小菜鸟在OpenGL里学写第一个cg

wingser

安好cg toolkit
就能在include 里找到header files, library files啦,别忘了include 和link它们
bin里的dll文件,丢到运行的文件夹使得运行文件可以link到, 当然罗, windows专用, windows rocks! 哈

1. 
   
2. /**main.cpp*/
   
3. #include <stdio.h>
   
4. #include <stdlib.h>
   
5. 
   
6. /**include cg headers*/
   
7. #include <Cg/cg.h>
   
8. #include <Cg/cgGL.h>
   
9. 
   
10. #include <gl/glut.h>
    
11. 
    
12. /**retain program reference for releasing*/
    
13. CGprogram program;
    
14. /**retain context reference for releasing*/
    
15. CGcontext context;
    
16. 
    
17. /**
    
18. display callback function
    
19. */
    
20. void display(void)
    
21. {
    
22.    glClear (GL_COLOR_BUFFER_BIT);/* clear all pixels  */
    
23.    glColor3f (1.0, 1.0, 1.0);
    
24.    glBegin(GL_POLYGON);/* draw white polygon with corners at(0.25, 0.25, 0.0) and (0.75, 0.75, 0.0)*/
    
25.       glVertex2f (0.25, 0.25);
    
26.       glVertex2f (0.75, 0.25);
    
27.       glVertex2f (0.75, 0.75);
    
28.       glVertex2f (0.25, 0.75);
    
29.    glEnd();
    
30.    glFlush ();/* start processing buffered OpenGL routines  */
    
31. }
    
32. 
    
33. /**
    
34. output cg errors
    
35. */
    
36. static void CheckCgError(int no)
    
37. {
    
38.   CGerror err = cgGetError();
    
39. 
    
40.   if (err != CG_NO_ERROR)
    
41.    {
    
42.            //output error number
    
43.            printf("%d: ",no);
    
44.      printf("CG error: %s\n", cgGetErrorString(err));
    
45. 
    
46.    }
    
47. }
    
48. 
    
49. void init (void)
    
50. {
    
51.         //create cg context
    
52.         context=cgCreateContext();
    
53.         CheckCgError(1);
    
54.         //get a valid profile
    
55.         CGprofile vertexProfile;
    
56.         if (cgGLIsProfileSupported(CG_PROFILE_ARBVP1)){
    
57.                 //store this profile
    
58.                 vertexProfile=CG_PROFILE_ARBVP1;
    
59.                 CheckCgError(2);
    
60.        
    
61.                 //get cg source code from a file named "MYVP1.cg", its entry function is "program1"
    
62.                 program=cgCreateProgramFromFile(context, CG_SOURCE,"MYVP1.cg",
    
63.                                                                                                 vertexProfile, "program1",NULL);
    
64.                 CheckCgError(3);
    
65.                 //load this program
    
66.                 cgGLLoadProgram(program);
    
67.                 CheckCgError(4);
    
68.                 //output the compiled information
    
69.                 printf("---- PROGRAM BEGIN ----\n%s---- PROGRAM END ----\n",
    
70.                         cgGetProgramString(program, CG_COMPILED_PROGRAM));
    
71.                 //enable the profile
    
72.                 cgGLEnableProfile(vertexProfile);
    
73.                 //bind the program
    
74.                 cgGLBindProgram(program);
    
75.         }
    
76.        
    
77. 
    
78.    glClearColor (0.0, 0.0, 0.0, 0.0);/* select clearing color  */
    
79.    glMatrixMode(GL_PROJECTION);
    
80.    glLoadIdentity();
    
81.    glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0);/* initialize viewing values  */
    
82. }
    
83. 
    
84. 
    
85. //release cg resource before end of program
    
86. void destoryApp(){
    
87.         cgDestroyProgram(program);
    
88.         cgDestroyContext(context);
    
89. }
    
90. 
    
91. int main(int argc, char** argv)
    
92. {
    
93.    glutInit(&argc, argv);
    
94.    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);/*Declare initial display mode(single buffer and RGBA).*/
    
95.    glutInitWindowSize (250, 250); /*Declare initial window size.*/
    
96.    glutInitWindowPosition (100, 100);/*Declare initial window position.*/
    
97.    glutCreateWindow ("hello");/*Open window with "hello"in its title bar.*/  
    
98.    init ();/*Call initialization routines.*/
    
99.    glutDisplayFunc(display); /*Register callback function to display graphics.*/
    
100.    glutMainLoop();/*Enter main loop and process events.*/
     
101. 
     
102.                
     
103.         destoryApp();
     
104.    return 0;   /* ANSI C requires main to return int. */
     
105. }
     
106. 
     
107. 
     
108. 
     
109. 
     
110. 
     
111. 
     
112. 
     
113. 
     
114. 
     
115. 
     
116. 
     
117. 
     
118. 
     
119. //MYVP1.cg
     
120. struct Output
     
121. {
     
122.     float4 position : POSITION;
     
123.     float4 color : COLOR;
     
124. };
     
125. 
     
126. Output program1(float2 position : POSITION)
     
127. {
     
128.     Output OUT;
     
129. 
     
130.     OUT.position = float4(position,0,1);
     
131.     if(position.x>0.5)
     
132.         OUT.color = float4(0,1,0,1);
     
133.     else
     
134.         OUT.color = float4(1,0,0,1);
     
135. 
     
136.     return OUT;
     
137. } // main
     

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强……

wingser

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