Answers of the Final Exam Review
Computer Graphics Review Questions:
1. Pixel/Raster
A pixel is a tiny on-screen dot. It is one of the smallest addressable picture components. Raster (array) of pixels is an image. A raster file is an image made of pixels.
2. 5. Framebuffer (and depth of a framebuffer), The working principle of framebuffer
The framebuffer, a component of the random-access memory, is where the pixels are stored. The depth of the framebuffer refers to how many bits are used for each pixel. So, framebuffer and depth of framebuffer are related to pixels and bits, respectively. Additionally, a framebuffer is a bitmap that includes the color depth among other things. Only the two-color values (0,0), (1,1), (0,1), and (1,0) are provided. When it’s 0, 0, we get black, but when it’s 1, 1, we get white.
3. Full-color system
True color and RGB are two names for the full-color system. This approach gives the graphics a more realistic representation. Red, Green, and Blue are all present in it. These colors are assigned bits within each pixel.
We obtain the first image, which is a full-color system, by combining these three colors.
4. The difference between a raster and vector graphics (pros/cons)
Raster graphics, which are made of pixels.
However, there are no pixels in a vector image because it is created using mathematical equations.
The resolution is another area of distinction. When using raster, the quality of your images will decline as you zoom in. Raster is what you see when the size is increased and the image becomes fragmented or blurry.
The image quality will not be affected by the resolution of vector drawings.
Raster is a technology used by digital photography as well as editors of images, photos, and graphics. Digital images, intricate designs, and logos are all created in vector.
6. 1-bit deep framebuffer allows two colors. How many colors does 8-bit deep framebuffer allow?
Answer is 256, 1 bit was used for each of the two colors in a pixel, and we assumed that 21 and that equaled 2. Consider the 28 now, which equals 256.
7. How many bits per pixel are there in full-color systems?
There are 24 bits in true color since there are 3 colors, 2³ = 8, and multiplying 3 results in 24. In every scenario when there are 32 bits per pixel, 24 bits are assigned to color, leaving 8 for alpha or unused.
8. How WebGL works (CPU/GPU/shader/etc. interaction)
Vertices, colors, and a buffer are defined in the CPU before meeting the GPU, which has shaders built in. We have a fragment that could be a pixel. CPU is outpaced by GPU. The GPU portion of rasterization is also taking place. Rasterization is the interaction of pixel positions, colors, and geometric entities. If you’re wondering where the lighting process takes place, it’s in the CPU, but the calculations are done in the GPU. Small programs called shaders regulate how vertices and fragments are processed. Vertex shaders and fragment shaders are the two different kinds of these. On the GPU, data is held in buffers. In the code section, we must have made clear how to generate and bind these buffers. Next, you used the attribute location in the uniform and attribute parts. Whenever something occurs, you can sketch the geometric entities.
9. Synthetic Camera Model
This camera model is utilized in computer vision and graphics to imitate the creation of images. Since computer-generated visuals don’t actually exist, we remembered the synthetic image. And it works similarly to how people and cameras interpret things. This camera model has an idealized, distortion-free lens. This serves as the foundation for many APIs, including WebGL and OpenGL.
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10. How images are formed (which elements form an image)?
3D objects include the viewer (camera) and real objects (like trees). It is a 2D image, though. Image creation is composed of three components: Viewer, Objects and the Light source.
29. What is alpha in RGBA? What is blending?
A is used to create fog effects, combine images, and increase or decrease transparency. It is kept in the framebuffer alongside RGB. blending is the mixing of colors from various sources (pixels or fragments). Based on the alpha value of the source and destination pixels, alpha blending blends the colors of those pixels. Fully transparent is 0 and fully opaque is 1.
33. Aspect ratio
It is the ratio of a given object’s width to height. If you state that the aspect ratio of the viewing rectangle set by the camera parameters should match the aspect ratio of the canvas’s window, then objects will be deformed.
51. Point-vector addition
The point becomes a new point when a vector is added. To get from one place to another, we need a directed line segment. Q+v=P.
68. Model-view matrix
The object (model) frame is where we specify geometry. Then, models are displayed to the public. We desire a camera view of these objects. In order to do it, we must go from the world frame to the camera (eye) frame. The model-view matrix is used to convert data.
82. Perspective projection
It is a rendering approach that simulates how objects seem in 3D space when seen from a particular angle. Positives: Visual hierarchy and realistic impression.
Cons: Loss of object dimensions, field of view restriction, and distortion.
96. What is refraction?
The meaning is hard to recall, but if you comprehend the example, it becomes simple. If you put a pencil in a glass of water, the part of the pencil that is immersed will bend.
This happens as a result of light waves diffracting when they travel from water to air.
103. Under which condition spotlight becomes a point source? Spotlight intensity how is defined?
When the light’s beam is highly concentrated and focused, it appears little. High intensity at the Focus and little light spill are necessary for a point source to exist. The brightness of the light emitted by a spotlight is measured by its intensity. energy of light per unit of angle in a specific direction.
112. Diffuse reflection. Explain how we get formula. Lambertian surface.
A reflector that is perfectly diffuse reflects the light it reflects. The surface of a perfectly diffuse object is so rough that no preferred angle of reflection exists. Such surfaces, also known as Lambertian surfaces, can be mathematically represented using Lambert’s law.
Id=kd(i*n)Ld if we include a reflection coefficient that represents the percentage of entering diffuse light that is reflected.
117. What is half vector?
In order to calculate the specular reflections of light on surfaces, it is also known as a midway vector.
between the viewer’s orientation and the direction of the light. H=normalize(L+V)
