KD-Tree

BoundingBox class, uses two vectors to measure the AABB.

KDNode class represents each node of the tree.

buildKDTree function constructs the tree. For choosing the split axis, I cycle through three axes instead of choosing the best axis because the latter approach is time consuming.

traverse_kd_tree function traverses the tree and if meets the leaf node, then calculate the intersected shape.

OpenMP

use #pragma omp parallel for collapse(2) before the main loop of pixels.

Anti-Aliasing Post-filter

Apply the blur filter from Project 2 with radius 5 as the post filter. The definition of the blur filter is in filterutils.cpp.

Super-Sampling

Apply traceRay function for the four corners of the aimed pixel and calculate the mean.

Collaboration/References

N/A

Known Bugs

There will be some black spots on the edges of objects due to inaccurate float comparisons.

Extra Credit

Acceleration data structure: KD-Tree

kdtree.cpp and boundingbox.cpp

Set acceleration = true inside the .ini file.

Use the following two command line arguments to compare the speed.

template_inis/intersect/extra_credit/kdtree_false.ini

template_inis/intersect/extra_credit/kdtree_true.ini

(use recursive_sphere_6.json)

Parallelization: Level1: OpenMP

Use #pragma omp parallel for collapse(2) before the main loop of pixels.

Set parallel = true inside the .ini file.

Use the following two command line arguments to compare the speed.

template_inis/intersect/extra_credit/parallel_false.ini

template_inis/intersect/extra_credit/parallel_true.ini

(use primitive_salad_2.json)

Anti-Aliasing: Blurring Post-filter

filterutil.cpp

Set anti-aliasing = true inside the .ini file.

Use the following two command line arguments to compare the output.

template_inis/intersect/extra_credit/antialising_false.ini

template_inis/intersect/extra_credit/antialising_true.ini

(use directional_light_2.json)

Super-Sampling: Stochastic Super-Sampling

Set super-sample = true inside the .ini file and num-samples = 10 to specify sample points.

Use the following two command line arguments to compare the output.

template_inis/intersect/extra_credit/supersample_false.ini

template_inis/intersect/extra_credit/supersample_true.ini

(use primitive_salad_1.json)

Create your own scene file

Use the following command line argument.

template_inis/intersect/extra_credit/customize.ini

(use torii.json)