57 lines
1.3 KiB
Standard ML
57 lines
1.3 KiB
Standard ML
structure Ndc =
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struct
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(* ndc = normalised device coordinates *)
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fun ltrbToVertex (left, top, right, bottom) =
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#[ left, bottom
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, right, bottom
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, left, top
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, left, top
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, right, bottom
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, right, top
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]
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fun ltrbToVertexRgb (left, top, right, bottom, r, g, b) =
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#[ left, bottom, r, g, b
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, right, bottom, r, g, b
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, left, top, r, g, b
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, left, top, r, g, b
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, right, bottom, r, g, b
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, right, top, r, g, b
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]
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fun fromPixelX (xpos, windowWidth, windowHeight) =
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let
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val halfWidth = (Real32.fromInt windowWidth) / 2.0
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val xpos = xpos - halfWidth
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in
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if windowWidth > windowHeight then
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let
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val difference = windowWidth - windowHeight
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val offset = Real32.fromInt (difference div 2)
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in
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xpos / (halfWidth - offset)
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end
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else
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xpos / halfWidth
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end
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fun fromPixelY (ypos, windowWidth, windowHeight) =
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let
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val halfHeight = (Real32.fromInt windowHeight) / 2.0
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val ypos = ~(ypos - halfHeight)
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in
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if windowHeight > windowWidth then
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let
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val difference = windowHeight - windowWidth
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val offset = Real32.fromInt (difference div 2)
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in
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ypos / (halfHeight - offset)
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end
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else
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ypos / halfHeight
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end
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end
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