From 2b6cd04c1fcf9807b6da9aa03e9920c28780db2c Mon Sep 17 00:00:00 2001
From: Ekaitz Zarraga <ekaitz@elenq.tech>
Date: Fri, 9 Dec 2022 19:43:16 +0100
Subject: Add basic bitmap font/text support

---
 src/graphics/font.cpp | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/graphics/font.h   | 35 +++++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 src/graphics/font.cpp
 create mode 100644 src/graphics/font.h

diff --git a/src/graphics/font.cpp b/src/graphics/font.cpp
new file mode 100644
index 0000000..42176b2
--- /dev/null
+++ b/src/graphics/font.cpp
@@ -0,0 +1,86 @@
+#include "font.h"
+
+using namespace Graphics;
+
+// Font
+
+Font::Font(const sf::Texture &texture, const std::string &mapping,
+        unsigned int numrows, unsigned int numcols)
+    : tex_(texture)
+    , mapping_(mapping)
+    , numrows_(numrows)
+    , numcols_(numcols)
+{
+    sf::Vector2u totalSize = tex_.getSize();
+    sf::Vector2f totalSize_f (totalSize.x, totalSize.y);
+    glyphSize_ = sf::Vector2f( totalSize.x / numcols_, totalSize.y / numrows_ );
+}
+
+std::array<sf::Vector2f, 4> Font::getGlyphMapping(const char ch){
+    unsigned int pos = static_cast<unsigned int>( mapping_.find_first_of(ch));
+    if (pos == std::string::npos){
+        // TODO: Error handling!
+        pos = 0;
+    }
+    unsigned int x = pos % numcols_;
+    unsigned int y = (pos - x) / numcols_;
+
+    sf::Vector2f basePos(x*glyphSize_.x, y*glyphSize_.y);
+
+    // 1 --- 2
+    // |     |
+    // 4 --- 3
+    return std::array<sf::Vector2f,4> {
+        basePos,
+        basePos + sf::Vector2f( glyphSize_.x, 0 ),
+        basePos + glyphSize_,
+        basePos + sf::Vector2f( 0, glyphSize_.y ),
+    };
+}
+
+sf::Vector2f Font::getGlyphSize(){
+    return glyphSize_;
+}
+
+const sf::Texture * Font::getTexture(){
+    return &tex_;
+}
+
+
+
+
+// Text
+
+Text::Text(Font &font, const std::string &text)
+    : font_(font)
+    , text_(text)
+    , vertices_(sf::Quads, text.size()*4)
+{
+    unsigned int length = vertices_.getVertexCount();
+    sf::Vector2f glyphSize = font_.getGlyphSize();
+    // TODO: this is the simplest rendering way: everything in one line
+    //       we should improve this to make it handle newlines or max witdths
+    for(unsigned int i=0; i < length; i=i+4){
+        vertices_[i+0].position = sf::Vector2f(glyphSize.x * i/4,       0);
+        vertices_[i+1].position = sf::Vector2f(glyphSize.x * (i/4 + 1), 0);
+        vertices_[i+2].position = sf::Vector2f(glyphSize.x * (i/4 + 1), glyphSize.y);
+        vertices_[i+3].position = sf::Vector2f(glyphSize.x * i/4,       glyphSize.y);
+
+        std::array<sf::Vector2f, 4> glyph = font_.getGlyphMapping(text_[i/4]);
+
+        vertices_[i+0].texCoords = glyph[0];
+        vertices_[i+1].texCoords = glyph[1];
+        vertices_[i+2].texCoords = glyph[2];
+        vertices_[i+3].texCoords = glyph[3];
+    }
+}
+
+void Text::draw(sf::RenderTarget& target, sf::RenderStates states) const
+{
+    // TODO: only repaint if needed: when repainting is needed
+    // vertices_.clear() and fun
+    states.transform *= getTransform();
+    states.texture = font_.getTexture();
+    // you may also override states.shader or states.blendMode if you want
+    target.draw(vertices_, states);
+}
diff --git a/src/graphics/font.h b/src/graphics/font.h
new file mode 100644
index 0000000..9a8e919
--- /dev/null
+++ b/src/graphics/font.h
@@ -0,0 +1,35 @@
+#ifndef GRAPHICS_FONT_H
+#define GRAPHICS_FONT_H
+
+#include<string>
+#include<array>
+#include"SFML/Graphics.hpp"
+
+namespace Graphics {
+    class Font {
+        private:
+            const sf::Texture &tex_;
+            const std::string mapping_;
+            const unsigned int numrows_, numcols_;
+            sf::Vector2f glyphSize_;
+        public:
+            Font(const sf::Texture &texture, const std::string &mapping,
+                    unsigned int numrows, unsigned int numcols);
+            std::array<sf::Vector2f,4> getGlyphMapping(const char ch);
+            sf::Vector2f getGlyphSize();
+            const sf::Texture *getTexture();
+    };
+
+    class Text : public sf::Drawable, public sf::Transformable  {
+        private:
+            Font &font_;
+            const std::string text_;
+            sf::VertexArray vertices_;
+        public:
+            Text(Font &font, const std::string &text);
+            virtual void draw(sf::RenderTarget& target,
+                    sf::RenderStates states) const override;
+    };
+}
+
+#endif // GRAPHICS_FONT_H
-- 
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