fix [#27607] Scene's render.filepath gets cropped to 159 characters

use 240 char limit, remove backbuffer path which wasn't used.

source/blender/blenkernel/intern/blender.c

@@ -180,7 +180,6 @@ static void clean_paths(Main *main)
 	BLI_bpathIterator_free(bpi);
 
 	for(scene= main->scene.first; scene; scene= scene->id.next) {
-		BLI_clean(scene->r.backbuf);
 		BLI_clean(scene->r.pic);
 	}
 }

source/blender/blenkernel/intern/scene.c

@@ -476,8 +476,7 @@ Scene *add_scene(const char *name)
 	sce->audio.doppler_factor = 1.0;
 	sce->audio.speed_of_sound = 343.3;
 
-	strcpy(sce->r.backbuf, "//backbuf");
-	strcpy(sce->r.pic, U.renderdir);
+	BLI_strncpy(sce->r.pic, U.renderdir, sizeof(sce->r.pic));
 
 	BLI_init_rctf(&sce->r.safety, 0.1f, 0.9f, 0.1f, 0.9f);
 	sce->r.osa= 8;

source/blender/makesdna/DNA_scene_types.h

@@ -350,7 +350,7 @@ typedef struct RenderData {
 	float bake_maxdist, bake_biasdist, bake_pad;
 
 	/* paths to backbufffer, output */
-	char backbuf[160], pic[160];
+	char pic[240];
 
 	/* stamps flags. */
 	int stamp;

source/blender/makesdna/DNA_userdef_types.h

@@ -305,7 +305,7 @@ typedef struct UserDef {
 	int savetime;
 	char tempdir[160];	// FILE_MAXDIR length
 	char fontdir[160];
-	char renderdir[160];
+	char renderdir[240]; // FILE_MAX length
 	char textudir[160];
 	char plugtexdir[160];
 	char plugseqdir[160];

source/blender/render/intern/source/pipeline.c

@@ -2070,8 +2070,7 @@ static void load_backbuffer(Render *re)
 	if(re->r.alphamode == R_ADDSKY) {
 		ImBuf *ibuf;
 		char name[256];
-		
-		BLI_strncpy(name, re->r.backbuf, sizeof(name));
+
 		BLI_path_abs(name, re->main->name);
 		BLI_path_frame(name, re->r.cfra, 0);
 		

source/creator/creator.c

@@ -538,7 +538,7 @@ static int set_output(int argc, const char **argv, void *data)
 	if (argc >= 1){
 		if (CTX_data_scene(C)) {
 			Scene *scene= CTX_data_scene(C);
-			BLI_strncpy(scene->r.pic, argv[1], FILE_MAXDIR);
+			BLI_strncpy(scene->r.pic, argv[1], sizeof(scene->r.pic));
 		} else {
 			printf("\nError: no blend loaded. cannot use '-o / --render-output'.\n");
 		}