// This code was created by Jeff Molofee '99 (ported to Linux/GLUT by Richard Campbell '99)
//
// If you've found this code useful, please let me know.
//
// Visit me at www.demonews.com/hosted/nehe
// (email Richard Campbell at ulmont@bellsouth.net)
//
#include <GL/glut.h> // Header File For The GLUT Library
#include <GL/gl.h> // Header File For The OpenGL32 Library
#include <GL/glu.h> // Header File For The GLu32 Library
#include <unistd.h> // Header file for sleeping.
#include <stdio.h> // Header file for standard file i/o.
#include <stdlib.h> // Header file for malloc/free.
void renderSphere()
{
GLUquadricObj *quadratic;
quadratic=gluNewQuadric(); // Create A Pointer To The Quadric Object ( NEW )
gluQuadricNormals(quadratic, GLU_SMOOTH); // Create Smooth Normals ( NEW )
gluQuadricTexture(quadratic, GL_TRUE);
gluSphere(quadratic,1.0f,32,32);
gluDeleteQuadric(quadratic);
}
void renderCube()
{
glBegin(GL_QUADS); // begin drawing a cube
// Front Face (note that the texture's corners have to match the quad's corners)
glNormal3f( 0.0f, 0.0f, 1.0f); // front face points out of the screen on z.
glVertex3f(-1.0f, -1.0f, 1.0f); // Bottom Left Of The Texture and Quad
glVertex3f( 1.0f, -1.0f, 1.0f); // Bottom Right Of The Texture and Quad
glVertex3f( 1.0f, 1.0f, 1.0f); // Top Right Of The Texture and Quad
glVertex3f(-1.0f, 1.0f, 1.0f); // Top Left Of The Texture and Quad
// Back Face
glNormal3f( 0.0f, 0.0f,-1.0f); // back face points into the screen on z.
glVertex3f(-1.0f, -1.0f, -1.0f); // Bottom Right Of The Texture and Quad
glVertex3f(-1.0f, 1.0f, -1.0f); // Top Right Of The Texture and Quad
glVertex3f( 1.0f, 1.0f, -1.0f); // Top Left Of The Texture and Quad
glVertex3f( 1.0f, -1.0f, -1.0f); // Bottom Left Of The Texture and Quad
// Top Face
glNormal3f( 0.0f, 1.0f, 0.0f); // top face points up on y.
glVertex3f(-1.0f, 1.0f, -1.0f); // Top Left Of The Texture and Quad
glVertex3f(-1.0f, 1.0f, 1.0f); // Bottom Left Of The Texture and Quad
glVertex3f( 1.0f, 1.0f, 1.0f); // Bottom Right Of The Texture and Quad
glVertex3f( 1.0f, 1.0f, -1.0f); // Top Right Of The Texture and Quad
// Bottom Face
glNormal3f( 0.0f, -1.0f, 0.0f); // bottom face points down on y.
glVertex3f(-1.0f, -1.0f, -1.0f); // Top Right Of The Texture and Quad
glVertex3f( 1.0f, -1.0f, -1.0f); // Top Left Of The Texture and Quad
glVertex3f( 1.0f, -1.0f, 1.0f); // Bottom Left Of The Texture and Quad
glVertex3f(-1.0f, -1.0f, 1.0f); // Bottom Right Of The Texture and Quad
// Right face
glNormal3f( 1.0f, 0.0f, 0.0f); // right face points right on x.
glVertex3f( 1.0f, -1.0f, -1.0f); // Bottom Right Of The Texture and Quad
glVertex3f( 1.0f, 1.0f, -1.0f); // Top Right Of The Texture and Quad
glVertex3f( 1.0f, 1.0f, 1.0f); // Top Left Of The Texture and Quad
glVertex3f( 1.0f, -1.0f, 1.0f); // Bottom Left Of The Texture and Quad
// Left Face
glNormal3f(-1.0f, 0.0f, 0.0f); // left face points left on x.
glVertex3f(-1.0f, -1.0f, -1.0f); // Bottom Left Of The Texture and Quad
glVertex3f(-1.0f, -1.0f, 1.0f); // Bottom Right Of The Texture and Quad
glVertex3f(-1.0f, 1.0f, 1.0f); // Top Right Of The Texture and Quad
glVertex3f(-1.0f, 1.0f, -1.0f); // Top Left Of The Texture and Quad
glEnd(); // done with the polygon.
