progs/tests/vpwarpmesh.c

   1 /*
   2  * Warp a triangle mesh with a vertex program.
   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 static float Xrot = -60.0, Yrot = 0.0, Zrot = 0.0;
  14 static GLboolean Anim = GL_TRUE;
  15 static GLfloat Phi = 0.0;
  16
  17
  18 static void Idle( void )
  19 {
  20    Phi += 0.01;
  21    glutPostRedisplay();
  22 }
  23
  24
  25 static void DrawMesh( int rows, int cols )
  26 {
  27    static const GLfloat colorA[3] = { 0, 1, 0 };
  28    static const GLfloat colorB[3] = { 0, 0, 1 };
  29    const float dx = 2.0 / (cols - 1);
  30    const float dy = 2.0 / (rows - 1);
  31    float x, y;
  32    int i, j;
  33
  34 #if 1
  35 #define COLOR3FV(c)     glVertexAttrib3fvNV(3, c)
  36 #define VERTEX2F(x, y)  glVertexAttrib2fNV(0, x, y)
  37 #else
  38 #define COLOR3FV(c)     glColor3fv(c)
  39 #define VERTEX2F(x, y)  glVertex2f(x, y)
  40 #endif
  41
  42    y = -1.0;
  43    for (i = 0; i < rows - 1; i++) {
  44       glBegin(GL_QUAD_STRIP);
  45       x = -1.0;
  46       for (j = 0; j < cols; j++) {
  47          if ((i + j) & 1)
  48             COLOR3FV(colorA);
  49          else
  50             COLOR3FV(colorB);
  51          VERTEX2F(x, y);
  52          VERTEX2F(x, y + dy);
  53          x += dx;
  54       }
  55       glEnd();
  56       y += dy;
  57    }
  58 }
  59
  60
  61 static void Display( void )
  62 {
  63    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  64
  65    glPushMatrix();
  66       glRotatef(Xrot, 1, 0, 0);
  67       glRotatef(Yrot, 0, 1, 0);
  68       glRotatef(Zrot, 0, 0, 1);
  69
  70       /* Position the gravity source */
  71       {
  72          GLfloat x, y, z, r = 0.5;
  73          x = r * cos(Phi);
  74          y = r * sin(Phi);
  75          z = 1.0;
  76          glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 30, x, y, z, 1);
  77          glDisable(GL_VERTEX_PROGRAM_NV);
  78          glBegin(GL_POINTS);
  79          glColor3f(1,1,1);
  80          glVertex3f(x, y, z);
  81          glEnd();
  82       }
  83
  84       glEnable(GL_VERTEX_PROGRAM_NV);
  85       DrawMesh(8, 8);
  86    glPopMatrix();
  87
  88    glutSwapBuffers();
  89 }
  90
  91
  92 static void Reshape( int width, int height )
  93 {
  94    float ar = (float) width / (float) height;
  95    glViewport( 0, 0, width, height );
  96    glMatrixMode( GL_PROJECTION );
  97    glLoadIdentity();
  98    glFrustum( -1.0 * ar, 1.0 * ar, -1.0, 1.0, 5.0, 25.0 );
  99    glMatrixMode( GL_MODELVIEW );
 100    glLoadIdentity();
 101    glTranslatef( 0.0, 0.0, -12.0 );
 102    glScalef(2, 2, 2);
 103 }
 104
 105
 106 static void Key( unsigned char key, int x, int y )
 107 {
 108    (void) x;
 109    (void) y;
 110    switch (key) {
 111       case 'a':
 112          Anim = !Anim;
 113          if (Anim)
 114             glutIdleFunc(Idle);
 115          else
 116             glutIdleFunc(NULL);
 117          break;
 118       case 'p':
 119          Phi += 0.2;
 120          break;
 121       case 'z':
 122          Zrot -= 5.0;
 123          break;
 124       case 'Z':
 125          Zrot += 5.0;
 126          break;
 127       case 27:
 128          exit(0);
 129          break;
 130    }
 131    glutPostRedisplay();
 132 }
 133
 134
 135 static void SpecialKey( int key, int x, int y )
