How can I anti-aliasing in OpenGL?

Document directory

• Enable anti-aliasing
• Anti-tooth Quality
• Line example
• Multiple sampling

Recently encountered problems in the project: When drawing a graph, the straight line will have obvious serrations, and the graph is extremely unattractive. The image changes significantly after anti-aliasing is used.

The main method of anti-aliasing is as follows:

When the point is very large, it is shown as follows:

What we actually want to see isDotInsteadRectangle

Effect after anti-aliasing is enabled

A little round

Code

glPointSize(10);glEnable (GL_POINT_SMOOTH);glHint (GL_POINT_SMOOTH, GL_NICEST);

Enable anti-aliasing

Or enable anti-aliasing with glEnable, which can be processed based on different images

1. GL_POINT_SMOOTH point
2. GL_LINE_SMOOTH line
3. GL_POLYGON_SMOOTH Polygon

Anti-tooth Quality

Of course, the better the effect, the slower the computer speed, that is, there is a parameter setting

GlHint is used to set the anti-sawtooth degree of point, line, and polygon.

1. GL_DONT_CARE should be the default.
2. GL_FASTEST speed first
3. GL_NICEST graphic display quality is preferred

Line example

Not Enabled

After enabling

Obviously, after anti-aliasing is enabled, the coarse line is changed to a rectangle, but not a parallelogram.

Code

glEnable (GL_LINE_SMOOTH);glHint (GL_LINE_SMOOTH, GL_NICEST);glLineWidth (10);

Multiple sampling

It has multiple colors, depths, and multi-group texture coordinates based on the number of pixel samples. It is especially suitable for polygon.

Three steps

1. Obtain a window that supports multisampling. With GLUT, you can ask for one by calling

Gluinitdisplaymode (glu_double | glu_rgb |

Glu_multisample );

2. After you 've opened a window, you will need to verify that multisampling

Is available. For instance, GLUT may give you a window

With "almost" what you have asked for. If querying the state variable

GL_SAMPLE_BUFFERS returns a value of one and GL_SAMPLES returns

A value greater than one, then you'll be able to use multisampling.

(GL_SAMPLES returns the number of subpixel samples. If there is only

One sample, multisampling is supported tively disabled .)

GLint bufs, samples;

GlGetIntegerv (GL_SAMPLE_BUFFERS, & bufs );

GlGetIntegerv (GL_SAMPLES, & samples );

3. To turn on multisampling, call

GlEnable (GL_MULTISAMPLE );

Comparison of the two figures below

These functions are supported by OpenGL.