[lib][tga] routines to decode Targa files
diff --git a/include/lib/tga.h b/include/lib/tga.h
new file mode 100644
index 0000000..62ffb43
--- /dev/null
+++ b/include/lib/tga.h
@@ -0,0 +1,10 @@
+#ifndef __LIB_TGA_H
+#define __LIB_TGA_H
+
+#include <lib/gfx.h>
+#include <sys/types.h>
+
+gfx_surface *tga_decode(const void *ptr, size_t len, gfx_format format);
+
+#endif
+
diff --git a/lib/tga/rules.mk b/lib/tga/rules.mk
new file mode 100644
index 0000000..8538f47
--- /dev/null
+++ b/lib/tga/rules.mk
@@ -0,0 +1,4 @@
+LOCAL_DIR := $(GET_LOCAL_DIR)
+
+OBJS += \
+ $(LOCAL_DIR)/tga.o
diff --git a/lib/tga/tga.c b/lib/tga/tga.c
new file mode 100644
index 0000000..7b38ded
--- /dev/null
+++ b/lib/tga/tga.c
@@ -0,0 +1,230 @@
+/*
+ * Copyright (c) 2008-2010 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * @file
+ * @brief Parse tga format files
+ *
+ * @ingroup graphics
+ */
+
+#include <debug.h>
+#include <compiler.h>
+#include <lib/tga.h>
+
+#define LOCAL_TRACE 0
+
+struct tga_header {
+ uint8_t idlength;
+ uint8_t colormaptype;
+ uint8_t datatypecode;
+ uint16_t colormaporigin;
+ uint16_t colormaplength;
+ uint8_t colormapdepth;
+ uint16_t x_origin;
+ uint16_t y_origin;
+ uint16_t width;
+ uint16_t height;
+ uint8_t bitsperpixel;
+ uint8_t imagedescriptor;
+} __PACKED;
+
+static void print_tga_info(const struct tga_header *header)
+{
+ LTRACEF("idlength %hhd\n", header->idlength);
+ LTRACEF("colormaptype %hhd\n", header->colormaptype);
+ LTRACEF("datatypecode %hhd\n", header->datatypecode);
+ LTRACEF("colormaporigin %hd\n", header->colormaporigin);
+ LTRACEF("colormaplength %hd\n", header->colormaplength);
+ LTRACEF("colormapdepth %hhd\n", header->colormapdepth);
+ LTRACEF("x_origin %hd\n", header->x_origin);
+ LTRACEF("y_origin %hd\n", header->y_origin);
+ LTRACEF("width %hd\n", header->width);
+ LTRACEF("height %hd\n", header->height);
+ LTRACEF("bitsperpixel %hhd\n", header->bitsperpixel);
+ LTRACEF("imagedescriptor %hhd\n", header->imagedescriptor);
+
+}
+
+static void decode_2byte(gfx_surface *surface, uint x, uint y, const void *input)
+{
+ const uint8_t *in = (const uint8_t *)input;
+
+// printf("in 0x%hhx 0x%hhx\n", in[0], in[1]);
+ uint r,g,b;
+
+ b = (in[0] & 0x1f) << 3;
+ g = (((in[0] >> 5) & 0x7) | ((in[1] & 0x3) << 3)) << 3;
+ r = ((in[1] >> 2) & 0x1f) << 3;
+
+ gfx_putpixel(surface, x, y, 0xff000000 | r << 16 | g << 8 | b);
+}
+
+static void decode_3byte(gfx_surface *surface, uint x, uint y, const void *input)
+{
+ const uint8_t *in = (const uint8_t *)input;
+
+// printf("in 0x%hhx 0x%hhx\n", in[0], in[1]);
+
+ gfx_putpixel(surface, x, y, 0xff000000 | in[2] << 16 | in[1] << 8 | in[0]);
+}
+
+static void decode_4byte(gfx_surface *surface, uint x, uint y, const void *input)
+{
+ const uint8_t *in = (const uint8_t *)input;
+
+// printf("in 0x%hhx 0x%hhx 0x%hhx 0x%hhx\n", in[0], in[1], in[2], in[3]);
+
+ if (in[3] == 0)
+ gfx_putpixel(surface, x, y, 0);
+ else
+ gfx_putpixel(surface, x, y, in[3] << 24 | in[2] << 16 | in[1] << 8 | in[0]);
+}
+
+/**
+ * @brief Decode a tga image
+ *
+ * @param ptr Pointer to tga data in memory
+ * @param len Length of tga data
+ * @param format Desired format of returned graphics surface
+ *
+ * @return Graphics surface or NULL on error.
