UIBackend.h

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#pragma once
#include "common/Export.h"
 
 
#include <SDL2/SDL.h>
#include <cstdint>
#include <memory>
 
namespace eve::graphics {
class Graphics;
class Texture;
}
 
namespace eve::ui {
 
class UIBackend {
public:
    virtual ~UIBackend() = default;
 
    virtual bool init(SDL_Window *window, eve::graphics::Graphics *gfx) = 0;
    virtual void shutdown() = 0;
    virtual bool isInitialized() const = 0;
 
    virtual void processEvent(const SDL_Event *event) = 0;
    virtual void newFrame() = 0;
 
    virtual bool wantCaptureMouse() const { return false; }
    virtual bool wantCaptureKeyboard() const { return false; }
 
    virtual void setScale(float /*scale*/) {}
    virtual float getScale() const { return 1.f; }
 
    [[nodiscard("retain the UI texture registration id or explicitly handle failure")]]
    virtual uint64_t registerTexture(graphics::Texture * /*tex*/) {
        return 0;
    }
    virtual void unregisterTexture(uint64_t /*id*/) {}
    virtual bool textureSize(uint64_t /*id*/, int * /*w*/, int * /*h*/) const { return false; }
    virtual void *textureHandle(uint64_t /*id*/) const { return nullptr; }
 
    virtual bool usesQueuedTextureDraws() const { return false; }
    virtual void queueTextureDraw(uint64_t /*id*/, float /*x*/, float /*y*/, float /*w*/, float /*h*/,
                                  float /*u0*/, float /*v0*/, float /*u1*/, float /*v1*/, float /*r*/,
                                  float /*g*/, float /*b*/, float /*a*/, bool /*opaque*/) {}
};
 
EVENGINE_API_WORLD std::unique_ptr<UIBackend> createImGuiBackend();
 
}  // namespace eve::ui