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Opengl drawing objects at random

Posted on 2011-03-15
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Last Modified: 2012-05-11
I am trying to draw objects at random. The bit I am having a problem with is the drawitem part in the code below, I am trying to draw them at random positions. But when I run the program the itme is just drawn once at the point of origin.
#include <stdio.h>
#include <windows.h>
#include <stdlib.h>
#include <GL/gl.h>
#include <GL/glut.h>

#include <math.h>
#include "Enemy.h"
#include "Item.h"
//angle of rotation
float xpos = 0, ypos = 0, zpos = 0, xrot = 0, yrot = 0, angle=0.0;
float cRadius = 10.0f; // our radius distance from our character
float lastx, lasty;
void DrawFloor();
void DrawSnowMan();
void DrawWeapon();
void drawitem();
void drawEnemy();
static int weapon = 0;
void skybox();
Enemy enemy;
Item item; 
//positions of the cubes
float positionz[10];
float positionx[10];
float positionzaxis[10];
float positionxaxis[10];
float positionzone[10];
float positionxone[10];
int Score = 0;
int frame = 0;
float Weaponangle = 0.0;
bool bWeaponIsActive;
// Load in textures 
#define SNOW 0
//#define HORIZON 0
//#define WOOD 0 


GLfloat light_diffuse[] = {1.0, 0.0, 0.0, 1.0};  /* Red diffuse light. */
GLfloat light_position[] = {1.0, 1.0, 1.0, 0.0};  /* Infinite light location. */


struct Vector3
{
float x;
float y;
float z;
};

struct BoundingBox
{
Vector3 max;
Vector3 min;
};

struct Image 
{
    unsigned long size_x;
    unsigned long size_y;
    char *data;
};

typedef struct Image Image;

const int textureCount = 1; // specifies # of textures


Image myTextureData[textureCount];  //array storing image texture info
GLuint theTexture[textureCount];  //array storing OpenGL texture info

/* texture filename list */
char* textureFilenames[textureCount] = {"Snow.bmp"};
int window_width = 800; //sets the width of the window
int window_height = 600; //sets the hight of the window

///////////////////////////////////////////////
//////////////////////////////////////////////

void output(GLfloat x, GLfloat y, char *format)
{
  va_list args;
  char buffer[200], *p;

  va_start(args, format);
  vsprintf(buffer, format, args);
  va_end(args);
  glPushMatrix();
  glTranslatef(x, y, 0);
  for (p = buffer; *p; p++)
    glutStrokeCharacter(GLUT_STROKE_ROMAN, *p);
  glPopMatrix();
}


/*void UpdateWeapon (void)
{
   if (bWeaponIsActive)
   {
      ++frame;

      if ((frame < 9) && (frame > 11))
      {
         angle = 90 * (sin (PI / 20 * frame));
      }
      
      if (frame == 20) bWeaponIsActive = false;  // hammer action is finished
   }
}*/


int imageLoader(const char *filename, Image *image) 
{
    FILE *file;

    unsigned long size;
    unsigned long i;
    unsigned short int planes;
    unsigned short int bpp;

    char temp;
	char finalName[80];

	glTexCoord2f(1.0, 0.0);

	strcpy(finalName, "" );
	strcat(finalName, filename);

    if ((file = fopen(finalName, "rb"))==NULL) 
	{
		printf("File Not Found : %s\n",finalName);
		return 0;
    }

    fseek(file, 18, SEEK_CUR);

	glTexCoord2f(1.0, 0.0);
    
	if ((i = fread(&image->size_x, 4, 1, file)) != 1) 
	{
		printf("Error reading width from %s.\n", finalName);
		return 0;
    }

    if ((i = fread(&image->size_y, 4, 1, file)) != 1) 
	{
		printf("Error reading height from %s.\n", finalName);
		return 0;
    }

    size = image->size_x * image->size_y * 3;

    if ((fread(&planes, 2, 1, file)) != 1) 
	{
		printf("Error reading planes from %s.\n", finalName);
		return 0;
    }

    if (planes != 1) 
	{
		printf("Planes from %s is not 1: %u\n", finalName, planes);
		return 0;
    }

    if ((i = fread(&bpp, 2, 1, file)) != 1) 
	{
		printf("Error reading bpp from %s.\n", finalName);
		return 0;
    }

    if (bpp != 24) 
	{
		printf("Bpp from %s is not 24: %u\n", finalName, bpp);
		return 0;
    }

    fseek(file, 24, SEEK_CUR);

