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nano511

SDL Surface not appearing

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I just made this new class for my "monster". But the monster is not appearing.

Here is the relevant code

Monster.cpp
[code]
Monster::Monster( Environment* GameEnvironment )
{
graphics = GameEnvironment->graphics;
monsterRight[0] = graphics->LoadImage( "Monster_Right_0.bmp" );
monsterRight[1] = graphics->LoadImage( "Monster_Right_1.bmp" );
monsterRight[2] = graphics->LoadImage( "Monster_Right_2.bmp" );
monsterRight[3] = graphics->LoadImage( "Monster_Right_3.bmp" );
monsterLeft[0] = graphics->LoadImage( "Monster_Left_0.bmp" );
monsterLeft[1] = graphics->LoadImage( "Monster_Left_1.bmp" );
monsterLeft[2] = graphics->LoadImage( "Monster_Left_2.bmp" );
monsterLeft[3] = graphics->LoadImage( "Monster_Left_3.bmp" );

direction = LEFT;
frame = 0;
int xPos = 490;
int health = 100;
}
[/code]
[code]
void Monster::Move( int playerX )
{
if( playerX < xPos )
{
direction = LEFT;
frame++;
xVel -= 3;
}
else if( playerX > xPos )
{
direction = RIGHT;
frame++;
xVel += 3;
}
}
[/code]
[code]
void Game::HandleEvents()
{
...

player->HandleEvents();
monster->Move( player->xPos );
}
[/code]
[code]
void Game::Logic()
{
...

monster->xPos += monster->xVel;

...
}
[/code]
[code]
void Game::Render()
{
...

if( monster->frame >= 4 )
monster->frame = 0;

...

// Draw the monster
if( monster->direction == RIGHT )
graphics->ApplySurface( monster->xPos, 311, monster->monsterRight[ monster->frame ], graphics->screen );
else if( monster->direction == LEFT )
graphics->ApplySurface( monster->xPos, 311, monster->monsterLeft[ monster->frame ], graphics->screen );


graphics->UpdateScreen();
}
[/code]

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In the constructor you have[code]int xPos = 490;
int health = 100;
[/code]These are local variables and they are not used anywhere. I think what you meant to do was to set Monster::xPos and Monster::health. I guess this could be what caused the problem because if xPos get a very large value the monster will not be within the screen.

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You also increment (or decrement) the velocity every frame - unless the monster position is exactly equal the player. Instead, you should use either an acceleration value (which should probably be limited to some reasonable maximum) or instead simply set the velocity, instead of incrementing it.

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[quote name='Wooh' timestamp='1312466354' post='4844485']
In the constructor you have[code]int xPos = 490;
int health = 100;
[/code]These are local variables and they are not used anywhere. I think what you meant to do was to set Monster::xPos and Monster::health. I guess this could be what caused the problem because if xPos get a very large value the monster will not be within the screen.
[/quote]

What do you mean they're local. Those are member variables. Health isnt used anywhere yet, but monster->xPos [i]is[/i] used in the code. The number is so large because i want him to start off the screen, then walk over to the player.

And thank you to the guy who said about setting the velocity instead of incrementing it.


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