From d163de65023223c730155959a905e96b7a52a97f Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom.smeding@gmail.com>
Date: Sun, 12 Apr 2020 17:55:40 +0200
Subject: More useful window

---
 window.h | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 67 insertions(+), 4 deletions(-)

diff --git a/window.h b/window.h
index 3ecfe57..d9ac9d9 100644
--- a/window.h
+++ b/window.h
@@ -9,6 +9,7 @@
 
 #include <string>
 #include <vector>
+#include <array>
 #include <functional>
 #include <stdexcept>
 #include <SDL.h>
@@ -21,7 +22,7 @@ public:
 		inline Opts() = default;
 
 		inline Opts& fullscreen(bool f) { _fullscreen = f; return *this; }
-		inline Opts& resizeable(bool r) { _resizable = r; return *this; }
+		inline Opts& resizable(bool r) { _resizable = r; return *this; }
 
 		inline bool fullscreen() const { return _fullscreen; }
 		inline bool resizable() const { return _resizable; }
@@ -40,8 +41,27 @@ public:
 
 	inline ~Window();
 
+	class Buffer {
+	public:
+		using Clr = std::array<uint8_t, 3>;
+
+		inline Buffer(int width, int height, std::vector<uint8_t> &arr);
+
+		inline std::vector<uint8_t>& raw() { return arr; }
+		inline int width() { return wid; }
+		inline int height() { return hei; }
+
+		inline void clear(Clr clr);
+		inline void plot(int x, int y, Clr clr, float alpha = 1.0);
+		inline void plotf(float x, float y, Clr clr, float alpha = 1.0);
+
+	private:
+		int wid, hei;
+		std::vector<uint8_t> &arr;
+	};
+
 	/// The draw buffer will be of size 3 * width * height; row-major order, RGB pixels.
-	using DrawHandler = std::function<void(std::vector<uint8_t> &drawbuf, int width, int height)>;
+	using DrawHandler = std::function<void(Buffer &buffer)>;
 	/// Return true to stop the event loop.
 	using EventHandler = std::function<bool(const SDL_Event&)>;
 
@@ -67,7 +87,7 @@ inline Window::Window(const std::string &title, int wid_sugg, int hei_sugg, Opts
 	}
 
 	Uint32 flags = 0;
-	if (opts.fullscreen()) flags |= SDL_WINDOW_FULLSCREEN;
+	if (opts.fullscreen()) flags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
 	if (opts.resizable()) flags |= SDL_WINDOW_RESIZABLE;
 
 	win = SDL_CreateWindow(
@@ -121,6 +141,49 @@ inline void Window::event_loop(EventHandler eventfunc, DrawHandler drawfunc) {
 			);
 		}
 
-		drawfunc(drawbuf, width, height);
+		{
+			Buffer buffer{width, height, drawbuf};
+			drawfunc(buffer);
+		}
+
+		SDL_Surface *winsurf = SDL_GetWindowSurface(win);
+		if (SDL_MUSTLOCK(winsurf)) SDL_LockSurface(winsurf);
+		SDL_BlitSurface(surface, nullptr, winsurf, nullptr);
+		if (SDL_MUSTLOCK(winsurf)) SDL_UnlockSurface(winsurf);
+
+		SDL_UpdateWindowSurface(win);
+	}
+}
+
+inline Window::Buffer::Buffer(int width, int height, std::vector<uint8_t> &arr)
+	: wid{width}, hei{height}, arr{arr}
+{}
+
+inline void Window::Buffer::clear(Clr clr) {
+	if (clr[0] == clr[1] && clr[1] == clr[2]) {
+		memset(arr.data(), clr[0], 3 * wid * hei);
+	} else {
+		for (int i = 0; i < wid * hei; i++) {
+			for (int j = 0; j < 3; j++) {
+				arr[3 * i + j] = clr[j];
+			}
+		}
+	}
+}
+
+inline void Window::Buffer::plot(int x, int y, Clr clr, float alpha) {
+	for (int i = 0; i < 3; i++) {
+		uint8_t &orig = arr[3 * (wid * y + x) + i];
+		orig = alpha * clr[i] + (1 - alpha) * orig;
 	}
 }
+
+inline void Window::Buffer::plotf(float x, float y, Clr clr, float alpha) {
+	const int x0 = x, y0 = y;
+	const float xal = (x - x0) * alpha;
+	const float yal = (y - y0) * alpha;
+	plot(x0    , y0    , clr, (1 - xal) * (1 - yal));
+	plot(x0 + 1, y0    , clr, xal       * (1 - yal));
+	plot(x0    , y0 + 1, clr, (1 - xal) * yal      );
+	plot(x0 + 1, y0 + 1, clr, xal       * yal      );
+}
-- 
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