Add starting help info, impl undo tri in progress

src/imgui_helper.hpp

@@ -5,6 +5,13 @@
 
 #include "state.hpp"
 
+#define SHOW_HELP_WIDTH (state->get_width() / 2.0f)
+#define SHOW_HELP_HEIGHT (state->get_height() / 2.0f)
+
+#ifndef NDEBUG
+# include <cstdio>
+#endif
+
 namespace Tri {
     // Seems misleading, but imgui handles setting up the window during update
     // so this should be called during update, not draw
@@ -14,11 +21,35 @@ namespace Tri {
             ImGui::SetNextWindowSize(sf::Vector2f(
                 state->get_width() - 20.0f,
                 state->get_height() - 20.0f));
+            ImGui::SetNextWindowBgAlpha(0.7f);
             ImGui::Begin("Help Window", nullptr, ImGuiWindowFlags_NoDecoration);
-            ImGui::Text("This is the help window.");
+            ImGui::Text("This is the help window. Press \"H\" to toggle this window.");
+            ImGui::Text("Click anywhere to create triangles, one point at a time");
+            ImGui::Text("Press \"U\" to undo. Clicking will remove all future undo history");
+            ImGui::Text("Press \"R\" to undo.");
             ImGui::End();
         }
     }
+
+    inline void draw_show_help(Tri::State *state) {
+        float alpha = state->get_starting_help_alpha();
+        if(alpha > 0.0f) {
+            ImGui::PushStyleVar(ImGuiStyleVar_Alpha, alpha);
+
+            ImGui::SetNextWindowPos(sf::Vector2f(
+                (state->get_width() - SHOW_HELP_WIDTH) / 2.0f,
+                (state->get_height() - SHOW_HELP_HEIGHT) / 2.0f));
+            ImGui::SetNextWindowSize(sf::Vector2f(
+                SHOW_HELP_WIDTH,
+                SHOW_HELP_HEIGHT));
+            ImGui::Begin("Use Help Window", nullptr, ImGuiWindowFlags_NoDecoration);
+            ImGui::SetWindowFontScale(3.0f);
+            ImGui::Text("Press \"H\" for help");
+            ImGui::End();
+
+            ImGui::PopStyleVar();
+        }
+    }
 }
 
 #endif

src/state.cpp

@@ -1,18 +1,27 @@
 #include "state.hpp"
 
 #include <cstring>
+#include <cassert>
 
 #include <imgui-SFML.h>
 
 #include "imgui_helper.hpp"
 
+#define STARTING_HELP_FADE_RATE 0.2f
+
+#ifndef NDEBUG
+# include <cstdio>
+#endif
+
 Tri::State::State(int argc, char **argv) :
 width(800),
 height(600),
 dt(sf::microseconds(16666)),
+starting_help_alpha(1.0f),
 window(sf::VideoMode(800, 600), "Triangles", sf::Style::Titlebar | sf::Style::Close),
 trisIndex(0),
-currentTri_state(CurrentState::NONE)
+currentTri_state(CurrentState::NONE),
+currentTri_maxState(CurrentState::NONE)
 {
     flags.set(1); // is running
     ImGui::SFML::Init(window);
@@ -40,23 +49,68 @@ void Tri::State::handle_events() {
             if(event.key.code == sf::Keyboard::H) {
                 flags.flip(0);
             } else if(event.key.code == sf::Keyboard::U) {
-                if(trisIndex > 0) {
+                if(currentTri_state > 0) {
+                    switch(currentTri_state) {
+                    case FIRST:
+                        currentTri_state = CurrentState::NONE;
+                        break;
+                    case SECOND:
+                        currentTri_state = CurrentState::FIRST;
+                        break;
+                    default:
+                        assert(!"Unreachable code");
+                        break;
+                    }
+                } else if(trisIndex > 0) {
                     --trisIndex;
                 }
             } else if(event.key.code == sf::Keyboard::R) {
-                if(tris.size() > trisIndex) {
+                if(currentTri_state != CurrentState::NONE
+                        && currentTri_state < currentTri_maxState) {
+                    switch(currentTri_state) {
+                    case NONE:
+                        currentTri_state = CurrentState::FIRST;
+                        break;
+                    case FIRST:
+                        currentTri_state = CurrentState::SECOND;
+                        break;
+                    default:
+                        assert(!"Unreachable code");
+                        break;
+                    }
+                } else if(tris.size() > trisIndex) {
                     ++trisIndex;
+                } else if(currentTri_state < currentTri_maxState) {
+                    switch(currentTri_state) {
+                    case NONE:
+                        currentTri_state = CurrentState::FIRST;
+                        break;
+                    case FIRST:
+                        currentTri_state = CurrentState::SECOND;
+                        break;
+                    default:
+                        assert(!"Unreachable code");
+                        break;
+                    }
                 }
             }
         } else if(event.type == sf::Event::MouseButtonPressed) {
             switch(currentTri_state) {
             case CurrentState::NONE:
                 currentTri[0] = sf::Vector2f(event.mouseButton.x, event.mouseButton.y);
+                if(trisIndex < tris.size()) {
+                    tris.resize(trisIndex);
+                }
                 currentTri_state = CurrentState::FIRST;
+                currentTri_maxState = CurrentState::FIRST;
                 break;
             case CurrentState::FIRST:
                 currentTri[1] = sf::Vector2f(event.mouseButton.x, event.mouseButton.y);
+                if(trisIndex < tris.size()) {
+                    tris.resize(trisIndex);
+                }
                 currentTri_state = CurrentState::SECOND;
+                currentTri_maxState = CurrentState::SECOND;
                 break;
             case CurrentState::SECOND:
                 currentTri[2] = sf::Vector2f(event.mouseButton.x, event.mouseButton.y);
@@ -70,6 +124,7 @@ void Tri::State::handle_events() {
                 tris.back().setPoint(2, currentTri[2]);
                 tris.back().setFillColor(sf::Color::White); // TODO use chosen color
                 currentTri_state = CurrentState::NONE;
+                currentTri_maxState = CurrentState::NONE;
                 break;
             }
         }
@@ -79,7 +134,15 @@ void Tri::State::handle_events() {
 void Tri::State::update() {
     ImGui::SFML::Update(window, dt);
 
