Modern Graphics Hardware

What is rendering?

A stepwise process which makes a 3D scene look life-like. Steps of rendering often include shading/lighting and texture mapping.

What piece of hardware is in charge of rendering?

The GPU

What is the GPU?

A specialised processor designed for processing graphics primitives in parallel, as opposed to the serial execution of the CPU. They often contain thousands of processors.

What are the steps of the modern graphics hardware system?

1. Graphics Commands

2. Graphics Processor

3. Frame Buffer

4. Display Controller

5. Computer Screen

What is the first step of the modern graphics hardware system (in detail)?

The CPU runs graphics applications, constantly generating graphics commands so that the screen is always updating.

What are graphics commands?

Simple commands like “draw polygons”, not “draw scene”.

What two kinds of graphics commands can we get, and what is different about how they are rendered?

• 2D graphics commands - based on (x, y) coordinates. When rendered objects overlap, objects are obscured.

• 3D graphics commands - based on (x, y, z) coordinates. When rendered objects overlap, z and depth values determine whether or not they are visible.

What is the second step of the modern graphics hardware system (in detail)?

The GPU receives and processes graphics commands using shaders. Most if not all of the things we study as part of this module take place within the GPU. After a graphics command is processed, the rendered result is drawn into a frame buffer.

What is the third step of the modern graphics hardware system (in detail)?

The frame buffer stores the rendered result from the GPU.

What is a frame buffer?

A memory space that stores a grid of colour/intensity values which are then mapped to every pixel on the screen.

What do we use at this stage to support complex graphics applications?

Double buffering - while the image in one buffer is being displayed, the GPU is rendering the next image into another frame buffer.

What is the fourth step of the modern graphics hardware system (in detail)?

The display controller reads the pixel data from the frame buffer and converts this pixel data into the required format for display. It also controls refresh rate.

What is refresh rate?

The video signal timing for when the frames are displayed.

What is the fifth step of the modern graphics hardware system (in detail)?

The computer screen - the display controller converts the pixel data into the required format, and sends this to the computer screen for display.

What is the thing VR game-developers have to take into account when making their games? What causes this?

Stereopsis - “solid sight”, or the impression of depth perceived when a scene is viewed with both eyes.

Stereopsis is caused by the retinal disparity of the eyes which causes two images to be produced which are fused by the brain to produce vision.