}
/* ascii codes for various special keys */
#define ESCAPE 27
#define PAGE_UP 73
#define PAGE_DOWN 81
#define UP_ARROW 72
#define DOWN_ARROW 80
#define LEFT_ARROW 75
#define RIGHT_ARROW 77
/* The number of our GLUT window */
int window;
/* lighting on/off (1 = on, 0 = off) */
int light;
/* L pressed (1 = yes, 0 = no) */
int lp;
/* F pressed (1 = yes, 0 = no) */
int fp;
GLfloat xrot; // x rotation
GLfloat yrot; // y rotation
GLfloat xspeed; // x rotation speed
GLfloat yspeed; // y rotation speed
GLfloat z=-5.0f; // depth into the screen.
/* white ambient light at half intensity (rgba) */
GLfloat LightAmbient[] = { 0.5f, 0.5f, 0.5f, 1.0f };
/* super bright, full intensity diffuse light. */
GLfloat LightDiffuse[] = { 0.0f, 0.0f, 0.0f, 1.0f };
/* position of light (x, y, z, (position of light)) */
GLfloat LightPosition[] = { 0.0f, 0.0f, 2.0f, 1.0f };
GLuint filter; /* Which Filter To Use (nearest/linear/mipmapped) */
GLuint texture[3]; /* Storage for 3 textures. */
/* Image type - contains height, width, and data */
struct Image {
unsigned long sizeX;
unsigned long sizeY;
char *data;
};
typedef struct Image Image;
// quick and dirty bitmap loader...for 24 bit bitmaps with 1 plane only.
// See http://www.dcs.ed.ac.uk/~mxr/gfx/2d/BMP.txt for more info.
// if mesa ever gets glaux, let me know.
int ImageLoad(char *filename, Image *image) {
FILE *file;
unsigned long size; // size of the image in bytes.
unsigned long i; // standard counter.
unsigned short int planes; // number of planes in image (must be 1)
unsigned short int bpp; // number of bits per pixel (must be 24)
char temp; // used to convert bgr to rgb color.
// make sure the file is there.
if ((file = fopen(filename, "rb"))==NULL)
{
printf("File Not Found : %s\n",filename);
return 0;
}
// seek through the bmp header, up to the width/height:
fseek(file, 18, SEEK_CUR);
// read the width
if ((i = fread(&image->sizeX, 4, 1, file)) != 1) {
printf("Error reading width from %s.\n", filename);
return 0;
}
printf("Width of %s: %lu\n", filename, image->sizeX);
// read the height
if ((i = fread(&image->sizeY, 4, 1, file)) != 1) {
printf("Error reading height from %s.\n", filename);
return 0;
}
printf("Height of %s: %lu\n", filename, image->sizeY);
// calculate the size (assuming 24 bits or 3 bytes per pixel).
size = image->sizeX * image->sizeY * 3;
// read the planes
if ((fread(&planes, 2, 1, file)) != 1) {
printf("Error reading planes from %s.\n", filename);
return 0;
}
if (planes != 1) {
printf("Planes from %s is not 1: %u\n", filename, planes);
return 0;
}
// read the bpp
if ((i = fread(&bpp, 2, 1, file)) != 1) {
printf("Error reading bpp from %s.\n", filename);
return 0;
}
if (bpp != 24) {
printf("Bpp from %s is not 24: %u\n", filename, bpp);
return 0;
}
// seek past the rest of the bitmap header.
fseek(file, 24, SEEK_CUR);
// read the data.
