Using translation, rotation and scale vectors to define transform of

node (matrix computed at update). GUI to modify transform adapted
accordingly. Initialization nodes done at first run of draw (prevents
mistake of forgetting to init).

ImGuiVisitor.cpp

@@ -31,31 +31,35 @@ void ImGuiVisitor::visit(Group &n)
     std::string id = std::to_string(n.id());
     if (ImGui::TreeNode(id.c_str(), "Group"))
     {
+        // MODEL VIEW
+        if (ImGuiToolkit::ButtonIcon(6, 15)) {
+            n.translation_.x = 0.f;
+            n.translation_.y = 0.f;
+        }
+        ImGui::SameLine(0, 10);
+        float translation[2] = { n.translation_.x, n.translation_.y};
+        if ( ImGui::SliderFloat2("position", translation, -5.0, 5.0) )
+        {
+            n.translation_.x = translation[0];
+            n.translation_.y = translation[1];
+        }
 
-        //    n.transform_
+        if (ImGuiToolkit::ButtonIcon(4, 15))
-            // MODEL VIEW
+            n.rotation_.z = 0.f;
-            float translation[2] = { n.transform_[3][0], n.transform_[3][1]};
+        ImGui::SameLine(0, 10);
-            if (ImGuiToolkit::ButtonIcon(6, 15)) {
+        ImGui::SliderAngle("slider angle", &(n.rotation_.z), -180.f, 180.f) ;
-                translation[0] = 0.f;
-                translation[1] = 0.f;
-            }
-            ImGui::SameLine(0, 10);
-            ImGui::SliderFloat2("position", translation, -5.0, 5.0);
 
-            float rotation = asin(n.transform_[0][1]);
+        if (ImGuiToolkit::ButtonIcon(3, 15))  {
-            if (ImGuiToolkit::ButtonIcon(4, 15)) rotation = 0.f;
+            n.scale_.x = 1.f;
-            ImGui::SameLine(0, 10);
+            n.scale_.y = 1.f;
-            ImGui::SliderFloat("rotation", &rotation, 0, glm::two_pi<float>());
+        }
-
+        ImGui::SameLine(0, 10);
-            float scale = n.transform_[2][2];
+        float scale = n.scale_.y;
-            if (ImGuiToolkit::ButtonIcon(3, 15))  scale = 1.f;
+        if ( ImGui::SliderFloat("scale", &scale, 0.1f, 10.f, "%.3f", 3.f) )
-            ImGui::SameLine(0, 10);
+        {
-            ImGui::SliderFloat("scale", &scale, 0.1f, 10.f, "%.3f", 3.f);
+            n.scale_.x = scale;
-
+            n.scale_.y = scale;
-            glm::mat4 View = glm::translate(glm::identity<glm::mat4>(), glm::vec3(translation[0], translation[1], 0.f));
+        }
-            View = glm::rotate(View, rotation, glm::vec3(0.0f, 0.0f, 1.0f));
-            glm::mat4 Model = glm::scale(glm::identity<glm::mat4>(), glm::vec3(scale, scale, scale));
-            n.transform_ = View * Model;
 
         // loop over members of a group
         for (int i = 0; i < n.numChildren(); ++i)
@@ -77,8 +81,10 @@ void ImGuiVisitor::visit(Primitive &n)
     ImGui::PushID(n.id());
     ImGui::Text("Primitive");
 
+    if (n.getShader())
+        n.getShader()->accept(*this);
+
 
-    n.getShader()->accept(*this);
     ImGui::PopID();
 }
 
@@ -90,7 +96,9 @@ void ImGuiVisitor::visit(ImageSurface &n)
 void ImGuiVisitor::visit(MediaSurface &n)
 {
     ImGui::Text("%s", n.getFilename().c_str());
-    n.getMediaPlayer()->accept(*this);
+
+    if (n.getMediaPlayer())
+        n.getMediaPlayer()->accept(*this);
 }
 
 void ImGuiVisitor::visit(MediaPlayer &n)

Primitives.cpp

@@ -50,7 +50,7 @@ void ImageSurface::init()
     else {
         float ar = 1.0;
         textureindex_ = Resource::getTextureImage(filename_, &ar);
-        transform_ = glm::scale(glm::identity<glm::mat4>(), glm::vec3(ar, 1.f, 1.f));
+        scale_.x = ar;
     }
     // create shader for textured image
     shader_ = new ImageShader();
@@ -74,6 +74,9 @@ void ImageSurface::init()
 
 void ImageSurface::draw(glm::mat4 modelview, glm::mat4 projection)
 {
+    if ( !initialized_ )
+        init();
+
     glBindTexture(GL_TEXTURE_2D, textureindex_);
 
     Primitive::draw(modelview, projection);
@@ -111,6 +114,9 @@ void MediaSurface::init()
 
 void MediaSurface::draw(glm::mat4 modelview, glm::mat4 projection)
 {
+    if ( !initialized_ )
+        init();
+
     if ( mediaplayer_->isOpen() )
         mediaplayer_->bind();
     else
@@ -126,7 +132,7 @@ void MediaSurface::update( float dt )
     if ( mediaplayer_->isOpen() )
         mediaplayer_->update();
 
-    transform_ = glm::scale(glm::identity<glm::mat4>(), glm::vec3(mediaplayer_->aspectRatio(), 1.f, 1.f));
+    scale_.x = mediaplayer_->aspectRatio();
 
     Primitive::update( dt );
 }
@@ -146,14 +152,21 @@ LineStrip::LineStrip(std::vector<glm::vec3> points, glm::vec3 color, uint linewi
         indices_.push_back ( i );
     }
 
-    shader_ = new Shader();
-
     drawingPrimitive_ = GL_LINE_LOOP;
     linewidth_ = linewidth;
 }
 
+void LineStrip::init()
+{
+    Primitive::init();
+    shader_ = new Shader();
+}
+
 void LineStrip::draw(glm::mat4 modelview, glm::mat4 projection)
 {
+    if ( !initialized_ )
+        init();
+
     glLineWidth(linewidth_);
     Primitive::draw(modelview, projection);
 }
@@ -201,7 +214,10 @@ void LineCircle::init()
         // 3. vao_ will not be deleted because deleteGLBuffers_() is empty
     }
 
+    shader_ = new Shader();
+
     visible_ = true;
+    initialized_ = true;
 }
 
 void LineCircle::accept(Visitor& v)

Primitives.h

@@ -66,6 +66,7 @@ class LineStrip : public Primitive {
 public:
     LineStrip(std::vector<glm::vec3> points, glm::vec3 color, uint linewidth = 1);
 
+    virtual void init() override;
     virtual void draw(glm::mat4 modelview, glm::mat4 projection) override;
     virtual void accept(Visitor& v) override;
 

Scene.cpp

@@ -17,6 +17,17 @@
 #include <chrono>
 #include <ctime>
 
+
+glm::mat4 transform(glm::vec3 translation, glm::vec3 rotation, glm::vec3 scale)
+{
+    glm::mat4 View = glm::translate(glm::identity<glm::mat4>(), translation);
+    View = glm::rotate(View, rotation.x, glm::vec3(1.f, 0.f, 0.f));
+    View = glm::rotate(View, rotation.y, glm::vec3(0.f, 1.f, 0.f));
+    View = glm::rotate(View, rotation.z, glm::vec3(0.f, 0.f, 1.f));
+    glm::mat4 Model = glm::scale(glm::identity<glm::mat4>(), scale);
+    return View * Model;
+}
+
 // Node
 Node::Node() : parent_(nullptr), visible_(false), initialized_(false)
 {
@@ -27,10 +38,14 @@ Node::Node() : parent_(nullptr), visible_(false), initialized_(false)
     worldToLocal_ = glm::identity<glm::mat4>();
     localToWorld_ = glm::identity<glm::mat4>();
     transform_ = glm::identity<glm::mat4>();
+    scale_ = glm::vec3(1.f);
+    rotation_ = glm::vec3(0.f);
+    translation_ = glm::vec3(0.f);
 }
 
 void Node::update( float dt )
 {
+    transform_ = transform(translation_, rotation_, scale_);
     if ( parent_ ) {
         localToWorld_ = dynamic_cast<Group*>(parent_)->getLocalToWorldMatrix() * transform_;
         worldToLocal_ = glm::inverse(transform_) * dynamic_cast<Group*>(parent_)->getWorldToLocalMatrix();
@@ -114,6 +129,9 @@ void Primitive::init()
 
 void Primitive::draw(glm::mat4 modelview, glm::mat4 projection)
 {
+    if ( !initialized_ )
+        init();
+
     if ( visible_ ) {
         //
         // prepare and use shader
@@ -171,6 +189,9 @@ void Group::update( float dt )
 
 void Group::draw(glm::mat4 modelview, glm::mat4 projection)
 {
+    if ( !initialized_ )
+        init();
+
     if ( visible_ ) {
 
