Basic Analysis of OpenGL programming in Ubuntu

This article focuses on how to implement basic OpenGL programming in Ubuntu. The main steps are as follows: 1. First of all, you must install some basic libraries and OpenGL files, mainly install the following two on the OK basic compilation Library: build-essentialsudoapt-getinstallbuild-essentialOpenGL: freeglut3-devsudoapt-getinstallfree

This article focuses on how to implement basic OpenGL programming in Ubuntu. The main steps are as follows:

1: first of all, of course, you need to install some basic compiling library and OpenGL library files. It is okay to install the following two files:

Basic compilation Library: build-essential

Sudo apt-get install build-essential

OpenGL tool Library: freeglut3-dev

Sudo apt-get install freeglut3-dev

The above is my installation prompt on the virtual machine, you can see that in addition to freeglut3, there are other additional software packages installed.

2: The second step, of course, is to write the code. You don't need to talk about it. You can post it yourself and study it if you have time.

/* Rotating cube with color interpolation */

# Include
# Include
 
GLfloat vertices [] [3] = {-1.0,-1.0,-1.0}, {1.0,-1.0,-1.0 },
{1.0, 1.0,-1.0}, {-1.0, 1.0,-1.0}, {-1.0,-1.0, 1.0 },
{1.0,-1.0, 1.0}, {1.0, 1.0, 1.0}, {-1.0, 1.0, 1.0 }};

GLfloat normals [] [3] = {-1.0,-1.0,-1.0}, {1.0,-1.0,-1.0 },
{1.0, 1.0,-1.0}, {-1.0, 1.0,-1.0}, {-1.0,-1.0, 1.0 },
{1.0,-1.0, 1.0}, {1.0, 1.0, 1.0}, {-1.0, 1.0, 1.0 }};

GLfloat colors [] [3] = {0.0, 0.0, 0.0}, {1.0, 0.0, 0.0 },
{1.0, 1.0, 0.0}, {0.0, 1.0, 0.0}, {0.0, 0.0, 1.0 },
{1.0, 0.0, 1.0 },{ 1.0, 1.0, 1.0 },{ 0.0, 1.0, 1.0 }};

Void polygon (int a, int B, int c, int d)
{
GlBegin (GL_POLYGON );
GlColor3fv (colors [a]);
GlNormal3fv (normals [a]);
GlVertex3fv (vertices [a]);
GlColor3fv (colors [B]);
GlNormal3fv (normals [B]);
GlVertex3fv (vertices [B]);
GlColor3fv (colors [c]);
GlNormal3fv (normals [c]);
GlVertex3fv (vertices [c]);
GlColor3fv (colors [d]);
GlNormal3fv (normals [d]);
GlVertex3fv (vertices [d]);
GlEnd ();
}
 
 
 
Void colorcube (void)
{
/* Map vertices to faces */

Polygon (0, 3, 2, 1 );
Polygon (2, 3, 7, 6 );
Polygon (0, 4, 7, 3 );
Polygon (1, 2, 6, 5 );
Polygon (4,5, 6,7 );
Polygon (0, 1, 5, 4 );
}

Static GLfloat theta [] = {0.0, 0.0, 0.0 };
Static GLint axis = 2;

Void display (void)
{
/* Display callback, clear frame buffer and z buffer,
Rotate cube and draw, swap buffers */

GlClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
GlLoadIdentity ();
GlRotatef (theta [0], 1.0, 0.0, 0.0 );
GlRotatef (theta [1], 0.0, 1.0, 0.0 );
GlRotatef (theta [2], 0.0, 0.0, 1.0 );
Colorcube ();
GlFlush ();
Gluswapbuffers ();
}
 
 

Void spinCube ()
{
/* Idle callback, spin cube 2 degrees about selected axis */
Theta [axis] + = 2.0;
If (theta [axis] & gt; 360.0) theta [axis]-= 360.0;
Display ();
}
 
 
 
Void mouse (int btn, int state, int x, int y)
{
/* Mouse callback, selects an axis about which to rotate */
If (btn = maid & state = maid) axis = 0;
If (btn = maid) axis = 1;
If (btn = maid & state = maid) axis = 2;
}
 
Void myReshape (int w, int h)
{
GlViewport (0, 0, w, h );
GlMatrixMode (GL_PROJECTION );
GlLoadIdentity ();
If (w <= h)
{
GlOrtho (-2.0, 2.0,-2.0 * (GLfloat) h/(GLfloat) w,
2.0 * (GLfloat) h/(GLfloat) w,-10.0, 10.0 );
}
Else
{
GlOrtho (-2.0 * (GLfloat) w/(GLfloat) h,
2.0 * (GLfloat) w/(GLfloat) h,-2.0, 2.0,-10.0, 10.0 );
}
 
GlMatrixMode (GL_MODELVIEW );
}
 

Main (int argc, char ** argv)
{
Gluinit (& argc, argv );
/* Need both double buffering and z buffer */

Fig );
Gluinitwindowsize (500,500 );
Ngcreatewindow ("colorcube ");
Glureshapefunc (myReshape );
Gludisplayfunc (display );
GlutIdleFunc (spinCube );
Glumousefunc (mouse );
Glable (GL_DEPTH_TEST);/* Enable hidden -- surface -- removal */
Glumainloop ();
 
Return 0;
 
}