Hi everyone I´m wondering why this error appears, I checked the code twice. still can’t realize where this error comes from and why I hope yo can help me. everything (libs and header files) has been linked properly but the program stops and throws the following error:
Exception thrown: read access violation.
keys was 0x7FFBEFDCFE2A
here´s the whole code:
#include <SDL.h>
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#define GLUT_DISABLE_ATEXIT_HACK
#include <GL/GL.h>
#include <GL/glu.h>
const GLsizei windowWidth = 500;
const GLsizei windowHeight = 500;
GLfloat cubeRotateX = 45.0f;
GLfloat cubeRotateY = 45.0f;
const Uint8 *keys = NULL;
GLvoid establishProjectionMatrix(GLsizei width, GLsizei height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(50.0f, (GLfloat)width / (GLfloat)height, 0.1f, 200.0f);
}
GLvoid initGL(GLsizei width, GLsizei height)
{
establishProjectionMatrix(width, height);
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glEnable(GL_PERSPECTIVE_CORRECTION_HINT);
}
GLvoid displayFPS(GLvoid)
{
static long lastTime = SDL_GetTicks();
static long loops = 0;
static GLfloat fps = 0.0f;
int newTime = SDL_GetTicks();
if (newTime - lastTime > 100)
{
float newFPS = (float)loops / float(newTime - lastTime) * 1000.0f;
fps = (fps + newFPS) / 2.0f;
char title[80];
printf(title, "OpenGL Demo - %2f", fps);
lastTime = newTime;
loops = 0;
}
loops++;
}
GLvoid drawScene(GLvoid)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0, 0, -5.0f);
glRotatef(cubeRotateX, 1, 0, 0);
glRotatef(cubeRotateY, 0, 1, 0);
//draw cube
glBegin(GL_QUADS);
//top face
glColor3f(1.0f, 0.5f, 0.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
//bottom face
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
//front face
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
//back face
glColor3f(1.0f, 1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
//left face
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
//right face
glColor3f(1.0f, 0.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glEnd();
glFlush();
displayFPS();
}
GLboolean checkKeys(GLvoid)
{
static long lastTime = SDL_GetTicks();
const GLfloat speed = 1.0f;
const long updateTime = 10;
if (keys[SDLK_ESCAPE])
return true;
long newTime = SDL_GetTicks();
if (newTime - lastTime > updateTime)
{
if (keys[SDLK_LEFT])
cubeRotateY -= speed;
if (keys[SDLK_RIGHT])
cubeRotateY += speed;
if (keys[SDLK_UP])
cubeRotateX -= speed;
if (keys[SDLK_DOWN])
cubeRotateX += speed;
}
return false;
}
int main(int argc, char** argv) {
SDL_Window* screen = SDL_CreateWindow("Cube",
10,
10,
windowWidth, windowHeight,
SDL_WINDOW_OPENGL);
if (SDL_Init(SDL_INIT_VIDEO) < 0)
{
//printf(stderr, "Unable to initialize SDL: %s\n", SDL_GetError());
//exit(1);
}
if (screen == NULL)
{
//printf(stderr, "Unable to create OpenGL scene: %s\n", SDL_GetError());
//exit(2);
}
initGL(windowWidth, windowHeight);
//SDL_GL_SwapWindow(screen);
int done = 0;
while (!done)
{
drawScene();
SDL_Event event;
while (SDL_PollEvent(&event))
{
if (event.type == SDL_QUIT)
done = 1;
keys = SDL_GetKeyboardState(NULL);
}
if (checkKeys())
done = 1;
}
SDL_Quit();
return 0;
}