camera

Echlib Camera System Guide

Introduction

This guide explains how to implement a camera system in Echlib, ensuring smooth player movement and camera tracking. The example provided demonstrates how to keep the camera centered on the player while supporting zoom functionality.

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Setting Up the Window

Before implementing the camera system, we need to create a window and set up the environment:

#include <echlib.h>
#include <cmath>  // For sqrt
#include <iostream>

using namespace ech;

int main()
{
    float PlayerX = 50.0f, PlayerY = 50.0f;
    float Speed = 400.0f;
    int WindowWidth = 800, WindowHeight = 800;
    int BasePlayerWidth = 100, BasePlayerHeight = 100; // Store original size

    MakeWindow(WindowWidth, WindowHeight, "Echlib Camera Example");
    SetTargetFps(60);

    LoadTexture(RESOURCES_PATH "Player/Player_Back.png", "player");
    LoadTexture(RESOURCES_PATH "Map/Map.png", "background");

    camera.x = PlayerX - (WindowWidth / 2.0f);
    camera.y = PlayerY - (WindowHeight / 2.0f);
    camera.zoom = 5.0f;

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Player Movement

We implement movement using IsKeyHeld() to check for user input:

    while (!WindowShouldClose())
    {
        float DeltaTime = GetDeltaTime();
        float moveX = 0.0f, moveY = 0.0f;

        if (IsKeyHeld(KEY_RIGHT)) moveX += 1.0f;
        if (IsKeyHeld(KEY_LEFT)) moveX -= 1.0f;
        if (IsKeyHeld(KEY_UP)) moveY += 1.0f;
        if (IsKeyHeld(KEY_DOWN)) moveY -= 1.0f;

        float magnitude = sqrt(moveX * moveX + moveY * moveY);
        if (magnitude > 0.0f)
        {
            moveX /= magnitude;
            moveY /= magnitude;
        }

        PlayerX += moveX * Speed * DeltaTime;
        PlayerY += moveY * Speed * DeltaTime;

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Camera Tracking & Zoom

The camera follows the player while maintaining zoom functionality:

        camera.x = PlayerX - (WindowWidth / 2.0f) / camera.zoom;
        camera.y = PlayerY - (WindowHeight / 2.0f) / camera.zoom;

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Rendering

Finally, we render the background and player relative to the camera position:

        StartDrawing();
        ClearBackground(GRAY);

        DrawTexturedRectangle(-camera.x, -camera.y, 2000, 2000, "background");
        DrawTexturedRectangle(
            PlayerX - camera.x, PlayerY - camera.y,
            BasePlayerWidth * camera.zoom, BasePlayerHeight * camera.zoom,
            "player"
        );

        EndDrawing();
    }

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Conclusion

This example demonstrates how to:

• Implement smooth player movement

• Keep the camera centered on the player

• Apply zoom effects without distorting the player size

• Collision