    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", finalName);
		return 0;
    }

    for (i=0;i<size;i+=3) 
	{
		temp = image->data[i];
		image->data[i] = image->data[i+2];
		image->data[i+2] = temp;
    }
    return 1;
}

//////////////////////////////////////////////////////
////Texture Loader
//////////////////////////////////////////////////////

void textureLoader() 
{
	/* set the pixel storage, GL_UNPACK_ALIGNMENT : specifies alignment requirements
	   for the start of each pixel row in memory 1 = byte-alignment*/
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

	for(int k=0; k < textureCount; k++) 
	{
		if(!imageLoader(textureFilenames[k], &myTextureData[k])) 
			exit(1);
		
		/* generate texture names */
		glGenTextures(1, &theTexture[k]);
		/* create a named texture bound to a texture target */
	    glBindTexture(GL_TEXTURE_2D, theTexture[k]);

		/* set the texture parameters */
		glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
		glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
		/* builds and load a set of mipmaps */
	   	gluBuild2DMipmaps(GL_TEXTURE_2D, 3, myTextureData[k].size_x, myTextureData[k].size_y, GL_RGB, GL_UNSIGNED_BYTE, myTextureData[k].data);
	}
}

void DrawWeapon(void)
{
   // Draw the Handle
   glPushMatrix();
   glRotatef(90.0f,5.0f,10.0f,5.0f);
   glScalef (2.0, 0.4, 1.0);
   glTranslatef(0.5f,-1.0f,0.6f);
   glRotatef ((GLfloat) weapon, 0.0, 0.0, 1.0);
   glutSolidCube (0.6);
   
   


   //Draw the hammer
   glTranslatef(0.6f,0.6f,-1.0f);
   glRotatef ((GLfloat) weapon, 0.0, 0.0, 1.0);
   glutSolidCube(0.9);
   glPopMatrix();



}


void DrawSnowMan(void)
{

  // Draw Body	

  /* if (box->min.x>x) box->min.x = x;
   if (box->min.y>y) box->min.y = y;
   if (box->min.z>z) box->min.z = z;

   if (box->max.x<x) box->max.x = x;
   if (box->max.y<y) box->max.y = y;
   if (box->max.z<z) box->max.z = z;*/
	glTranslatef(0.0f ,0.1f, 0.0f);
	glutSolidSphere(0.75f,20,20);

  

  // Draw Head
	glTranslatef(0.0f, 1.0f, 0.0f);
	glutSolidSphere(0.4f,20,20);

   // Draw Hand 
	glPushMatrix();
    glTranslatef(0.5f ,-0.5f, 0.0f);
	glutSolidSphere(0.4f,20,20);
    glPopMatrix();

	//Draw Second hand
	glPushMatrix();
    glTranslatef(-0.5f ,-0.5f, 0.0f);
	glutSolidSphere(0.4f,20,20);
	
    glPopMatrix();


// Draw Eyes
	glPushMatrix();
	glColor3f(0.0f,0.0f,0.0f);
	glTranslatef(0.05f, 0.10f, -0.4f);
	glutSolidSphere(0.05f,10,10);
	glTranslatef(-0.1f, 0.0f, 0.0f);
	glutSolidSphere(0.05f,10,10);
	glPopMatrix();


// Draw Nose
	glPushMatrix();
	glColor3f(1.0f, 0.5f , 0.5f);
	
	glTranslatef(0.0f,0.0f,-0.2f);
	glRotatef(180.0f,0.0f,0.0f,0.0f);
	glutSolidCone(0.08f,0.5f,10,2);
	
    glPopMatrix();
	
}

void Itempositions (void) {
   
         for (int i=0;i<10;i++)
    {
    positionzaxis[i] = rand()%20 + 3;
    positionxaxis[i] = rand()%10 + 3;
    }


