experimenting with UI

1 files changed, 138 insertions, 0 deletions

diff --git a/sources/tga.c b/sources/tga.c
new file mode 100644
index 0000000..ccdd64d
--- /dev/null
+++ b/sources/tga.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2024 dwlr <dweller@cabin.digital>
+ *
+ * BSD 3-Clause License (BSD-3-Clause)
+ * See LICENSE for details
+ */
+
+typedef struct packed tga_head
+{
+    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_head;
+
+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;
+
+
+/* FIXME: return 1x1 magenta tex on fail? */
+bool tga2tex_from_mem(texture* tex, const u8* data)
+{
+    tga_head* hdr = NULL;
+    rgba*     raw = NULL;
+    usize     sz  = 0;
+
+    assert(tex);
+    assert(data);
+
+    hdr = (tga_head*)data;
+    if(hdr->img_type != TGA_IMG_RAW_TRUE) return false;
+    if(hdr->cmap_type) return false;
+
+    /* FIXME: check pixel depth */
+    /* FIXME: 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[0]) * tex->width * tex->height;
+    tex->texels = malloc(sz);
+    if(!tex->texels) return false;
+
+    raw = (rgba*)(((u8*)hdr) + sizeof(*hdr) + hdr->id_len);
+
+    /* FIXME: convert if needed */
+    /* XXX: possibly misaligned */
+    memcpy(tex->texels, raw, sz);
+
+    return true;
+}
+
+
+bool tga2tex_from_file(texture* tex, const char* path)
+{
+    struct stat stat = {0};
+
+    bool   ret  = false;
+    s32    fd   = -1;
+    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);
+
+    munmap(file, stat.st_size);
+clean_close:
+    close(fd);
+
+    return ret;
+}