- Fix a display glitch with float image painting and undo.

- Fix a crash with float images texture mapped onto meshes, it didn't
  always do conversion from float to byte before uploading to OpenGL.

source/blender/src/drawmesh.c

@@ -43,6 +43,7 @@
 #include "BLI_arithb.h"
 #include "BLI_edgehash.h"
 
+#include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
 
 #include "DNA_image_types.h"
@@ -303,9 +304,11 @@ int set_tpage(TFace *tface)
 			glDisable(GL_TEXTURE_2D);
 			return 0;
 		}
-		
 	}
 
+	if ((ima->ibuf->rect==NULL) && ima->ibuf->rect_float)
+		IMB_rect_from_float(ima->ibuf);
+
 	if(ima->tpageflag & IMA_TWINANIM) fCurtile= ima->lastframe;
 	else fCurtile= tface->tile;
 
@@ -443,6 +446,9 @@ void update_realtime_image(Image *ima, int x, int y, int w, int h)
 		int skip_pixels = glaGetOneInteger(GL_UNPACK_SKIP_PIXELS);
 		int skip_rows = glaGetOneInteger(GL_UNPACK_SKIP_ROWS);
 
+		if ((ima->ibuf->rect==NULL) && ima->ibuf->rect_float)
+			IMB_rect_from_float(ima->ibuf);
+
 		glBindTexture(GL_TEXTURE_2D, ima->bindcode);
 
 		glPixelStorei(GL_UNPACK_ROW_LENGTH, ima->ibuf->x);