progs/fp/point-position.c

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