Wierd C++ Problems, OpenGL game - c++

Question

Aight so, I'm in the process of making a simple terrain program, not exactly a game, but hey maybe someday. I'll start with describing the basics of how my program works. I'm using an two-dimension array to store the coordinates of the vertexes which make up a grid of triangles. The x and z values are assigned in the follow code:
//Sets up the array for the vertexes
int e = 0;
int p = 0;
for (int r = 0; r < 10; r++) {
for (int x = 0; x < 5; x++) {
grid[p][0] = x * 2;
grid[p][2] = e;
p++;
}
e += 2;
}
Okay, so the grid array is the one I use for storing the values of all the vertexes in the program, the first argument (the value in the first set of []) is used to choose a point, the second set of [] is the x, y, and z values, the code snippet above only sets values for the x and z coordinates.
The y value, height, is randomised at the start of the program using the following code:
//Random heights for the terrain
if (fir == true) {
for (int h = 0; h < 64; h++) {
grid[h][1] = rand() % 3;
}
fir = false;
}
And the code for drawing the triangles:
for (int q = 0; q < 11; q++) {
a = q * 5;
b = a + 1;
c = a + 5;
glBegin(GL_TRIANGLE_STRIP);
for (int dw = 0; dw < 8; dw++) {
//a
glColor3f(grid[a][1], grid[a][1], grid[a][1]);
glVertex3f(grid[a][0], grid[a][1], grid[a][2]);
//b
glColor3f(grid[b][1], grid[b][1], grid[b][1]);
glVertex3f(grid[b][0], grid[b][1], grid[b][2]);
//c
glColor3f(1, 0, 0);
glVertex3f(grid[c][0], grid[c][1], grid[c][2]);
a = c;
t = b;
b = a + 1;
c = t;
}
glEnd();
}
glutSwapBuffers();
}
The problem I'm having is that I can't make the size of the grid bigger without the program breaking, I would like to be able to change the size of the grid of triangles to whatever I like. when I try to change the for loop which goes through the x values (first code snippet) the program breaks, my movement speed drastically increases, moving the mouse has no effect on the camera rotation. When I do manage to find a set of values to work the grid of triangles is messed up, any points after the 5th row are all set to 0, I'll post the whole program, I don't know if it will run for everyone, but I think the problem is something that requires the whole program to be looked at in order to solve.
I think the problem may be due to variables being shared by different parts of the program, I have looked and looked but can't seem to find any cause. This is my last resort to solving this nightmare of a problem...
main.cpp
/*
*/
#include <iostream>
#include <glut.h>
#include <gl\GL.h>
#define _USE_MATH_DEFINES
#include <math.h>
#include <cstdlib>
#include "vector3f.h"
using namespace std;
//Variables
const int WINDOW_WIDTH = 1280;
const int WINDOW_HEIGHT = 720;
const char* WINDOW_TITLE = "Terrain";
const float WALKING_SPEED = 5.0;
const float MOUSE_SENSITIVITY = 0.3;
const float MAX_TILT = 90.0;
float grid[200][3];
float LAST_TIME;
float CURRENT_TIME;
float DELTA_TIME;
bool KEY[256];
int a;
int b;
int c;
int t;
int MOUSE_LAST_X;
int MOUSE_LAST_Y;
int MOUSE_CURRENT_X;
int MOUSE_CURRENT_Y;
int MOUSE_DELTA_X;
int MOUSE_DELTA_Y;
float red;
float green;
float blue;
bool fir = true;
//Object
vector3f CAMERA_POSITION;
vector3f CAMERA_ROTATION;
//Functions
void initialize();
void display();
void reshape(int w, int h);
void keyboardDown(unsigned char key, int x, int y);
void keyboardUp(unsigned char key, int x, int y);
