examples/PoolBox/application/src/font_writer.cpp

@@ -23,7 +23,7 @@ void font_writer_setup() {
 void font_writer_update() {
     auto state = JabyEngine::State::create(JabyEngine::Make::PositionI16(8, 8), wiggle_count);
     new_font_writer.write(state, "012345 ABCDEFGHIJKL\nabcedfghijkl\n", JabyEngine::GPU::Color24::Blue(), &wiggle);
-    new_font_writer.write(state, "Miau: %i", JabyEngine::GPU::Color24::Red(), &wiggle, 12345);
+    new_font_writer.write(state, "Mi%iau:", JabyEngine::GPU::Color24::Yellow(), &wiggle, 12345);
 
     if(timer.is_expired_for(50_ms)) {
         timer.reset();

include/stdarg.h

@@ -4,5 +4,6 @@
 typedef __builtin_va_list va_list;
 #define va_start __builtin_va_start
 #define va_end   __builtin_va_end
+#define next_arg __builtin_next_arg 
 
 #endif // !__STDARG__H

support/src/FontWriter/src/font_writer.cpp

@@ -4,6 +4,30 @@
 #include <stdio.h>
 
 namespace JabyEngine {
+    static const char* simple_itoa(char (&buffer)[32], int value, int base) {
+        const bool is_neg = value < 0;
+        int        i      = 32 - 2;
+
+        if(is_neg) {
+            value *= -1;
+        }
+    
+        for(; value && i; i--, value /= base) {
+            char chr = '0' + value%base;
+            if(chr > '9') {
+                chr += ('A' - '9');
+            }
+            buffer[i] = chr;
+        }
+
+        buffer[32 - 1] = '\0';
+        if(is_neg) {
+            buffer[i] = '-';
+            return &buffer[i];
+        }
+        return &buffer[i+1];
+    }
+
     void FontWriter :: setup(const FontBufferInfo& buffer_info, const SimpleTIM& vram_dst, const GPU::SizeI16& font_size) {
         this->prim_buffer   = buffer_info;
         this->tex_page      = Make::TexPage(vram_dst.get_texture_position(), GPU::TexturePageColor::$4bit).linked();
@@ -39,12 +63,19 @@ namespace JabyEngine {
             state.pos.move(primitive->size.width, 0);
             return true;
         };
-        const auto  old_x         = state.pos.x;
+        const auto  old_x    = state.pos.x;
+        const char* prev_str = nullptr;
+        char        buffer[32]; 
 
         while(true) {
-            const auto cur_char = *str++;
+            auto cur_char = *str++;
             switch(cur_char) {
                 case '\0':
+                    if(prev_str) {
+                        str = prev_str;
+                        prev_str = nullptr;
+                        continue;
+                    }
                     return;
 
                 case '\n':
@@ -56,6 +87,18 @@ namespace JabyEngine {
                     state.pos.x += font_size.width;
                     continue;
 
+                case '%':
+                    switch(*str) {
+                        case 'i':
+                            prev_str = str + 1;
+                            str = simple_itoa(buffer, -505, 10);
+                            continue;
+
+                        case '%':
+                            str++;
+                            break;
+                    }
+
                 default:
                     auto& primitive = *this->cur_primitive++;
                     if(!push_char(state, primitive, cur_char)) {