From 6d766d6dd9177ececb14ebfe2ac68cc581eeeb44 Mon Sep 17 00:00:00 2001
From: ubq323 <ubq323@ubq323.website>
Date: Fri, 22 Mar 2024 23:52:56 +0000
Subject: movement, multiple surfaces (sort of)

---
 drawing.ha | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

(limited to 'drawing.ha')

diff --git a/drawing.ha b/drawing.ha
index ff2aa71..804aee4 100644
--- a/drawing.ha
+++ b/drawing.ha
@@ -1,14 +1,13 @@
 use sdl2;
 
-
 // 2d position, x and y
-type pos = (int, int);
+type pos = (i32, i32);
 
 type drawing_state = struct {
 	// is the mouse button held down?
 	drawing: bool,
 	pos: pos,
-	picture: picture,
+	picture: *picture,
 };
 
 type picture = struct {
@@ -16,6 +15,7 @@ type picture = struct {
 	w: size,
 	h: size,
 };
+
 // Returns array index of the pixel at position pos.
 // Bounds check happens in here instead of using a slice type, so
 // that it's easier to remove later.
@@ -29,22 +29,42 @@ fn pidx(pic: *picture, pos: pos) size = {
 
 	return xs + pic.w*ys;
 };
-fn pic_set(pic: *picture, pos: pos, val: u32) void = pic.d[pidx(pic,pos)] = val;
+
+fn pic_set(pic: *picture, pos: pos, val: u32) void =
+	pic.d[pidx(pic,pos)] = val;
+
 fn picture_from_surface(surf: *sdl2::SDL_Surface) picture = picture {
 	w = surf.w: size,
 	h = surf.h: size,
 	d = (surf.pixels as *opaque: *[*]u32),
 };
 
-fn min(a: int, b: int) int = if (a<b) a else b;
-fn max(a: int, b: int) int = if (a<b) b else a;
+fn clear_picture(pic: *picture, color: u32) void = {
+	for (let i = 0z; i < pic.w*pic.h; i+=1) pic.d[i] = color;
+};
 
-fn circle(dstate: *drawing_state, c: pos, r: int, color: u32) void = {
+fn outline_picture(pic: *picture) void = {
+	for (let x = 0; x:size < pic.w; x+=1) {
+		pic_set(pic, (x, 0), 0);
+		pic_set(pic, (x, pic.h:int-1), 0);
+	};
+	for (let y = 0; y:size < pic.h; y+=1) {
+		pic_set(pic, (0, y), 0);
+		pic_set(pic, (pic.w:int-1, y), 0);
+	};
+};
+
+fn min(a: i32, b: i32) i32 = if (a<b) a else b;
+fn max(a: i32, b: i32) i32 = if (a<b) b else a;
+
+// Draws a circle onto the dstate's picture, at given position radius color
+// Clips at the boundaries of the picture to avoid overflow.
+fn circle(dstate: *drawing_state, c: pos, r: i32, color: u32) void = {
 	const (cx,cy) = c;
 	const ymin = max(0, cy-r);
-	const ymax = min(dstate.picture.h:int-1, cy+r);
+	const ymax = min(dstate.picture.h:i32-1, cy+r);
 	const xmin = max(0, cx-r);
-	const xmax = min(dstate.picture.w:int-1, cx+r);
+	const xmax = min(dstate.picture.w:i32-1, cx+r);
 
 	const r2 = r*r + r;
 
@@ -53,11 +73,10 @@ fn circle(dstate: *drawing_state, c: pos, r: int, color: u32) void = {
 		for (let x = xmin; x<=xmax; x+=1) {
 			const xd = x-cx;
 			if (yd*yd + xd*xd <= r2) {
-				pic_set(&dstate.picture, (x,y), color);
+				pic_set(dstate.picture, (x,y), color);
 			};
 		};
 	};
-
 };
 
 fn do_drawing(dstate: *drawing_state) void = {
-- 
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