マウスとキーボードの入力を利用して、OpenGL (フレームワークとして SDL を使用) で FPS スタイルのゲームを作成しています。何らかの理由で、キーボードで「カメラ位置」を同時に移動しながらマウスを使用して方向を変える（回転する）と、（マウスが使用されていないときにキーボードで移動するのとは対照的に）移動が大幅に高速化されます。
コードの何が問題になっていますか?
main.cpp
#define PI 3.14159265
#include <sdl.h>
#include <string>
#include "SDL_opengl.h"
#include <gl\gl.h>
#include <gl\glu.h>
#include <stdio.h>
#include <math.h>
#include <time.h>
#include <stdlib.h>
using namespace std;
float urad(0), drad(0), slrad(0), srrad(0);
int mousex(0), mousey(0);
float transx(0), transy(-.3), transz(0), yrot(0), luad(0);
float rotx(0), roty(0);
bool up,down,right,left,tr,tl, sl,sr,lu,ld;
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
const int SCREEN_BPP = 32;
SDL_Event event;
GLfloat zpos(0);
GLfloat rot(0);
bool exited(false);
void drawstuff(); //Function Prototype
void startGL()
{
SDL_Init(SDL_INIT_EVERYTHING);
SDL_SetVideoMode(800, 500, 32, SDL_OPENGL | SDL_HWPALETTE);
glViewport(0,0,800,500);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0f,(GLfloat)800/(GLfloat)500,0.1f,100.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glEnable(GL_POLYGON_SMOOTH);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
}
void drawstuff()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glRotatef(roty, 0, 1, 0);
glRotatef(luad, 1, 0, 0);
glTranslatef(transx, transy, transz);
glBegin(GL_QUADS); // Draw A Quad
glColor3f(0.0f,1.0f,0.0f); // Set The Color To Green
glVertex3f( 1.0f, 1.0f,-1.0f); // Top Right Of The Quad (Top)
glVertex3f(-1.0f, 1.0f,-1.0f); // Top Left Of The Quad (Top)
glVertex3f(-1.0f, 1.0f, 1.0f); // Bottom Left Of The Quad (Top)
glVertex3f( 1.0f, 1.0f, 1.0f); // Bottom Right Of The Quad (Top)
glColor3f(1.0f,0.5f,0.0f); // Set The Color To Orange
glVertex3f( 1.0f,-1.0f, 1.0f); // Top Right Of The Quad (Bottom)
glVertex3f(-1.0f,-1.0f, 1.0f); // Top Left Of The Quad (Bottom)
glVertex3f(-1.0f,-1.0f,-1.0f); // Bottom Left Of The Quad (Bottom)
glVertex3f( 1.0f,-1.0f,-1.0f); // Bottom Right Of The Quad (Bottom)
glColor3f(1.0f,0.0f,0.0f); // Set The Color To Red
glVertex3f( 1.0f, 1.0f, 1.0f); // Top Right Of The Quad (Front)
glVertex3f(-1.0f, 1.0f, 1.0f); // Top Left Of The Quad (Front)
glVertex3f(-1.0f,-1.0f, 1.0f); // Bottom Left Of The Quad (Front)
glVertex3f( 1.0f,-1.0f, 1.0f); // Bottom Right Of The Quad (Front)
glColor3f(1.0f,1.0f,0.0f); // Set The Color To Yellow
glVertex3f( 1.0f,-1.0f,-1.0f); // Top Right Of The Quad (Back)
glVertex3f(-1.0f,-1.0f,-1.0f); // Top Left Of The Quad (Back)
glVertex3f(-1.0f, 1.0f,-1.0f); // Bottom Left Of The Quad (Back)
glVertex3f( 1.0f, 1.0f,-1.0f); // Bottom Right Of The Quad (Back)
glColor3f(0.0f,0.0f,1.0f); // Set The Color To Blue
glVertex3f(-1.0f, 1.0f, 1.0f); // Top Right Of The Quad (Left)
glVertex3f(-1.0f, 1.0f,-1.0f); // Top Left Of The Quad (Left)
glVertex3f(-1.0f,-1.0f,-1.0f); // Bottom Left Of The Quad (Left)
glVertex3f(-1.0f,-1.0f, 1.0f); // Bottom Right Of The Quad (Left)
glColor3f(1.0f,0.0f,1.0f); // Set The Color To Violet
glVertex3f( 1.0f, 1.0f,-1.0f); // Top Right Of The Quad (Right)
glVertex3f( 1.0f, 1.0f, 1.0f); // Top Left Of The Quad (Right)
glVertex3f( 1.0f,-1.0f, 1.0f); // Bottom Left Of The Quad (Right)
glVertex3f( 1.0f,-1.0f,-1.0f); // Bottom Right Of The Quad (Right)
glEnd(); // Done Drawing The Quad
}
void EventListener()
{
Uint8 *keystate = SDL_GetKeyState(NULL);
SDL_PumpEvents();
if (keystate[SDLK_LEFT]) tl=true;
else tl=false;
if (keystate[SDLK_RIGHT]) tr=true;
else tr=false;
if (keystate['w'] ) up=true;
else up=false;
if (keystate['s'] ) down=true;
else down=false;
if (keystate['a'] ) sl=true;
else sl=false;
if (keystate['d'] ) sr=true;
else sr=false;
}
void EventHandler()
{
if (tl)
{
roty-=2;
if (roty >360)
{
roty -= 360;
}
}
if (tr)
{
roty+=2;
if (roty <-360)
{
roty += 360;
}
}
if (up)
{
urad = roty*PI/180;
transx+=sin(-urad) * .06;
transz+=cos(-urad) * .06;
}
if (down)
{
drad = roty*PI/180;
transx-=sin(-drad) * .06;
transz-=cos(-drad) * .06;
}
if (sl)
{
slrad = roty*PI/180;
transx += cos(slrad) * .04;
transz += sin(slrad) * .04;
}
if (sr)
{
srrad = roty*PI/180;
transx -= cos(srrad) * .04;
transz -= sin(srrad) * .04;
}
SDL_PumpEvents();
SDL_GetMouseState(&mousex, &mousey);
roty=mousex*.5;
}
int main (int argc, char* args[])
{
SDL_Surface* screen = NULL;
SDL_Init( SDL_INIT_EVERYTHING );
screen = SDL_SetVideoMode( 800, 500, 32, SDL_SWSURFACE);
SDL_Flip( screen );
SDL_WM_SetCaption("OpenGL", NULL);
startGL();
SDL_EnableKeyRepeat(1, 10);
while(exited == false)
{
while( SDL_PollEvent( &event ) )
{
if( event.type == SDL_QUIT )
{
exited = true;
}
EventListener();
EventHandler();
}
glClear(GL_COLOR_BUFFER_BIT);
drawstuff();
SDL_GL_SwapBuffers();
SDL_Delay(16);
}
SDL_Quit();
return 1;
}