void mouseMove(int x, int y);
void movement();
double degreesToRadians(double degrees);
double dsin(double theta);
double dcos(double theta);
double dtan(double theta);
void display() {
//cout << KEY[' '] << endl;
movement();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
//Camera transformations
glRotatef(CAMERA_ROTATION.x, 1, 0, 0);
glRotatef(CAMERA_ROTATION.y, 0, 1, 0);
glRotatef(CAMERA_ROTATION.z, 0, 0, 1);
glTranslatef(-CAMERA_POSITION.x, -CAMERA_POSITION.y, CAMERA_POSITION.z);
//Draw the basic triangle
glBegin(GL_TRIANGLES);
glColor3f(0.0, 0.0, 1.0);
glVertex3f(-1.0, -1.0, -3.0);
glColor3f(0.0, 1.0, 0.0);
glVertex3f(0.0, 1.0, -3.0);
glColor3f(1.0, 0.0, 0.0);
glVertex3f(10.0, -1.0, -3.0);
glEnd();
/*
1 0,0,0
2 2,0,0
3 4,0,0
4 6,0,0
5 0,0,2
6 2,0,2
7 4,0,2
8 6,0,2
9 0,0,4
10 2,0,4
11 4,0,4
12 6,0,4
13 0,0,6
14 2,0,6
15 4,0,6
16 6,0,6
*/
/*//Option 1 (2 for loops, four if statements)
for (int p = 0; p < 16; p++) {
for (int x = 0; x < 7; x += 2) {
grid[p][0] = x;
}
grid[p][1] = 0;
if (p < 4) {
grid[p][2] = 0;
}
if (p < 8 && p >= 4) {
grid[p][2] = 2;
}
if (p < 12 && p >= 8) {
grid[p][2] = 4;
}
if (p < 16 && p >= 12) {
grid[p][2] = 6;
}
}
*/
//Option 2 (three for loops)
//Sets up the array for the vertexes
int e = 0;
int p = 0;
for (int r = 0; r < 10; r++) {
for (int x = 0; x < 5; x++) {
grid[p][0] = x * 2;
grid[p][2] = e;
p++;
}
e += 2;
}
//Random heights for the terrain
if (fir == true) {
for (int h = 0; h < 64; h++) {
grid[h][1] = rand() % 3;
}
fir = false;
}
//cout << "point 0: " << grid[0][0] << ", " << grid[0][1] << ", " << grid[0][2] << endl;
//cout << "point 1: " << grid[1][0] << ", " << grid[1][1] << ", " << grid[1][2] << endl;
//cout << "point 2: " << grid[2][0] << ", " << grid[2][1] << ", " << grid[2][2] << endl;
//cout << "point 3: " << grid[3][0] << ", " << grid[3][1] << ", " << grid[3][2] << endl;
//cout << "point 4: " << grid[4][0] << ", " << grid[4][1] << ", " << grid[4][2] << endl;
//cout << "point 5: " << grid[5][0] << ", " << grid[5][1] << ", " << grid[5][2] << endl;
//cout << "point 6: " << grid[6][0] << ", " << grid[6][1] << ", " << grid[6][2] << endl;
//cout << "point 7: " << grid[7][0] << ", " << grid[7][1] << ", " << grid[7][2] << endl;
//cout << "point 8: " << grid[8][0] << ", " << grid[8][1] << ", " << grid[8][2] << endl;
//cout << "point 9: " << grid[9][0] << ", " << grid[9][1] << ", " << grid[9][2] << endl;
//cout << "point 10: " << grid[10][0] << ", " << grid[10][1] << ", " << grid[10][2] << endl;
//cout << "point 11: " << grid[11][0] << ", " << grid[11][1] << ", " << grid[11][2] << endl;
//cout << "point 12: " << grid[12][0] << ", " << grid[12][1] << ", " << grid[12][2] << endl;
//cout << "point 13: " << grid[13][0] << ", " << grid[13][1] << ", " << grid[13][2] << endl;
//cout << "point 14: " << grid[14][0] << ", " << grid[14][1] << ", " << grid[14][2] << endl;
//cout << "point 15: " << grid[15][0] << ", " << grid[15][1] << ", " << grid[15][2] << endl;
for (int q = 0; q < 11; q++) {
a = q * 5;
b = a + 1;
c = a + 5;
glBegin(GL_TRIANGLE_STRIP);
for (int dw = 0; dw < 8; dw++) {
//a
glColor3f(grid[a][1], grid[a][1], grid[a][1]);
glVertex3f(grid[a][0], grid[a][1], grid[a][2]);
//b
glColor3f(grid[b][1], grid[b][1], grid[b][1]);
glVertex3f(grid[b][0], grid[b][1], grid[b][2]);
//c
glColor3f(1, 0, 0);
glVertex3f(grid[c][0], grid[c][1], grid[c][2]);
a = c;
t = b;
b = a + 1;
c = t;
}
glEnd();
}
