Define sources & backends

1 files changed, 49 insertions, 0 deletions

diff --git a/src/source.h b/src/source.h
new file mode 100644
index 0000000..6f051e3
--- /dev/null
+++ b/src/source.h
@@ -0,0 +1,49 @@
+#ifndef IMV_SOURCE_H
+#define IMV_SOURCE_H
+
+#include <stdbool.h>
+#include "bitmap.h"
+
+/* Generic source of one or more bitmaps. Essentially a single image file */
+struct imv_source {
+  /* usually the path of the image this is the source of */
+  char *name; 
+
+  /* source's image dimensions */
+  int width;
+  int height;
+
+  /* Usually 1, more if animated */
+  int num_frames;
+
+  /* Frames are returned using SDL events. These two fields must be
+   * populated by callers before calling any frame loading functionality
+   * on the source.
+   */
+  unsigned int image_event_id;
+  unsigned int error_event_id;
+
+  /* Trigger loading of the first frame. */
+  void (*load_first_frame)(struct imv_source *src); 
+
+  /* Trigger loading of next frame.  */
+  void (*load_next_frame)(struct imv_source *src); 
+
+  /* Notify source of time passing, automatically triggers loading of
+   * the next frame when due. */
+  void (*time_passed)(struct imv_source *src, double dt); 
+
+  /* Asks the source how long we can sleep for before the next frame is due */
+  double (*time_left)(struct imv_source *src);
+
+  /* Safely free contents of this source. After this returns
+   * it is safe to dealocate/overwrite the imv_source instance.
+   */
+  void (*free)(struct imv_source *src);
+
+  /* Implementation private data */
+  void *private;
+};
+
+
+#endif