 136 {
 137    const GLfloat step = 3.0;
 138    (void) x;
 139    (void) y;
 140    switch (key) {
 141       case GLUT_KEY_UP:
 142          Xrot -= step;
 143          break;
 144       case GLUT_KEY_DOWN:
 145          Xrot += step;
 146          break;
 147       case GLUT_KEY_LEFT:
 148          Yrot -= step;
 149          break;
 150       case GLUT_KEY_RIGHT:
 151          Yrot += step;
 152          break;
 153    }
 154    glutPostRedisplay();
 155 }
 156
 157
 158 static void Init( void )
 159 {
 160    /*
 161     * c[0..3] = modelview matrix
 162     * c[4..7] = inverse modelview matrix
 163     * c[30] = gravity source location
 164     * c[31] = gravity source strength
 165     * c[32] = light pos
 166     * c[35] = diffuse color
 167     */
 168    static const char prog[] =
 169       "!!VP1.0\n"
 170
 171       "# Compute distance from vertex to gravity source\n"
 172       "ADD   R1, c[30], -v[OPOS]; # vector from vertex to gravity\n"
 173       "DP3   R2, R1, R1;          # dot product\n"
 174       "RSQ   R2, R2.x;            # square root = distance\n"
 175       "MUL   R2, R2, c[31].xxxx;  # scale by the gravity factor\n"
 176
 177       "# Displace vertex by gravity factor along R1 vector\n"
 178       "MAD   R3, R1, R2, v[OPOS];\n"
 179
 180       "# Continue with typical modelview/projection\n"
 181       "DP4   o[HPOS].x, c[0], R3 ;      # object x MVP -> clip\n"
 182       "DP4   o[HPOS].y, c[1], R3 ;\n"
 183       "DP4   o[HPOS].z, c[2], R3 ;\n"
 184       "DP4   o[HPOS].w, c[3], R3 ;\n"
 185
 186       "MOV   o[COL0], v[COL0];\n       # copy input color to output color\n"
 187
 188       "END";
 189
 190    if (!glutExtensionSupported("GL_NV_vertex_program")) {
 191       printf("Sorry, this program requires GL_NV_vertex_program\n");
 192       exit(1);
 193    }
 194
 195    glLoadProgramNV(GL_VERTEX_PROGRAM_NV, 1,
 196                    strlen(prog), (const GLubyte *) prog);
 197    assert(glIsProgramNV(1));
 198    glBindProgramNV(GL_VERTEX_PROGRAM_NV, 1);
 199
 200    /* Load the program registers */
 201    glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
 202    glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
 203
 204    /* Light position */
 205    glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 32, 2, 2, 4, 1);
 206    /* Diffuse material color */
 207    glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 35, 0.25, 0, 0.25, 1);
 208
 209    /* Gravity strength */
 210    glProgramParameter4fNV(GL_VERTEX_PROGRAM_NV, 31, .5, 0, 0, 0);
 211
 212    glEnable(GL_DEPTH_TEST);
 213    glClearColor(0.3, 0.3, 0.3, 1);
 214    glShadeModel(GL_FLAT);
 215    glPointSize(3);
 216    printf("glGetError = %d\n", (int) glGetError());
 217 }
 218
 219
 220 int main( int argc, char *argv[] )
 221 {
 222    glutInit( &argc, argv );
 223    glutInitWindowPosition( 0, 0 );
 224    glutInitWindowSize( 250, 250 );
 225    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
 226    glutCreateWindow(argv[0]);
 227    glewInit();
 228    glutReshapeFunc( Reshape );
 229    glutKeyboardFunc( Key );
 230    glutSpecialFunc( SpecialKey );
 231    glutDisplayFunc( Display );
 232    if (Anim)
 233       glutIdleFunc(Idle);
 234    Init();
 235    glutMainLoop();
 236    return 0;
 237 }