--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/Internals/OpenGLTextProgram.cpp	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,229 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) 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
+ * Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "OpenGLTextProgram.h"
+#include "OpenGLShaderVersionDirective.h"
+
+#include "../../Fonts/OpenGLTextCoordinates.h"
+
+#include <OrthancException.h>
+
+
+static const unsigned int COMPONENTS = 2;
+
+static const char* VERTEX_SHADER = 
+  ORTHANC_STONE_OPENGL_SHADER_VERSION_DIRECTIVE
+  "attribute vec2 a_texcoord;             \n"
+  "attribute vec4 a_position;             \n"
+  "uniform mat4 u_matrix;                 \n"
+  "varying vec2 v_texcoord;               \n"
+  "void main()                            \n"
+  "{                                      \n"
+  "  gl_Position = u_matrix * a_position; \n"
+  "  v_texcoord = a_texcoord;             \n"
+  "}";
+
+static const char* FRAGMENT_SHADER = 
+  ORTHANC_STONE_OPENGL_SHADER_VERSION_DIRECTIVE
+  "uniform sampler2D u_texture;                  \n"
+  "uniform vec3 u_color;                         \n"
+  "varying vec2 v_texcoord;                      \n"
+  "void main()                                   \n"
+  "{                                             \n"
+  "  vec4 v = texture2D(u_texture, v_texcoord);  \n"
+  "  gl_FragColor = vec4(u_color * v.w, v.w);    \n"   // Premultiplied alpha
+  "}";
+
+
+namespace OrthancStone
+{
+  namespace Internals
+  {
+    OpenGLTextProgram::OpenGLTextProgram(OpenGL::IOpenGLContext&  context) :
+      context_(context)
+    {
+      if (!context_.IsContextLost())
+      {
+        context_.MakeCurrent();
+
+        program_.reset(new OpenGL::OpenGLProgram(context_));
+        program_->CompileShaders(VERTEX_SHADER, FRAGMENT_SHADER);
+
+        positionLocation_ = program_->GetAttributeLocation("a_position");
+        textureLocation_ = program_->GetAttributeLocation("a_texcoord");
+      }
+    }
+
+
+    OpenGLTextProgram::Data::Data(OpenGL::IOpenGLContext& context,
+                                  const GlyphTextureAlphabet& alphabet,
+                                  const TextSceneLayer& layer) :
+      context_(context),
+      red_(layer.GetColor().GetRedAsFloat()),
+      green_(layer.GetColor().GetGreenAsFloat()),
+      blue_(layer.GetColor().GetBlueAsFloat()),
+      x_(layer.GetX()),
+      y_(layer.GetY()),
+      border_(layer.GetBorder()),
+      anchor_(layer.GetAnchor())
+    {
+      OpenGL::OpenGLTextCoordinates coordinates(alphabet, layer.GetText());
+      textWidth_ = coordinates.GetTextWidth();
+      textHeight_ = coordinates.GetTextHeight();
+
+      if (coordinates.IsEmpty())
+      {
+        coordinatesCount_ = 0;
+      }
+      else
+      {
+        coordinatesCount_ = coordinates.GetRenderingCoords().size();
+
+        if (!context_.IsContextLost())
+        {
+          context_.MakeCurrent();
+          glGenBuffers(2, buffers_);
+          ORTHANC_OPENGL_CHECK("glGenBuffers");
+
+          glBindBuffer(GL_ARRAY_BUFFER, buffers_[0]);
+          ORTHANC_OPENGL_CHECK("glBindBuffer");
+          glBufferData(GL_ARRAY_BUFFER, sizeof(float) * coordinatesCount_,
+            &coordinates.GetRenderingCoords()[0], GL_STATIC_DRAW);
+          ORTHANC_OPENGL_CHECK("glBufferData");
+
+          glBindBuffer(GL_ARRAY_BUFFER, buffers_[1]);
+          ORTHANC_OPENGL_CHECK("glBindBuffer");
+          glBufferData(GL_ARRAY_BUFFER, sizeof(float) * coordinatesCount_,
+            &coordinates.GetTextureCoords()[0], GL_STATIC_DRAW);
+          ORTHANC_OPENGL_CHECK("glBufferData");
+        }
+      }
+    }
+
+    
+    OpenGLTextProgram::Data::~Data()
+    {
+      if (!context_.IsContextLost() && !IsEmpty())
+      {
+        try
+        {
+          context_.MakeCurrent();
+          ORTHANC_OPENGL_TRACE_CURRENT_CONTEXT("About to call glDeleteBuffers");
+          glDeleteBuffers(2, buffers_);
+          ORTHANC_OPENGL_CHECK("glDeleteBuffers");
+        }
+        catch (const Orthanc::OrthancException& e)
+        {
+          if (e.HasDetails())
+          {
+            LOG(ERROR) << "OrthancException in ~Data: " << e.What() << " Details: " << e.GetDetails();
+          }
+          else
+          {
+            LOG(ERROR) << "OrthancException in ~Data: " << e.What();
+          }
+        }
+        catch (const std::exception& e)
+        {
+          LOG(ERROR) << "std::exception in ~Data: " << e.what();
+        }
+        catch (...)
