1 files changed, 108 insertions, 0 deletions
diff --git a/src/til_fb.h b/src/til_fb.h
new file mode 100644
index 0000000..792c6e3
--- /dev/null
+++ b/src/til_fb.h
@@ -0,0 +1,108 @@
+#ifndef _TIL_FB_H
+#define _TIL_FB_H
+
+#include <stdint.h>
+#include <string.h>
+
+#include "til_settings.h"
+
+/* All renderers should target fb_fragment_t, which may or may not represent
+ * a full-screen mmap.  Helpers are provided for subdividing fragments for
+ * concurrent renderers.
+ */
+typedef struct til_fb_fragment_t {
+	uint32_t	*buf;		/* pointer to the first pixel in the fragment */
+	unsigned	x, y;		/* absolute coordinates of the upper left corner of this fragment */
+	unsigned	width, height;	/* width and height of this fragment */
+	unsigned	frame_width;	/* width of the frame this fragment is part of */
+	unsigned	frame_height;	/* height of the frame this fragment is part of */
+	unsigned	stride;		/* number of bytes from the end of one row to the start of the next */
+	unsigned	pitch;		/* number of bytes separating y from y + 1, including any padding */
+	unsigned	number;		/* this fragment's number as produced by fragmenting */
+	unsigned	zeroed:1;	/* if this fragment has been zeroed since last flip */
+} til_fb_fragment_t;
+
+/* This is a page handle object for page flip submission/life-cycle.
+ * Outside of fb_page_get()/fb_page_put(), you're going to be interested in
+ * fb_fragment_t.  The fragment included here describes the whole page,
+ * it may be divided via fb_fragment_divide().
+ */
+typedef struct til_fb_page_t {
+	til_fb_fragment_t	fragment;
+} til_fb_page_t;
+
+typedef struct til_fb_t til_fb_t;
+
+/* Supply this struct to fb_new() with the appropriate context */
+typedef struct til_fb_ops_t {
+	int	(*setup)(const til_settings_t *settings, til_setting_desc_t **next);
+	int	(*init)(const til_settings_t *settings, void **res_context);
+	void	(*shutdown)(til_fb_t *fb, void *context);
+	int	(*acquire)(til_fb_t *fb, void *context, void *page);
+	void	(*release)(til_fb_t *fb, void *context);
+	void *	(*page_alloc)(til_fb_t *fb, void *context, til_fb_page_t *res_page);
+	int	(*page_free)(til_fb_t *fb, void *context, void *page);
+	int	(*page_flip)(til_fb_t *fb, void *context, void *page);
+} til_fb_ops_t;
+
+til_fb_page_t * til_fb_page_get(til_fb_t *fb);
+void til_fb_page_put(til_fb_t *fb, til_fb_page_t *page);
+til_fb_t * til_fb_free(til_fb_t *fb);
+void til_fb_get_put_pages_count(til_fb_t *fb, unsigned *count);
+int til_fb_new(const til_fb_ops_t *ops, til_settings_t *settings, int n_pages, til_fb_t **res_fb);
+void til_fb_rebuild(til_fb_t *fb);
+void * til_fb_context(til_fb_t *fb);
+int til_fb_flip(til_fb_t *fb);
+void til_fb_fragment_divide(til_fb_fragment_t *fragment, unsigned n_fragments, til_fb_fragment_t fragments[]);
+int til_fb_fragment_slice_single(const til_fb_fragment_t *fragment, unsigned n_fragments, unsigned num, til_fb_fragment_t *res_fragment);
+int til_fb_fragment_tile_single(const til_fb_fragment_t *fragment, unsigned tile_size, unsigned num, til_fb_fragment_t *res_fragment);
+
+
+/* checks if a coordinate is contained within a fragment */
+static inline int til_fb_fragment_contains(til_fb_fragment_t *fragment, int x, int y)
+{
+	if (x < fragment->x || x >= fragment->x + fragment->width ||
+	    y < fragment->y || y >= fragment->y + fragment->height)
+		return 0;
+
+	return 1;
+}
+
+
+/* puts a pixel into the fragment, no bounds checking is performed. */
+static inline void til_fb_fragment_put_pixel_unchecked(til_fb_fragment_t *fragment, int x, int y, uint32_t pixel)
+{
+	uint32_t	*pixels = ((void *)fragment->buf) + (y - fragment->y) * fragment->pitch;
+
+	pixels[x - fragment->x] = pixel;
+}
+
+
+/* puts a pixel into the fragment, bounds checking is performed with a draw performed return status */
+static inline int til_fb_fragment_put_pixel_checked(til_fb_fragment_t *fragment, int x, int y, uint32_t pixel)
+{
+	if (!til_fb_fragment_contains(fragment, x, y))
+		return 0;
+
+	til_fb_fragment_put_pixel_unchecked(fragment, x, y, pixel);
+
+	return 1;
+}
+
+
+/* zero a fragment */
+static inline void til_fb_fragment_zero(til_fb_fragment_t *fragment)
+{
+	void	*buf = fragment->buf;
+
+	if (fragment->zeroed)
+		return;
+
+	/* TODO: there should be a fast-path for non-divided fragments where there's no stride to skip */
+	for (int y = 0; y < fragment->height; y++, buf += fragment->pitch)
+		memset(buf, 0, fragment->pitch - fragment->stride);
+
+	fragment->zeroed = 1;
+}
+
+#endif