35 lines
1.1 KiB
Text
35 lines
1.1 KiB
Text
function bresLine(sequence screenData, integer x0, integer y0, integer x1, integer y1, integer colour)
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-- The line algorithm
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integer deltaX = abs(x1-x0),
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deltaY = abs(y1-y0),
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stepX = iff(x0<x1,1,-1),
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stepY = iff(y0<y1,1,-1),
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lineError = iff(deltaX>deltaY,deltaX,-deltaY),
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prevle
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lineError = round(lineError/2,1)
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while 1 do
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if x0>=1 and x0<=length(screenData)
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and y0>=1 and y0<=length(screenData[x0]) then
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screenData[x0][y0] = colour
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end if
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if x0=x1 and y0=y1 then exit end if
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prevle = lineError
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if prevle>-deltaX then
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lineError -= deltaY
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x0 += stepX
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end if
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if prevle<deltaY then
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lineError += deltaX
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y0 += stepY
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end if
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end while
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return screenData
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end function
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sequence screenData = new_image(400,300,black)
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screenData = bresLine(screenData,100,1,50,300,red)
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screenData = bresLine(screenData,1,180,400,240,green)
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screenData = bresLine(screenData,200,1,400,150,white)
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screenData = bresLine(screenData,195,1,205,300,blue)
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write_ppm("bresenham.ppm",screenData)
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