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