+ *
+ * @ingroup graphics
+ */
+gfx_surface *tga_decode(const void *ptr, size_t len, gfx_format format)
+{
+ const struct tga_header *header = (const struct tga_header *)ptr;
+
+ LTRACEF("ptr %p, len %zu\n", ptr, len);
+
+#if LOCAL_TRACE > 0
+ print_tga_info(header);
+#endif
+
+ /* do some sanity checks */
+ if (header->datatypecode != 2 && header->datatypecode != 10) {
+ dprintf(INFO, "tga_decode: unknown data type %d\n", header->datatypecode);
+ return NULL;
+ }
+ if (header->bitsperpixel != 16 && header->bitsperpixel != 24 && header->bitsperpixel != 32) {
+ dprintf(INFO, "tga_decode: unsupported bits per pixel %d\n", header->bitsperpixel);
+ return NULL;
+ }
+ if (header->colormaptype != 0) {
+ dprintf(INFO, "tga_decode: has colormap, can't handle\n");
+ return NULL;
+ }
+
+ const void *imagestart = ((const uint8_t *)ptr + sizeof(struct tga_header) + header->idlength);
+
+ /* create a surface to hold the decoded bits */
+ gfx_surface *surface = gfx_create_surface(NULL, header->width, header->height, header->width, format);
+ DEBUG_ASSERT(surface);
+
+ /* copy the bits out */
+ void (*decodefunc)(gfx_surface *, uint x, uint y, const void *) = NULL;
+
+ uint step = 1;
+ if (header->bitsperpixel == 16) {
+ step = 2;
+ decodefunc = decode_2byte;
+ } else if (header->bitsperpixel == 24) {
+ step = 3;
+ decodefunc = decode_3byte;
+ } else if (header->bitsperpixel == 32) {
+ step = 4;
+ decodefunc = decode_4byte;
+ }
+
+ if (header->datatypecode == 2) {
+ /* no RLE */
+ uint pos = 0;
+ uint x, y;
+ uint surfacey;
+
+ for (y = 0; y < header->height; y++) {
+
+ if ((header->imagedescriptor & (1 << 5)) == 0)
+ surfacey = (surface->height - 1) - y;
+ else
+ surfacey = y;
+
+ for (x = 0; x < header->width; x++) {
+ decodefunc(surface, x, surfacey, (const uint8_t *)imagestart + pos);
+ pos += step;
+ }
+ }
+ } else if (header->datatypecode == 10) {
+ /* RLE compression */
+ uint pos = 0;
+ uint count = 0;
+ uint x, y;
+
+ x = 0;
+ if ((header->imagedescriptor & (1 << 5)) == 0)
+ y = header->height - 1;
+ else
+ y = 0;
+
+ while (count < (uint)header->height * (uint)header->width) {
+ uint runpos;
+
+ uint8_t run = *((const uint8_t *)imagestart + pos);
+ bool repeat_run = (run & 0x80);
+ uint runlen = (run & 0x7f) + 1;
+
+// printf("pos 0x%x count %u run 0x%hhx runtype %d runlen %u\n", pos, count, run, run & 0x80, runlen);
+
+ /* consume the run byte */
+ pos++;
+
+ /* start of a run */
+ for (runpos = 0; runpos < runlen; runpos++) {
+ decodefunc(surface, x, y, (const uint8_t *)imagestart + pos);
+ count++;
+
+ x++;
+ if (x == surface->width) {
+ if ((header->imagedescriptor & (1 << 5)) == 0)
+ y--;
+ else
+ y++;
+ x = 0;
+ }
+
+ /* if a run of raw pixels, consume an input pixel */
+ if (!repeat_run)
+ pos += step;
+ }
+ /* if this was a run of repeated pixels, consume the one input pixel we repeated */
+ if (repeat_run)
+ pos += step;
+
+ }
+// printf("done with RLE: x %d, y %d, pos %d, count %d\n", x, y, pos, count);
+ }
+
+ return surface;
+}
+