}

void Enemypositions (void) {
   
         for (int i=0;i<10;i++)
    {
    positionzone[i] = rand()%20 + 3;
    positionxone[i] = rand()%10 + 3;
    }


}


void drawEnemy (void) 
{

    for (int i=0;i<10 - 1;i++)
    {
     
    glPushMatrix();
    
    glTranslated(-positionxaxis[i + 1] * 10, 0, -positionzaxis[i + 1] * 10); //translate the items
	glPushMatrix();
    enemy.DrawEnemy(0.0f,0.0f,0.0f);
	glPopMatrix();
    glPopMatrix();
	}
}

void drawitems (void) 
{

    for (int i=0;i<10 - 1;i++)
    {
     
    glPushMatrix();
    
    glTranslated(-positionxaxis[i + 1] * 10, 0, -positionzaxis[i + 1] * 10); //translate the items
	glPushMatrix();
    item.DrawItem();
	glPopMatrix();
    glPopMatrix();
	}
}


void cubepositions (void) { //set the positions of the cubes

    for (int i=0;i<10;i++)
    {
    positionz[i] = rand()%10 + 3;
    positionx[i] = rand()%10 + 3;
    }
}
//draw the cube
void cube (void) {
    for (int i=0;i<10 - 1;i++)
    {
     
    glPushMatrix();
    
    glTranslated(-positionx[i + 1] * 10, 0, -positionz[i + 1] * 10); //translate the cube
	
    // house
    glPushMatrix();
	glTranslatef(0,5,0);
    //glBindTexture(GL_TEXTURE_2D,texture[0]);
    glutSolidCube(12);                 // building
    
    glTranslatef(0,5,0);
    glPushMatrix();                   // roof
    glRotatef(-90,1,0,0);
    glutSolidCone(10.5,10,16,19);
    glPopMatrix();

    glTranslatef(.75,.20,-.75);         
    glPushMatrix();                   // chimney
    glScalef(2,8,2);
    glutSolidCube(.25);
    glPopMatrix();
    glPopMatrix();

    glTranslatef(0,-.65,2);
   // glutSolidCube(2); //draw the cube
    glPopMatrix();
    }
}
void init (void) {

    glEnable (GL_LIGHTING); //enable the lighting
    glEnable (GL_LIGHT0); //enable LIGHT0, our Diffuse Light
    cubepositions();
    glEnable(GL_TEXTURE_2D);
 
   
	
}


void enable (void) {
    glEnable (GL_DEPTH_TEST); //enable the depth testing
    
    glEnable (GL_COLOR_MATERIAL);
    glShadeModel (GL_SMOOTH); //set the shader to smooth shader
    glEnable(GL_TEXTURE_2D);
}



void display (void) {
    glClearColor (0.0,0.0,0.0,1.0); //clear the screen to 
//blacks
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
//clear the color buffer and the depth buffer
    

    enable();
     

     
    glLoadIdentity(); 
    textureLoader();
   // glutSolidCube(12);
   
    glTranslatef(0.0f, 0.0f, -cRadius);
    glRotatef(xrot,1.0,0.0,0.0);
    glColor3f(1.0f, 0.0f, 0.0f);
	glColor3f(1.0f, 1.0f, 1.0f);
    output(80, 2800, "SnowMan Game Score.");


    if (Score == 100)
	{
        output(80, 2800, "You Win.");

	}
    //glutSolidCube(2); //Our character to follow*/
	glTranslatef(0.4f,0.0f,0.0f);
    DrawSnowMan();
	glPushMatrix();
	DrawWeapon();
    glRotatef ((GLfloat) weapon, 0.0, 0.0, 1.0);
	glPopMatrix();
    glRotatef(yrot,0.0,1.0,0.0);  
    glTranslated(-xpos,0.0f,-zpos); 
    glColor3f(1.0f, 1.0f, 1.0f);
    cube(); //call the cube drawing function
    //Weapon();`
    glPushMatrix();
   glScalef (2.0, 0.4, 1.0);
   DrawFloor();
   //enemy.DrawEnemy(1.0f,0.0f,0.0f);
   drawitems();
  // glutWireCube (5.0);
    glPopMatrix();
    glutSwapBuffers(); //swap the buffers
	
