Practical 5 - Elements of solution¶
This page provides elements of solution for the Texturing practical.
Exercise 1: Wrapping and filtering¶
The interpretation of these texturing parameters was discussed in class, come back to us for more information.
Exercise 2: Load models with explicit texture coordinates¶
Make sure you modified your vertex shader with the attribute tex_coord provided by the loader.
When available in a .obj mesh, the loader will always send the following attributes:
in vec3 position;
in vec3 normal;
in vec2 tex_coord;
Look at the load function in core.py to locate when these data are added in the attributes dictionary.
Exercise 3: Phong and Texture¶
No solution for this exercise. The aim is to combine previous solutions for Phong illumination (see Practical 4 - Elements of solution) and what you have just done with texturing.
Tips would be:
write a new shader merging
phong.[vert|frag]andtexture.[vert|frag].the illumination color and texture can simply be multiplied (an addition could induce saturation, i.e. color components overflowing 1.0 thus clipped at 1.0)
do not forget to add a light in your scene (yes, some of you did forget!)
Exercise 3: Multi-texturing¶
No solution for this exercise. Tips would be:
do not forget to set up the texture coordinates. They can be shared for the two texture images… or not.
in your fragment shader, compute a texture color from each
sampler2D- there are many ways to combine these two texture colors to compute the output color of the fragment:
test simple operators like addition or multiplication
a common combination when one of the images contains transparent texels (as in
flowers.png) is:out_color = mix(color1, color2, color2.a);. Analyse what is done here.