progs/fp/tri-depth2.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    /* scale of 10.0 gives me a visible result on nv hardware.
  13     */
  14    static const char *modulate2D =
  15       "!!ARBfp1.0\n"
  16       "TEMP R0;\n"
  17       "MUL R0, fragment.position.z, {10.0}.x;\n"
  18       "MOV result.color, R0; \n"
  19       "END"
  20       ;
  21    GLuint modulateProg;
  22
  23    if (!GLEW_ARB_fragment_program) {
  24       printf("Error: GL_ARB_fragment_program not supported!\n");
  25       exit(1);
  26    }
  27    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
  28
  29    /* Setup the fragment program */
  30    glGenProgramsARB(1, &modulateProg);
  31    glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, modulateProg);
  32    glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
  33                         strlen(modulate2D), (const GLubyte *)modulate2D);
  34
  35    printf("glGetError = 0x%x\n", (int) glGetError());
  36    printf("glError(GL_PROGRAM_ERROR_STRING_ARB) = %s\n",
  37           (char *) glGetString(GL_PROGRAM_ERROR_STRING_ARB));
  38
  39    glEnable(GL_FRAGMENT_PROGRAM_ARB);
  40
  41    glClearColor(.3, .3, .3, 0);
  42 }
  43
  44 static void Reshape(int width, int height)
  45 {
  46
  47     glViewport(0, 0, (GLint)width, (GLint)height);
  48
  49     glMatrixMode(GL_PROJECTION);
  50     glLoadIdentity();
  51     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  52     glMatrixMode(GL_MODELVIEW);
  53 }
  54
  55 static void Key(unsigned char key, int x, int y)
  56 {
  57
  58     switch (key) {
  59       case 27:
  60         exit(1);
  61       default:
  62         break;
  63     }
  64
  65     glutPostRedisplay();
  66 }
  67
  68 static void Draw(void)
  69 {
  70    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  71    glEnable(GL_DEPTH_TEST);
  72
  73    glBegin(GL_TRIANGLES);
  74    glColor3f(0,0,1);
  75         glVertex3f( 0.9, -0.9, -30.0);
  76         glVertex3f( 0.9,  0.9, -30.0);
  77         glVertex3f(-0.9,  0.0, -30.0);
  78    glColor3f(0,1,0);
  79         glVertex3f(-0.9, -0.9, -40.0);
  80         glVertex3f(-0.9,  0.9, -40.0);
  81         glVertex3f( 0.9,  0.0, -25.0);
  82    glEnd();
  83
  84    glFlush();
  85
  86
  87 }
  88
  89
  90 int main(int argc, char **argv)
  91 {
  92     GLenum type;
  93
  94     glutInit(&argc, argv);
  95
  96
  97
  98     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
  99
 100     type = GLUT_RGB | GLUT_DEPTH;
 101     type |= GLUT_SINGLE;
 102     glutInitDisplayMode(type);
 103
 104     if (glutCreateWindow("First Tri") == GL_FALSE) {
 105         exit(1);
 106     }
 107
 108     glewInit();
 109
 110     Init();
 111
 112     glutReshapeFunc(Reshape);
 113     glutKeyboardFunc(Key);
 114     glutDisplayFunc(Draw);
 115     glutMainLoop();
 116         return 0;
 117 }