1 files changed, 90 insertions, 0 deletions
diff --git a/bmpconv.c b/bmpconv.c
new file mode 100644
index 0000000..446af30
--- /dev/null
+++ b/bmpconv.c
@@ -0,0 +1,90 @@
+#include <stdio.h>
+#include <string.h>
+
+#include "render.h"
+
+int main(int argc, char** argv) {
+	FILE* outfile, * infile;
+	char bmp_magic[2];
+	int ret = 0;
+	unsigned bmp_offset;
+	int bmp_w, bmp_h, x, y, i, s;
+	unsigned short bmp_bits;
+	char magic[4] = { 'I', 'M', 'A', 'G' };
+	Colour pixel;
+	unsigned char t;
+
+	if (argc < 3) {
+		fprintf(stderr, "Usage: %s infile outfile.\n", argv[0]);
+		return 1;
+	}
+
+	infile = fopen(argv[1], "rb");
+	if (!infile) {
+		fprintf(stderr, "Failed to open %s.\n", argv[1]);
+		return 2;
+	}
+
+	outfile = fopen(argv[2], "wb");
+	if (!outfile) {
+		fprintf(stderr, "Failed to open %s.\n", argv[2]);
+		fclose(infile);
+		return 2;
+	}
+
+	fread(bmp_magic, 2, 1, infile);
+	if (bmp_magic[0] != 'B' || bmp_magic[1] != 'M') {
+		ret = 3;
+		fprintf(stderr, "Not a valid bitmap file.\n");
+		goto end;
+	}
+	
+	fseek(infile, 10, SEEK_SET);
+	fread(&bmp_offset, 4, 1, infile);
+
+	fseek(infile, 18, SEEK_SET);
+	fread(&bmp_w,    4, 1, infile);
+	fread(&bmp_h,    4, 1, infile);
+	fseek(infile, 28, SEEK_SET);
+	fread(&bmp_bits, 2, 1, infile);
+
+	if (bmp_bits != 32) {
+		ret = 4;
+		fprintf(stderr, "Bitmap must have 32 bit pixels. %d\n", bmp_bits);
+		goto end;
+	}
+
+	fseek(infile, bmp_offset, SEEK_SET);
+
+	fwrite(magic,  1, 4, outfile);
+	fwrite(&bmp_w, 1, 4, outfile);
+	fwrite(&bmp_h, 1, 4, outfile);
+
+	s = bmp_w * bmp_h;
+	/* Allocate space. */
+	for (i = 0; i < s; i++) {
+		fwrite(&pixel, 1, 4, outfile);
+	}
+
+	fseek(outfile, 12, SEEK_SET);
+	for (y = 0; y < bmp_h; y++) {
+		for (x = 0; x < bmp_w; x++) {
+			fread(&pixel, 1, 4, infile);
+			t = pixel.r;
+			pixel.r = pixel.b;
+			pixel.b = t;
+			/* Do a lil flip. */
+			fseek(
+				outfile,
+				12 + (x + (bmp_h - y - 1) * bmp_w) * 4,
+				SEEK_SET
+			);
+			fwrite(&pixel, 1, 4, outfile);
+		}
+	}
+
+end:
+	fclose(infile);
+	fclose(outfile);
+	return ret;
+}