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authorfrosch <frosch@openttd.org>2009-07-29 20:27:24 +0000
committerfrosch <frosch@openttd.org>2009-07-29 20:27:24 +0000
commitd51c4b6f6efff85b6f611e5040358a46aab1d806 (patch)
treeec4d58961534bd69b7442e486e594583de643108
parent3a6c0a9f220598a546f19bfed2b5b00483f747a9 (diff)
downloadopenttd-d51c4b6f6efff85b6f611e5040358a46aab1d806.tar.xz
(svn r16984) -Codechange: Document and assertify (Start|End)SpriteCombine.
-rw-r--r--src/viewport.cpp45
1 files changed, 39 insertions, 6 deletions
diff --git a/src/viewport.cpp b/src/viewport.cpp
index 3e1932bf2..f26e7086e 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -106,6 +106,15 @@ enum FoundationPart {
FOUNDATION_PART_END
};
+/** Mode of "sprite combining"
+ * @see StartSpriteCombine
+ */
+enum SpriteCombineMode {
+ SPRITE_COMBINE_NONE, ///< Every #AddSortableSpriteToDraw start its own bounding box
+ SPRITE_COMBINE_PENDING, ///< %Sprite combining will start with the next unclipped sprite.
+ SPRITE_COMBINE_ACTIVE, ///< %Sprite combining is active. #AddSortableSpriteToDraw outputs child sprites.
+};
+
typedef SmallVector<TileSpriteToDraw, 64> TileSpriteToDrawVector;
typedef SmallVector<StringSpriteToDraw, 4> StringSpriteToDrawVector;
typedef SmallVector<ParentSpriteToDraw, 64> ParentSpriteToDrawVector;
@@ -124,7 +133,7 @@ struct ViewportDrawer {
int *last_child;
- byte combine_sprites;
+ SpriteCombineMode combine_sprites; ///< Current mode of "sprite combining". @see StartSpriteCombine
int foundation[FOUNDATION_PART_END]; ///< Foundation sprites (index into parent_sprites_to_draw).
FoundationPart foundation_part; ///< Currently active foundation for ground sprite drawing.
@@ -619,7 +628,7 @@ void AddSortableSpriteToDraw(SpriteID image, SpriteID pal, int x, int y, int w,
pal = PALETTE_TO_TRANSPARENT;
}
- if (_vd.combine_sprites == 2) {
+ if (_vd.combine_sprites == SPRITE_COMBINE_ACTIVE) {
AddCombinedSprite(image, pal, x, y, z, sub);
return;
}
@@ -683,17 +692,41 @@ void AddSortableSpriteToDraw(SpriteID image, SpriteID pal, int x, int y, int w,
_vd.last_child = &ps->first_child;
- if (_vd.combine_sprites == 1) _vd.combine_sprites = 2;
+ if (_vd.combine_sprites == SPRITE_COMBINE_PENDING) _vd.combine_sprites = SPRITE_COMBINE_ACTIVE;
}
+/**
+ * Starts a block of sprites, which are "combined" into a single bounding box.
+ *
+ * Subsequent calls to #AddSortableSpriteToDraw will be drawn into the same bounding box.
+ * That is: The first sprite that is not clipped by the viewport defines the bounding box, and
+ * the following sprites will be child sprites to that one.
+ *
+ * That implies:
+ * - The drawing order is definite. No other sprites will be sorted between those of the block.
+ * - You have to provide a valid bounding box for all sprites,
+ * as you won't know which one is the first non-clipped one.
+ * Preferable you use the same bounding box for all.
+ * - You cannot use #AddChildSpriteScreen inside the block, as its result will be indefinite.
+ *
+ * The block is terminated by #EndSpriteCombine.
+ *
+ * You cannot nest "combined" blocks.
+ */
void StartSpriteCombine()
{
- _vd.combine_sprites = 1;
+ assert(_vd.combine_sprites == SPRITE_COMBINE_NONE);
+ _vd.combine_sprites = SPRITE_COMBINE_PENDING;
}
+/**
+ * Terminates a block of sprites started by #StartSpriteCombine.
+ * Take a look there for details.
+ */
void EndSpriteCombine()
{
- _vd.combine_sprites = 0;
+ assert(_vd.combine_sprites != SPRITE_COMBINE_NONE);
+ _vd.combine_sprites = SPRITE_COMBINE_NONE;
}
/**
@@ -1451,7 +1484,7 @@ void ViewportDoDraw(const ViewPort *vp, int left, int top, int right, int bottom
_vd.dpi.zoom = vp->zoom;
int mask = ScaleByZoom(-1, vp->zoom);
- _vd.combine_sprites = 0;
+ _vd.combine_sprites = SPRITE_COMBINE_NONE;
_vd.dpi.width = (right - left) & mask;
_vd.dpi.height = (bottom - top) & mask;