progs/fp/point-position.c

   1
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5 #include <GL/glew.h>
   6 #include <GL/glut.h>
   7
   8
   9
  10 static void Init( void )
  11 {
  12    static const char *modulate2D =
  13       "!!ARBfp1.0\n"
  14       "MUL result.color, fragment.position, {.005}.x; \n"
  15       "END"
  16       ;
  17    GLuint modulateProg;
  18
  19    if (!GLEW_ARB_fragment_program) {
  20       printf("Error: GL_ARB_fragment_program not supported!\n");
  21       exit(1);
  22    }
  23    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
  24
  25    /* Setup the fragment program */
  26    glGenProgramsARB(1, &modulateProg);
  27    glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, modulateProg);
  28    glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
  29                         strlen(modulate2D), (const GLubyte *)modulate2D);
  30
  31    printf("glGetError = 0x%x\n", (int) glGetError());
  32    printf("glError(GL_PROGRAM_ERROR_STRING_ARB) = %s\n",
  33           (char *) glGetString(GL_PROGRAM_ERROR_STRING_ARB));
  34
  35    glEnable(GL_FRAGMENT_PROGRAM_ARB);
  36
  37    glClearColor(.3, .3, .3, 0);
  38 }
  39
  40 static void Reshape(int width, int height)
  41 {
  42
  43     glViewport(0, 0, (GLint)width, (GLint)height);
  44
  45     glMatrixMode(GL_PROJECTION);
  46     glLoadIdentity();
  47     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  48     glMatrixMode(GL_MODELVIEW);
  49 }
  50
  51 static void Key(unsigned char key, int x, int y)
  52 {
  53
  54     switch (key) {
  55       case 27:
  56         exit(1);
  57       default:
  58         return;
  59     }
  60
  61     glutPostRedisplay();
  62 }
  63
  64 static void Draw(void)
  65 {
  66    glClear(GL_COLOR_BUFFER_BIT);
  67
  68 #if 0
  69    glBegin(GL_QUADS);
  70    glTexCoord2f(1,0);
  71    glVertex3f( 0.9, -0.9, -30.0);
  72    glTexCoord2f(1,1);
  73    glVertex3f( 0.9,  0.9, -30.0);
  74    glTexCoord2f(0,1);
  75    glVertex3f(-0.9,  0.9, -30.0);
  76    glTexCoord2f(0,0);
  77    glVertex3f(-0.9,  -0.9, -30.0);
  78    glEnd();
  79 #else
  80    glPointSize(100);
  81    glBegin(GL_POINTS);
  82    glColor3f(0,0,1);
  83    glVertex3f( 0, 0, -30.0);
  84    glEnd();
  85 #endif
  86
  87    glFlush();
  88
  89
  90 }
  91
  92
  93 int main(int argc, char **argv)
  94 {
  95     GLenum type;
  96
  97     glutInit(&argc, argv);
  98
  99
 100
 101     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 102
 103     type = GLUT_RGB;
 104     type |= GLUT_SINGLE;
 105     glutInitDisplayMode(type);
 106
 107     if (glutCreateWindow("First Tri") == GL_FALSE) {
 108         exit(1);
 109     }
 110
 111     glewInit();
 112
 113     Init();
 114
 115     glutReshapeFunc(Reshape);
 116     glutKeyboardFunc(Key);
 117     glutDisplayFunc(Draw);
 118     glutMainLoop();
 119         return 0;
 120 }