How are vertex normals defined on the same vertex?
In some cases, the vertex normals defined on a vertex shared by 2, 3 or more triangles are the same (they point in the same direction) but you can achieve different effects by providing them different directions (you can for example fake some hard edges in the surface).
How are normals and vertex normals used in shading?
A Simple Shading Effect: Facing Ratio. Now that we know how to compute the normal of a point on the surface of an object, we have enough information already to create a simple shading effect called facing ratio. This technique consists of computing the dot product of the normal of the point that we want to shade and the viewing direction.
When do vertex normals have to be computed on the fly?
Sometimes triangles mesh are not directly converted from a smooth surface, and vertex normals have to be computed on the fly. Different techniques for computing vertex normals when there is not smooth surface to compute them from exist, but we won’t study them in this lesson.
Are there normals for the vertices of a triangle?
For now, use a software such as Maya or Blender to do this job for you (in Maya you can select your polygon mesh and select the option Soften Edge in the Normals menu). In fact, from a practical and technical point of view, each triangle has its own set of 3 vertex normals.
How is the vertex and fragment stage programmable?
The vertex stage and fragment stage are programmable, so you write functions for them in Metal Shading Language (MSL). The rasterization stage has fixed behavior. Rendering starts with a drawing command, which includes a vertex count and what kind of primitive to render.
How does the GPU call the vertex function?
When you execute a render command, the GPU calls your vertex function multiple times, generating a unique value for each vertex. The second argument, vertices, is an array that contains the vertex data, using the AAPLVertex struct previously defined.
How to calculate vertex normals in modern OpenGL?
I’m learning modern OpenGL and i just got started so go easy on me :). Right now im trying to understand normals but im having some difficulties. On my program i have this class which i use to draw primitives and i also implemented the assimp model loader which uses this class to load and draw meshes.