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/*
* Copyright (C) 2024 dwlr <dweller@cabin.digital>
*
* BSD 3-Clause License (BSD-3-Clause)
* See LICENSE for details
*/
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
typedef struct packed tga_hdr
{
u8 id_len;
u8 cmap_type;
u8 img_type;
struct packed
{
u16 first_entry_idx;
u16 length;
u8 entry_size;
} cmap_spec;
struct packed
{
u16 xorig;
u16 yorig;
u16 width;
u16 height;
u8 depth;
u8 desc;
} img_spec;
} tga_hdr;
typedef enum tga_img_type
{
TGA_IMG_NONE,
TGA_IMG_RAW_CMAP,
TGA_IMG_RAW_TRUE,
TGA_IMG_RAW_BW,
TGA_IMG_RLE_CMAP,
TGA_IMG_RLE_TRUE,
TGA_IMG_RLE_BW,
TGA_IMG_TYPE_SIZE
} tga_img_type;
typedef union rgba
{
u32 rgba;
struct
{
u8 b;
u8 g;
u8 r;
u8 a;
} c;
} rgba;
#define A c.a
#define R c.r
#define G c.g
#define B c.b
typedef struct texture
{
ssize width;
ssize height;
rgba* texels;
} texture;
bool tga2tex_from_mem(texture* tex, const u8* data, ssize sz)
{
tga_hdr* hdr = NULL;
rgba* img_dat = NULL;
assert(tex);
assert(data);
assert(sz > 0);
hdr = (tga_hdr*)data;
if(hdr->img_type != TGA_IMG_RAW_TRUE) return false;
if(hdr->cmap_type) return false;
/* FIXME(dwlr): check pixel depth */
/* FIXME(dwlr): check bit 5 and 4 of img_spec.desc (ordering) */
tex->width = hdr->img_spec.width;
tex->height = hdr->img_spec.height;
sz = sizeof(*tex->texels) * tex->width * tex->height;
tex->texels = malloc(sz);
img_dat = (rgba*)(((u8*)hdr) + sizeof(*hdr) + hdr->id_len);
/* FIXME(dwlr): convert if needed */
memcpy(tex->texels, img_dat, sz);
return true;
}
bool tga2tex_from_file(texture* tex, const char* path)
{
struct stat stat = {0};
bool ret = false;
s32 fd = -1;
ssize sz = 0;
u8* file = NULL;
assert(tex);
assert(path);
fd = open(path, O_RDONLY);
if(fd < 0) goto clean_close;
if(fstat(fd, &stat) != 0) goto clean_close;
file = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
if(file == MAP_FAILED) goto clean_close;
ret = tga2tex_from_mem(tex, file, sz);
munmap(file, stat.st_size);
clean_close:
close(fd);
return ret;
}
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