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use a rect for the destination area

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this isn't strictly needed now, but will be useful in a future change
that changes how clipping works in rotozoom blits
This commit is contained in:
Gered 2022-11-08 14:15:41 -05:00
parent acbf36ee28
commit 5e65d63540
1 changed files with 8 additions and 6 deletions
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14
libretrogd/src/graphics/bitmap/blit.rs
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@ -345,10 +345,12 @@ unsafe fn per_pixel_rotozoom_blit(
// HACK: -/+ 1's because this seems to fix some destination area accidental clipping for _some_
// rotation angles ... ? i guess some other math is probably wrong somewhere or some
// floating point rounding fun perhaps?
let x1 = top_left_x.min(bottom_left_x).min(top_right_x).min(bottom_right_x) as i32 - 1;
let x2 = top_left_x.max(bottom_left_x).max(top_right_x).max(bottom_right_x) as i32 + 1;
let y1 = top_left_y.min(bottom_left_y).min(top_right_y).min(bottom_right_y) as i32 - 1;
let y2 = top_left_y.max(bottom_left_y).max(top_right_y).max(bottom_right_y) as i32 + 1;
let dest_region = Rect::from_coords(
top_left_x.min(bottom_left_x).min(top_right_x).min(bottom_right_x) as i32 - 1,
top_left_y.min(bottom_left_y).min(top_right_y).min(bottom_right_y) as i32 - 1,
top_left_x.max(bottom_left_x).max(top_right_x).max(bottom_right_x) as i32 + 1,
top_left_y.max(bottom_left_y).max(top_right_y).max(bottom_right_y) as i32 + 1
);
// now we're ready to draw. we'll be iterating through each pixel on the area we calculated
// just above -- that is (x1,y1)-(x2,y2) -- on the DESTINATION bitmap and for each of these
@ -363,8 +365,8 @@ unsafe fn per_pixel_rotozoom_blit(
let scale_x = 1.0 / scale_x;
let scale_y = 1.0 / scale_y;
for y in y1..=y2 {
for x in x1..=x2 {
for y in dest_region.y..=dest_region.bottom() {
for x in dest_region.x..=dest_region.right() {
// map the destination bitmap x/y coordinate we're currently at to it's source bitmap
// x/y coordinate by applying a reverse rotation/scale.
// note that for these transformations, we're doing a "weird" thing by utilizing the