InputSampleSystem.hpp

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#pragma once
 
#include "ecs/components/InputSnapshot.hpp"
#include "ecs/components/LocalPlayer.hpp"
#include "ecs/registry/Registry.hpp"
 
#include <SDL3/SDL.h>
 
#include <algorithm>
#include <cmath>
#include <glm/trigonometric.hpp>
 
namespace systems
{
 
inline void runMouseLook(Registry& registry, float mouseSensitivity)
{
    float mdx = 0.0f;
    float mdy = 0.0f;
    SDL_GetRelativeMouseState(&mdx, &mdy);
 
    registry.view<InputSnapshot, LocalPlayer>().each([&](InputSnapshot& snap) {
        // Negate: SDL mdx is positive when moving right, but positive yaw
        // rotates toward +X which maps to screen-left via glm::lookAt's
        // cross(forward, up) convention.  Negating gives the standard
        // "mouse right = look right" behaviour.
        snap.yaw -= mdx * mouseSensitivity;
 
        // Wrap yaw to [-π, π] to avoid float precision drift over time.
        snap.yaw = std::remainder(snap.yaw, glm::radians(360.0f));
 
        // Clamp pitch to avoid gimbal-lock at the poles.
        snap.pitch = std::clamp(snap.pitch + mdy * mouseSensitivity, -glm::radians(89.0f), glm::radians(89.0f));
    });
}
 
inline void runMovementKeys(Registry& registry)
{
    const bool* const kKeys = SDL_GetKeyboardState(nullptr);
 
    registry.view<InputSnapshot, LocalPlayer>().each([&](InputSnapshot& snap) {
        snap.forward = kKeys[SDL_SCANCODE_W];
        snap.back = kKeys[SDL_SCANCODE_S];
        snap.left = kKeys[SDL_SCANCODE_A];
        snap.right = kKeys[SDL_SCANCODE_D];
        snap.jump = kKeys[SDL_SCANCODE_SPACE];
        snap.crouch = kKeys[SDL_SCANCODE_LCTRL];
        snap.sprint = kKeys[SDL_SCANCODE_LSHIFT];
        snap.grapple = kKeys[SDL_SCANCODE_E];
    });
}
 
inline void runWeaponKeys(Registry& registry)
{
    const bool* const kKeys = SDL_GetKeyboardState(nullptr);
    const SDL_MouseButtonFlags mouse = SDL_GetMouseState(nullptr, nullptr);
 
    registry.view<InputSnapshot, LocalPlayer>().each([&](InputSnapshot& snap) {
        snap.shooting =
            (mouse & SDL_BUTTON_LMASK) != 0; // Apply bitmask to mouse input, true if left click is held down.
        snap.switchToPrimary = kKeys[SDL_SCANCODE_1];
        snap.switchToSecondary = kKeys[SDL_SCANCODE_2];
        snap.switchToTertiary = kKeys[SDL_SCANCODE_3];
        snap.switchToQuaternary = kKeys[SDL_SCANCODE_4];
        snap.reload = kKeys[SDL_SCANCODE_R];
    });
}
 
inline void runInputSample(Registry& registry, float mouseSensitivity = 0.001f)
{
    runMouseLook(registry, mouseSensitivity);
    runMovementKeys(registry);
    runWeaponKeys(registry);
}
 
} // namespace systems