From bdbb811ac1a60920f87a5640f2f68e7f349fe2c0 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Thu, 4 May 2023 22:55:50 +0100
Subject: Include PNG images as data

---
 tr8as.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

(limited to 'tr8as.c')

diff --git a/tr8as.c b/tr8as.c
index 30beda6..c9bd816 100644
--- a/tr8as.c
+++ b/tr8as.c
@@ -29,6 +29,10 @@
 #include <strings.h>
 #include <ctype.h>
 
+#define STB_IMAGE_IMPLEMENTATION
+#define STBI_ONLY_PNG
+#include "stb_image.h"
+
 #define MAX_LINE 1024
 #define MAX_ID 0x40
 #define MAX_LABELS 0x200
@@ -88,6 +92,27 @@ typedef struct
     uint8_t (*parse)(As *, char *);
 } InstParse;
 
+/* used to map RGB values to palette index when including a PNG image */
+static uint8_t palette[16][3] =
+{
+    { 0x00, 0x00, 0x00 },
+    { 0x00, 0x00, 0xaa },
+    { 0x00, 0xaa, 0x00 },
+    { 0x00, 0xaa, 0xaa },
+    { 0xaa, 0x00, 0x00 },
+    { 0xaa, 0x00, 0xaa },
+    { 0xaa, 0x55, 0x00 },
+    { 0xaa, 0xaa, 0xaa },
+    { 0x55, 0x55, 0x55 },
+    { 0x55, 0x55, 0xff },
+    { 0x55, 0xff, 0x55 },
+    { 0x55, 0xff, 0xff },
+    { 0xff, 0x55, 0x55 },
+    { 0xff, 0x55, 0xff },
+    { 0xff, 0xff, 0x55 },
+    { 0xff, 0xff, 0xff },
+};
+
 static uint8_t error_l(const char *msg, Location *loc, const char *reason)
 {
     fprintf(stderr, "%s (%s:%d): %s\n", msg, loc->filename, loc->line, reason);
@@ -431,6 +456,64 @@ static uint8_t parse_include(As *as, char *c)
     return 1;
 }
 
+static uint8_t parse_incpng(As *as, char *c)
+{
+    /* XXX: may be support longer filenames */
+    char word[MAX_ID + 1];
+    uint8_t wlen;
+
+    /* .incpng "filename" */
+
+    next_string(c, word, &wlen);
+    if (wlen == 0)
+        return error_l("Syntax error", &as->loc, "expected string");
+
+    if (strcasecmp(word + wlen - 4, ".png"))
+        return error_l("Invalid input", &as->loc, "expected PNG file");
+
+    int x, y, n;
+    uint8_t rc = 1;
+
+    unsigned char *data = stbi_load(word, &x, &y, &n, 3);
+    if (!data)
+        return error_l("Invalid input", &as->loc, "expected PNG file");
+
+    if (x * y + as->addr > UINT16_MAX)
+    {
+        rc = error_l("Overflow in incpng", &as->loc, word);
+        goto exit_parseinc;
+    }
+
+    /* TODO: mask */
+
+    uint16_t addr = as->addr;
+    uint8_t index;
+
+    /* map RGB values to the palette indexes */
+    for (int i = 0; i < x * y * 3; i += 3)
+    {
+        for (index = 0; index < 16; index++)
+            if (data[i] == palette[index][0]
+                    && data[i + 1] == palette[index][1]
+                    && data[i + 2] == palette[index][2])
+            {
+                as->out[addr++] = index;
+                break;
+            }
+        if (index == 16)
+            addr++;
+    }
+
+    as->addr = addr;
+    if (as->addr > as->size)
+        as->size = as->addr;
+
+exit_parseinc:
+    stbi_image_free(data);
+
+    return rc;
+}
+
 static uint8_t parse_incbin(As *as, char *c)
 {
     /* XXX: may be support longer filenames */
@@ -1312,6 +1395,7 @@ static uint8_t parse_ld(As *as, char *c)
 
 static InstParse insts[] = {
     { ".include", parse_include },
+    { ".incpng", parse_incpng },
     { ".incbin", parse_incbin },
     { ".org", parse_org },
     { ".equ", parse_equ },
-- 
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