Super Mario Bros

Gravity

Simple function that adds gravity to sprites not colliding with a platform (not on the ground). Function is calledd at each frame and adds a small amount in the Y direction (down).

void AddGravity(float deltaTime)
{
 float increment;
 increment = deltaTime * 25;
 mPosition.y += increment;
}

Platform logic

First the function calculates all the X and Y positions neccesary to know if the object is colliding with the floor / top of the brick. Then using some logic to set the variable to true if the bottom of the player is colliding with the top of the brick / floor and not exceeding the X coordinate bounds.

void CheckOnPlatform(SDL_Rect BrickRect)
{
 int CharLeft = GetCollisionBox().x;
 int BrickRight = BrickRect.x + BrickRect.w;
 int CharRight = GetCollisionBox().x + GetCollisionBox().w;
 int BrickLeft = BrickRect.x;
 int CharBottom = GetCollisionBox().y + GetCollisionBox().h;
 int BrickTop = BrickRect.y;
 int CharTop = GetCollisionBox().y;
 int BrickBottom = BrickRect.y + BrickRect.h;
 if (CharBottom >= BrickTop && CharBottom < BrickBottom && mCollidingY && CharRight >= BrickLeft && CharLeft <= BrickRight)
 {
  mOnPlatform = true;
 }
}