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Diffstat (limited to 'progs/demos/spectex.c')
| -rw-r--r-- | progs/demos/spectex.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/progs/demos/spectex.c b/progs/demos/spectex.c new file mode 100644 index 00000000000..412f442e4ad --- /dev/null +++ b/progs/demos/spectex.c @@ -0,0 +1,277 @@ +/* $Id: spectex.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */ + +/* + * GLUT demonstration of texturing with specular highlights. + * + * When drawing a lit, textured surface one usually wants the specular + * highlight to override the texture colors. However, OpenGL applies + * texturing after lighting so the specular highlight is modulated by + * the texture. + * + * The solution here shown here is a two-pass algorithm: + * 1. Draw the textured surface without specular lighting. + * 2. Enable blending to add the next pass: + * 3. Redraw the surface with a matte white material and only the + * specular components of light sources enabled. + * + * Brian Paul February 1997 + */ + + +/* + * $Log: spectex.c,v $ + * Revision 1.1 1999/08/19 00:55:40 jtg + * Initial revision + * + * Revision 3.2 1999/03/28 18:22:05 brianp + * minor clean-up + * + * Revision 3.1 1998/02/14 18:47:48 brianp + * added OpenGL 1.2 separate specular interpolation support + * + * Revision 3.0 1998/02/14 18:42:29 brianp + * initial rev + * + */ + + +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include <GL/glut.h> + + +static GLUquadricObj *Quadric; +static GLuint Sphere; +static GLfloat LightPos[4] = {10.0, 10.0, 10.0, 1.0}; +static GLfloat Delta = 1.0; +static GLint Mode = 0; + +/*static GLfloat Blue[4] = {0.0, 0.0, 1.0, 1.0};*/ +/*static GLfloat Gray[4] = {0.5, 0.5, 0.5, 1.0};*/ +static GLfloat Black[4] = {0.0, 0.0, 0.0, 1.0}; +static GLfloat White[4] = {1.0, 1.0, 1.0, 1.0}; + + + +static void Idle( void ) +{ + LightPos[0] += Delta; + if (LightPos[0]>15.0) + Delta = -1.0; + else if (LightPos[0]<-15.0) + Delta = 1.0; + + glutPostRedisplay(); +} + + +static void Display( void ) +{ + glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); + + glLightfv(GL_LIGHT0, GL_POSITION, LightPos); + + glPushMatrix(); + glRotatef(90.0, 1.0, 0.0, 0.0); + + if (Mode==0) { + /* Typical method: diffuse + specular + texture */ + glEnable(GL_TEXTURE_2D); + glLightfv(GL_LIGHT0, GL_DIFFUSE, White); /* enable diffuse */ + glLightfv(GL_LIGHT0, GL_SPECULAR, White); /* enable specular */ +#ifdef GL_VERSION_1_2 + glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SINGLE_COLOR); +#endif + glCallList(Sphere); + } + else if (Mode==1) { + /* just specular highlight */ + glDisable(GL_TEXTURE_2D); + glLightfv(GL_LIGHT0, GL_DIFFUSE, Black); /* disable diffuse */ + glLightfv(GL_LIGHT0, GL_SPECULAR, White); /* enable specular */ +#ifdef GL_VERSION_1_2 + glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SINGLE_COLOR); +#endif + glCallList(Sphere); + } + else if (Mode==2) { + /* diffuse textured */ + glEnable(GL_TEXTURE_2D); + glLightfv(GL_LIGHT0, GL_DIFFUSE, White); /* enable diffuse */ + glLightfv(GL_LIGHT0, GL_SPECULAR, Black); /* disable specular */ +#ifdef GL_VERSION_1_2 + glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SINGLE_COLOR); +#endif + glCallList(Sphere); + } + else if (Mode==3) { + /* 2-pass: diffuse textured then add specular highlight*/ + glEnable(GL_TEXTURE_2D); + glLightfv(GL_LIGHT0, GL_DIFFUSE, White); /* enable diffuse */ + glLightfv(GL_LIGHT0, GL_SPECULAR, Black); /* disable specular */ +#ifdef GL_VERSION_1_2 + glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SINGLE_COLOR); +#endif + glCallList(Sphere); + /* specular highlight */ + glDepthFunc(GL_EQUAL); /* redraw same pixels */ + glDisable(GL_TEXTURE_2D); + glEnable(GL_BLEND); /* add */ + glLightfv(GL_LIGHT0, GL_DIFFUSE, Black); /* disable diffuse */ + glLightfv(GL_LIGHT0, GL_SPECULAR, White); /* enable specular */ + glCallList(Sphere); + glDepthFunc(GL_LESS); + glDisable(GL_BLEND); + } + else if (Mode==4) { + /* OpenGL 1.2's separate diffuse and specular color */ + glEnable(GL_TEXTURE_2D); + glLightfv(GL_LIGHT0, GL_DIFFUSE, White); /* enable diffuse */ + glLightfv(GL_LIGHT0, GL_SPECULAR, White); /* enable specular */ +#ifdef GL_VERSION_1_2 + glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR); +#endif + glCallList(Sphere); + } + + glPopMatrix(); + + glutSwapBuffers(); +} + + +static void Reshape( int width, int height ) +{ + glViewport( 0, 0, width, height ); + glMatrixMode( GL_PROJECTION ); + glLoadIdentity(); + glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 ); + glMatrixMode( GL_MODELVIEW ); + glLoadIdentity(); + glTranslatef( 0.0, 0.0, -12.0 ); +} + + +static void Key( unsigned char key, int x, int y ) +{ + (void) x; + (void) y; + switch (key) { + case 27: + exit(0); + break; + } + glutPostRedisplay(); +} + + +static void SpecialKey( int key, int x, int y ) +{ + (void) x; + (void) y; + switch (key) { + case GLUT_KEY_UP: + break; + case GLUT_KEY_DOWN: + break; + } + glutPostRedisplay(); +} + + +static void Init( void ) +{ + int i, j; + GLubyte texImage[64][64][3]; + + glEnable(GL_LIGHTING); + glEnable(GL_LIGHT0); + glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 0); + glLightModelfv(GL_LIGHT_MODEL_AMBIENT, Black); + + glMaterialfv(GL_FRONT, GL_DIFFUSE, White); + glMaterialfv(GL_FRONT, GL_SPECULAR, White); + glMaterialf(GL_FRONT, GL_SHININESS, 20.0); + + /* Actually, these are set again later */ + glLightfv(GL_LIGHT0, GL_DIFFUSE, White); + glLightfv(GL_LIGHT0, GL_SPECULAR, White); + + Quadric = gluNewQuadric(); + gluQuadricTexture( Quadric, GL_TRUE ); + + Sphere= glGenLists(1); + glNewList( Sphere, GL_COMPILE ); + gluSphere( Quadric, 1.0, 24, 24 ); + glEndList(); + + glEnable(GL_DEPTH_TEST); + glEnable(GL_CULL_FACE); + + for (i=0;i<64;i++) { + for (j=0;j<64;j++) { + int k = ((i>>3)&1) ^ ((j>>3)&1); + texImage[i][j][0] = 255*k; + texImage[i][j][1] = 255*(1-k); + texImage[i][j][2] = 0; + } + } + + glPixelStorei(GL_UNPACK_ALIGNMENT, 1); + glTexImage2D( GL_TEXTURE_2D, + 0, + 3, + 64, 64, + 0, + GL_RGB, GL_UNSIGNED_BYTE, + texImage ); + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); + glEnable(GL_TEXTURE_2D); + + glBlendFunc(GL_ONE, GL_ONE); +} + + +static void ModeMenu(int entry) +{ + if (entry==99) + exit(0); + Mode = entry; +} + + +int main( int argc, char *argv[] ) +{ + + glutInit( &argc, argv ); + glutInitWindowPosition( 0, 0 ); + glutInitWindowSize( 300, 300 ); + + glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH ); + + glutCreateWindow( "spectex" ); + + Init(); + + glutReshapeFunc( Reshape ); + glutKeyboardFunc( Key ); + glutSpecialFunc( SpecialKey ); + glutDisplayFunc( Display ); + glutIdleFunc( Idle ); + + glutCreateMenu( ModeMenu ); + glutAddMenuEntry("1-pass lighting + texturing", 0); + glutAddMenuEntry("specular lighting", 1); + glutAddMenuEntry("diffuse lighting + texturing", 2); + glutAddMenuEntry("2-pass lighting + texturing", 3); +#ifdef GL_VERSION_1_2 + glutAddMenuEntry("OpenGL 1.2 separate specular", 4); +#endif + glutAddMenuEntry("Quit", 99); + glutAttachMenu(GLUT_RIGHT_BUTTON); + + glutMainLoop(); + return 0; +} |