Code to deal with multiple pixel formats

diff --git a/com32/lib/sys/vesa/fmtpixel.h b/com32/lib/sys/vesa/fmtpixel.h
new file mode 100644 (file)
index 0000000..0f9d57e
--- /dev/null
+++ b/com32/lib/sys/vesa/fmtpixel.h
@@ -0,0 +1,71 @@
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2006 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *   
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *   
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * fmtpixel.h
+ *
+ * Inline function to format a single pixel
+ */
+
+#ifndef LIB_SYS_VESA_FMTPIXEL_H
+#define LIB_SYS_VESA_FMTPIXEL_H
+
+#include <inttypes.h>
+#include "video.h"
+
+/* Format a pixel and return the advanced pointer.
+   THIS FUNCTION IS ALLOWED TO WRITE BEYOND THE END OF THE PIXEL. */
+
+static inline void *format_pixel(void *ptr, uint32_t rgba,
+                                enum vesa_pixel_format fmt)
+{
+  switch (fmt) {
+  case PXF_BGRA32:
+    *(uint32_t *)ptr = rgba;
+    return (uint32_t *)ptr + 1;
+
+  case PXF_BGR24:
+    *(uint32_t *)ptr = rgba;
+    return (uint8_t *)ptr + 3;
+    
+  case PXF_LE_RGB16_565:
+    {
+      uint16_t pxv =
+       ((rgba >> 3) & 0x1f) |
+       ((rgba >> (2+8-5)) & (0x3f << 5)) |
+       ((rgba >> (3+16-11)) & (0x1f << 11));
+
+      *(uint16_t *)ptr = pxv;
+      return (uint16_t *)ptr + 1;
+    }
+
+  case PXF_NONE:               /* Shuts up gcc */
+    return ptr;
+  }
+}
+
+#endif /* LIB_SYS_VESA_FMTPIXEL_H */

diff --git a/com32/lib/sys/vesa/video.h b/com32/lib/sys/vesa/video.h
index d13021c..3bf93e3 100644 (file)
--- a/com32/lib/sys/vesa/video.h
+++ b/com32/lib/sys/vesa/video.h
@@ -51,6 +51,14 @@ struct vesa_char {
   uint8_t pad;                 /* Currently unused */
 };
 
+/* Pixel formats in order of decreasing preference; PXF_NONE should be last */
+enum vesa_pixel_format {
+  PXF_BGRA32,                  /* 32-bit BGRA */
+  PXF_BGR24,                   /* 24-bit BGR */
+  PXF_LE_RGB16_565,            /* 16-bit littleendian 5:6:5 RGB */
+  PXF_NONE
+};
+
 extern struct vesa_char *__vesacon_text_display;
 
 extern int __vesacon_font_height, __vesacon_text_rows;