image->data = (char *) malloc(size);
if (image->data == NULL) {
printf("Error allocating memory for color-corrected image data");
return 0;
}
if ((i = fread(image->data, size, 1, file)) != 1) {
printf("Error reading image data from %s.\n", filename);
return 0;
}
for (i=0;i<size;i+=3) { // reverse all of the colors. (bgr -> rgb)
temp = image->data[i];
image->data[i] = image->data[i+2];
image->data[i+2] = temp;
}
// we're done.
return 1;
}
// Load Bitmaps And Convert To Textures
GLvoid LoadGLTextures(GLvoid) {
// Load Texture
Image *image1;
// allocate space for texture
image1 = (Image *) malloc(sizeof(Image));
if (image1 == NULL) {
printf("Error allocating space for image");
exit(0);
}
if (!ImageLoad("Data/lesson7/crate.bmp", image1)) {
exit(1);
}
// Create Textures
glGenTextures(3, &texture[0]);
// texture 1 (poor quality scaling)
glBindTexture(GL_TEXTURE_2D, texture[0]); // 2d texture (x and y size)
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST); // cheap scaling when image bigger than texture
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST); // cheap scaling when image smalled than texture
// 2d texture, level of detail 0 (normal), 3 components (red, green, blue), x size from image, y size from image,
// border 0 (normal), rgb color data, unsigned byte data, and finally the data itself.
glTexImage2D(GL_TEXTURE_2D, 0, 3, image1->sizeX, image1->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image1->data);
// texture 2 (linear scaling)
glBindTexture(GL_TEXTURE_2D, texture[1]); // 2d texture (x and y size)
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // scale linearly when image bigger than texture
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); // scale linearly when image smalled than texture
glTexImage2D(GL_TEXTURE_2D, 0, 3, image1->sizeX, image1->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image1->data);
// texture 3 (mipmapped scaling)
glBindTexture(GL_TEXTURE_2D, texture[2]); // 2d texture (x and y size)
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // scale linearly when image bigger than texture
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST); // scale linearly + mipmap when image smalled than texture
glTexImage2D(GL_TEXTURE_2D, 0, 3, image1->sizeX, image1->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image1->data);
// 2d texture, 3 colors, width, height, RGB in that order, byte data, and the data.
gluBuild2DMipmaps(GL_TEXTURE_2D, 3, image1->sizeX, image1->sizeY, GL_RGB, GL_UNSIGNED_BYTE, image1->data);
};
/* A general OpenGL initialization function. Sets all of the initial parameters. */
GLvoid InitGL(GLsizei Width, GLsizei Height) // We call this right after our OpenGL window is created.
{
LoadGLTextures(); // load the textures.
//glEnable(GL_TEXTURE_2D); // Enable texture mapping.
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LESS); // The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); // Reset The Projection Matrix
gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f); // Calculate The Aspect Ratio Of The Window
glMatrixMode(GL_MODELVIEW);
// set up light number 1.
glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient); // add lighting. (ambient)
glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse); // add lighting. (diffuse).
glLightfv(GL_LIGHT1, GL_POSITION,LightPosition); // set light position.
glEnable(GL_LIGHT1); // turn light 1 on.
glEnable(GL_LIGHTING);
light = 1;
}
/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
GLvoid ReSizeGLScene(GLsizei Width, GLsizei Height)
{
if (Height==0) // Prevent A Divide By Zero If The Window Is Too Small
Height=1;
glViewport(0, 0, Width, Height); // Reset The Current Viewport And Perspective Transformation
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW);
}
/* The main drawing function. */
GLvoid DrawGLScene(GLvoid)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The View
glTranslatef(0.0f,0.0f,z); // move z units out from the screen.
