batcher and spritefont support utf8 strings

include/blah/containers/str.h

@@ -75,6 +75,14 @@ namespace Blah
 
 		// ensures the string has the given capacity
 		void reserve(int capacity);
+		
+		// Returns the unicode value at the given index.
+		// Assumes the index is a valid utf8 starting point.
+		uint32_t utf8_at(int index) const;
+
+		// Returns the byte-length of the utf8 character.
+		// Assumes the index is a valid utf8 starting point.
+		int utf8_length(int index) const;
 
 		// appends the given character
 		Str& append(char c);

src/containers/str.cpp

@@ -79,6 +79,50 @@ void Str::set_length(int len)
 	m_length = len;
 }
 
+uint32_t Str::utf8_at(int index) const
+{
+	uint32_t charcode = 0;
+	
+	int t = (unsigned char)(this->operator[](index++));
+	if (t < 128)
+		return t;
+
+	int high_bit_mask = (1 << 6) - 1;
+	int high_bit_shift = 0;
+	int total_bits = 0;
+	int other_bits = 6;
+
+	while ((t & 0xC0) == 0xC0)
+	{
+		t <<= 1;
+		t &= 0xff;
+		total_bits += 6;
+		high_bit_mask >>= 1;
+		high_bit_shift++;
+		charcode <<= other_bits;
+		charcode |= ((unsigned char)(this->operator[](index++))) & ((1 << other_bits) - 1);
+	}
+	charcode |= ((t >> high_bit_shift) & high_bit_mask) << total_bits;
+
+	return charcode;
+}
+
+int Str::utf8_length(int index) const
+{
+	auto c = this->operator[](index);
+	if ((c & 0xFE) == 0xFC)
+		return 6;
+	if ((c & 0xFC) == 0xF8)
+		return 5;
+	if ((c & 0xF8) == 0xF0)
+		return 4;
+	else if ((c & 0xF0) == 0xE0)
+		return 3;
+	else if ((c & 0xE0) == 0xC0)
+		return 2;
+	return 1;
+}
+
 Str& Str::append(char c)
 {
 	reserve(m_length + 1);

src/drawing/batch.cpp

@@ -1046,6 +1046,7 @@ void Batch::str(const SpriteFont& font, const String& text, const Vec2& pos, Tex
 	else
 		offset.y = (font.ascent + font.descent + font.height() - font.height_of(text)) * 0.5f;
 
+	uint32_t last = 0;
 	for (int i = 0, l = text.length(); i < l; i++)
 	{
 		if (text[i] == '\n')
@@ -1061,29 +1062,34 @@ void Batch::str(const SpriteFont& font, const String& text, const Vec2& pos, Tex
 			else
 				offset.x = -font.width_of_line(text, i + 1) * 0.5f;
 
+			last = 0;
 			continue;
 		}
 
-		// TODO:
-		// This doesn't parse Unicode! 
-		// It will assume it's a 1-byte ASCII char which is incorrect
-		const auto& ch = font[text[i]];
+		// get the character
+		uint32_t next = text.utf8_at(i);
+		const auto& ch = font[next];
 
+		// draw it, if the subtexture exists
 		if (ch.subtexture.texture)
 		{
 			Vec2 at = offset + ch.offset;
 
 			if (i > 0 && text[i - 1] != '\n')
-			{
-				// TODO:
-				// This doesn't parse Unicode! 
-				at.x += font.get_kerning(text[i - 1], text[i]);
-			}
+				at.x += font.get_kerning(last, next);
 
 			tex(ch.subtexture, at, color);
 		}
 
+		// move forward
 		offset.x += ch.advance;
+
+		// increment past current character
+		// (minus 1 since the for loop iterator increments as well)
+		i += text.utf8_length(i) - 1;
+		
+		// keep last codepoint for next char for kerning
+		last = next;
 	}
 
 	pop_matrix();

src/drawing/spritefont.cpp

@@ -77,18 +77,33 @@ SpriteFont& SpriteFont::operator=(SpriteFont && src) noexcept
 float SpriteFont::width_of(const String& text) const
 {
 	float width = 0;
-	float lineWidth = 0;
-	for (auto it = text.begin(); it != text.end(); it++)
+	float line_width = 0;
+
+	uint32_t last;
+	for (int i = 0; i < text.length(); i ++)
 	{
-		if (*it == '\n')
-			lineWidth = 0;
+		if (text[i] == '\n')
+		{
+			line_width = 0;
+			continue;
+		}
 
-		// TODO: this doesn't account for Unicode values!
-		uint32_t codepoint = *it;
+		// get codepoint
+		auto next = text.utf8_at(i);
 
-		lineWidth += this->operator[](codepoint).advance;
-		if (lineWidth > width)
-			width = lineWidth;
+		// increment length
+		line_width += this->operator[](next).advance;
+		
+		// add kerning
+		if (i > 0)
+			line_width += get_kerning(last, next);
+
+		if (line_width > width)
+			width = line_width;
+
+		// move to thext utf8 character
+		i += text.utf8_length(i) - 1;
+		last = next;
 	}
 
 	return width;
@@ -99,19 +114,31 @@ float SpriteFont::width_of_line(const String& text, int start) const
 	if (start < 0) return 0;
 	if (start >= text.length()) return 0;
 
-	float lineWidth = 0;
-	for (auto it = text.begin() + start; it != text.end(); it++)
+	float width = 0;
+
+	uint32_t last;
+	for (int i = start; i < text.length(); i ++)
 	{
-		if (*it == '\n')
-			return lineWidth;
+		if (text[i] == '\n')
+			return width;
 
-		// TODO: this doesn't account for Unicode values!
-		uint32_t codepoint = *it;
+		// get codepoint
+		auto next = text.utf8_at(i);
 
-		lineWidth += this->operator[](codepoint).advance;
+		// increment length
+		width += this->operator[](next).advance;
+		
+		// add kerning
+		if (i > 0)
+			width += get_kerning(last, next);
+
+		// move to thext utf8 character
+		i += text.utf8_length(i) - 1;
+
+		last = next;
 	}
 
-	return lineWidth;
+	return width;
 }
 
 float SpriteFont::height_of(const String& text) const
@@ -120,10 +147,11 @@ float SpriteFont::height_of(const String& text) const
 		return 0;
 
 	float height = line_height();
-	for (auto it = text.begin(); it != text.end(); it++)
+	for (int i = 0; i < text.length(); i ++)
 	{
-		if (*it == '\n')
+		if (text[i] == '\n')
 			height += line_height();
+		i += text.utf8_length(i) - 1;
 	}
 
 	return height - line_gap;