I created a 5 face box and put a ball inside of it and allowed it to bounce around inside the box. I created this using glOrtho.
I want to create a 3d Brick breaker style game for my course so I want to get my camera down into the box. I changed from glOrtho to gluPerspective. I had to change some values for my box to render correctly but the ball seems to have gone missing unless i put it on the origin.
This is my value initialization:
void variableInits(){
//Floor Plane
pl1.pos.x = 0; pl1.pos.y = -50; pl1.pos.z = 0;
pl1.norm.x = 0; pl1.norm.y = 1; pl1.norm.z = 0;
//Ceiling Plane
pl2.pos.x = 0; pl2.pos.y = 50; pl2.pos.z = 0;
pl2.norm.x = 0; pl2.norm.y = -1; pl2.norm.z = 0;
//Right Wall Plane
pl3.pos.x = 50; pl3.pos.y = 0; pl3.pos.z = 0;
pl3.norm.x = -1; pl3.norm.y = 0; pl3.norm.z = 0;
//Left Wall Plane
pl4.pos.x = -50; pl4.pos.y = 0; pl4.pos.z = 0;
pl4.norm.x = 1; pl4.norm.y = 0; pl4.norm.z = 0;
//Back Wall Plane
pl5.pos.x = 0; pl5.pos.y = 0; pl5.pos.z = -100;
pl5.norm.x = 0; pl5.norm.y = 0; pl5.norm.z = 1;
//Paddle Plane
paddlePlane.max.x=.25; paddlePlane.max.y=.25; paddlePlane.max.z=1;
paddlePlane.min.x=-.25; paddlePlane.min.y=-.25; paddlePlane.min.z=1;
paddlePlane.normals.x=0; paddlePlane.normals.y=0;paddlePlane.normals.z=-0;
//Ball Init
b1.radius = 10;
b1.pathDirection.x = 0; b1.pathDirection.y = 0; b1.pathDirection.z = 0;
b1.pos.x = 0; b1.pos.y = 0, b1.pos.z = -25;
}
So my ball should draw with a radius of 10 on -25 value of the Z axis. Sadly it does not.
Maybe its an issue with my gluPerspective call?
void reshape(int width, int height)
{
if (height==0)
{
height=1;
}
glViewport(0,0,width,height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.0f,50.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
Ill go ahead and post my complete code but it is a bit long.
#include <stdio.h>
#include <gl/glut.h>
#include "pHeader.h"
#define EPSILON 1.0e-8
#define ZERO EPSILON
int g_mainWindow = -1;
float g_lightPos[] = {0, 0, 0, -50};
int angle = 0;
int g_moving;
int g_mouse_x;
int g_mouse_y;
int g_x_angle;
int g_y_angle;
double mX,mY,mZ;
float speed = 1;
plane pl1, pl2, pl3, pl4 ,pl5;
paddlePl paddlePlane;
float collDist = 1000;
ball b1;
void mouse(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state==GLUT_DOWN)
{
g_moving = 1;
g_mouse_x = x;
g_mouse_y = y;
}
else {
g_moving = 0;
}
}
void mouseDrag(int x, int y)
{
int dx, dy;
if (g_moving){
dx = x - g_mouse_x;
dy = y - g_mouse_y;
g_x_angle += dy;
g_y_angle += dx;
g_mouse_x = x;
g_mouse_y = y;
}
}
void paddle(int x, int y){
GLint viewport[4];
GLdouble modelview[16],projection[16];
glGetIntegerv(GL_VIEWPORT,viewport);
glGetDoublev(GL_MODELVIEW_MATRIX,modelview);
glGetDoublev(GL_PROJECTION_MATRIX,projection);
gluUnProject(x,viewport[3]-y,0,modelview,projection,viewport,&mX,&mY,&mZ);
}
/*************************************************
Vector Math
**************************************************/
float dot(vector XYZ , vector nXYZ){
return (XYZ.x * nXYZ.x) + (XYZ.y * nXYZ.x) + (XYZ.z * nXYZ.z);
}
vector cross(vector v1 , vector v2){
vector result;
result.x = v1.y * v2.z - v1.z * v2.y;
result.y = v1.z * v2.x - v1.x * v2.z;
result.z = v1.x * v2.y - v1.y * v2.x;
return result;
}
vector vectScale(float scale, vector v1){
vector result;
result.x = v1.x * scale;
result.y = v1.y * scale;
result.z = v1.z * scale;
return result;
}
