Add more error explanations in the BMP image loader

This closes #32166 and closes #30629.

1 files changed, 19 insertions, 12 deletions

diff --git a/modules/bmp/image_loader_bmp.cpp b/modules/bmp/image_loader_bmp.cpp
index ac4e534983..757afeb9e3 100644
--- a/modules/bmp/image_loader_bmp.cpp
+++ b/modules/bmp/image_loader_bmp.cpp
@@ -51,16 +51,20 @@ Error ImageLoaderBMP::convert_to_image(Ref<Image> p_image,
 
 		if (bits_per_pixel == 1) {
 			// Requires bit unpacking...
-			ERR_FAIL_COND_V(width % 8 != 0, ERR_UNAVAILABLE);
-			ERR_FAIL_COND_V(height % 8 != 0, ERR_UNAVAILABLE);
+			ERR_FAIL_COND_V_MSG(width % 8 != 0, ERR_UNAVAILABLE,
+					vformat("1-bpp BMP images must have a width that is a multiple of 8, but the imported BMP is %d pixels wide.", int(width)));
+			ERR_FAIL_COND_V_MSG(height % 8 != 0, ERR_UNAVAILABLE,
+					vformat("1-bpp BMP images must have a height that is a multiple of 8, but the imported BMP is %d pixels tall.", int(height)));
 
 		} else if (bits_per_pixel == 4) {
 			// Requires bit unpacking...
-			ERR_FAIL_COND_V(width % 2 != 0, ERR_UNAVAILABLE);
-			ERR_FAIL_COND_V(height % 2 != 0, ERR_UNAVAILABLE);
+			ERR_FAIL_COND_V_MSG(width % 2 != 0, ERR_UNAVAILABLE,
+					vformat("4-bpp BMP images must have a width that is a multiple of 2, but the imported BMP is %d pixels wide.", int(width)));
+			ERR_FAIL_COND_V_MSG(height % 2 != 0, ERR_UNAVAILABLE,
+					vformat("4-bpp BMP images must have a height that is a multiple of 2, but the imported BMP is %d pixels tall.", int(height)));
 
 		} else if (bits_per_pixel == 16) {
-			ERR_FAIL_V(ERR_UNAVAILABLE);
+			ERR_FAIL_V_MSG(ERR_UNAVAILABLE, "16-bpp BMP images are not supported.");
 		}
 
 		// Image data (might be indexed)
@@ -72,7 +76,7 @@ Error ImageLoaderBMP::convert_to_image(Ref<Image> p_image,
 		} else { // color
 			data_len = width * height * 4;
 		}
-		ERR_FAIL_COND_V(data_len == 0, ERR_BUG);
+		ERR_FAIL_COND_V_MSG(data_len == 0, ERR_BUG, "Couldn't parse the BMP image data.");
 		err = data.resize(data_len);
 
 		uint8_t *data_w = data.ptrw();
@@ -215,13 +219,15 @@ Error ImageLoaderBMP::load_image(Ref<Image> p_image, FileAccess *f,
 
 			// Info Header
 			bmp_header.bmp_info_header.bmp_header_size = f->get_32();
-			ERR_FAIL_COND_V(bmp_header.bmp_info_header.bmp_header_size < BITMAP_INFO_HEADER_MIN_SIZE, ERR_FILE_CORRUPT);
+			ERR_FAIL_COND_V_MSG(bmp_header.bmp_info_header.bmp_header_size < BITMAP_INFO_HEADER_MIN_SIZE, ERR_FILE_CORRUPT,
+					vformat("Couldn't parse the BMP info header. The file is likely corrupt: %s", f->get_path()));
 
 			bmp_header.bmp_info_header.bmp_width = f->get_32();
 			bmp_header.bmp_info_header.bmp_height = f->get_32();
 
 			bmp_header.bmp_info_header.bmp_planes = f->get_16();
-			ERR_FAIL_COND_V(bmp_header.bmp_info_header.bmp_planes != 1, ERR_FILE_CORRUPT);
+			ERR_FAIL_COND_V_MSG(bmp_header.bmp_info_header.bmp_planes != 1, ERR_FILE_CORRUPT,
+					vformat("Couldn't parse the BMP planes. The file is likely corrupt: %s", f->get_path()));
 
 			bmp_header.bmp_info_header.bmp_bit_count = f->get_16();
 			bmp_header.bmp_info_header.bmp_compression = f->get_32();
@@ -236,10 +242,10 @@ Error ImageLoaderBMP::load_image(Ref<Image> p_image, FileAccess *f,
 				case BI_RLE4:
 				case BI_CMYKRLE8:
 				case BI_CMYKRLE4: {
-					// Stop parsing
-					String bmp_path = f->get_path();
+					// Stop parsing.
 					f->close();
-					ERR_FAIL_V_MSG(ERR_UNAVAILABLE, "Compressed BMP files are not supported: " + bmp_path + ".");
+					ERR_FAIL_V_MSG(ERR_UNAVAILABLE,
+							vformat("Compressed BMP files are not supported: %s", f->get_path()));
 				} break;
 			}
 			// Don't rely on sizeof(bmp_file_header) as structure padding
@@ -255,7 +261,8 @@ Error ImageLoaderBMP::load_image(Ref<Image> p_image, FileAccess *f,
 			if (bmp_header.bmp_info_header.bmp_bit_count <= 8) {
 				// Support 256 colors max
 				color_table_size = 1 << bmp_header.bmp_info_header.bmp_bit_count;
-				ERR_FAIL_COND_V(color_table_size == 0, ERR_BUG);
+				ERR_FAIL_COND_V_MSG(color_table_size == 0, ERR_BUG,
+						vformat("Couldn't parse the BMP color table: %s", f->get_path()));
 			}
 
 			Vector<uint8_t> bmp_color_table;