glutSwapBuffers();
}
void keyboardDown(unsigned char key, int x, int y) {
KEY[key] = true;
}
void keyboardUp(unsigned char key, int x, int y) {
KEY[key] = false;
}
void movement() {
CURRENT_TIME = ((float)glutGet(GLUT_ELAPSED_TIME) / 1000);
DELTA_TIME = CURRENT_TIME - LAST_TIME;
LAST_TIME = CURRENT_TIME;
MOUSE_DELTA_X = MOUSE_CURRENT_X - MOUSE_LAST_X;
MOUSE_DELTA_Y = MOUSE_CURRENT_Y - MOUSE_LAST_Y;
MOUSE_LAST_X = MOUSE_CURRENT_X;
MOUSE_LAST_Y = MOUSE_CURRENT_Y;
CAMERA_ROTATION.y += (float)MOUSE_DELTA_X * MOUSE_SENSITIVITY;
CAMERA_ROTATION.x += (float)MOUSE_DELTA_Y * MOUSE_SENSITIVITY;
if (CAMERA_ROTATION.x > MAX_TILT) {
CAMERA_ROTATION.x = MAX_TILT;
}
if (CAMERA_ROTATION.x < -MAX_TILT) {
CAMERA_ROTATION.x = -MAX_TILT;
}
if (KEY['w'] == true) {
CAMERA_POSITION.x += (WALKING_SPEED * DELTA_TIME) * dsin(CAMERA_ROTATION.y);
CAMERA_POSITION.z += (WALKING_SPEED * DELTA_TIME) * dcos(CAMERA_ROTATION.y);
CAMERA_POSITION.y += (WALKING_SPEED * DELTA_TIME) * dsin(CAMERA_ROTATION.x + 180);
}
if (KEY['s'] == true) {
CAMERA_POSITION.x += (WALKING_SPEED * DELTA_TIME) * dsin(CAMERA_ROTATION.y + 180);
CAMERA_POSITION.z += (WALKING_SPEED * DELTA_TIME) * dcos(CAMERA_ROTATION.y + 180);
CAMERA_POSITION.y += (WALKING_SPEED * DELTA_TIME) * dsin(CAMERA_ROTATION.x);
}
if (KEY['a'] == true) {
CAMERA_POSITION.x += (WALKING_SPEED * DELTA_TIME) * dsin(CAMERA_ROTATION.y + 270);
CAMERA_POSITION.z += (WALKING_SPEED * DELTA_TIME) * dcos(CAMERA_ROTATION.y + 270);
}
if (KEY['d'] == true) {
CAMERA_POSITION.x += (WALKING_SPEED * DELTA_TIME) * dsin(CAMERA_ROTATION.y + 90);
CAMERA_POSITION.z += (WALKING_SPEED * DELTA_TIME) * dcos(CAMERA_ROTATION.y + 90);
}
if (KEY[' '] == true) {
CAMERA_POSITION.y += (WALKING_SPEED * DELTA_TIME);
}
if (KEY['e'] == true) {
exit(1);
}
}
void mouseMove(int x, int y) {
MOUSE_CURRENT_X = x;
MOUSE_CURRENT_Y = y;
}
double degreesToRadians(double degrees){
return degrees * M_PI / 180;
}
double dsin(double theta) {
return sin(degreesToRadians(theta));
}
double dcos(double theta) {
return cos(degreesToRadians(theta));
}
double dtan(double theta) {
return tan(degreesToRadians(theta));
}
void reshape(int w, int h) {
//Stops the ratio from dividing by 0
if (h == 0) {
h = 1;
}
float fRatio = (float)w / h;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0, 0, w, h);
gluPerspective(60, fRatio, 0.1, 1000);
glMatrixMode(GL_MODELVIEW);
}
void initialize() {
glClearColor(0.0, 0.0, 102.0 / 255.0, 0.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);
}
int main(int iArgc, char** cArgv) {
//Initialise OpenGL and GLUT
glutInit(&iArgc, cArgv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
//Setup window
glutInitWindowPosition(0, 0);
glutInitWindowSize(WINDOW_WIDTH, WINDOW_HEIGHT);
glutCreateWindow(WINDOW_TITLE);
//Setup GLUT callback functions
initialize();
glutReshapeFunc(reshape);
glutDisplayFunc(display);
glutIdleFunc(display);
glutKeyboardFunc(keyboardDown);
glutKeyboardUpFunc(keyboardUp);
glutMotionFunc(mouseMove);
glutPassiveMotionFunc(mouseMove);
glEnable(GL_DEPTH_TEST);
//Enter main loop
glutMainLoop();
return 0;
}

Answer 1

Some quick remarks:
your loops access different number of points!
1st loop (r, x) initialize 50 points
2nd loop (h) initialize 64 points
3rd loop (q, dw) access 59 points
glColor3f values should be between 0 and 1 but, using your grid y values, you get 0, 1 or 2
beware of the gimbal lock problem when trying to rotate your view!