#getting theta from a mouse

1 messages · Page 1 of 1 (latest)

strange cedar
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Hi, I am making a zombie shooter for an honors project. How would you get theta in relation to the sprite so that the sprite is pointing towards the mouse?

survivor-idle_rifle_0.png
ruby yarrowBOT
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<@&987246487241105418> please have a look, thanks.

ruby yarrowBOT
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tall terrace
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not sure what u mean by theta and what specifically is ur problem or unclear to u

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if its the math, its this:

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so u just measure the angle between the mouse coordinates and the center of the unit

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and then rotate the sprite by that angle

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as u might remember from school, sin(alpha) = opposite/hypotenuse

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opposite is the y difference between the two coordinates

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so opposite = mouse_y - unit_y

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and the hypotenuse is given with pythagoras

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a^2 = b^2 + c^2

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the adjacent is the x diff of both coords

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adjacent = mouse_x - unit_x

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plug in and u get the hypotenuse

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then plug in and u get sin(alpha)

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(undo sine to get the angle in degrees)

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once u have the angle, rotate the sprite in that angle and its pointing to ur mouse

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quite satisfying to watch when it does that. enjoy! 🙂

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if u want to shortcut the math a bit, theres something called atan2

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the formula is:

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Math.atan2(mouse.y - unit.y, mouse.x - unit.x)

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for the angle directly

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but its a bit trickier to understand that, hence i went for the other more straightforward route

strange cedar
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Thanks, I’m new to javafx and I’m making my first game so this helps a lot.