src/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 #include <glad/glad.h>
  14 #include "glut_wrap.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 static GLint Win;
  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 #if defined(GL_NV_fragment_program)
  41       NAMED_PARAMETER4FV(FragProg, "LightPos", LightPos);
  42       glEnable(GL_FRAGMENT_PROGRAM_NV);
  43       glEnable(GL_VERTEX_PROGRAM_NV);
  44 #endif
  45       glDisable(GL_LIGHTING);
  46    }
  47    else {
  48       glLightfv(GL_LIGHT0, GL_POSITION, LightPos);
  49 #if defined(GL_NV_fragment_program)
  50       glDisable(GL_FRAGMENT_PROGRAM_NV);
  51       glDisable(GL_VERTEX_PROGRAM_NV);
  52 #endif
  53       glEnable(GL_LIGHTING);
  54    }
  55
  56    glPushMatrix();
  57    glRotatef(Xrot, 1, 0, 0);
  58    glRotatef(Yrot, 0, 1, 0);
  59
  60 #if 1
  61    glutSolidSphere(2.0, 10, 5);
  62 #else
  63    {
  64       GLUquadricObj *q = gluNewQuadric();
  65       gluQuadricNormals(q, GL_SMOOTH);
  66       gluQuadricTexture(q, GL_TRUE);
  67       glRotatef(90, 1, 0, 0);
  68       glTranslatef(0, 0, -1);
  69       gluCylinder(q, 1.0, 1.0, 2.0, 24, 1);
  70       gluDeleteQuadric(q);
  71    }
  72 #endif
  73
  74    glPopMatrix();
  75
  76    glutSwapBuffers();
  77 }
  78
  79
  80 static void Idle(void)
  81 {
  82    LightPos[0] += Delta;
  83    if (LightPos[0] > 25.0)
  84       Delta = -1.0;
  85    else if (LightPos[0] <- 25.0)
  86       Delta = 1.0;
  87    glutPostRedisplay();
  88 }
  89
  90
  91 static void Reshape( int width, int height )
  92 {
  93    glViewport( 0, 0, width, height );
  94    glMatrixMode( GL_PROJECTION );
  95    glLoadIdentity();
  96    glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
  97    /*glOrtho( -2.0, 2.0, -2.0, 2.0, 5.0, 25.0 );*/
  98    glMatrixMode( GL_MODELVIEW );
  99    glLoadIdentity();
 100    glTranslatef( 0.0, 0.0, -15.0 );
 101 }
 102
 103
 104 static void Key( unsigned char key, int x, int y )
 105 {
 106    (void) x;
 107    (void) y;
 108    switch (key) {
 109      case ' ':
 110         Anim = !Anim;
 111         if (Anim)
 112            glutIdleFunc(Idle);
 113         else
 114            glutIdleFunc(NULL);
 115         break;
 116       case 'x':
 117          LightPos[0] -= 1.0;
 118          break;
 119       case 'X':
 120          LightPos[0] += 1.0;
 121          break;
 122       case 'w':
 123          Wire = !Wire;
 124          if (Wire)
 125             glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 126          else
 127             glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 128          break;
 129       case 'p':
 130          PixelLight = !PixelLight;
 131          if (PixelLight) {
 132             printf("Per-pixel lighting\n");
 133          }
 134          else {
 135             printf("Conventional lighting\n");
 136          }
 137          break;
 138       case 27:
 139          glutDestroyWindow(Win);
 140          exit(0);
 141    }
 142    glutPostRedisplay();
 143 }
 144
 145 static void SpecialKey( int key, int x, int y )
 146 {
 147    const GLfloat step = 3.0;
 148    (void) x;
 149    (void) y;
 150    switch (key) {
 151       case GLUT_KEY_UP:
 152          Xrot -= step;
 153          break;
 154       case GLUT_KEY_DOWN:
 155          Xrot += step;
 156          break;
 157       case GLUT_KEY_LEFT:
 158          Yrot -= step;
 159          break;
 160       case GLUT_KEY_RIGHT:
 161          Yrot += step;
 162          break;
 163    }
 164    glutPostRedisplay();
 165 }
 166
 167
 168 static void Init( void )
 169 {
 170    static const char *fragProgramText =
 171       "!!FP1.0\n"
 172       "DECLARE Diffuse; \n"
 173       "DECLARE Specular; \n"
 174       "DECLARE LightPos; \n"
 175
 176       "# Compute normalized LightPos, put it in R0\n"
