Computer Graphics-Assignment 15 Direct Light Models Solved

In this assignment you have to complete the Fragment Shader contained in file

shaders/PhongShader.frag , to implement Direct, Point and Spot light models. The file must be compiled into shaders/PhongFrag.spv as seen in Assignment 10. For each light model, function ending with …_light_dir() should return a vec3 vector containing the direction of the light for the considered point on the object, and the function …_light_color() should return a vec3 containing the RGB color of the light, which includes both the hue and the intensity of the considered source. Both functions receives an argument vec3 pos, containg the world space position of the considered point on the object. An uniform block called gubo, contains all the parameters required to implement the light models. In particular:

 

•       gubo.lightDir -> a vec3 containing the direction of the light (for spot and directional lights).

•       gubo.lightPos -> a vec3 containing the position of the light (for spot and point lights).

•       gubo.lightColor -> a vec3 containing the basic color of the light.

•       gubo.coneInOutDecayExp.x-> a float component containing the cosine of the outer angle of a spot light.

•       gubo.coneInOutDecayExp.y-> a float component containing the cosine of the inner angle of a spot light.

•       gubo.coneInOutDecayExp.z-> a float component containing the basic distance g for both spot and point lights.

•       gubo.coneInOutDecayExp.w-> a float component containing the denominator

exponent b for both spot and point lights: 0 for no decay, 1 for linear decay and 2 for quadratic fading.

•       Object gubo also contains fields eyePos and selector, which however are not meaningful for the exercise and are required for other parts of the shader already implemented. 

 

The following GLSL standard procedures can be helpful in solving this exercise:

 

normalize() pow() dot() length() clamp() max() min() 

 

If you need help about GLSL, you can refer to the following tutorial:

 

https://cgvr.cs.uni-bremen.de/teaching/cg2_07/literatur/glsl_tutorial/index.html

 

Starting from the section “Data Types and Variables”, at around 1/3 of the page. Please ignore what is presented before since it refers to a very old version of OpenGL which uses concepts that are now deprecated and not valid for Vulkan.

 

               

The expect results should be similar to the following:

 

  

 

Users can move the view using the same keys as in Assingnment 0, and remove the texture pressing the T key.

 

ESC – quit the application
 
SPACE BAR – move to the next light  |  T: toggle the texture
Q: roll left
W: forward
E: roll right
R: up
 
↑: look up
 
A: left
S: backward
D: right
F: down
←: look left
↓: look down
→: look right