progs/trivial/vbo-drawarrays.c

   1 /* Basic VBO */
   2
   3 #include <assert.h>
   4 #include <string.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <math.h>
   8 #include <GL/glew.h>
   9 #include <GL/glut.h>
  10
  11
  12 struct {
  13    GLfloat pos[3];
  14    GLubyte color[4];
  15 } verts[] =
  16 {
  17    { {  0.9, -0.9, 0.0 },
  18      { 0x00, 0x00, 0xff, 0x00 }
  19    },
  20
  21    { {  0.9,  0.9, 0.0 },
  22      { 0x00, 0xff, 0x00, 0x00 }
  23    },
  24
  25    { { -0.9,  0.9, 0.0 },
  26      { 0xff, 0x00, 0x00, 0x00 }
  27    },
  28
  29    { { -0.9, -0.9, 0.0 },
  30      { 0xff, 0xff, 0xff, 0x00 }
  31    },
  32 };
  33
  34 GLuint arrayObj, elementObj;
  35
  36 static void Init( void )
  37 {
  38    GLint errno;
  39    GLuint prognum;
  40
  41    static const char *prog1 =
  42       "!!ARBvp1.0\n"
  43       "MOV  result.color, vertex.color;\n"
  44       "MOV  result.position, vertex.position;\n"
  45       "END\n";
  46
  47    glGenProgramsARB(1, &prognum);
  48    glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
  49    glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
  50                       strlen(prog1), (const GLubyte *) prog1);
  51
  52    assert(glIsProgramARB(prognum));
  53    errno = glGetError();
  54    printf("glGetError = %d\n", errno);
  55    if (errno != GL_NO_ERROR)
  56    {
  57       GLint errorpos;
  58
  59       glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
  60       printf("errorpos: %d\n", errorpos);
  61       printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
  62    }
  63
  64
  65    glEnableClientState( GL_VERTEX_ARRAY );
  66    glEnableClientState( GL_COLOR_ARRAY );
  67
  68    glGenBuffersARB(1, &arrayObj);
  69    glBindBufferARB(GL_ARRAY_BUFFER_ARB, arrayObj);
  70    glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(verts), verts, GL_STATIC_DRAW_ARB);
  71
  72    glVertexPointer( 3, GL_FLOAT, sizeof(verts[0]), 0 );
  73    glColorPointer( 4, GL_UNSIGNED_BYTE, sizeof(verts[0]), (void *)(3*sizeof(float)) );
  74
  75 }
  76
  77
  78
  79 static void Display( void )
  80 {
  81    glClearColor(0.3, 0.3, 0.3, 1);
  82    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  83
  84    glEnable(GL_VERTEX_PROGRAM_ARB);
  85
  86    /* glDrawArrays( GL_TRIANGLES, 0, 3 ); */
  87    glDrawArrays( GL_TRIANGLES, 1, 3 );
  88
  89    glFlush();
  90 }
  91
  92
  93 static void Reshape( int width, int height )
  94 {
  95    glViewport( 0, 0, width, height );
  96    glMatrixMode( GL_PROJECTION );
  97    glLoadIdentity();
  98    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  99    glMatrixMode( GL_MODELVIEW );
 100    glLoadIdentity();
 101    /*glTranslatef( 0.0, 0.0, -15.0 );*/
 102 }
 103
 104
 105 static void Key( unsigned char key, int x, int y )
 106 {
 107    (void) x;
 108    (void) y;
 109    switch (key) {
 110       case 27:
 111          exit(0);
 112          break;
 113    }
 114    glutPostRedisplay();
 115 }
 116
 117
 118
 119
 120 int main( int argc, char *argv[] )
 121 {
 122    glutInit( &argc, argv );
 123    glutInitWindowPosition( 0, 0 );
 124    glutInitWindowSize( 250, 250 );
 125    glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
 126    glutCreateWindow(argv[0]);
 127    glewInit();
 128    glutReshapeFunc( Reshape );
 129    glutKeyboardFunc( Key );
 130    glutDisplayFunc( Display );
 131    Init();
 132    glutMainLoop();
 133    return 0;
 134 }