Perspective refers to the angles between the lines that lend the illusion of three dimensions.
Colors and Shading
Moving beyond line drawing, we need to add color to create a solid object. Shading refers to the way the color is applied to the polygon. Shading can be of two types in OpenGL - Flat or Smooth.
Lights and Shadows
Plain solid color doesn’t offer enough realism. By applying Lighting effects we can make objects appear as they would in reality depending on their material properties and the lighting parameters. Adding a shadow further increases realism.
With Texture Mapping we can have wood grains, cloth textures, brick like textures etc instead of plain materials. This technique of applying an image to the surface of a polygon is called Texture Mapping. The image we use is called the Texture and the individual elements of the texture are called Texels.
Fog is an atmospheric effect that adds haziness to objects in a scene depending on how far the objects are from the viewer.
Blending and Transparency
Blending is the combination of colors of objects on the screen. This effect can be used for a variety of purposes. By varying the amount each object is blended with the scene we can make objects look transparent.
Aliasing is an effect that is visible on screen due to the fact that an image consists of discrete pixels. By carefully blending the lines with the background color we can eliminate jagged edges and give them a smooth appearance. This blending technique is called anti-aliasing.
#include <windows.h> //Required for every Windows Program
#include <gl\glut.h> //Required for using the GLUT library
//Perform OpenGL Initialization here
//Set the background clearing color to blue
//The drawing callback function
//Clear the color buffer
//Flush the rendering pipeline
//Choose the display mode settings
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);//初始化显示模式(单缓冲,RGB)
//Create the Window
//Set the RenderScsne function as the display callback
//Start the GLUT framework