Player World Collisions

[JeffM2501]

This is a simple collision system that checks a player against multiple world obstacles.

#include "raylib.h"
#include "raymath.h"


bool CollideBox(Vector2* newPos, Vector2* oldPos, float playerSize, Rectangle* obstacle)
{
    Rectangle newRect = { newPos->x,newPos->y, playerSize, playerSize };

    if (!CheckCollisionRecs(newRect, *obstacle))
        return false;

    float offset = 1;

    if (oldPos->x + playerSize < obstacle->x)
    {
        // we started from the left and went right
        newPos->x = obstacle->x - playerSize - offset;
    }
    else if (oldPos->x > obstacle->x + obstacle->width)
    {
        // we started from the right and went left
        newPos->x = obstacle->x + obstacle->width + offset;
    }

    if (oldPos->y + playerSize < obstacle->y)
    {
        // we started from the top and went down
        newPos->y = obstacle->y - playerSize - offset;
    }
    else if (oldPos->y > obstacle->y + obstacle->height)
    {
        // we started from the bottom and went up
        newPos->y = obstacle->y + obstacle->height + offset;
    }

    return true;
}

int main(void)
{
    const int screenWidth = 1024;
    const int screenHeight = 1024;
    int playerSize = 25;

    // setup raylib
    InitWindow(screenWidth, screenHeight, "Collisions");

    SetTargetFPS(144);

    Vector2 pos = { screenWidth * 0.5f, screenHeight * 0.5f };  // player position
    float speed = 200;        
                                  // speed ( in pixels per second )
    Rectangle obstacles[10];
    for (int i = 0; i < 10; i++)
    {
        int width = GetRandomValue(50, 200);
        int height = GetRandomValue(50, 200);

        Rectangle rec;
        bool good = false;
        while (!good)
        {
            rec.x = GetRandomValue(0, screenWidth - width);
            rec.y = GetRandomValue(0, screenHeight - height);
            rec.width = width;
            rec.height = height;

            good = !CollideBox(&pos, &pos, playerSize, &rec);
        }

        obstacles[i] = rec;
    }

    while (!WindowShouldClose())
    {
        Vector2 input = { 0 };

        // see what directions we want to go
        if (IsKeyDown(KEY_W))
            input.y -= 1;
        if (IsKeyDown(KEY_S))
            input.y += 1;
        if (IsKeyDown(KEY_A))
            input.x -= 1;
        if (IsKeyDown(KEY_D))
            input.x += 1;

        // add our input dir + thrust for this frame to our velocity
        Vector2 newPos = Vector2Add(pos, Vector2Scale(input, speed * GetFrameTime()));

        for (int i = 0; i < 10; i++)
            CollideBox(&newPos, &pos, playerSize, &obstacles[i]);
      
        // update to our new position
        pos = newPos;

        // draw the scene
        BeginDrawing();
        ClearBackground(RAYWHITE);

        // draw the player
        for (int i = 0; i < 10; i++)
        DrawRectangleRec(obstacles[i], BLACK);

        // draw the player
        DrawRectangle(pos.x, pos.y, playerSize, playerSize, RED);

        DrawFPS(0, 0);

        EndDrawing();
    }
}

[JeffM2501]

[nezvers]

It gets stuck when rectangles are tiled together as they would be in tile-based games.
Also, that offset might not be appealing for pixel art games, especially with exact size hole tunnels.
Here is the modified main function to demonstrate stucking.

int main(void)
{
    const int screenWidth = 640;
    const int screenHeight = 360;
    int playerSize = 16;
    int obstacleCount = 20;

    // setup raylib
    InitWindow(screenWidth, screenHeight, "Collisions");

    SetTargetFPS(144);

    Vector2 pos = { screenWidth * 0.5f, screenHeight * 0.5f };  // player position
    float speed = 200;        
                                  // speed ( in pixels per second )
    Rectangle obstacles[obstacleCount];
    int width = playerSize;
    int height = playerSize;
    for (int i = 0; i < 10; i++)
    {
        obstacles[i].x = screenWidth / 2;
        obstacles[i].y = screenHeight / 2 - (4 * height) + (height * i);
        obstacles[i].width = width;
        obstacles[i].height = height;
    }
    for (int i = 0; i < 10; i++)
    {
        obstacles[i+10].x = (screenWidth / 2) - (4 * width) + (width * i);
        obstacles[i+10].y = screenHeight / 2;
        obstacles[i+10].width = width;
        obstacles[i+10].height = height;
    }

    while (!WindowShouldClose())
    {
        Vector2 input = { 0 };

        // see what directions we want to go
        if (IsKeyDown(KEY_W))
            input.y -= 1;
        if (IsKeyDown(KEY_S))
            input.y += 1;
        if (IsKeyDown(KEY_A))
            input.x -= 1;
        if (IsKeyDown(KEY_D))
            input.x += 1;

        // add our input dir + thrust for this frame to our velocity
        Vector2 newPos = Vector2Add(pos, Vector2Scale(input, speed * GetFrameTime()));

        for (int i = 0; i < obstacleCount; i++)
            CollideBox(&newPos, &pos, playerSize, &obstacles[i]);
      
        // update to our new position
        pos = newPos;

        // draw the scene
        BeginDrawing();
        ClearBackground(RAYWHITE);

        // draw the player
        for (int i = 0; i < obstacleCount; i++)
            DrawRectangleRec(obstacles[i], BLACK);

        // draw the player
        DrawRectangle(pos.x, pos.y, playerSize, playerSize, RED);

        DrawFPS(0, 0);

        EndDrawing();
    }
}

[siddharthroy12]

I think I did it

yay-2021-09-14_08.20.43.mp4

[nezvers]

HERE is my solution/example project.

It's a bit similar collision resolve as @JeffM2501 except I don't have offset and pass the velocity instead of the new position.