Add PNG renderer

1 files changed, 167 insertions, 0 deletions

diff --git a/image.c b/image.c
new file mode 100644
index 0000000..ef583e9
--- /dev/null
+++ b/image.c
@@ -0,0 +1,167 @@
+/* Copyright (C) 2018  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <zlib.h>
+
+#include "torus.h"
+
+static const uint8_t Palette[16][3] = {
+	{ 0x00, 0x00, 0x00 },
+	{ 0xAA, 0x00, 0x00 },
+	{ 0x00, 0xAA, 0x00 },
+	{ 0xAA, 0x55, 0x00 },
+	{ 0x00, 0x00, 0xAA },
+	{ 0xAA, 0x00, 0xAA },
+	{ 0x00, 0xAA, 0xAA },
+	{ 0xAA, 0xAA, 0xAA },
+	{ 0x55, 0x55, 0x55 },
+	{ 0xFF, 0x55, 0x55 },
+	{ 0x55, 0xFF, 0x55 },
+	{ 0xFF, 0xFF, 0x55 },
+	{ 0x55, 0x55, 0xFF },
+	{ 0xFF, 0x55, 0xFF },
+	{ 0x55, 0xFF, 0xFF },
+	{ 0xFF, 0xFF, 0xFF },
+};
+
+static uint32_t crc;
+static void pngWrite(const void *ptr, size_t size) {
+	fwrite(ptr, size, 1, stdout);
+	if (ferror(stdout)) err(EX_IOERR, "(stdout)");
+	crc = crc32(crc, ptr, size);
+}
+static void pngInt(uint32_t host) {
+	uint32_t net = htonl(host);
+	pngWrite(&net, 4);
+}
+static void pngChunk(char type[static 4], uint32_t size) {
+	pngInt(size);
+	crc = crc32(0, Z_NULL, 0);
+	pngWrite(type, 4);
+}
+
+int main(int argc, char *argv[]) {
+	const char *fontPath = "default8x16.psfu";
+	const char *dataPath = "torus.dat";
+	uint32_t tileX = TileInitX;
+	uint32_t tileY = TileInitY;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "d:f:x:y:"))) {
+		switch (opt) {
+			break; case 'd': dataPath = optarg;
+			break; case 'f': fontPath = optarg;
+			break; case 'x': tileX = strtoul(optarg, NULL, 0) % TileCols;
+			break; case 'y': tileY = strtoul(optarg, NULL, 0) % TileRows;
+			break; default:  return EX_USAGE;
+		}
+	}
+
+	FILE *file = fopen(fontPath, "r");
+	if (!file) err(EX_NOINPUT, "%s", fontPath);
+
+	struct {
+		uint32_t magic;
+		uint32_t version;
+		uint32_t size;
+		uint32_t flags;
+		struct {
+			uint32_t len;
+			uint32_t size;
+			uint32_t height;
+			uint32_t width;
+		} glyph;
+	} psf;
+	size_t len = fread(&psf, sizeof(psf), 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", fontPath);
+	if (len < 1) errx(EX_DATAERR, "%s: truncated header", fontPath);
+
+	uint8_t glyphs[psf.glyph.len][psf.glyph.height][(psf.glyph.width + 7) / 8];
+	len = fread(glyphs, psf.glyph.size, psf.glyph.len, file);
+	if (ferror(file)) err(EX_IOERR, "%s", fontPath);
+	if (len < 1) errx(EX_DATAERR, "%s: truncated glyphs", fontPath);
+	fclose(file);
+
+	int fd = open(dataPath, O_RDONLY);
+	if (fd < 0) err(EX_NOINPUT, "%s", dataPath);
+
+	struct Tile *tile = mmap(
+		NULL, sizeof(struct Tile),
+		PROT_READ, MAP_SHARED,
+		fd, sizeof(struct Tile) * (TileRows * tileY + tileX)
+	);
+	if (tile == MAP_FAILED) err(EX_IOERR, "mmap");
+	close(fd);
+
+	pngWrite("\x89PNG\r\n\x1A\n", 8);
+
+	uint32_t width = CellCols * psf.glyph.width;
+	uint32_t height = CellRows * psf.glyph.height;
+
+	pngChunk("IHDR", 13);
+	pngInt(width);
+	pngInt(height);
+	pngWrite("\x08\x03\x00\x00\x00", 5);
+	pngInt(crc);
+
+	pngChunk("PLTE", sizeof(Palette));
+	pngWrite(Palette, sizeof(Palette));
+	pngInt(crc);
+
+	uint8_t data[height][1 + width];
+	memset(data, 0, sizeof(data));
+
+	for (uint32_t y = 0; y < CellRows; ++y) {
+		for (uint32_t x = 0; x < CellCols; ++x) {
+			uint8_t cell = tile->cells[y][x];
+			uint8_t fg = tile->colors[y][x] & 0x0F;
+			uint8_t bg = tile->colors[y][x] >> 4;
+
+			uint32_t row = psf.glyph.height * y;
+			uint32_t col = psf.glyph.width * x;
+			for (uint8_t gy = 0; gy < psf.glyph.height; ++gy) {
+				for (uint8_t gx = 0; gx < psf.glyph.width; ++gx) {
+					uint8_t bit = glyphs[cell][gy][gx / 8] >> (7 - gx % 8) & 1;
+					data[row + gy][1 + col + gx] = (bit ? fg : bg);
+				}
+			}
+		}
+	}
+
+	uLong size = compressBound(sizeof(data));
+	uint8_t deflate[size];
+	int error = compress(deflate, &size, (Byte *)data, sizeof(data));
+	if (error != Z_OK) errx(EX_SOFTWARE, "compress: %d", error);
+
+	pngChunk("IDAT", size);
+	pngWrite(deflate, size);
+	pngInt(crc);
+
+	pngChunk("IEND", 0);
+	pngInt(crc);
+
+	return EX_OK;
+}