Add attenuation to light
Sat Mar 17, 2012 10:22 pm
In this example we add light attenuation affect on object by controlling the light attenuation factor , there different type of effectors : GL_CONSTANT_ATTENUATION,GL_LINEAR_ATTENUATION and GL_QUADRATIC_ATTENUATION.
- Code:
#include <GL\glut.h>
#include <math.h> // For math routines (such as sqrt & trig).
GLdouble radius=1;
GLfloat qaBlack[] = {0.0, 0.0, 0.0, 1.0}; //Black Color
GLfloat qaGreen[] = {0.0, 1.0, 0.0, 1.0}; //Green Color
GLfloat qaWhite[] = {1.0, 1.0, 1.0, 1.0}; //White Color
GLfloat qaRed[] = {1.0, 0.0, 0.0, 1.0}; //Red Color
GLfloat qaBlue[] = {0.0, 0.0, 1.0, 1.0}; //Blue Color
// Set lighting intensity and color
GLfloat qaAmbientLight[] = {0.1, 0.1, 0.1, 1.0};
GLfloat qaDiffuseLight[] = {1, 1, 1, 1.0};
// Light source position
GLfloat qaLightPosition[] = {-2, 0, -14.5, 1};// Positional Light
GLfloat qaLightDirection[] = {1, 1, 1, 0};// Directional Light
void display(void);
void reshape(int x, int y);
void initLighting()
{
// Enable lighting
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
// Set lighting intensity and color
glLightfv(GL_LIGHT0, GL_AMBIENT, qaAmbientLight);
glLightfv(GL_LIGHT0, GL_DIFFUSE, qaDiffuseLight);
glLightfv(GL_LIGHT0, GL_POSITION, qaLightPosition);
////////////////////////////////////////////////
//glLightf( GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.2f );
glLightf( GL_LIGHT0, GL_LINEAR_ATTENUATION , 0.5f );
//glLightf( GL_LIGHT0, GL_QUADRATIC_ATTENUATION , 0.009f );
}
void keyboard(unsigned char key, int x, int y)
{
if (key == 'l' || key == 'L')
{
glEnable(GL_LIGHTING);
}
else if (key == 'd' || key == 'D')
{
glDisable(GL_LIGHTING);
}
}
int main (int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );
glutInitWindowSize(750,750);
glutCreateWindow("Teapot -light attenuation");
initLighting();
glutDisplayFunc(display);
glutKeyboardFunc(keyboard); // Register keyboard callback
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}
void display(void)
{
glMatrixMode(GL_MODELVIEW);
// clear the drawing buffer.
glClear(GL_COLOR_BUFFER_BIT);
// clear the identity matrix.
glLoadIdentity();
glTranslatef(0.0,0.0,-10.0);
glPushMatrix();
glTranslatef(2.0,0.0,-2.0);
// Set material properties
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, qaRed);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, qaRed);
glutSolidTeapot(radius);
glPopMatrix();
glPushMatrix();
glTranslatef(-2.0,0.0,-2.0);
// Set material properties
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, qaRed);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, qaRed);
glutSolidTeapot(radius);
glPopMatrix();
glFlush();
glutSwapBuffers();
}
void reshape(int x, int y)
{
if (y == 0 || x == 0) return;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(39.0,(GLdouble)x/(GLdouble)y,0.6,40.0);
glMatrixMode(GL_MODELVIEW);
glViewport(0,0,x,y); //Use the whole window for rendering
}
- Attachments
-
- Attenuation.jpg (15.37 KiB) Viewed 8308 times
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