progs/demos/fplight.c

   1 /*
   2  * Use GL_NV_fragment_program to implement per-pixel lighting.
   3  *
   4  * Brian Paul
   5  * 7 April 2003
   6  */
   7
   8 #include <assert.h>
   9 #include <string.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <math.h>
  13 #define GL_GLEXT_PROTOTYPES
  14 #include <GL/glut.h>
  15
  16
  17 static GLfloat Diffuse[4] = { 0.5, 0.5, 1.0, 1.0 };
  18 static GLfloat Specular[4] = { 0.8, 0.8, 0.8, 1.0 };
  19 static GLfloat LightPos[4] = { 0.0, 10.0, 20.0, 1.0 };
  20 static GLfloat Delta = 1.0;
  21
  22 static GLuint FragProg;
  23 static GLuint VertProg;
  24 static GLboolean Anim = GL_TRUE;
  25 static GLboolean Wire = GL_FALSE;
  26 static GLboolean PixelLight = GL_TRUE;
  27
  28 static GLfloat Xrot = 0, Yrot = 0;
  29
  30
  31 #define NAMED_PARAMETER4FV(prog, name, v)        \
  32   glProgramNamedParameter4fvNV(prog, strlen(name), (const GLubyte *) name, v)
  33
  34
  35 static void Display( void )
  36 {
  37    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  38
  39    if (PixelLight) {
  40       NAMED_PARAMETER4FV(FragProg, "LightPos", LightPos);
  41       glEnable(GL_FRAGMENT_PROGRAM_NV);
  42       glEnable(GL_VERTEX_PROGRAM_NV);
  43       glDisable(GL_LIGHTING);
  44    }
  45    else {
  46       glLightfv(GL_LIGHT0, GL_POSITION, LightPos);
  47       glDisable(GL_FRAGMENT_PROGRAM_NV);
  48       glDisable(GL_VERTEX_PROGRAM_NV);
  49       glEnable(GL_LIGHTING);
  50    }
  51
  52    glPushMatrix();
  53    glRotatef(Xrot, 1, 0, 0);
  54    glRotatef(Yrot, 0, 1, 0);
  55
  56 #if 1
  57    glutSolidSphere(2.0, 10, 5);
  58 #else
  59    {
  60       GLUquadricObj *q = gluNewQuadric();
  61       gluQuadricNormals(q, GL_SMOOTH);
  62       gluQuadricTexture(q, GL_TRUE);
  63       glRotatef(90, 1, 0, 0);
  64       glTranslatef(0, 0, -1);
  65       gluCylinder(q, 1.0, 1.0, 2.0, 24, 1);
  66       gluDeleteQuadric(q);
  67    }
  68 #endif
  69
  70    glPopMatrix();
  71
  72    glutSwapBuffers();
  73 }
  74
  75
  76 static void Idle(void)
  77 {
  78    LightPos[0] += Delta;
  79    if (LightPos[0] > 25.0)
  80       Delta = -1.0;
  81    else if (LightPos[0] <- 25.0)
  82       Delta = 1.0;
  83    glutPostRedisplay();
  84 }
  85
  86
  87 static void Reshape( int width, int height )
  88 {
  89    glViewport( 0, 0, width, height );
  90    glMatrixMode( GL_PROJECTION );
  91    glLoadIdentity();
  92    glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
  93    /*glOrtho( -2.0, 2.0, -2.0, 2.0, 5.0, 25.0 );*/
  94    glMatrixMode( GL_MODELVIEW );
  95    glLoadIdentity();
  96    glTranslatef( 0.0, 0.0, -15.0 );
  97 }
  98
  99
 100 static void Key( unsigned char key, int x, int y )
 101 {
 102    (void) x;
 103    (void) y;
 104    switch (key) {
 105      case ' ':
 106         Anim = !Anim;
 107         if (Anim)
 108            glutIdleFunc(Idle);
 109         else
 110            glutIdleFunc(NULL);
 111         break;
 112       case 'x':
 113          LightPos[0] -= 1.0;
 114          break;
 115       case 'X':
 116          LightPos[0] += 1.0;
 117          break;
 118       case 'w':
 119          Wire = !Wire;
 120          if (Wire)
 121             glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 122          else
 123             glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 124          break;
 125       case 'p':
 126          PixelLight = !PixelLight;
 127          if (PixelLight) {
 128             printf("Per-pixel lighting\n");
 129          }
 130          else {
 131             printf("Conventional lighting\n");
 132          }
 133          break;
 134       case 27:
 135          exit(0);
 136          break;
 137    }
 138    glutPostRedisplay();
 139 }
 140
 141 static void SpecialKey( int key, int x, int y )
 142 {
 143    const GLfloat step = 3.0;
 144    (void) x;
 145    (void) y;
 146    switch (key) {
 147       case GLUT_KEY_UP:
 148          Xrot -= step;
 149          break;
 150       case GLUT_KEY_DOWN:
 151          Xrot += step;
 152          break;
 153       case GLUT_KEY_LEFT:
 154          Yrot -= step;
 155          break;
 156       case GLUT_KEY_RIGHT:
