add GLTexture class; use from Font::Glyph

src/gui/Font.cc

@@ -58,14 +58,6 @@ namespace jes
         m_loaded = false;
     }
 
-    Font::Glyph::~Glyph()
-    {
-        if (m_loaded)
-        {
-            glDeleteTextures(1, &m_texture_id);
-        }
-    }
-
     bool Font::Glyph::load(FT_Face face, FT_ULong char_code)
     {
         if (FT_Load_Char(face, char_code, FT_LOAD_RENDER) != 0)
@@ -84,24 +76,30 @@ namespace jes
                    width);
         }
 
-        glGenTextures(1, &m_texture_id);
         glActiveTexture(GL_TEXTURE0);
-        glBindTexture(GL_TEXTURE_2D, m_texture_id);
+        m_texture = new GLTexture();
+        m_texture->create(width, height);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
-        glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, texture);
+        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_ALPHA, GL_UNSIGNED_BYTE, texture);
         delete[] texture;
 
-        float s = 1.0 / (width * 2);
-        float t = 1.0 / (height * 2);
+        float s_min = 0.5 / m_texture->get_width();
+        float s_max = (width - 0.5) / m_texture->get_width();
+        float t_min = 0.5 / m_texture->get_height();
+        float t_max = (height - 0.5) / m_texture->get_height();
         GLfloat box[4][4] = {
-            {(GLfloat)left, (GLfloat)(top - height), s, t},
-            {(GLfloat)(left + width - 1), (GLfloat)(top - height), 1 - s, t},
-            {(GLfloat)left, (GLfloat)(top - 1), s, 1 - t},
-            {(GLfloat)(left + width - 1), (GLfloat)(top - 1), 1 - s, 1 - t},
+            {(GLfloat)left, (GLfloat)(top - height),
+                s_min, t_min},
+            {(GLfloat)(left + width - 1), (GLfloat)(top - height),
+                s_max, t_min},
+            {(GLfloat)left, (GLfloat)(top - 1),
+                s_min, t_max},
+            {(GLfloat)(left + width - 1), (GLfloat)(top - 1),
+                s_max, t_max},
         };
         glGenBuffers(1, &m_vbo_id);
         glBindBuffer(GL_ARRAY_BUFFER, m_vbo_id);

src/gui/Font.h

@@ -6,6 +6,7 @@
 #include FT_FREETYPE_H
 #include "gl3w.h"
 #include <unordered_map>
+#include "GLTexture.h"
 
 namespace jes
 {
@@ -16,12 +17,11 @@ namespace jes
         {
         public:
             Glyph();
-            ~Glyph();
             bool load(FT_Face face, FT_ULong char_code);
             int get_advance() { return m_advance; }
             void render()
             {
-                glBindTexture(GL_TEXTURE_2D, m_texture_id);
+                m_texture->bind();
                 glEnableVertexAttribArray(0);
                 glBindBuffer(GL_ARRAY_BUFFER, m_vbo_id);
                 glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);
@@ -30,7 +30,7 @@ namespace jes
         protected:
             bool m_loaded;
             int m_advance;
-            GLuint m_texture_id;
+            GLTextureRef m_texture;
             GLuint m_vbo_id;
         };
         typedef Ref<Glyph> GlyphRef;

src/gui/GLTexture.cc

@@ -0,0 +1,43 @@
+#include "GLTexture.h"
+#include <iostream>
+
+using namespace std;
+
+namespace jes
+{
+    GLTexture::GLTexture()
+    {
+        glGenTextures(1, &m_id);
+        m_width = 0u;
+        m_height = 0u;
+    }
+
+    GLTexture::~GLTexture()
+    {
+        glDeleteTextures(1, &m_id);
+    }
+
+    uint32_t GLTexture::next_power_of_2(uint32_t n)
+    {
+        n--;
+        n |= n >> 1u;
+        n |= n >> 2u;
+        n |= n >> 4u;
+        n |= n >> 8u;
+        n |= n >> 16u;
+        n++;
+        return n;
+    }
+
+    void GLTexture::create(unsigned int width, unsigned int height)
+    {
+        m_width = width = next_power_of_2(width);
+        m_height = height = next_power_of_2(height);
+        uint8_t * d = new uint8_t[width * height];
+        memset(d, 0, width * height);
+        bind();
+        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, d);
+        delete[] d;
+    }
+}

src/gui/GLTexture.h

@@ -0,0 +1,29 @@
+#ifndef GLTEXTURE_H
+#define GLTEXTURE_H
+
+#include "jes/Ref.h"
+#include "gl3w.h"
+#include <stdint.h>
+
+namespace jes
+{
+    class GLTexture
+    {
+    public:
+        GLTexture();
+        ~GLTexture();
+        GLuint get_id() { return m_id; }
+        void bind() { glBindTexture(GL_TEXTURE_2D, m_id); }
+        static uint32_t next_power_of_2(uint32_t n);
+        void create(unsigned int width, unsigned int height);
+        unsigned int get_width() { return m_width; }
+        unsigned int get_height() { return m_height; }
+    protected:
+        GLuint m_id;
+        unsigned int m_width;
+        unsigned int m_height;
+    };
+    typedef Ref<GLTexture> GLTextureRef;
+}
+
+#endif