progs/trivial/vbo-tri.c

   1 /* Even simpler for many drivers than trivial/tri -- pass-through
   2  * vertex shader and vertex data in a VBO.
   3  */
   4
   5 #include <assert.h>
   6 #include <string.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <math.h>
  10 #include <GL/glew.h>
  11 #include <GL/glut.h>
  12
  13
  14 struct {
  15    GLfloat pos[4];
  16    GLfloat color[4];
  17 } verts[] =
  18 {
  19    { {  -0.9, -0.9, 0.0, 1.0 },
  20      {.8,0,0, 1},
  21    },
  22
  23    { {  0.9,  -0.9, 0.0, 1.0 },
  24      { 0, .9, 0, 1 },
  25    },
  26
  27    { { 0,  0.9, 0.0, 1.0 },
  28      {0,0,.7, 1},
  29    },
  30 };
  31
  32 GLuint arrayObj;
  33
  34 static void Init( void )
  35 {
  36    GLint errno;
  37    GLuint prognum;
  38
  39    static const char *prog1 =
  40       "!!ARBvp1.0\n"
  41       "MOV  result.color, vertex.color;\n"
  42       "MOV  result.position, vertex.position;\n"
  43       "END\n";
  44
  45
  46    glGenProgramsARB(1, &prognum);
  47
  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( 4, GL_FLOAT, sizeof(verts[0]), 0 );
  73    glColorPointer( 4, GL_FLOAT, sizeof(verts[0]), (void *)(4*sizeof(float)) );
  74 }
  75
  76
  77
  78 static void Display( void )
  79 {
  80    glClearColor(0.3, 0.3, 0.3, 1);
  81    glClear( GL_COLOR_BUFFER_BIT );
  82
  83    glEnable(GL_VERTEX_PROGRAM_NV);
  84    glDrawArrays( GL_TRIANGLES, 0, 3 );
  85
  86    glutSwapBuffers();
  87 }
  88
  89
  90 static void Reshape( int width, int height )
  91 {
  92    glViewport( 0, 0, width, height );
  93    glMatrixMode( GL_PROJECTION );
  94    glLoadIdentity();
  95    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  96    glMatrixMode( GL_MODELVIEW );
  97    glLoadIdentity();
  98    /*glTranslatef( 0.0, 0.0, -15.0 );*/
  99 }
 100
 101
 102 static void Key( unsigned char key, int x, int y )
 103 {
 104    (void) x;
 105    (void) y;
 106    switch (key) {
 107       case 27:
 108          exit(0);
 109          break;
 110    }
 111    glutPostRedisplay();
 112 }
 113
 114
 115
 116
 117 int main( int argc, char *argv[] )
 118 {
 119    glutInit( &argc, argv );
 120    glutInitWindowPosition( 0, 0 );
 121    glutInitWindowSize( 250, 250 );
 122    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 123    glutCreateWindow(argv[0]);
 124    glewInit();
 125    glutReshapeFunc( Reshape );
 126    glutKeyboardFunc( Key );
 127    glutDisplayFunc( Display );
 128    Init();
 129    glutMainLoop();
 130    return 0;
 131 }