    angle++; //increase the angle
}



void reshape (int w, int h) {
    glViewport (0, 0, (GLsizei)w, (GLsizei)h); //set the viewport
 //to the current window specifications
    glMatrixMode (GL_PROJECTION); //set the matrix to projection
     
    glLoadIdentity ();
    gluPerspective (60, (GLfloat)w / (GLfloat)h, 0.1, 100.0); //set the perspective (angle of sight, width, height, , depth

    glMatrixMode (GL_MODELVIEW); //set the matrix back to model

}
void keyboard (unsigned char key, int x, int y) {
    if (key=='q')
    {
    xrot += 1;
    if (xrot >360) xrot -= 360;
    }
    if (key=='z')
    {
    xrot -= 1;
    if (xrot < -360) xrot += 360;
    }
    if (key=='w')
    {
    float xrotrad, yrotrad;
    yrotrad = (yrot / 180 * 3.141592654f);
    xrotrad = (xrot / 180 * 3.141592654f); 
    xpos += float(sin(yrotrad));
    zpos -= float(cos(yrotrad));
    ypos -= float(sin(xrotrad));
    }
    if (key=='s')
    {
    float xrotrad, yrotrad;
    yrotrad = (yrot / 180 * 3.141592654f);
    xrotrad = (xrot / 180 * 3.141592654f); 
    xpos -= float(sin(yrotrad));
    zpos += float(cos(yrotrad));
    ypos += float(sin(xrotrad));
    }
    if (key=='d')
    {
    float yrotrad;
    yrotrad = (yrot / 180 * 3.141592654f);
    xpos += float(cos(yrotrad)) * 0.2;
    zpos += float(sin(yrotrad)) * 0.2;
    }
    if (key=='e')
	{
        weapon = (weapon + 5) % 360;
        glutPostRedisplay();
	}
    if (key=='a')
    {
    float yrotrad;
    yrotrad = (yrot / 180 * 3.141592654f);
    xpos -= float(cos(yrotrad)) * 0.2;
    zpos -= float(sin(yrotrad)) * 0.2;
    }
    if (key==27)
    {
    exit(0);
    }
}

void DrawFloor(void) { 

	   
       glBindTexture(GL_TEXTURE_2D, theTexture[SNOW]);
       glTranslatef(0.0f,-3.0f,0.0f);

 glBegin(GL_QUADS);
       
        glTexCoord2f(1.0f,0.0f);
        //glColor3f(0.2f, 0.2f, 0.2f);
        glVertex3f(-100.0,-0.5, -100);
        glTexCoord2f(1.0f,1.0f);
       // glColor3f(0.4f, 0.4f, 0.4f);
        glVertex3f(-100.0,-0.5, 100.0);
        glTexCoord2f(0,1.0f);
       // glColor3f(0.6f, 0.6f, 0.6f);
        glVertex3f(100.0, -0.5, 100.0);
        glTexCoord2f(0,0);
       // glColor3f(0.8f, 0.8f, 0.8f);
        glVertex3f(100.0, -0.5, -100.0);        
    glEnd();

}

void mouseMovement(int x, int y) {
    int diffx=x-lastx; //check the difference between the 
//current x and the last x position
    int diffy=y-lasty; //check the difference between the 
//current y and the last y position
    lastx=x; //set lastx to the current x position
    lasty=y; //set lasty to the current y position
    xrot += (float) diffy; //set the xrot to xrot with the addition
 //of the difference in the y position
    yrot += (float) diffx;    //set the xrot to yrot with the addition
 //of the difference in the x position
}

