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(Samples app) Preserve world position of mouse cursor after scroll zoom #1021

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(Samples app) Preserve world position of mouse cursor after scroll zoom #1021

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9 changes: 9 additions & 0 deletions samples/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -378,6 +378,11 @@ static void ScrollCallback( GLFWwindow* window, double dx, double dy )
return;
}

double xd, yd;
glfwGetCursorPos( window, &xd, &yd );
b2Vec2 ps = { float( xd ), float( yd ) };
b2Vec2 pwBefore = ConvertScreenToWorld( &s_context.camera, ps );

if ( dy > 0 )
{
s_context.camera.zoom /= 1.1f;
Expand All @@ -386,6 +391,10 @@ static void ScrollCallback( GLFWwindow* window, double dx, double dy )
{
s_context.camera.zoom *= 1.1f;
}

b2Vec2 pwAfter = ConvertScreenToWorld( &s_context.camera, ps );
b2Vec2 delta = pwAfter - pwBefore;
s_context.camera.center -= delta;
}

static void UpdateUI()
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