OpenGL Computer Graphics 3

Question 1

In GLSL, which built-in variable contains the interpolated texture coordinate passed from the vertex shader to the fragment shader?

Accepted Answer

A user-defined 'varying' or 'in' variable

Answer

Texture coordinates are user-defined 'out' variables in the vertex shader and matching 'in' variables in the fragment shader, interpolated by the rasterizer.

Question 2

What OpenGL call uploads a 2D texture image to the GPU?

Accepted Answer

glTexImage2D()

Answer

glTexImage2D() specifies the mipmap level, internal format, dimensions, and pixel data for a 2D texture.

Question 3

What is mipmapping in OpenGL texturing?

Accepted Answer

A series of pre-computed, progressively smaller texture images for minification

Answer

Mipmaps are pre-filtered downsampled versions of a texture used when the textured surface is far from the camera to avoid aliasing.

Question 4

Which matrix transforms 3D eye-space coordinates into clip coordinates in a classic OpenGL pipeline?

Accepted Answer

Projection matrix

Answer

The projection matrix (perspective or orthographic) maps eye-space coordinates to the clip volume, defining the viewing frustum.

Question 5

What does the GLSL function 'normalize()' return?

Accepted Answer

A vector with the same direction but a magnitude of 1.0

Answer

normalize(v) divides the vector by its length, returning a unit vector used frequently in lighting calculations.

OpenGL Practice Test

OpenGL Practice Test

OpenGL Computer Graphics 3