vector vectorSub(vector v1, vector v2){
vector result;
result.x = v1.x - v2.x;
result.y = v1.y - v2.y;
result.z = v1.z - v2.y;
return result;
}
vector flipVect(vector v1){
vector result;
result.x = -v1.x;
result.y = -v1.y;
result.z = -v1.z;
return result;
}
vector vectorAdd(vector v1, vector v2){
vector result;
result.x = v1.x + v2.x;
result.y = v1.y + v2.y;
result.z = v1.z + v2.z;
return result;
}
/****************************************************
End Vecotor Math
****************************************************/
void planeCollision(){
//Check Ceiling
if(b1.pos.y + b1.radius >= 50){
b1.pathDirection = vectorAdd((2 * dot(flipVect(b1.pathDirection), pl2.norm) , pl2.norm) , b1.pathDirection);
}
//Check Floor
if(b1.pos.y-b1.radius <= -50){
b1.pathDirection = vectorAdd((2 * dot(flipVect(b1.pathDirection), pl1.norm) , pl1.norm) , b1.pathDirection);
}
//Check Right Wall
if(b1.pos.x + b1.radius >= 1){
b1.pathDirection = vectorAdd((2 * dot(flipVect(b1.pathDirection), pl3.norm) , pl3.norm) , b1.pathDirection);
}
//Check Left Wall
if(b1.pos.x - b1.radius <= -1){
b1.pathDirection = vectorAdd((2 * dot(flipVect(b1.pathDirection), pl4.norm) , pl4.norm) , b1.pathDirection);
}
//Check Back Wall
if(b1.pos.z - b1.radius <= -1){
b1.pathDirection = vectorAdd((2 * dot(flipVect(b1.pathDirection), pl5.norm) , pl5.norm) , b1.pathDirection);
}
//Check paddle
if(b1.pos.z + b1.radius >= paddlePlane.max.z && b1.pos.x >= paddlePlane.min.x && b1.pos.x <= paddlePlane.max.x && b1.pos.y >= paddlePlane.min.y && b1.pos.y <= paddlePlane.max.y){
b1.pathDirection = vectorAdd((2 * dot(flipVect(b1.pathDirection), paddlePlane.normals) , paddlePlane.normals) , b1.pathDirection);
}
}
void drawPlanes(){
glBegin(GL_QUADS);
//Floor
glColor3f(1,0,0);
glNormal3f( 0.0f , 1.0f, 0.0f);
glVertex3f( 050.0f , -050.0f , -100.0f);
glVertex3f(-050.0f , -050.0f , -100.0f);
glVertex3f(-050.0f , -050.0f , 000.0f);
glVertex3f( 050.0f , -050.0f , 000.0f);
//Ceiling
glColor3f(1,0,1);
glNormal3f(0.0f,-1.0f,0.0f);
glVertex3f( 050.0f, 050.0f, -100.0f);
glVertex3f(-050.0f, 050.0f, -100.0f);
glVertex3f(-050.0f, 050.0f, 000.0f);
glVertex3f( 050.0f, 050.0f, 000.0f);
//Right Wall
glColor3f(0,1,0);
glNormal3f( -1.0f , 0.0f, 0.0f);
glVertex3f(050.0f , 050.0f , 000.0f);
glVertex3f(050.0f , 050.0f , -100.0f);
glVertex3f(050.0f ,-050.0f , -100.0f);
glVertex3f(050.0f ,-050.0f, 000.0f);
//LeftWall
glColor3f(0,1,1);
glNormal3f( 1.0f , 0.0f, 0.0f);
glVertex3f(-050.0f , 050.0f , -100.0f);
glVertex3f(-050.0f , 050.0f , 000.0f);
glVertex3f(-050.0f , -050.0f , 000.0f);
glVertex3f(-050.0f , -050.0f , -100.0f);
//Back Wall
glColor3f(0,0,1);
glNormal3f( 0.0f , 0.0f, 1.0f);
glVertex3f( 050.0f , 050.0f , -100.0f);
glVertex3f(-050.0f , 050.0f , -100.0f);
glVertex3f(-050.0f , -050.0f , -100.0f);
glVertex3f( 050.0f , -050.0f , -100.0f);
glEnd();
}
void ballMove(){
glPushMatrix();
glColor3f(1,1,0);
b1.pos.x += (b1.pathDirection.x * speed); b1.pos.y += (b1.pathDirection.y * speed); b1.pos.z += (b1.pathDirection.z * speed);
glTranslatef(b1.pos.x,b1.pos.y,b1.pos.z);
glutSolidSphere(b1.radius,100,100);
printf("%.2f %.2f %.2f\n", b1.pos.x, b1.pos.y, b1.pos.z);
glPopMatrix();
planeCollision();
}
void drawPaddle(){
//printf("x %f y %f\n" , mX , mY);
glPushMatrix();
glPolygonMode( GL_FRONT_AND_BACK, GL_LINE);
glBegin(GL_QUADS);
glColor3f(1,1,1);
glVertex3f(mX + 25.0f , mY + 25.0f , 0.0f);
