Map rendering and camera movement.

1 files changed, 119 insertions, 0 deletions

diff --git a/render.c b/render.c
index b2a59e2..c18d74d 100644
--- a/render.c
+++ b/render.c
@@ -261,3 +261,122 @@ void render_bitmap_col(
 		src += sstride;
 	}
 }
+
+void blit(
+	Bitmap* to,
+	const Bitmap* from,
+	int x,
+	int y,
+	const Rectangle* rect
+) {
+	int i, j, stride, sstride, n;
+	Colour* dst;
+	const Colour* src;
+	Rectangle sub;
+
+	sub = *rect;
+
+	if (sub.w <= 0) { return; }
+	if (sub.h <= 0) { return; }
+	if (sub.w > from->w) { return; }
+	if (sub.h > from->h) { return; }
+
+	if ((n = -x) > 0) {
+		sub.w -= n;
+		sub.x += n;
+		x += n;
+	}
+	
+	if ((n = -y) > 0) {
+		sub.h -= n;
+		sub.y += n;
+		y += n;
+	}
+	
+	if ((n = x + sub.w - to->w) > 0) {
+		sub.w -= n;
+	}
+
+	if ((n = y + sub.h - to->h) > 0) {
+		sub.h -= n;
+	}
+
+	if (sub.w <= 0) { return; }
+	if (sub.h <= 0) { return; }
+
+	dst = to->pixels   + (x     + y     * to->w);
+	src = from->pixels + (sub.x + sub.y * from->w);
+
+	stride = to->w - sub.w;
+	sstride = from->w - sub.w;
+
+	for (i = 0; i < sub.h; i++) {
+		for (j = 0; j < sub.w; j++) {
+			*dst = blend(*dst, *src);
+			dst++;
+			src++;
+		}
+		dst += stride;
+		src += sstride;
+	}
+}
+
+void blit_col(
+	Bitmap* to,
+	const Bitmap* from,
+	int x,
+	int y,
+	const Rectangle* rect,
+	Colour colour
+) {
+	int i, j, stride, sstride, n;
+	Colour* dst;
+	const Colour* src;
+	Rectangle sub;
+
+	sub = *rect;
+
+	if (sub.w <= 0) { return; }
+	if (sub.h <= 0) { return; }
+	if (sub.w > from->w) { return; }
+	if (sub.h > from->h) { return; }
+
+	if ((n = -x) > 0) {
+		sub.w -= n;
+		sub.x += n;
+		x += n;
+	}
+	
+	if ((n = -y) > 0) {
+		sub.h -= n;
+		sub.y += n;
+		y += n;
+	}
+	
+	if ((n = x + sub.w - to->w) > 0) {
+		sub.w -= n;
+	}
+
+	if ((n = y + sub.h - to->h) > 0) {
+		sub.h -= n;
+	}
+
+	if (sub.w <= 0) { return; }
+	if (sub.h <= 0) { return; }
+
+	dst = to->pixels   + (x     + y     * to->w);
+	src = from->pixels + (sub.x + sub.y * from->w);
+
+	stride = to->w - sub.w;
+	sstride = from->w - sub.w;
+
+	for (i = 0; i < sub.h; i++) {
+		for (j = 0; j < sub.w; j++) {
+			*dst = blend_mod(*dst, *src, colour);
+			dst++;
+			src++;
+		}
+		dst += stride;
+		src += sstride;
+	}
+}