From 6c080c486f987ba30e7efe209f1310c6cfca0beb Mon Sep 17 00:00:00 2001
From: dweller <dweller@cabin.digital>
Date: Wed, 31 Jul 2024 02:37:41 +0300
Subject: initial commit

---
 example/tga.c | 145 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 example/tga.c

(limited to 'example/tga.c')

diff --git a/example/tga.c b/example/tga.c
new file mode 100644
index 0000000..6e8eb34
--- /dev/null
+++ b/example/tga.c
@@ -0,0 +1,145 @@
+/*
+ * 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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