diff options
author | ubq323 <ubq323@ubq323.website> | 2024-03-22 19:38:29 +0000 |
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committer | ubq323 <ubq323@ubq323.website> | 2024-03-22 19:38:29 +0000 |
commit | d302628e8665572bc515c254a8d52909cc6db2ae (patch) | |
tree | bdff2d6e6213b8bd2f6221ee0798e1f39806b871 /drawing.ha | |
parent | 32f8d37ad94a9ea3413c3f9587bb2000f14c61d1 (diff) |
refactor
Diffstat (limited to 'drawing.ha')
-rw-r--r-- | drawing.ha | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/drawing.ha b/drawing.ha new file mode 100644 index 0000000..ff2aa71 --- /dev/null +++ b/drawing.ha @@ -0,0 +1,65 @@ +use sdl2; + + +// 2d position, x and y +type pos = (int, int); + +type drawing_state = struct { + // is the mouse button held down? + drawing: bool, + pos: pos, + picture: picture, +}; + +type picture = struct { + d: *[*]u32, + 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. +fn pidx(pic: *picture, pos: pos) size = { + const (x,y) = pos; + const (xs,ys) = (x:size, y:size); + assert(0 <= x, "x position must not be less than 0"); + assert(0 <= y, "y position must not be less than 0"); + assert(xs < pic.w, "x position must be less than picture width"); + assert(ys < pic.h, "y position must be less than picture height"); + + return xs + pic.w*ys; +}; +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 circle(dstate: *drawing_state, c: pos, r: int, color: u32) void = { + const (cx,cy) = c; + const ymin = max(0, cy-r); + const ymax = min(dstate.picture.h:int-1, cy+r); + const xmin = max(0, cx-r); + const xmax = min(dstate.picture.w:int-1, cx+r); + + const r2 = r*r + r; + + for (let y = ymin; y<=ymax; y+=1) { + const yd = y-cy; + 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); + }; + }; + }; + +}; + +fn do_drawing(dstate: *drawing_state) void = { + if (dstate.drawing) circle(dstate, dstate.pos, 20, 0xff0088); +}; |