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Hi i am trying to make a jump and run game in Visual C++ using SDL

I have been following a tutorial(http://jnrdev.72dpiarmy.com/) which was very good but finished before everything was covered.
In a game lik mario, the players will navigate over jumps and onto ledges ect. I am using tilebased collsion and was hoping someone would be able to help me figure out how to create the map inwhich the players navigate. does anyone know how this works?

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  • Latest Post Latest Post by Hidden_mistakes

Dani AI

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— the tutorial stops where the tricky bits begin. ’s one-word reply didn’t help, and was right to ask for details. Below is a compact, practical approach you can apply in SDL/C++ to build maps and handle tile-based collisions for a platformer.

Keep the map simple: store a 2D array (or a 1D array with width*height) of tile IDs. Give each tile type a small property bitfield (SOLID, ONE_WAY, SLOPE, etc.). Pick a sensible tileSize (16 or 32 px). At runtime convert world coords to tile indices with tileX = floor(x / tileSize). Only test tiles overlapping the player’s axis-aligned bounding box (AABB) — that keeps checks cheap.

Use separate-axis movement + resolution: move X, fix horizontal collisions, then move Y, fix vertical collisions. That order makes “grounded” detection simple. Example pseudocode (trimmed to the essentials):

// TS = tileSize, isSolid(tx,ty) checks map
void movePlayer(Player &p, float dx, float dy) {
    // horizontal
    p.rect.x += dx;
    for (int ty = floor(p.rect.y/TS); ty <= floor((p.rect.y+p.rect.h-1)/TS); ++ty)
      for (int tx = floor(p.rect.x/TS); tx <= floor((p.rect.x+p.rect.w-1)/TS); ++tx)
        if (isSolid(tx,ty)) {
          if (dx > 0) p.rect.x = tx*TS - p.rect.w;
          else p.rect.x = (tx+1)*TS;
          p.vx = 0;
        }

    // vertical
    p.rect.y += dy;
    for (int ty = floor(p.rect.y/TS); ty <= floor((p.rect.y+p.rect.h-1)/TS); ++ty)
      for (int tx = floor(p.rect.x/TS); tx <= floor((p.rect.x+p.rect.w-1)/TS); ++tx)
        if (isSolid(tx,ty)) {
          if (dy > 0) { p.rect.y = ty*TS - p.rect.h; p.onGround = true; }
          else { p.rect.y = (ty+1)*TS; }
          p.vy = 0;
        }
}

Handle special cases: one-way platforms collide only when falling and the player’s feet cross into tile; slopes can be implemented with per-tile height functions or small polygons; ledge grabs use raycasts or extra checks on the tile edge. Troubleshooting tips: draw AABBs and tile bounds while debugging, clamp velocities or use substeps to avoid tunneling, and keep the collision box slightly smaller than the sprite to prevent snagging on corners.

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Member Avatar for Member #46692

does anyone know how this works?

Yes

Member Avatar for Hidden_mistakes

Well that was helpful, Thanks.
Any chance you will share your knowledge? or else i don't see any reason for you to have posted on my thread.

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