glRotatef(xrot,1.0f,0.0f,0.0f); // Rotate On The X Axis
glRotatef(yrot,0.0f,1.0f,0.0f); // Rotate On The Y Axis
//Setze Lichtquelle
const GLfloat LightDirection[] = { 0.0f, 0.0f, 1.0f, 0.0f };
const GLfloat LightSpecular[] = { 1.0f, 0.0f, 0.0f, 1.0f };
glLightfv(GL_LIGHT1, GL_POSITION, LightDirection);
glLightfv(GL_LIGHT1, GL_SPECULAR, LightSpecular);
const GLfloat specular[] = {1.0f,0.0f,0.0f,1.0f};
glMaterialf(GL_FRONT, GL_SHININESS, 1.0f);
glMaterialfv( GL_FRONT, GL_SPECULAR, specular );
//Sphere:
renderSphere();
//Cube
//renderCube();
xrot+=xspeed; // X Axis Rotation
yrot+=yspeed; // Y Axis Rotation
// since this is double buffered, swap the buffers to display what just got drawn.
glutSwapBuffers();
}
/* The function called whenever a normal key is pressed. */
void keyPressed(unsigned char key, int x, int y)
{
/* avoid thrashing this procedure */
usleep(100);
switch (key) {
case ESCAPE: // kill everything.
/* shut down our window */
glutDestroyWindow(window);
/* exit the program...normal termination. */
exit(1);
break; // redundant.
case 76:
case 108: // switch the lighting.
printf("L/l pressed; light is: %d\n", light);
light = light ? 0 : 1; // switch the current value of light, between 0 and 1.
printf("Light is now: %d\n", light);
if (!light) {
glDisable(GL_LIGHTING);
} else {
glEnable(GL_LIGHTING);
}
break;
case 70:
case 102: // switch the filter.
printf("F/f pressed; filter is: %d\n", filter);
filter+=1;
if (filter>2) {
filter=0;
}
printf("Filter is now: %d\n", filter);
break;
default:
break;
}
}
/* The function called whenever a normal key is pressed. */
void specialKeyPressed(int key, int x, int y)
{
/* avoid thrashing this procedure */
usleep(100);
switch (key) {
case GLUT_KEY_PAGE_UP: // move the cube into the distance.
z-=0.02f;
break;
case GLUT_KEY_PAGE_DOWN: // move the cube closer.
z+=0.02f;
break;
case GLUT_KEY_UP: // decrease x rotation speed;
xspeed-=0.01f;
break;
case GLUT_KEY_DOWN: // increase x rotation speed;
xspeed+=0.01f;
break;
case GLUT_KEY_LEFT: // decrease y rotation speed;
yspeed-=0.01f;
break;
case GLUT_KEY_RIGHT: // increase y rotation speed;
yspeed+=0.01f;
break;
default:
break;
}
}
int main(int argc, char **argv)
{
/* Initialize GLUT state - glut will take any command line arguments that pertain to it or
X Windows - look at its documentation at http://reality.sgi.com/mjk/spec3/spec3.html */
glutInit(&argc, argv);
/* Select type of Display mode:
Double buffer
RGBA color
Alpha components supported
Depth buffer */
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH);
/* get a 640 x 480 window */
glutInitWindowSize(640, 480);
/* the window starts at the upper left corner of the screen */
glutInitWindowPosition(0, 0);
/* Open a window */
window = glutCreateWindow("Jeff Molofee's GL Code Tutorial ... NeHe '99");
/* Register the function to do all our OpenGL drawing. */
glutDisplayFunc(&DrawGLScene);
/* Go fullscreen. This is as soon as possible. */
glutFullScreen();
/* Even if there are no events, redraw our gl scene. */
glutIdleFunc(&DrawGLScene);
/* Register the function called when our window is resized. */
glutReshapeFunc(&ReSizeGLScene);
/* Register the function called when the keyboard is pressed. */
glutKeyboardFunc(&keyPressed);
/* Register the function called when special keys (arrows, page down, etc) are pressed. */
glutSpecialFunc(&specialKeyPressed);
/* Initialize our window. */
InitGL(640, 480);
/* Start Event Processing Engine */
glutMainLoop();
return 1;
}
