1 files changed, 158 insertions, 0 deletions
diff --git a/Project/OpenGLText.cpp b/Project/OpenGLText.cpp
new file mode 100644
index 0000000..ebbc763
--- /dev/null
+++ b/Project/OpenGLText.cpp
@@ -0,0 +1,158 @@
+/*
+ *  Copyright (C) 2017  Thales Lima Oliveira <thales@ufu.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "OpenGLText.h"
+
+OpenGLText::OpenGLText() { Init(); }
+OpenGLText::OpenGLText(wxString text)
+{
+    Init();
+    SetText(text);
+}
+
+OpenGLText::~OpenGLText()
+{
+    if(m_textureID) {
+        glDeleteTextures(1, m_textureID);
+    }
+}
+
+void OpenGLText::Init()
+{
+    m_textCoord = new wxPoint2DDouble[2];
+    m_textCoord[0] = wxPoint2DDouble(0, 1);
+    m_textCoord[1] = wxPoint2DDouble(1, 0);
+}
+
+void OpenGLText::Draw(wxPoint2DDouble position) const
+{
+    if(m_textureID) {
+        glPushMatrix();
+        
+        glTranslated(position.m_x - m_bitmapSize.GetWidth() / 2, position.m_y - m_bitmapSize.GetHeight() / 2, 0);
+
+        glEnable(GL_TEXTURE_2D);
+        glBindTexture(GL_TEXTURE_2D, m_textureID[0]);
+
+        glBegin(GL_QUADS);
+
+        glTexCoord2f(m_textCoord[0].m_x, m_textCoord[0].m_y);
+        glVertex2f(0, 0);
+
+        glTexCoord2f(m_textCoord[1].m_x, m_textCoord[0].m_y);
+        glVertex2f(m_bitmapSize.GetWidth(), 0);
+
+        glTexCoord2f(m_textCoord[1].m_x, m_textCoord[1].m_y);
+        glVertex2f(m_bitmapSize.GetWidth(), m_bitmapSize.GetHeight());
+
+        glTexCoord2f(m_textCoord[0].m_x, m_textCoord[1].m_y);
+        glVertex2f(0, m_bitmapSize.GetHeight());
+        glEnd();
+
+        glDisable(GL_TEXTURE_2D);
+
+        glPopMatrix();
+    }
+}
+
+void OpenGLText::SetText(wxString text)
+{
+    m_text = text;
+    TextToBitmap();
+    LoadTextTexture();
+}
+
+int OpenGLText::RoundToPowerOfTwo(int value, int min)
+{
+    //[Ref] https://stackoverflow.com/questions/466204/rounding-up-to-next-power-of-2
+    double baseOfTwo = std::log(static_cast<double>(value)) / std::log(2.0);
+    int powerOfTwo = static_cast<int>(std::pow(2.0, static_cast<int>(std::ceil(baseOfTwo))));
+    return std::max(min, powerOfTwo);
+}
+
+void OpenGLText::TextToBitmap()
+{
+    wxFont font = wxFont(m_fontSize, wxFONTFAMILY_DEFAULT, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_NORMAL);
+
+    wxMemoryDC memDC;
+    memDC.SetFont(font);
+    m_bitmapSize = memDC.GetTextExtent(m_text);
+
+    int p2w = RoundToPowerOfTwo(m_bitmapSize.GetWidth());
+    int p2h = RoundToPowerOfTwo(m_bitmapSize.GetHeight());
+
+    m_bitmap = wxBitmap(p2w, p2h);
+
+    memDC.SelectObject(m_bitmap);
+    memDC.SetBackground(*wxWHITE_BRUSH);
+    memDC.Clear();
+    memDC.DrawText(m_text, 0, 0);
+
+    m_textCoord[1].m_x = static_cast<double>(m_bitmapSize.GetWidth()) / static_cast<double>(p2w);
+    m_textCoord[1].m_y = 1.0 - static_cast<double>(m_bitmapSize.GetHeight()) / static_cast<double>(p2h);
+}
+
+void OpenGLText::LoadTextTexture()
+{
+    if(m_textureID) glDeleteTextures(1, m_textureID);
+    m_textureID = new GLuint[1];
+    glGenTextures(1, &m_textureID[0]);
+
+    glBindTexture(GL_TEXTURE_2D, *m_textureID);
+
+    wxImage img = m_bitmap.ConvertToImage();
+
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+
+    const int w = img.GetWidth(), h = img.GetHeight();
+    int bytesPerPixel = 4;
+    GLubyte* bitmapData = img.GetData();
+    int imageSize = w * h * bytesPerPixel;
+    GLubyte* imageData = new GLubyte[imageSize];
+    int revVal = h - 1;
+
+    for(int y = 0; y < h; y++) {
+        for(int x = 0; x < w; x++) {
+            imageData[(x + y * w) * bytesPerPixel + 0] = 255;
+            imageData[(x + y * w) * bytesPerPixel + 1] = 255;
+            imageData[(x + y * w) * bytesPerPixel + 2] = 255;
+
+            // alpha
+            imageData[(x + y * w) * bytesPerPixel + 3] = 255 - bitmapData[(x + (revVal - y) * w) * 3];
+        }
+    }
+
+    glTexImage2D(GL_TEXTURE_2D, 0, bytesPerPixel, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
+    delete imageData;
+
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
+}
+
+OpenGLText* OpenGLText::GetCopy()
+{
+    OpenGLText* copy = new OpenGLText();
+    *copy = *this;
+    copy->m_textureID = NULL;
+    copy->m_bitmapSize = wxSize(0, 0);
+    copy->m_bitmap = wxNullBitmap;
+    copy->SetText(copy->m_text);
+    return copy;
+}