Some practical functions for learning OpenGL Based on glut

 

 

I recently started learning OpenGL again. Some practical functions I wrote during the learning process can be shared here:

1. The following functions can output some information about current OpenGL in the console (to be called after the window is created, otherwise null value will be obtained)

Void printglinfo () <br/>{< br/> const glubyte * name = glgetstring (gl_vendor); <br/> const glubyte * biaoshifu = glgetstring (gl_renderer ); <br/> const glubyte * openglversion = glgetstring (gl_version); <br/> const glubyte * gluversion = glugetstring (glu_version ); <br/> printf ("OpenGL implementation vendor name: % s/n", name); <br/> printf ("Renderer identifier: % s/n ", biaoshifu); <br/> printf ("OpenGL implementation version: % s/n", openglversion); <br/> printf ("Glu tool library version: % s/n ", gluversion); <br/>} 

2. The following function is used to specify it as a processing function for mouse events through fig (Mouse, this allows you to scale the rotation of the view image and the observed distance between the scroll observer and the view when you drag the mouse (My glut library does not support scroll events, is the http://www.cnblogs.com/dabaopku/archive/2010/07/07/1773233.html implemented by referring to the article here)

Void mouse (INT button, int state, int X, int y) <br/>{< br/> switch (button) <br/>{< br/> case glu_left_button: <br/>{< br/> If (State = glu_down) <br/>{< br/> isdrag = true; <br/> prex = X; <br/> prey = y; <br/>}< br/> If (State = glu_up) <br/>{< br/> isdrag = false; <br/>}< br/>} break; <br/> case MAID: <br/>{< br/> closefactor + = 0.1; <br/>} break; <br/> case MAID: <br/>{< br/> closefactor-= 0.1; <br/>} break; <br/> default: break; <br/>}< br/> glupostredisplay (); <br/>} 

Register the following functions as a processing function by moving the mouse using the glumotionfunc () function. Then, you can use the above function to move the mouse to rotate the view and zoom the observer distance with the scroll wheel.

 

Void motion (glint X, glint y) <br/>{< br/> If (isdrag <br/>{< br/> spiny = spiny + (X-prex) * 0.5; <br/> spinx = spinx + (Y-Prey) * 0.5; <br/> prex = x; <br/> prey = y; <br/> maid (); <br/>}< br/>} 

3. The last practical function is to draw the X, Y, and Z coordinate axes of the world coordinate system in the view, so that you do not know the position of the object in the view.

(You can adjust the axis length as needed)

Void drawglobalaxis () <br/>{< br/> gldisable (gl_lighting); <br/> glbegin (gl_lines); <br/> glcolor3f (1.0, 0.0, 0.0 ); // draw the X axis in red <br/> glvertex3f (-100.0, 0.0, 0.0); <br/> glvertex3f (100.0, 0.0, 0.0); <br/> glcolor3f (0.0, 1.0, 0.0); // green draw Z axis <br/> glvertex3f (0.0, 0.0,-100.0); <br/> glvertex3f (0.0, 0.0, 100.0 ); <br/> glcolor3f (0.0, 0.0, 1.0); // draw the Y axis in blue. <br/> glvertex3f (0.0,-100.0 ,. 0); <br/> glvertex3f (0.0, 100.0, 0.0); <br/> glend (); </P> <p> glable (gl_lighting ); <br/>}