 157          Yrot += step;
 158          break;
 159    }
 160    glutPostRedisplay();
 161 }
 162
 163
 164 static void Init( void )
 165 {
 166    static const char *fragProgramText =
 167       "!!FP1.0\n"
 168       "DECLARE Diffuse; \n"
 169       "DECLARE Specular; \n"
 170       "DECLARE LightPos; \n"
 171
 172       "# Compute normalized LightPos, put it in R0\n"
 173       "DP3 R0.x, LightPos, LightPos;\n"
 174       "RSQ R0.y, R0.x;\n"
 175       "MUL R0, LightPos, R0.y;\n"
 176
 177       "# Compute normalized normal, put it in R1\n"
 178       "DP3 R1, f[TEX0], f[TEX0]; \n"
 179       "RSQ R1.y, R1.x;\n"
 180       "MUL R1, f[TEX0], R1.y;\n"
 181
 182       "# Compute dot product of light direction and normal vector\n"
 183       "DP3 R2, R0, R1;"
 184
 185       "MUL R3, Diffuse, R2;    # diffuse attenuation\n"
 186
 187       "POW R4, R2.x, {20.0}.x; # specular exponent\n"
 188
 189       "MUL R5, Specular, R4;   # specular attenuation\n"
 190
 191       "ADD o[COLR], R3, R5;    # add diffuse and specular colors\n"
 192       "END \n"
 193       ;
 194
 195    static const char *vertProgramText =
 196       "!!VP1.0\n"
 197       "# typical modelview/projection transform\n"
 198       "DP4   o[HPOS].x, c[0], v[OPOS] ;\n"
 199       "DP4   o[HPOS].y, c[1], v[OPOS] ;\n"
 200       "DP4   o[HPOS].z, c[2], v[OPOS] ;\n"
 201       "DP4   o[HPOS].w, c[3], v[OPOS] ;\n"
 202       "# transform normal by inv transpose of modelview, put in tex0\n"
 203       "DP4   o[TEX0].x, c[4], v[NRML] ;\n"
 204       "DP4   o[TEX0].y, c[5], v[NRML] ;\n"
 205       "DP4   o[TEX0].z, c[6], v[NRML] ;\n"
 206       "DP4   o[TEX0].w, c[7], v[NRML] ;\n"
 207       "END\n";
 208    ;
 209
 210    if (!glutExtensionSupported("GL_NV_vertex_program")) {
 211       printf("Sorry, this demo requires GL_NV_vertex_program\n");
 212       exit(1);
 213    }
 214    if (!glutExtensionSupported("GL_NV_fragment_program")) {
 215       printf("Sorry, this demo requires GL_NV_fragment_program\n");
 216       exit(1);
 217    }
 218
 219    glGenProgramsNV(1, &FragProg);
 220    assert(FragProg > 0);
 221    glGenProgramsNV(1, &VertProg);
 222    assert(VertProg > 0);
 223
 224    /*
 225     * Fragment program
 226     */
 227    glLoadProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg,
 228                    strlen(fragProgramText),
 229                    (const GLubyte *) fragProgramText);
 230    assert(glIsProgramNV(FragProg));
 231    glBindProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg);
 232
 233    NAMED_PARAMETER4FV(FragProg, "Diffuse", Diffuse);
 234    NAMED_PARAMETER4FV(FragProg, "Specular", Specular);
 235
 236    /*
 237     * Vertex program
 238     */
 239    glLoadProgramNV(GL_VERTEX_PROGRAM_NV, VertProg,
 240                    strlen(vertProgramText),
 241                    (const GLubyte *) vertProgramText);
 242    assert(glIsProgramNV(VertProg));
 243    glBindProgramNV(GL_VERTEX_PROGRAM_NV, VertProg);
 244    glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
 245    glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
 246
 247    /*
 248     * Misc init
 249     */
 250    glClearColor(0.3, 0.3, 0.3, 0.0);
 251    glEnable(GL_DEPTH_TEST);
 252    glEnable(GL_LIGHT0);
 253    glEnable(GL_LIGHTING);
 254    glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, Diffuse);
 255    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, Specular);
 256    glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 20.0);
 257
 258    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 259    printf("Press p to toggle between per-pixel and per-vertex lighting\n");
 260 }
 261
 262
 263 int main( int argc, char *argv[] )
 264 {
 265    glutInit( &argc, argv );
 266    glutInitWindowPosition( 0, 0 );
 267    glutInitWindowSize( 200, 200 );
 268    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
 269    glutCreateWindow(argv[0]);
 270    glutReshapeFunc( Reshape );
 271    glutKeyboardFunc( Key );
 272    glutSpecialFunc( SpecialKey );
 273    glutDisplayFunc( Display );
 274    if (Anim)
 275       glutIdleFunc(Idle);
 276    Init();
 277    glutMainLoop();
 278    return 0;
 279 }