Ok, I've been going through SDL tutorials at www.lazyfoo.net and have run onto an issue with getting keyboard input to move a dot around on the screen.
So here is the set up. I have an object class which is basically just some object you see on the screen that can move around. In my case it is a dot. It has x and y coords and velocity. It also have a handleInput and move method. Now for some reason when I call the dot's handleInput method is doesn't seem to register that a keydown event has happened when I push keys down.
The only difference I really see from my code to the tutorials code is that I have a header file containing my globals for SDL one of which is the SDL_Event. These are all declared static to prevent multiply defined symbols. I'm not sure if the fact that it is static is causing any issue or not. So anyway, here is some code...
Object.cpp
#include "Object.h"
#include "SDL_Globals.h"
const int DOT_WIDTH = 20;
const int DOT_HEIGHT = 20;
Object::Object() {
x = 0;
y = 0;
xVel = 0;
yVel = 0;
}
Object::~Object() {}
void Object::handleInput() {
if(event.type == SDL_KEYDOWN) {
switch(event.key.keysym.sym) {
case SDLK_UP : yVel -= DOT_HEIGHT / 2; break;
case SDLK_DOWN : yVel += DOT_HEIGHT / 2; break;
case SDLK_LEFT : xVel -= DOT_WIDTH / 2; break;
case SDLK_RIGHT : xVel += DOT_WIDTH / 2; break;
}
}
else if(event.type == SDL_KEYUP) {
switch(event.key.keysym.sym) {
case SDLK_UP : yVel += DOT_HEIGHT / 2; break;
case SDLK_DOWN : yVel -= DOT_HEIGHT / 2; break;
case SDLK_LEFT : xVel += DOT_WIDTH / 2; break;
case SDLK_RIGHT : xVel -= DOT_WIDTH / 2; break;
}
}
}
void Object::move() {
x += xVel;
y += yVel;
}
int Object::getX() {return x;}
int Object::getY() {return y;}
int Object::getXVel() {return xVel;}
int Object::getYVel() {return yVel;}
SDL_Globals.h
#ifndef SDL_GLOBALS_H
#define SDL_GLOBALS_H
#include "SDL/SDL.h"
#include "SDL/SDL_ttf.h"
static SDL_Event event;
static SDL_Color textColor = {0, 0, 0};
static TTF_Font* font = NULL;
#endif
Chunk of my game loop
while(quit == false) {
fps.start();
while(SDL_PollEvent(&event)) {
dot.handleInput();
if(event.type == SDL_QUIT) quit = true;
else if(event.type == SDL_KEYDOWN) {
if(event.key.keysym.sym == SDLK_c) {
fpsCap = !fpsCap;
if(fpsCap) capToggle = TTF_RenderText_Solid(font, "Framerate cap: on", textColor);
else capToggle = TTF_RenderText_Solid(font, "Framerate cap: off", textColor);
}
}
}
// Update x and y coordinates for our dot object
dot.move();
Any ideas about whats happening? The environment I'm using is VS 2008. Thanks!
