MouseReleased double trigger

[Pagghiu]

This change should be reverted in my opinion, because it has broken current MouseRelease handling.
It makes MouseReleased == true for two subsequent frames after mouseDown[i] changes from true to false.

     g.IO.MousePosPrev = g.IO.MousePos;
     for (int i = 0; i < IM_ARRAYSIZE(g.IO.MouseDown); i++)
     {
+        g.IO.MouseClicked[i] = g.IO.MouseDown[i] && g.IO.MouseDownDuration[i] < 0.0f;
+        g.IO.MouseReleased[i] = !g.IO.MouseDown[i] && g.IO.MouseDownDurationPrev[i] >= 0.0f;
         g.IO.MouseDownDurationPrev[i] = g.IO.MouseDownDuration[i];
         g.IO.MouseDownDuration[i] = g.IO.MouseDown[i] ? (g.IO.MouseDownDuration[i] < 0.0f ? 0.0f : g.IO.MouseDownDuration[i] + g.IO.DeltaTime) : -1.0f;
-        g.IO.MouseClicked[i] = g.IO.MouseDownDuration[i] == 0.0f;
-        g.IO.MouseReleased[i] = g.IO.MouseDownDurationPrev[i] >= 0.0f && !g.IO.MouseDown[i];
         g.IO.MouseDoubleClicked[i] = false;

It's trivial to check wrong behaviour by modifying the demo as follows.
You will see that you get two mouse releases for each click.

        if (ImGui::TreeNode("Keyboard & Mouse State"))
        {
            ImGuiIO& io = ImGui::GetIO();

            ImGui::Text("MousePos: (%g, %g)", io.MousePos.x, io.MousePos.y);
            static int numReleases = 0;
            ImGui::Text("Mouse down:");     for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++) if (io.MouseDownDuration[i] >= 0.0f)   { ImGui::SameLine(); ImGui::Text("b%d (%.02f secs)", i, io.MouseDownDuration[i]); }
            ImGui::Text("Mouse clicked:");  for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++) if (ImGui::IsMouseClicked(i))          { ImGui::SameLine(); ImGui::Text("b%d", i); }
            ImGui::Text("Mouse dbl-clicked:"); for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++) if (ImGui::IsMouseDoubleClicked(i)) { ImGui::SameLine(); ImGui::Text("b%d", i); }
            ImGui::Text("Mouse released (%d):", numReleases); for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++) if (ImGui::IsMouseReleased(i))         { ImGui::SameLine(); ImGui::Text("b%d", i); numReleases++; }
            ImGui::Text("MouseWheel: %.1f", io.MouseWheel);

[ocornut]

The change was meant to make mouse functions with 0.0 deltatime so ideally we'd want that without the new bug. I'll look into it maybe tonight, if you can find the correct fix before feel free to PR :)

[ocornut]

Thanks and sorry I couldn't look earlier.

I haven't merged your change from #362

But changed
g.IO.MouseReleased[i] = !g.IO.MouseDown[i] && g.IO.MouseDownDurationPrev[i] >= 0.0f;
to
g.IO.MouseReleased[i] = !g.IO.MouseDown[i] && g.IO.MouseDownDuration[i] >= 0.0f;

Which I think it's more clear. Testing Prev[] was a mistake here. It would miss a release event if mouse was held for a single frame.
Those lines are rather confusing but such a simple operation. Can probably clarify when we add support for timestamped events.