Computer Graphics-Assignment 17 Ambient lighting Solved

In this assignment you have to complete both the Vertex and the Fragment Shader contained in files

shaders/BRDFShader.vert  and shaders/BRDFShader.frag, approximate the rendering equation for three different materials and lighting conditions. The files must be compiled into shaders/BRDFVert.spv and shaders/BRDFFrag.spv as seen in Assignment 10.

 

First, the correct location ids for input and output should defined both in Vertex and Fragment Shaders:

 

 
 
Vertex Shader 
 
 
 
in 
 
 
out 
 
var 
 
 
location 
var 
 
 
location 
inPosition 
 
 
0
fragPos 
 
 
0
inNormal 
 
 
1
fragNorm 
 
 
1
inTexCoord 
 
 
2
fragTexCoord 
 
 
2
 
 
Fragment Shader 
 
 
 
in 
 
 
out 
 
var 
 
 
location 
var 
 
 
location 
fragPos 
 
 
0
outColor 
 
 
0
fragNorm 
 
 
1
 
 
 
 
fragTexCoord 
 
 
2
 
 
 
 
 

Then, for each scenario, function ending with Casex_BRDF() should be implemented to return a vec3 vector containing the RGB color computed by corresponding the model. Each function receives the following parameters:

 

•       vec3 N : the direction of the normal vector (unitary vector)

•       vec3 V : the direction of the view vector (unitary vector)

•       vec3 Ca : ambient color of the surface

 

The functions receive also other parameters relevant to the particular model. Refer to the comments in the code for their definition. Lights parameters are instead defined inside a Uniform Block called gubo. The first two models are lit by a single directional light, while the last uses four directional lights. Each model uses a different ambient light model. In particular:

 

•       gubo.lightDir0 -> a vec3 containing the direction of the first or only light (for spot and directional lights).

•       gubo.lightColor0 -> a vec3 containing the basic color of the light first or only light.

•       gubo.lightDir1, gubo.lightDir2, gubo.lightDir3 -> three vec3 containing the direction of the second, third and fourth lights (for model 3).

•       gubo.lightColor1, gubo.lightColor2, gubo.lightColor3 -> a vec3 containing the basic color of the second, third and fourth light.

•       gubo.AmbColor -> a vec3 containing the basic ambient color. For model 2, it corresponds to the bottom color, and for model 3 to the constant component for Spherical Harmonics lighting.

•       gubo.TopColor -> a vec3 containing the top ambient color for model 2, and to the difference related to the y component of the normal direction for Spherical Harmonics lighting in model 3.

•       gubo.DzColor, gubo.DxColor -> two vec3 containing the difference related to the z and x components of the normal direction for Spherical Harmonics lighting in model 3.

•       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 expect results should be similar to the following: