| 摘要 |
A method and a device for determining shadows in a computer-generated image are provided, wherein the determination whether a pixel x is in shadow is based on a shadow test function f(d(x), z(P)), d(x) representing the depth of the pixel x with respect to the light source and z(p) being a shadow map z for the computer-generated image. According to the invention, the shadow test function f satisfies <maths id="MATH-US-00001" num="00001"> <math overflow="scroll"> <mrow> <mrow> <mi>f</mi> <mo></mo> <mrow> <mo>(</mo> <mrow> <mrow> <mi>d</mi> <mo></mo> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mrow> <mo>,</mo> <mrow> <mi>z</mi> <mo></mo> <mrow> <mo>(</mo> <mi>p</mi> <mo>)</mo> </mrow> </mrow> </mrow> <mo>)</mo> </mrow> </mrow> <mo>=</mo> <mrow> <munderover> <mo>∑</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <mo></mo> <mrow> <mrow> <msub> <mi>a</mi> <mi>i</mi> </msub> <mo></mo> <mrow> <mo>(</mo> <mrow> <mi>d</mi> <mo></mo> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </mrow> <mo>)</mo> </mrow> </mrow> <mo></mo> <mrow> <msub> <mi>B</mi> <mi>i</mi> </msub> <mo></mo> <mrow> <mo>(</mo> <mrow> <mi>z</mi> <mo></mo> <mrow> <mo>(</mo> <mi>p</mi> <mo>)</mo> </mrow> </mrow> <mo>)</mo> </mrow> </mrow> </mrow> </mrow> </mrow> </math> </maths> wherein ai are weighting coefficients depending on d, Bi are basis functions in terms of z and N is a natural number.
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