+    if(starting_help_alpha > 0.0f) {
+        starting_help_alpha -= dt.asSeconds() * STARTING_HELP_FADE_RATE;
+        if(starting_help_alpha < 0.0f) {
+            starting_help_alpha = 0.0f;
+        }
+    }
+
     // Seems misleading, but imgui handles setting up the window during update
+    Tri::draw_show_help(this);
     Tri::draw_help(this);
 
     ImGui::EndFrame();
@@ -87,7 +150,6 @@ void Tri::State::update() {
 
 void Tri::State::draw() {
     window.clear();
-    ImGui::SFML::Render(window);
 
     // draw tris
     for(unsigned int i = 0; i < trisIndex; ++i) {
@@ -100,17 +162,24 @@ void Tri::State::draw() {
         window.draw(pointCircle);
     }
 
+    // draw gui stuff
+    ImGui::SFML::Render(window);
+
     window.display();
 }
 
-unsigned int Tri::State::get_width() {
+unsigned int Tri::State::get_width() const {
     return width;
 }
 
-unsigned int Tri::State::get_height() {
+unsigned int Tri::State::get_height() const {
     return height;
 }
 
 const Tri::State::BitsetType Tri::State::get_flags() const {
     return flags;
 }
+
+float Tri::State::get_starting_help_alpha() const {
+    return starting_help_alpha;
+}

src/state.hpp

@@ -12,22 +12,26 @@ namespace Tri {
     public:
         State(int argc, char **argv);
         ~State();
+
+        enum CurrentState {NONE = 0, FIRST = 1, SECOND = 2};
+    private:
         /*
          * 0 - display help
          * 1 - is running
          */
-    private:
         typedef std::bitset<64> BitsetType;
         BitsetType flags;
         unsigned int width;
         unsigned int height;
         const sf::Time dt;
+        float starting_help_alpha;
 
         sf::RenderWindow window;
         std::vector<sf::ConvexShape> tris;
         unsigned int trisIndex;
         sf::Vector2f currentTri[3];
-        enum CurrentState { NONE = 0, FIRST = 1, SECOND = 2} currentTri_state;
+        CurrentState currentTri_state;
+        CurrentState currentTri_maxState;
         sf::CircleShape pointCircle;
 
         sf::Event event;
@@ -37,10 +41,12 @@ namespace Tri {
         void update();
         void draw();
 
-        unsigned int get_width();
+        unsigned int get_width() const;
-        unsigned int get_height();
+        unsigned int get_height() const;
 
         const BitsetType get_flags() const;
+
+        float get_starting_help_alpha() const;
     };
 }