+        {
+          LOG(ERROR) << "Unknown exception in ~Data";
+        }
+      }
+    }
+
+
+    GLuint OpenGLTextProgram::Data::GetSceneLocationsBuffer() const
+    {
+      if (IsEmpty())
+      {
+        LOG(ERROR) << "OpenGLTextProgram::Data::GetSceneLocationsBuffer(): (IsEmpty())";
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+      }
+      else
+      {
+        return buffers_[0];
+      }
+    }
+
+    GLuint OpenGLTextProgram::Data::GetTextureLocationsBuffer() const
+    {
+      if (IsEmpty())
+      {
+        LOG(ERROR) << "OpenGLTextProgram::Data::GetTextureLocationsBuffer(): (IsEmpty())";
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+      }
+      else
+      {
+        return buffers_[1];
+      }
+    }
+
+    void OpenGLTextProgram::Apply(OpenGL::OpenGLTexture& fontTexture,
+                                  const Data& data,
+                                  const AffineTransform2D& transform)
+    {
+      if (!context_.IsContextLost() && !data.IsEmpty())
+      {
+        context_.MakeCurrent();
+        program_->Use();
+
+        double dx, dy;  // In pixels
+        ComputeAnchorTranslation(dx, dy, data.GetAnchor(), 
+                                 data.GetTextWidth(), data.GetTextHeight(),
+                                 static_cast<unsigned int>(data.GetBorder()));
+      
+        double x = data.GetX();
+        double y = data.GetY();
+        transform.Apply(x, y);
+
+        const AffineTransform2D t = AffineTransform2D::CreateOffset(x + dx, y + dy);
+
+        float m[16];
+        t.ConvertToOpenGLMatrix(m, context_.GetCanvasWidth(), context_.GetCanvasHeight());
+
+        fontTexture.Bind(program_->GetUniformLocation("u_texture"));
+        glUniformMatrix4fv(program_->GetUniformLocation("u_matrix"), 1, GL_FALSE, m);
+        glUniform3f(program_->GetUniformLocation("u_color"), 
+                    data.GetRed(), data.GetGreen(), data.GetBlue());
+
+        glBindBuffer(GL_ARRAY_BUFFER, data.GetSceneLocationsBuffer());
+        glEnableVertexAttribArray(positionLocation_);
+        glVertexAttribPointer(positionLocation_, COMPONENTS, GL_FLOAT, GL_FALSE, 0, 0);
+
+        glBindBuffer(GL_ARRAY_BUFFER, data.GetTextureLocationsBuffer());
+        glEnableVertexAttribArray(textureLocation_);
+        glVertexAttribPointer(textureLocation_, COMPONENTS, GL_FLOAT, GL_FALSE, 0, 0);
+
+        glEnable(GL_BLEND);
+        glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+        glDrawArrays(GL_TRIANGLES, 0, 
+          static_cast<GLsizei>(data.GetCoordinatesCount() / COMPONENTS));
+        glDisable(GL_BLEND);
+
+        glDisableVertexAttribArray(positionLocation_);
+        glDisableVertexAttribArray(textureLocation_);
+      }
+    }
+  }
+}