progs/trivial/vbo-drawrange.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 #define ELTOBJ 0
  12
  13 struct {
  14    GLfloat pos[3];
  15    GLubyte color[4];
  16 } verts[] =
  17 {
  18    { {  0.9, -0.9, 0.0 },
  19      { 0x00, 0x00, 0xff, 0x00 }
  20    },
  21
  22    { {  0.9,  0.9, 0.0 },
  23      { 0x00, 0xff, 0x00, 0x00 }
  24    },
  25
  26    { { -0.9,  0.9, 0.0 },
  27      { 0xff, 0x00, 0x00, 0x00 }
  28    },
  29
  30    { { -0.9, -0.9, 0.0 },
  31      { 0xff, 0xff, 0xff, 0x00 }
  32    },
  33 };
  34
  35 GLuint indices[] = { 1, 2, 3 };
  36
  37 GLuint arrayObj, elementObj;
  38
  39 static void Init( void )
  40 {
  41    GLint errno;
  42    GLuint prognum;
  43
  44    static const char *prog1 =
  45       "!!ARBvp1.0\n"
  46       "MOV  result.color, vertex.color;\n"
  47       "MOV  result.position, vertex.position;\n"
  48       "END\n";
  49
  50    glGenProgramsARB(1, &prognum);
  51    glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
  52    glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
  53                       strlen(prog1), (const GLubyte *) prog1);
  54
  55    assert(glIsProgramARB(prognum));
  56    errno = glGetError();
  57    printf("glGetError = %d\n", errno);
  58    if (errno != GL_NO_ERROR)
  59    {
  60       GLint errorpos;
  61
  62       glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
  63       printf("errorpos: %d\n", errorpos);
  64       printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
  65    }
  66
  67
  68    glEnableClientState( GL_VERTEX_ARRAY );
  69    glEnableClientState( GL_COLOR_ARRAY );
  70
  71    glGenBuffersARB(1, &arrayObj);
  72    glBindBufferARB(GL_ARRAY_BUFFER_ARB, arrayObj);
  73    glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(verts), verts, GL_STATIC_DRAW_ARB);
  74
  75 #if ELTOBJ
  76    glGenBuffersARB(1, &elementObj);
  77    glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, elementObj);
  78    glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, sizeof(indices), indices, GL_STATIC_DRAW_ARB);
  79 #endif
  80
  81    glVertexPointer( 3, GL_FLOAT, sizeof(verts[0]), 0 );
  82    glColorPointer( 4, GL_UNSIGNED_BYTE, sizeof(verts[0]), (void *)(3*sizeof(float)) );
  83
  84 }
  85
  86
  87
  88 static void Display( void )
  89 {
  90    glClearColor(0.3, 0.3, 0.3, 1);
  91    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  92
  93    glEnable(GL_VERTEX_PROGRAM_ARB);
  94
  95 #if ELTOBJ
  96    glDrawRangeElements( GL_TRIANGLES, 1, 3, 3, GL_UNSIGNED_INT, NULL );
  97 #else
  98    glDrawRangeElements( GL_TRIANGLES, 1, 3, 3, GL_UNSIGNED_INT, indices );
  99 #endif
 100
 101    glFlush();
 102 }
 103
 104
 105 static void Reshape( int width, int height )
 106 {
 107    glViewport( 0, 0, width, height );
 108    glMatrixMode( GL_PROJECTION );
 109    glLoadIdentity();
 110    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
 111    glMatrixMode( GL_MODELVIEW );
 112    glLoadIdentity();
 113    /*glTranslatef( 0.0, 0.0, -15.0 );*/
 114 }
 115
 116
 117 static void Key( unsigned char key, int x, int y )
 118 {
 119    (void) x;
 120    (void) y;
 121    switch (key) {
 122       case 27:
 123          exit(0);
 124          break;
 125    }
 126    glutPostRedisplay();
 127 }
 128
 129
 130
 131
 132 int main( int argc, char *argv[] )
 133 {
 134    glutInit( &argc, argv );
 135    glutInitWindowPosition( 0, 0 );
 136    glutInitWindowSize( 250, 250 );
 137    glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
 138    glutCreateWindow(argv[0]);
 139    glewInit();
 140    glutReshapeFunc( Reshape );
 141    glutKeyboardFunc( Key );
 142    glutDisplayFunc( Display );
 143    Init();
 144    glutMainLoop();
 145    return 0;
 146 }