#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/glut.h>
static GLfloat Diffuse[4] = { 0.5, 0.5, 1.0, 1.0 };
static GLfloat Specular[4] = { 0.8, 0.8, 0.8, 1.0 };
static GLfloat LightPos[4] = { 0.0, 10.0, 20.0, 1.0 };
static GLfloat Delta = 1.0;
static GLuint FragProg;
static GLuint VertProg;
static GLboolean Anim = GL_TRUE;
static GLboolean Wire = GL_FALSE;
static GLboolean PixelLight = GL_TRUE;
static GLint Win;
static GLfloat Xrot = 0, Yrot = 0;
#define NAMED_PARAMETER4FV(prog, name, v) \
glProgramNamedParameter4fvNV(prog, strlen(name), (const GLubyte *) name, v)
static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
if (PixelLight) {
#if defined(GL_NV_fragment_program)
NAMED_PARAMETER4FV(FragProg, "LightPos", LightPos);
glEnable(GL_FRAGMENT_PROGRAM_NV);
glEnable(GL_VERTEX_PROGRAM_NV);
#endif
glDisable(GL_LIGHTING);
}
else {
glLightfv(GL_LIGHT0, GL_POSITION, LightPos);
#if defined(GL_NV_fragment_program)
glDisable(GL_FRAGMENT_PROGRAM_NV);
glDisable(GL_VERTEX_PROGRAM_NV);
#endif
glEnable(GL_LIGHTING);
}
glPushMatrix();
glRotatef(Xrot, 1, 0, 0);
glRotatef(Yrot, 0, 1, 0);
#if 1
glutSolidSphere(2.0, 10, 5);
#else
{
GLUquadricObj *q = gluNewQuadric();
gluQuadricNormals(q, GL_SMOOTH);
gluQuadricTexture(q, GL_TRUE);
glRotatef(90, 1, 0, 0);
glTranslatef(0, 0, -1);
gluCylinder(q, 1.0, 1.0, 2.0, 24, 1);
gluDeleteQuadric(q);
}
#endif
glPopMatrix();
glutSwapBuffers();
}
static void Idle(void)
{
LightPos[0] += Delta;
if (LightPos[0] > 25.0)
Delta = -1.0;
else if (LightPos[0] <- 25.0)
Delta = 1.0;
glutPostRedisplay();
}
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, -15.0 );
}
static void Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case ' ':
Anim = !Anim;
if (Anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
case 'x':
LightPos[0] -= 1.0;
break;
case 'X':
LightPos[0] += 1.0;
break;
case 'w':
Wire = !Wire;
if (Wire)
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
else
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
break;
case 'p':
PixelLight = !PixelLight;
if (PixelLight) {
printf("Per-pixel lighting\n");
}
else {
printf("Conventional lighting\n");
}
break;
case 27:
glutDestroyWindow(Win);
exit(0);
}
glutPostRedisplay();
}
static void SpecialKey( int key, int x, int y )
{
const GLfloat step = 3.0;
(void) x;
(void) y;
switch (key) {
case GLUT_KEY_UP:
Xrot -= step;
break;
case GLUT_KEY_DOWN:
Xrot += step;
break;
case GLUT_KEY_LEFT:
Yrot -= step;
break;
case GLUT_KEY_RIGHT:
Yrot += step;
break;
}
glutPostRedisplay();
}
static void Init( void )
{
static const char *fragProgramText =
"!!FP1.0\n"
"DECLARE Diffuse; \n"
"DECLARE Specular; \n"
"DECLARE LightPos; \n"
"# Compute normalized LightPos, put it in R0\n"
"DP3 R0.x, LightPos, LightPos;\n"
"RSQ R0.y, R0.x;\n"
"MUL R0, LightPos, R0.y;\n"
"# Compute normalized normal, put it in R1\n"
"DP3 R1, f[TEX0], f[TEX0]; \n"
"RSQ R1.y, R1.x;\n"
"MUL R1, f[TEX0], R1.y;\n"
"# Compute dot product of light direction and normal vector\n"
"DP3_SAT R2, R0, R1;"
"MUL R3, Diffuse, R2; # diffuse attenuation\n"
"POW R4, R2.x, {20.0}.x; # specular exponent\n"
"MUL R5, Specular, R4; # specular attenuation\n"
"ADD o[COLR], R3, R5; # add diffuse and specular colors\n"
"END \n"
;
static const char *vertProgramText =
"!!VP1.0\n"
"# typical modelview/projection transform\n"
"DP4 o[HPOS].x, c[0], v[OPOS] ;\n"
"DP4 o[HPOS].y, c[1], v[OPOS] ;\n"
"DP4 o[HPOS].z, c[2], v[OPOS] ;\n"
"DP4 o[HPOS].w, c[3], v[OPOS] ;\n"
"# transform normal by inv transpose of modelview, put in tex0\n"
"DP3 o[TEX0].x, c[4], v[NRML] ;\n"
"DP3 o[TEX0].y, c[5], v[NRML] ;\n"
"DP3 o[TEX0].z, c[6], v[NRML] ;\n"
"DP3 o[TEX0].w, c[7], v[NRML] ;\n"
"END\n";
;
if (!glutExtensionSupported("GL_NV_vertex_program")) {
printf("Sorry, this demo requires GL_NV_vertex_program\n");
exit(1);
}
if (!glutExtensionSupported("GL_NV_fragment_program")) {
printf("Sorry, this demo requires GL_NV_fragment_program\n");
exit(1);
}
#if defined(GL_NV_fragment_program)
glGenProgramsNV(1, &FragProg);
assert(FragProg > 0);
glGenProgramsNV(1, &VertProg);
assert(VertProg > 0);
glLoadProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg,
strlen(fragProgramText),
(const GLubyte *) fragProgramText);
assert(glIsProgramNV(FragProg));
glBindProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg);
NAMED_PARAMETER4FV(FragProg, "Diffuse", Diffuse);
NAMED_PARAMETER4FV(FragProg, "Specular", Specular);
glLoadProgramNV(GL_VERTEX_PROGRAM_NV, VertProg,
strlen(vertProgramText),
(const GLubyte *) vertProgramText);
assert(glIsProgramNV(VertProg));
glBindProgramNV(GL_VERTEX_PROGRAM_NV, VertProg);
glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
#endif
glClearColor(0.3, 0.3, 0.3, 0.0);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHTING);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, Diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, Specular);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 20.0);
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
printf("Press p to toggle between per-pixel and per-vertex lighting\n");
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 200, 200 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
Win = glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
if (Anim)
glutIdleFunc(Idle);
Init();
glutMainLoop();
return 0;
}