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/*
* A lit, rotating torus via vertex program
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/glut.h>
static float Xrot = 0.0, Yrot = 0.0, Zrot = 0.0;
static GLboolean Anim = GL_TRUE;
static void Idle( void )
{
Xrot += .3;
Yrot += .4;
Zrot += .2;
glutPostRedisplay();
}
static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
glRotatef(Xrot, 1, 0, 0);
glRotatef(Yrot, 0, 1, 0);
glRotatef(Zrot, 0, 0, 1);
glutSolidTorus(0.75, 2.0, 10, 20);
glPopMatrix();
glutSwapBuffers();
}
static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -2.0, 2.0, -2.0, 2.0, 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 ' ':
Xrot = Yrot = Zrot = 0;
break;
case 'a':
Anim = !Anim;
if (Anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
case 'z':
Zrot -= 5.0;
break;
case 'Z':
Zrot += 5.0;
break;
case 27:
exit(0);
break;
}
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 )
{
GLint errno;
GLuint prognum;
/* borrowed from an nvidia demo:
* c[0..3] = modelview matrix
* c[4..7] = invtrans modelview matrix
* c[32] = light pos
* c[35] = diffuse color
*/
static const char prog[] =
"!!ARBvp1.0\n"
"OPTION ARB_position_invariant ;"
"TEMP R0, R1; \n"
"# normal x MV-1T -> lighting normal\n"
"DP3 R1.x, state.matrix.modelview.invtrans.row[0], vertex.normal ;\n"
"DP3 R1.y, state.matrix.modelview.invtrans.row[1], vertex.normal;\n"
"DP3 R1.z, state.matrix.modelview.invtrans.row[2], vertex.normal;\n"
"DP3 R0, program.local[32], R1; # L.N\n"
#if 0
"MUL result.color.xyz, R0, program.local[35] ; # col = L.N * diffuse\n"
#else
"MUL result.color.primary.xyz, R0, program.local[35] ; # col = L.N * diffuse\n"
#endif
"MOV result.texcoord, vertex.texcoord;\n"
"END";
if (!glutExtensionSupported("GL_ARB_vertex_program")) {
printf("Sorry, this program requires GL_ARB_vertex_program");
exit(1);
}
glGenProgramsARB(1, &prognum);
glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
strlen(prog), (const GLubyte *) prog);
assert(glIsProgramARB(prognum));
errno = glGetError();
printf("glGetError = %d\n", errno);
if (errno != GL_NO_ERROR)
{
GLint errorpos;
glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
printf("errorpos: %d\n", errorpos);
printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
}
/* Light position */
glProgramLocalParameter4fARB(GL_VERTEX_PROGRAM_ARB, 32, 2, 2, 4, 1);
/* Diffuse material color */
glProgramLocalParameter4fARB(GL_VERTEX_PROGRAM_ARB, 35, 0.25, 0, 0.25, 1);
glEnable(GL_VERTEX_PROGRAM_ARB);
glEnable(GL_DEPTH_TEST);
glClearColor(0.3, 0.3, 0.3, 1);
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 250, 250 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
if (Anim)
glutIdleFunc(Idle);
Init();
glutMainLoop();
return 0;
}
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