What are the small cells containing liquid crystals in an LCD display called, and what does the array size of these cells determine?
The small cells in the LCD display are called pixels (picture elements). The size of this array determines the resolution of the display.
What is the 2D array of memory on the graphics card that stores the pixel data and produces the electrical signal for the display?
The frame buffer.
Why is it recommended to use an LCD monitor’s native resolution?
Because changing the display resolution in the operating system will cause the display to approximate the new resolution, which produces a blurry or hard-to-read image.
How is the image sent to the screen in an organized way (the scanning pattern)?
The pixels are sent one at a time , starting from the top left corner and proceeding row by row until the bottom row is reached
What is the definition of the refresh rate?
he refresh rate is the number of times per second that the image is sent to the screen
What three colors form the basis of the RGB color space approximation used in computer graphics?
Red, Green, and blue
How is a color typically represented in the RGB color space (mathematically and numerically)?
A color is a triple (r, g, b) , where r, g, and b are either integers (usually 0 to 255) or floating point numbers (0 to 1)
What term describes the total color space that a display is capable of producing?
Gamut
What vector property is essential for determining how light is reflected off a triangle surface?
Normal vectors
Briefly describe the difference between Gouraud shading and Phong shading in terms of what is interpolated across the triangle.
- Gouraud shading interpolates the color (computed at the vertices) across the surface of the triangle.
- Phong shading interpolates the normal vector (over the surface) and then computes the color at each pixel.
What is the process of converting geometrical information (the model) into the pixels in the framebuffer called?
Rendering
What is the fundamental trade-off that exists between rendering algorithms like OpenGL and Global Illumination?
The trade-off is between speed and quality. OpenGL focuses on speed (real-time) at the expense of quality, while Global Illumination is the opposite.
In computer graphics, what simple geometric primitive is commonly used to represent almost anything in a 3D model, as long as enough of them are used?
Triangles
The graphics pipeline is divided into steps to facilitate what type of implementation?
Implementation in hardware
What are the two primary components that define the two ends of the graphics pipeline?
The Model (e.g., triangles) and the Display (e.g., pixels)
What is the process of eliminating triangles that are outside the viewing frustum (or processing only the visible part) called?
Clipping
What is the hidden surface problem?
The problem where surfaces of solid objects hide the other surfaces behind them , meaning some triangles are in front of and partially or completely hide other triangles.
How do current graphics cards solve the hidden surface problem, and what is the primary condition for drawing a new pixel?
They solve it in hardware using a depth buffer (or z buffer). The new pixel is drawn if its depth is less than (closer to the viewer) the current contents of the z-buffer.
The graphics pipeline is divided into two main parts. What are the GPU programs called that run in the first part (geometrical information) and the second part (individual pixels/fragments)?
- First part (Geometrical): Vertex programs.
- Second part (Fragments): Fragment programs
How is color represented in computer graphics?
Color is represented using the RGB model, a triple (r,g,b). They are integer values [0 to 25] or floats [0.1 0.0]. Each of the values represents how much red, green, and blue light is used. The color gamut is the range of colors a display device can produce.
What is a frame buffer?
A frame buffer is a block of memory in the graphics card that contains information about the color values of each pixel on the screen. It is transferred to the monitor using scanning patterns. There is a one-to-one mapping between the pixel in the frame buffer and the pixel on the screen.
What operations are performed in vertex processing?
Vertices are first transformed from local object coordinates to world coordinates using the model matrix. Then transformed into eye (camera) coordinates. Eye coordinates are converted to clip space via perspective projection. This defines the viewing frustum. Vertices outside the clip volume are clipped. Basic lighting is computed using normal vectors via phong shading.
Explain the difference between local and global illumination.
- Local illumination only considers light-object interaction. Fast, real time rendering, if your goal is speed (e.g gaming).
- Global illumination considers light bouncing, shadows, and reflections. However, it is slower than local illumination. It is commonly used in movie production.
What is the difference between Gouraud and Phong shading? Why is Phong more realistic?
Gouraud shading computes color per vertex and interpolates. Phong shading interpolates normals and computes color per pixel, making it more realistic.