glVertex3f(mX + -25.0f , mY + 25.0f , 0.0f);
glVertex3f(mX + -25.0f , mY + -25.0f , 0.0f);
glVertex3f(mX + 25.0f , mY + -25.0f , 0.0f);
glEnd();
glPolygonMode( GL_FRONT_AND_BACK, GL_FILL);
glPopMatrix();
paddlePlane.max.x=mX + 0.25f; paddlePlane.max.y=mY + 0.25f; paddlePlane.max.z=1;
paddlePlane.min.x=mX + -0.25f; paddlePlane.min.y=mY + -0.25f; paddlePlane.min.z=1;
}
void display()
{
float red[] = {1,0,0,1};
float blue[] = {0,0,1,1};
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_NORMALIZE);
glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
glPushMatrix();
glRotated(g_y_angle, 0, 1, 0);
glRotated(g_x_angle,1,0,0);
glTranslated(0,0,-100);
drawPaddle();
ballMove();
drawPlanes();
glPopMatrix();
angle += 1;
glFlush();
glutSwapBuffers();
}
void reshape(int width, int height)
{
if (height==0)
{
height=1;
}
glViewport(0,0,width,height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.0f,50.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void idle()
{
glutSetWindow(g_mainWindow);
glutPostRedisplay();
}
void variableInits(){
//Floor Plane
pl1.pos.x = 0; pl1.pos.y = -50; pl1.pos.z = 0;
pl1.norm.x = 0; pl1.norm.y = 1; pl1.norm.z = 0;
//Ceiling Plane
pl2.pos.x = 0; pl2.pos.y = 50; pl2.pos.z = 0;
pl2.norm.x = 0; pl2.norm.y = -1; pl2.norm.z = 0;
//Right Wall Plane
pl3.pos.x = 50; pl3.pos.y = 0; pl3.pos.z = 0;
pl3.norm.x = -1; pl3.norm.y = 0; pl3.norm.z = 0;
//Left Wall Plane
pl4.pos.x = -50; pl4.pos.y = 0; pl4.pos.z = 0;
pl4.norm.x = 1; pl4.norm.y = 0; pl4.norm.z = 0;
//Back Wall Plane
pl5.pos.x = 0; pl5.pos.y = 0; pl5.pos.z = -100;
pl5.norm.x = 0; pl5.norm.y = 0; pl5.norm.z = 1;
//Paddle Plane
paddlePlane.max.x=.25; paddlePlane.max.y=.25; paddlePlane.max.z=1;
paddlePlane.min.x=-.25; paddlePlane.min.y=-.25; paddlePlane.min.z=1;
paddlePlane.normals.x=0; paddlePlane.normals.y=0;paddlePlane.normals.z=-0;
//Ball Init
b1.radius = 10;
b1.pathDirection.x = 0; b1.pathDirection.y = 0; b1.pathDirection.z = 0;
b1.pos.x = 0; b1.pos.y = 0, b1.pos.z = -25;
}
int main(int ac, char* av[])
{
glutInit(&ac, av);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
g_mainWindow = glutCreateWindow("Hello, glut");
variableInits();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutIdleFunc(idle);
glutMouseFunc(mouse);
glutMotionFunc(mouseDrag);
glutPassiveMotionFunc(paddle);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
glLightfv(GL_LIGHT0, GL_POSITION, g_lightPos);
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
glClearDepth(1.0f);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glutMainLoop(); //no return
}
Header
#pragma once
#ifndef pHeader_INCLUDED
#define pHeader_H_INCLUDED
typedef struct vector{
float x,y,z;
}vector;
typedef struct ball{
float radius;
vector pathDirection;
vector pos;
} ball;
typedef struct planeStruc{
vector pos;
vector norm;
} plane;
typedef struct paddlePlane{
vector min;
vector max;
vector normals;
} paddlePl;
#endif
gluPerspectivecannot have a value of 0.0 for the near plane, it either generates an error (I’m not sure) or causes some weird infinity math to happen that’s certainly not what you want.You should make the value of the near plane greater than zero, and ideally as large as possible without cutting off things that you want to see. If you make it too small you’ll lose a ton of z precision.
Try a value of 0.1 to start with.