--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Scene2D/Internals/OpenGLTextureProgram.cpp	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,137 @@
+/**
+ * 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 "OpenGLTextureProgram.h"
+#include "OpenGLShaderVersionDirective.h"
+
+#include <OrthancException.h>
+
+static const unsigned int COMPONENTS = 2;
+static const unsigned int COUNT = 6;  // 2 triangles in 2D
+
+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"
+  "}";
+
+
+namespace OrthancStone
+{
+  namespace Internals
+  {
+    void OpenGLTextureProgram::InitializeExecution(OpenGL::OpenGLTexture& texture,
+                                                   const AffineTransform2D& transform)
+    {
+      if (!context_.IsContextLost())
+      {
+        context_.MakeCurrent();
+        program_->Use();
+
+        AffineTransform2D scale = AffineTransform2D::CreateScaling
+        (texture.GetWidth(), texture.GetHeight());
+
+        AffineTransform2D t = AffineTransform2D::Combine(transform, scale);
+
+        float m[16];
+        t.ConvertToOpenGLMatrix(m, context_.GetCanvasWidth(), context_.GetCanvasHeight());
+
+        texture.Bind(program_->GetUniformLocation("u_texture"));
+        glUniformMatrix4fv(program_->GetUniformLocation("u_matrix"), 1, GL_FALSE, m);
+
+        glBindBuffer(GL_ARRAY_BUFFER, buffers_[0]);
+        glEnableVertexAttribArray(positionLocation_);
+        glVertexAttribPointer(positionLocation_, COMPONENTS, GL_FLOAT, GL_FALSE, 0, 0);
+
+        glBindBuffer(GL_ARRAY_BUFFER, buffers_[1]);
+        glEnableVertexAttribArray(textureLocation_);
+        glVertexAttribPointer(textureLocation_, COMPONENTS, GL_FLOAT, GL_FALSE, 0, 0);
+      }
+    }
+
+    void OpenGLTextureProgram::FinalizeExecution()
+    {
+      if (!context_.IsContextLost())
+      {
+        glDisableVertexAttribArray(positionLocation_);
+        glDisableVertexAttribArray(textureLocation_);
+      }
+    }
+
+    OpenGLTextureProgram::OpenGLTextureProgram(OpenGL::IOpenGLContext& context,
+                                               const char* fragmentShader) :
+      context_(context)
+    {
+      static const float POSITIONS[COMPONENTS * COUNT] = {
+        0, 0,
+        0, 1,
+        1, 0,
+        1, 0,
+        0, 1,
+        1, 1
+      };
+
+      if (!context_.IsContextLost())
+      {
+        context_.MakeCurrent();
+
+        program_.reset(new OpenGL::OpenGLProgram(context_));
+        program_->CompileShaders(VERTEX_SHADER, fragmentShader);
+
+        positionLocation_ = program_->GetAttributeLocation("a_position");
+        textureLocation_ = program_->GetAttributeLocation("a_texcoord");
+
+        glGenBuffers(2, buffers_);
+
+        glBindBuffer(GL_ARRAY_BUFFER, buffers_[0]);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(float) * COMPONENTS * COUNT, POSITIONS, GL_STATIC_DRAW);
+
+        glBindBuffer(GL_ARRAY_BUFFER, buffers_[1]);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(float) * COMPONENTS * COUNT, POSITIONS, GL_STATIC_DRAW);
+      }
+    }
+
+    OpenGLTextureProgram::~OpenGLTextureProgram()
+    {
+      if (!context_.IsContextLost())
+      {
+        ORTHANC_OPENGL_TRACE_CURRENT_CONTEXT("OpenGLTextureProgram::~OpenGLTextureProgram() | About to call glDeleteBuffers");
+        context_.MakeCurrent();
+        glDeleteBuffers(2, buffers_);
+      }
+    }
+
+
+    void OpenGLTextureProgram::Execution::DrawTriangles()
+    {
+      if (!that_.context_.IsContextLost())
+      {
+        glDrawArrays(GL_TRIANGLES, 0, COUNT);
+      }
+    }
+  }
+}