- fixed C89 compliance issues with the last commit (rlebitmap/minifx)

[dosdemo] / src / rlebmap.h

diff --git a/src/rlebmap.h b/src/rlebmap.h
new file mode 100644 (file)
index 0000000..3f36b16
--- /dev/null
+++ b/src/rlebmap.h
@@ -0,0 +1,66 @@
+#ifndef __RLE_BITMAP_H__
+#define __RLE_BITMAP_H__
+
+/* Limit streak count per scanline so we can directly jump to specific scanline
+ */
+#define RLE_STREAKS_PER_SCANLINE 4
+
+/* Streaks will not exceed this many pixels. This allows us to optimize with a
+ * padded framebuffer. If a streak start position happens to lie within
+ * framebuffer, we will blit it without checking for out of bounds */
+#define RLE_MAX_STREAK_LENGTH 32
+
+/* Using the following type for storing start and for storing length in (start,
+ * length) pairs. */
+#define RLE_TYPE unsigned char
+
+/* For now, keep a static fill color. We can change this. Not that much about
+ * speed, but let's keep function definitions more compact. */
+#define RLE_FILL_COLOR 0
+
+/* Two entries of RLE_FILL_COLOR (16 bits) packed one after the other. */
+#define RLE_FILL_COLOR_32 ((RLE_FILL_COLOR << 16) | RLE_FILL_COLOR)
+
+/* For fixed-point arithmetic. Used for scaling. */
+#define RLE_FIXED_BITS 16
+
+/* This is a bitmap (image in 1bpp), encoded as streaks of consecutive pixels.
+ */
+typedef struct {
+       unsigned int w, h;
+
+       /* Each scan is RLE_BYTES_PER_SCANLINE long and contains pairs of
+        * (start, length). */
+       RLE_TYPE *scans;
+} RleBitmap;
+
+/* Constructor */
+RleBitmap *rleCreate(unsigned int w, unsigned int h);
+
+/* Destructor */
+void rleDestroy(RleBitmap *rle);
+
+/* Clears 'rle' to "all transparent" */
+void rleClear(RleBitmap *rle);
+
+/* Encode 'pixels' into 'rle' and also return it. Pixels are either 0 or 1. This
+ * will create an RleBitmap of 'h' scanlines. */
+RleBitmap *rleEncode(RleBitmap *rle, unsigned char *pixels, unsigned int pixelsW,
+                    unsigned int pixelsH);
+
+/* Rearranges the streaks to make it less frequent that they produce garbege when interpolated */
+void rleDistributeStreaks(RleBitmap *rle);
+
+/* Blits without scaling */
+void rleBlit(RleBitmap *rle, unsigned short *dst, int dstW, int dstH, int dstStride, int blitX,
+            int blitY);
+
+/* Scaled blit */
+void rleBlitScale(RleBitmap *rle, unsigned short *dst, int dstW, int dstH, int dstStride, int blitX,
+                 int blitY, float scaleX, float scaleY);
+
+/* Inverted blit (upside down) */
+void rleBlitScaleInv(RleBitmap *rle, unsigned short *dst, int dstW, int dstH, int dstStride,
+                    int blitX, int blitY, float scaleX, float scaleY);
+
+#endif // __RLE_BITMAP_H__