help rotating turret using mouse
Author
Im trying to get my turret to roate as according to where the mouse is.In other words i want my turrer to face my mouse pointer, where ever it is on the screen, whilst still in the same poistion.
and i also have a problem getting my bulle to fire at the mouse pointer
void init()
{
allegro_init();
install_timer();
install_mouse();
install_keyboard();
set_color_depth(32);
set_gfx_mode(GFX_AUTODETECT,ResX,ResY,0,0);
screen_buffer=create_bitmap(ResX,ResY);
select_mouse_cursor(MOUSE_CURSOR_ALLEGRO);
}
void spawn_bullet(double x,double y)
{
for(int i=0;i<Max_objs;i++)
if(obj.status == 0)
{
obj.status = 1;
obj.AItype=2;
obj.size = 8;
obj.angle=10;
obj.ptrSprite=3;
obj.positionX = x+16;
obj.positionY= y+16;
//obj.desX;
//obj.desY;
i=Max_objs;
}
}
void spawn_turret()
{
for(int i=0;i<Max_objs;i++)
if(obj.status == 0)
{
obj.status=1;
obj.AItype=3;
obj.ptrSprite=4;
obj.size = 64;
obj.angle=0;
obj.positionX=50;
obj.positionY=59;
obj.sides=2;// 1=foe; 2=friend
i=Max_objs;
}
}
void AICalcXY(int i)
{
double dx,dy;
dx=sin(obj.angle);
dy=cos(obj.angle);
dx*=obj.speed;
dy*=obj.speed;
obj.positionX+=dx;
obj.positionY+=dy;
}
void AICalcAngle(int i)
{
double dx=obj.desX-obj.positionX;//+obj.size/2 -obj.positionX;
double dy=obj.desY-obj.positionY;
if(dx==0)dx=1;
if(dy==0)dy=1;
double newAngle=atan2(dy,dx);
newAngle=(newAngle/M_PI)*180;
while(newAngle<0)
{
newAngle+=360;
}
obj.angle=newAngle;
}
void AIbullet(int i)
{
AICalcAngle(i);
AICalcXY(i);
}
void AIturret(int i)
{
AICalcAngle(i);
}
void ai()
{
for(int i=0;i<Max_objs;i++)
{
if(obj.AItype==1)
//AIexplosion(i);
if(obj.AItype==3)
AIturret(i);
if(obj.AItype==4)
AIbullet(i);
}
}
void drawsprite(int arrPos)
{
double topLeftX=obj[arrPos].positionX;
double topLeftY=obj[arrPos].positionY;
double BtmRX=topLeftX+obj[arrPos].size;
double BtmRY=topLeftY+obj[arrPos].size;
int sX,sY;//source X
int cX,cY;
if(topLeftX<0)
{
sX=-topLeftX;
topLeftX=0;
}
else
{
sX=0;
}
if(topLeftY<0)
{
sY=-topLeftY;
topLeftY=0;
}
else
{
sY=0;
}
if(BtmRX>ResX)
{
BtmRX=ResX;
}
if(BtmRY>ResY)
{
BtmRY=ResY;
}
cX=BtmRX-topLeftX;
cY=BtmRY-topLeftY;
int pX = (int)(obj[arrPos].angle/10)*obj[arrPos].size;
if(cX>0 && cY>0)
{
for(int y=0;y<cY;++y)
for(int x=0;x<cX;++x)
{
int col=getpixel(sprite[obj[arrPos].ptrSprite],x+sX+pX,y+sY);
putpixel(screen_buffer,topLeftX+x,topLeftY+y,col);
}
}
}
void rotate()
{
BITMAP* temp1, *temp2;
temp1=load_bitmap("shooter.bmp",NULL);
sprite[4]=create_bitmap(64*36,64);
temp2=load_bitmap("bullet.bmp",NULL);
sprite[3]=create_bitmap(8*36,8);
for (int rotNr=0; rotNr<36;rotNr++)
{
rotate_sprite(sprite[3],temp2,rotNr*8,0,itofix(7.1*rotNr));
rotate_sprite(sprite[4],temp1,rotNr*64,0,itofix(7.1*rotNr));
}
}
void window()
{
for(int i=0;i<Max_objs;i++)
drawsprite(i);
}
void mouse()
{
if (mouse_b & 1)
{
for(int i=0;i<Max_objs;i++)
{
if(obj.sides==2)
spawn_bullet(obj.positionX,obj.positionY);
i=Max_objs;
}
for(int x=0;x<Max_objs;x++)
{
if(obj[x].AItype==2)
obj[x].desX=mouse_x;
obj[x].desY=mouse_y;
x=Max_objs;
}
}
}
void passive_to_active()
{
show_mouse(screen_buffer);
blit(screen_buffer,screen,0,0,0,0,ResX,ResY);
clear_to_color(screen_buffer,makecol(0,0,0));
show_mouse(NULL);
}
void fse()
{
ai();
mouse();
window();
passive_to_active();
}
int main()
{
init();
rotate();
spawn_turret();
while(!key[KEY_ESC])
{
fse();
}
}
END_OF_MAIN()
Put your code into [source] tags so that it's rather easier to read (source colouring, the formatting's kept and only so much on screen at one time).
Here's some C++-style pseudocode for you, though:
MousePosition = GetMousePosition(); // Get screen-space co-ords of mouse
ScreenToWorldCoordinates(MousePosition); // Convert to world space
int xToMouse = MousePosition.x - TurretPosition.x;
int yToMouse = MousePosition.y - TurretPosition.y;
// Normalize direction
int length = sqrt((x * x) + (y * y));
xToMouse /= length;
yToMouse /= length;
FireDirection(xToMouse, yToMouse);
EDIT: Or if you want an angle (in radians): FireDirection(atan2(yToMouse, xToMouse));.
EDIT2: Fixed odd expression (*= 1 / length rather than simply /= length). Don't know quite what I was thinking.
[Edited by - TheUnbeliever on April 23, 2007 11:23:13 AM]
Here's some C++-style pseudocode for you, though:
MousePosition = GetMousePosition(); // Get screen-space co-ords of mouse
ScreenToWorldCoordinates(MousePosition); // Convert to world space
int xToMouse = MousePosition.x - TurretPosition.x;
int yToMouse = MousePosition.y - TurretPosition.y;
// Normalize direction
int length = sqrt((x * x) + (y * y));
xToMouse /= length;
yToMouse /= length;
FireDirection(xToMouse, yToMouse);
EDIT: Or if you want an angle (in radians): FireDirection(atan2(yToMouse, xToMouse));.
EDIT2: Fixed odd expression (*= 1 / length rather than simply /= length). Don't know quite what I was thinking.
[Edited by - TheUnbeliever on April 23, 2007 11:23:13 AM]
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