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The Code So Far

Prev: Moving the Camera II Next: The Mouse
 

Here is the complete code for the previous example:

#include <stdlib.h>
#include <math.h>

#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

// angle of rotation for the camera direction
float angle = 0.0f;
// actual vector representing the camera's direction
float lx=0.0f,lz=-1.0f;
// XZ position of the camera
float x=0.0f, z=5.0f;
// the key states. These variables will be zero
//when no key is being presses
float deltaAngle = 0.0f;
float deltaMove = 0;

void changeSize(int w, int h) {

	// Prevent a divide by zero, when window is too short
	// (you cant make a window of zero width).
	if (h == 0)
		h = 1;
	float ratio =  w * 1.0 / h;

	// Use the Projection Matrix
	glMatrixMode(GL_PROJECTION);

	// Reset Matrix
	glLoadIdentity();

	// Set the viewport to be the entire window
	glViewport(0, 0, w, h);

	// Set the correct perspective.
	gluPerspective(45.0f, ratio, 0.1f, 100.0f);

	// Get Back to the Modelview
	glMatrixMode(GL_MODELVIEW);
}

void drawSnowMan() {

	glColor3f(1.0f, 1.0f, 1.0f);

// Draw Body

	glTranslatef(0.0f ,0.75f, 0.0f);
	glutSolidSphere(0.75f,20,20);

// Draw Head
	glTranslatef(0.0f, 1.0f, 0.0f);
	glutSolidSphere(0.25f,20,20);

// Draw Eyes
	glPushMatrix();
	glColor3f(0.0f,0.0f,0.0f);
	glTranslatef(0.05f, 0.10f, 0.18f);
	glutSolidSphere(0.05f,10,10);
	glTranslatef(-0.1f, 0.0f, 0.0f);
	glutSolidSphere(0.05f,10,10);
	glPopMatrix();

// Draw Nose
	glColor3f(1.0f, 0.5f , 0.5f);
	glRotatef(0.0f,1.0f, 0.0f, 0.0f);
	glutSolidCone(0.08f,0.5f,10,2);
}

void computePos(float deltaMove) {

	x += deltaMove * lx * 0.1f;
	z += deltaMove * lz * 0.1f;
}

void computeDir(float deltaAngle) {

	angle += deltaAngle;
	lx = sin(angle);
	lz = -cos(angle);
}

void renderScene(void) {

	if (deltaMove)
		computePos(deltaMove);
	if (deltaAngle)
		computeDir(deltaAngle);

	// Clear Color and Depth Buffers
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// Reset transformations
	glLoadIdentity();
	// Set the camera
	gluLookAt(	x, 1.0f, z,
				x+lx, 1.0f,  z+lz,
				0.0f, 1.0f,  0.0f);

// Draw ground

	glColor3f(0.9f, 0.9f, 0.9f);
	glBegin(GL_QUADS);
		glVertex3f(-100.0f, 0.0f, -100.0f);
		glVertex3f(-100.0f, 0.0f,  100.0f);
		glVertex3f( 100.0f, 0.0f,  100.0f);
		glVertex3f( 100.0f, 0.0f, -100.0f);
	glEnd();

// Draw 36 SnowMen

	for(int i = -3; i < 3; i++)
		for(int j=-3; j < 3; j++) {
			glPushMatrix();
			glTranslatef(i*10.0,0,j * 10.0);
			drawSnowMan();
			glPopMatrix();
		}

	glutSwapBuffers();
}


void pressKey(int key, int xx, int yy) {

	switch (key) {
		case GLUT_KEY_LEFT : deltaAngle = -0.01f; break;
		case GLUT_KEY_RIGHT : deltaAngle = 0.01f; break;
		case GLUT_KEY_UP : deltaMove = 0.5f; break;
		case GLUT_KEY_DOWN : deltaMove = -0.5f; break;
	}
}

void releaseKey(int key, int x, int y) {

	switch (key) {
		case GLUT_KEY_LEFT :
		case GLUT_KEY_RIGHT : deltaAngle = 0.0f;break;
		case GLUT_KEY_UP :
		case GLUT_KEY_DOWN : deltaMove = 0;break;
	}
}

int main(int argc, char **argv) {

	// init GLUT and create window
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
	glutInitWindowPosition(100,100);
	glutInitWindowSize(320,320);
	glutCreateWindow("Lighthouse3D - GLUT Tutorial");

	// register callbacks
	glutDisplayFunc(renderScene);
	glutReshapeFunc(changeSize);
	glutIdleFunc(renderScene);

	glutSpecialFunc(pressKey);

	// here are the new entries
	glutIgnoreKeyRepeat(1);
	glutSpecialUpFunc(releaseKey);

	// OpenGL init
	glEnable(GL_DEPTH_TEST);

	// enter GLUT event processing cycle
	glutMainLoop();

	return 1;
}

The code can be downloaded from this section.

 

Prev: Moving the Camera II Next: The Mouse
 

3 Responses to “The Code So Far”

  1. For which reason if i remove the 2 for loop to draw snowmen in the renderscene function the camera became much faster?

  2. You implemented processNormalKeys, but you did not call glutKeyboardFunc(). (Which only means that Escape can’t be used to exit the program in this example.)

    • Quite right! The processNormalKeys function was from the previous example and it was kept although, as you mention, not useful at all. The function has been removed from the source code. Thanks.

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