 177       "DP3 R0.x, LightPos, LightPos;\n"
 178       "RSQ R0.y, R0.x;\n"
 179       "MUL R0, LightPos, R0.y;\n"
 180
 181       "# Compute normalized normal, put it in R1\n"
 182       "DP3 R1, f[TEX0], f[TEX0]; \n"
 183       "RSQ R1.y, R1.x;\n"
 184       "MUL R1, f[TEX0], R1.y;\n"
 185
 186       "# Compute dot product of light direction and normal vector\n"
 187       "DP3_SAT R2, R0, R1;"
 188
 189       "MUL R3, Diffuse, R2;    # diffuse attenuation\n"
 190
 191       "POW R4, R2.x, {20.0}.x; # specular exponent\n"
 192
 193       "MUL R5, Specular, R4;   # specular attenuation\n"
 194
 195       "ADD o[COLR], R3, R5;    # add diffuse and specular colors\n"
 196       "END \n"
 197       ;
 198
 199    static const char *vertProgramText =
 200       "!!VP1.0\n"
 201       "# typical modelview/projection transform\n"
 202       "DP4   o[HPOS].x, c[0], v[OPOS] ;\n"
 203       "DP4   o[HPOS].y, c[1], v[OPOS] ;\n"
 204       "DP4   o[HPOS].z, c[2], v[OPOS] ;\n"
 205       "DP4   o[HPOS].w, c[3], v[OPOS] ;\n"
 206       "# transform normal by inv transpose of modelview, put in tex0\n"
 207       "DP3   o[TEX0].x, c[4], v[NRML] ;\n"
 208       "DP3   o[TEX0].y, c[5], v[NRML] ;\n"
 209       "DP3   o[TEX0].z, c[6], v[NRML] ;\n"
 210       "DP3   o[TEX0].w, c[7], v[NRML] ;\n"
 211       "END\n";
 212    ;
 213
 214    if (!glutExtensionSupported("GL_NV_vertex_program")) {
 215       printf("Sorry, this demo requires GL_NV_vertex_program\n");
 216       exit(1);
 217    }
 218    if (!glutExtensionSupported("GL_NV_fragment_program")) {
 219       printf("Sorry, this demo requires GL_NV_fragment_program\n");
 220       exit(1);
 221    }
 222
 223 #if defined(GL_NV_fragment_program)
 224    glGenProgramsNV(1, &FragProg);
 225    assert(FragProg > 0);
 226    glGenProgramsNV(1, &VertProg);
 227    assert(VertProg > 0);
 228
 229    /*
 230     * Fragment program
 231     */
 232    glLoadProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg,
 233                    strlen(fragProgramText),
 234                    (const GLubyte *) fragProgramText);
 235    assert(glIsProgramNV(FragProg));
 236    glBindProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg);
 237
 238    NAMED_PARAMETER4FV(FragProg, "Diffuse", Diffuse);
 239    NAMED_PARAMETER4FV(FragProg, "Specular", Specular);
 240
 241    /*
 242     * Vertex program
 243     */
 244    glLoadProgramNV(GL_VERTEX_PROGRAM_NV, VertProg,
 245                    strlen(vertProgramText),
 246                    (const GLubyte *) vertProgramText);
 247    assert(glIsProgramNV(VertProg));
 248    glBindProgramNV(GL_VERTEX_PROGRAM_NV, VertProg);
 249    glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
 250    glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
 251 #endif
 252
 253    /*
 254     * Misc init
 255     */
 256    glClearColor(0.3, 0.3, 0.3, 0.0);
 257    glEnable(GL_DEPTH_TEST);
 258    glEnable(GL_LIGHT0);
 259    glEnable(GL_LIGHTING);
 260    glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, Diffuse);
 261    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, Specular);
 262    glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 20.0);
 263
 264    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 265    printf("Press p to toggle between per-pixel and per-vertex lighting\n");
 266 }
 267
 268
 269 int main( int argc, char *argv[] )
 270 {
 271    glutInitWindowSize( 200, 200 );
 272    glutInit( &argc, argv );
 273    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
 274    Win = glutCreateWindow(argv[0]);
 275    gladLoadGL();
 276    glutReshapeFunc( Reshape );
 277    glutKeyboardFunc( Key );
 278    glutSpecialFunc( SpecialKey );
 279    glutDisplayFunc( Display );
 280    if (Anim)
 281       glutIdleFunc(Idle);
 282    Init();
 283    glutMainLoop();
 284    return 0;
 285 }