Dirty rect & UI features

- dirty rectangle (and the math library thereof)
  - drawing it
- no more std::vector in Sandbox
- single step
- cycle counter display

1 files changed, 50 insertions, 9 deletions

diff --git a/src/ui.cpp b/src/ui.cpp
index f356afa..cb68c66 100644
--- a/src/ui.cpp
+++ b/src/ui.cpp
@@ -12,26 +12,67 @@ static void AddSand(Sandbox& sb) {
     }
 }
 
+constexpr int kWidth = 40;
+constexpr int kHeight = 100;
+constexpr float kScale = 4.0f;
+constexpr ImVec2 kSize(kWidth* kScale, kHeight* kScale);
+
+static ImVec2 TrSandbox2Screen(ImVec2 origin, Pt pt) {
+    return ImVec2(origin.x + kScale * pt.x, origin.y - kScale * pt.y);
+}
+
+struct ImRect {
+    ImVec2 top_left;
+    ImVec2 bottom_right;
+};
+// Assuming inclusive-inclusive rectangle
+static ImRect TrSandbox2Screen(ImVec2 origin, Rect r) {
+    return {
+        ImVec2(origin.x + kScale * r.bl.x, origin.y - kScale * (r.tr.y+1)),
+        ImVec2(origin.x + kScale * (r.tr.x + 1), origin.y - kScale * r.bl.y),
+    };
+}
+
 void ShowEverything() {
     ImGui::Begin("Sandbox");
-    constexpr int kWidth = 40;
-    constexpr int kHeight = 100;
-    static bool running = false;
     static Sandbox sandbox(40, 100);
     static OglImage gl;
-    sandbox.simulate_step();
-    gl.upload(reinterpret_cast<const char*>(sandbox._bitmap.data()), kWidth, kHeight);
 
-    if (ImGui::Button("Reset sandbox")) {
-        sandbox = Sandbox(40, 100);
+    static bool running = false;
+    ImGui::Checkbox("Run", &running);
+    static bool show_dirty_rect = true;
+    ImGui::Checkbox("Show dirty rects", &show_dirty_rect);
+
+    ImGui::Text("ncycle = %d", sandbox.ncycle);
+    ImGui::SameLine();
+    bool step = ImGui::Button("Step");
+
+    if (step || running) {
+        sandbox.simulate_step();
+        gl.upload(reinterpret_cast<const char*>(sandbox.bitmap), kWidth, kHeight);
     }
+
+    // TODO this makes things very wrong (no proper assignment operator)
+    // if (ImGui::Button("Reset sandbox")) {
+    //     sandbox = Sandbox(40, 100);
+    // }
+    // ImGui::SameLine();
     if (ImGui::Button("Add sand")) {
         AddSand(sandbox);
     }
 
-    constexpr float kScale = 4.0f;
-    constexpr ImVec2 kSize(kWidth * kScale, kHeight * kScale);
+    auto sandbox_topleft = ImGui::GetCursorScreenPos();
     ImGui::Image(gl.as_imgui(), kSize, ImVec2(0, 1), ImVec2(1, 0));
+    // bottom-left corner of the sandbox, in screen space
+    auto origin = sandbox_topleft;
+    origin.y += kSize.y;
+
+    if (show_dirty_rect) {
+        auto dl = ImGui::GetWindowDrawList();
+        auto [top_left, bottom_right] = TrSandbox2Screen(origin, sandbox.dirty_writeto);
+        dl->AddRect(top_left, bottom_right, IM_COL32(255, 0, 0, 255));
+    }
+
     ImGui::End();
 
     ImGui::ShowDemoWindow();