void skybox(void)
{
   
  glBindTexture(GL_TEXTURE_2D, theTexture[SNOW]);
  glNormal3f( 0.0f, 0.0f, 0.5f);					
		 glVertex3f(-300.0f, -300.0f,  300.0f);
		 glVertex3f( 300.0f, -300.0f,  300.0f);
         glVertex3f( 300.0f,  300.0f,  300.0f);
		 glVertex3f(-300.0f,  300.0f,  300.0f);
		// Back Face
		glNormal3f( 0.0f, 0.0f,-0.5f);					
	    glVertex3f(-300.0f, -300.0f, -300.0f);
	    glVertex3f(-300.0f,  300.0f, -300.0f);
	    glVertex3f( 300.0f,  300.0f, -300.0f);
	    glVertex3f( 300.0f, -300.0f, -300.0f);
		// Top Face
		glNormal3f( 0.0f, 0.5f, 0.0f);					
	    glVertex3f(-300.0f,  300.0f, -300.0f);
	    glVertex3f(-300.0f,  300.0f,  300.0f);
	    glVertex3f( 300.0f,  300.0f,  300.0f);
	    glVertex3f( 300.0f,  300.0f, -300.0f);
		// Bottom Face
		glNormal3f( 0.0f,-0.5f, 0.0f);					
	    glVertex3f(-300.0f, -300.0f, -300.0f);
	    glVertex3f( 300.0f, -300.0f, -300.0f);
	    glVertex3f( 300.0f, -300.0f,  300.0f);
	    glVertex3f(-300.0f, -300.0f,  300.0f);
		// Right Face
		glNormal3f( 0.5f, 0.0f, 0.0f);					
	    glVertex3f( 300.0f, -300.0f, -300.0f);
	    glVertex3f( 300.0f,  300.0f, -300.0f);
	    glVertex3f( 300.0f,  300.0f,  300.0f);
	    glVertex3f( 300.0f, -300.0f,  300.0f);
		// Left Face
		glNormal3f(-0.5f, 0.0f, 0.0f);					
	    glVertex3f(-300.0f, -300.0f, -300.0f);
	    glVertex3f(-300.0f, -300.0f,  300.0f);
	    glVertex3f(-300.0f,  300.0f,  300.0f);
	    glVertex3f(-300.0f,  300.0f, -300.0f);


}

int main (int argc, char **argv) {
    glutInit (&argc, argv);
    glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB); 
    glutInitWindowSize (500, 500); 
    glutInitWindowPosition (100, 100);
    glutCreateWindow ("Snow Man Game"); 
    init (); 
	glEnable(GL_TEXTURE_2D);
    
	
	
    glutDisplayFunc (display); 
    glutIdleFunc (display); 
    glutReshapeFunc (reshape);
    glutPassiveMotionFunc(mouseMovement); //check for mouse

    glutKeyboardFunc (keyboard); 
    glutMainLoop (); 
    return 0;
}

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Question by:tango2009
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6 Comments
 
LVL 40

Expert Comment

by:Kyle Abrahams
ID: 35139783
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Author Comment

by:tango2009
ID: 35141398
How do you use srand it doesn't seem to be an option you can use in opengl?
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Expert Comment

by:Kyle Abrahams
ID: 35158021
http://www.cplusplus.com/reference/clibrary/cstdlib/srand/

should be able to it's a c++ call.  make sure you have these libraries:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

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Author Comment

by:tango2009
ID: 35159926
I am trying to use it like this below


void Enemypositions (void) {
   
       
    {
    positionzone = srand(1)% 100;
    positionxone = srand(1)% 100;
    }


}

But I am getting these errors

 error C2296: '%' : illegal, left operand has type 'void'
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Accepted Solution

by:
Kyle Abrahams earned 500 total points
ID: 35164820
you use srand once at the beginning

then call rand.

srand(time(0));
int number=1;  //start with a value less than 20000
int count=1;
while (count<20000)
      {
      number = rand()%maxrange;  // generate a random number
                           //between 0 and whatever max you want
      count++; //increase loop count

     cout << "number is" << number;
     cout << "generated on try #: " << count;
     }

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Author Comment

by:tango2009
ID: 35169103
Using it just at the beginning I just get these two errors and it says look how srand is defined.

1>f:\snowman\snowman\main.cpp(75) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>f:\snowman\snowman\main.cpp(75) : error C2365: 'srand' : redefinition; previous definition was 'function'

does srand need to set as a double?
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