         // append the instance transform to the ctm
@@ -220,6 +241,9 @@ void Switch::update( float dt )
 
 void Switch::draw(glm::mat4 modelview, glm::mat4 projection)
 {
+    if ( !initialized_ )
+        init();
+
     if ( visible_ ) {
         // append the instance transform to the ctm
         glm::mat4 ctm = modelview * transform_;

Scene.h

@@ -4,6 +4,7 @@
 #include <vector>
 #include <glm/glm.hpp>
 
+glm::mat4 transform(glm::vec3 translation, glm::vec3 rotation, glm::vec3 scale);
 
 // Forward declare classes referenced
 class Shader;
@@ -33,6 +34,7 @@ public:
     glm::mat4 worldToLocal_;
     glm::mat4 localToWorld_;
     glm::mat4 transform_;
+    glm::vec3 scale_, rotation_, translation_;
 };
 
 

SessionVisitor.cpp

@@ -26,8 +26,12 @@ void SessionVisitor::visit(Node &n)
     XMLElement *newelement = xmlDoc_->NewElement("Node");
     newelement->SetAttribute("visible", n.visible_);
 
-    XMLElement *transform = XMLElementFromGLM(xmlDoc_, n.transform_);
+    XMLElement *scale = XMLElementFromGLM(xmlDoc_, n.scale_);
-    newelement->InsertEndChild(transform);
+    newelement->InsertEndChild(scale);
+    XMLElement *translation = XMLElementFromGLM(xmlDoc_, n.translation_);
+    newelement->InsertEndChild(translation);
+    XMLElement *rotation = XMLElementFromGLM(xmlDoc_, n.rotation_);
+    newelement->InsertEndChild(rotation);
 
     // insert into hierarchy
     xmlCurrent_->InsertEndChild(newelement);

Shader.cpp

@@ -205,6 +205,7 @@ void Shader::reset()
 
 void Shader::setModelview(float x, float y, float angle, float scale, float aspect_ratio)
 {
+
     glm::mat4 View = glm::translate(glm::identity<glm::mat4>(), glm::vec3(x, y, 0.f));
     View = glm::rotate(View, angle, glm::vec3(0.0f, 0.0f, 1.0f));
     glm::mat4 Model = glm::scale(glm::identity<glm::mat4>(), glm::vec3(scale * aspect_ratio, scale, scale));

main.cpp

@@ -252,29 +252,22 @@ int main(int, char**)
 //    UserInterface::manager().OpenTextEditor( Resource::getText("shaders/texture-shader.fs") );
 
     // init the scene
-    scene.root_.init();
     Rendering::manager().PushFrontDrawCallback(drawScene);
 
     // init elements to the scene
-    testnode1.init();
+    //testnode3.getShader()->blending = Shader::BLEND_OPACITY;
-    testnode2.init();
-    testnode3.init();
-    testnode3.getShader()->blending = Shader::BLEND_ADD;
 
     glm::vec3 color( 1.f, 1.f, 0.f );
     LineCircle border(color);
 //    LineSquare border(color);
-    border.init();
 
     Group g1;
-    g1.init();
+    g1.translation_ = glm::vec3(1.f, 1.f, 0.f);
-    g1.transform_ = glm::translate(glm::identity<glm::mat4>(), glm::vec3(1.f, 1.f, 0.f));
+    g1.scale_ = glm::vec3(2.f, 2.f, 1.f);
-    g1.transform_ = glm::scale(g1.transform_, glm::vec3(2.f, 2.f, 2.f));
 
     Switch g2;
-    g2.init();
+    g2.translation_ = glm::vec3(-1.f, -1.f, 0.f);
-    g2.transform_ = glm::translate(glm::identity<glm::mat4>(), glm::vec3(-1.f, -1.f, 0.f));
+//    g2.rotation_ = glm::vec3(0.0f, 0.0f, 1.0f);
-    g2.transform_ = glm::rotate(g2.transform_, 0.672f, glm::vec3(0.0f, 0.0f, 1.0f));
 
     // build tree
     g1.addChild(&testnode3);