drawBegin/drawEnd

5 files changed, 86 insertions, 2 deletions

diff --git a/demo.cpp b/demo.cpp
index ea5d525..a7e569b 100644
--- a/demo.cpp
+++ b/demo.cpp
@@ -10,5 +10,9 @@ main()
 	});
 	if (fld.init())
 		return 1;
+	if (fld.drawBegin())
+		return 1;
+	if (fld.drawEnd())
+		return 1;
 	return 0;
 }
diff --git a/src/FLD.hpp b/src/FLD.hpp
index cae4cf8..65111f8 100644
--- a/src/FLD.hpp
+++ b/src/FLD.hpp
@@ -2,7 +2,7 @@
 #include <SDL2/SDL_render.h>
 #include <string>
 
-#define READONLY(T, X, V) private: T _##X = V; public: T const& X = _##X
+#define READONLY(T, X, V) private: T _##X = V; public: decltype(_##X) const& X = _##X
 
 class FLD {
 public:
@@ -20,13 +20,28 @@ public:
 	READONLY(SDL_Window *, window, nullptr);
 	READONLY(SDL_Renderer *, renderer, nullptr);
 	READONLY(SDL_Texture *, target, nullptr);
+	READONLY(unsigned long, tick, 0);
+private:
+	struct {
+		bool managed = false;
+		Uint64 min_dt;
+		Uint64 next_time;
+	} fps;
+	struct {
+		float scale = 1.0;
+		int off_x = 0;
+		int off_y = 0;
+	} transform;
 public:
 	using Error = int;
 
 	FLD(const Config& config);
 	FLD(const Config&& config);
-	[[nodiscard]] Error init();
 	~FLD();
+	[[nodiscard]] Error init();
+
+	[[nodiscard]] Error drawBegin() const;
+	[[nodiscard]] Error drawEnd();
 private:
 	Error sdl_error() const;
 	[[nodiscard]] Error initBasepath() const;
diff --git a/src/drawBegin.cpp b/src/drawBegin.cpp
new file mode 100644
index 0000000..fc25ae3
--- /dev/null
+++ b/src/drawBegin.cpp
@@ -0,0 +1,11 @@
+#include "FLD.hpp"
+
+FLD::Error
+FLD::drawBegin() const
+{
+	if (SDL_SetRenderTarget(_renderer, _target) < 0)
+		return sdl_error();
+	if (SDL_SetRenderDrawBlendMode(_renderer, SDL_BLENDMODE_BLEND))
+		return sdl_error();
+	return 0;
+}
diff --git a/src/drawEnd.cpp b/src/drawEnd.cpp
new file mode 100644
index 0000000..ead7bed
--- /dev/null
+++ b/src/drawEnd.cpp
@@ -0,0 +1,48 @@
+#include "FLD.hpp"
+#include <SDL2/SDL_timer.h>
+
+FLD::Error
+FLD::drawEnd()
+{
+	if (SDL_SetRenderTarget(_renderer, nullptr) < 0)
+		return sdl_error();
+	if (SDL_SetRenderDrawColor(_renderer, 0, 0, 0, 0xff) < 0)
+		return sdl_error();
+	if (SDL_RenderClear(_renderer) < 0)
+		return sdl_error();
+
+	int win_w, win_h;
+	SDL_GetWindowSize(_window, &win_w, &win_h);
+	win_w = win_w ? win_w : 1;
+	win_h = win_h ? win_h : 1;
+
+	const float ratio_w = win_w / static_cast<float>(config.width);
+	const float ratio_h = win_h / static_cast<float>(config.height);
+	transform.scale = (ratio_w < ratio_h) ? ratio_w : ratio_h;
+	if (transform.scale > 1.0f && config.pixel_perfect)
+		transform.scale = static_cast<int>(transform.scale);
+	transform.off_x = (win_w - config.width * transform.scale) / 2;
+	transform.off_y = (win_h - config.height * transform.scale) / 2;
+
+	const SDL_Rect dest = {
+		.x = transform.off_x,
+		.y = transform.off_y,
+		.w = static_cast<int>(config.width * transform.scale),
+		.h = static_cast<int>(config.height * transform.scale)
+	};
+	if (SDL_RenderCopy(_renderer, _target, nullptr, &dest) < 0)
+		return sdl_error();
+
+	if (fps.managed) {
+		fps.next_time += fps.min_dt;
+		const Uint64 cur_time = SDL_GetTicks64();
+		if (fps.next_time <= cur_time)
+			fps.next_time = cur_time;
+		else
+			SDL_Delay(fps.next_time - cur_time);
+	}
+
+	SDL_RenderPresent(_renderer);
+	_tick += 1;
+	return 0;
+}
diff --git a/src/init.cpp b/src/init.cpp
index a6689a3..d5f5dfd 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -23,6 +23,12 @@ FLD::init()
 			sdl_error();
 	}
 
+	fps.managed = (config.target_fps > 0);
+	if (fps.managed) {
+		fps.min_dt = 1000 / config.target_fps;
+		fps.next_time = SDL_GetTicks64();
+	}
+
 	return 0;
 }