Question

我正在尝试为我正在处理的项目编写HLSL像素着色器。基本上我想要做的是，如果纹理具有浮点值为0.52的像素（在0-255的范围内是132.6）我想要输出133 60％的时间并输出132 40％的时间。现在写我只是想输出RGB值的小数余数（即将像素向上碰撞的机会）然而我总是得到零值）我认为这是因为颜色被量化为0-255比例在它们到达着色器之前但我不知道为什么会这样，因为我使用的是A32B32G32R32f格式，它应该能够存储大量有关颜色的信息。这是我非常简单的着色器代码。如果重要，我正在使用SlimDX（DX9）。

sampler2D Tex0 : register(s0);
float4 DitherByChance(float2 coords : TEXCOORD0) : COLOR
{
    float4 newColor = float4(0, 0, 0, 0);   // The pixel color to return
    double4 oldColor = tex2D(Tex0, coords);
    double scale = 0.0039215686274509803921568627451;  // 1 / 255

    double rPercentChance = frac(oldColor.r / scale);   //Chance to round red channel up
    double gPercentChance = frac(oldColor.g / scale);   //Chance to round green channel up
    double bPercentChance = frac(oldColor.b / scale);   //Chance to round blue channel up

    newColor.r = rPercentChance;
    newColor.g = gPercentChance;
    newColor.b = bPercentChance;

    newColor.a = 1;

    return newColor;
}

technique DitherViaChance  
{  
    pass Pass1  
    {  
        PixelShader = compile ps_2_0 DitherByChance();      
    }  
}

如果重要的话，这是我的slimDX代码：

Public Class TextStimulusDisplay
    Inherits BaseStimulusDisplay

    Protected ditherByChanceEffect As PixelShader
    Protected psByteCode As ShaderBytecode
    Protected gStream As DataStream
    Protected ditherBC As Effect

    Protected tex As Texture
    Protected spriteRender As Sprite

    Public displaySettings As DisplaySettings
    Public charText As Texture
    Public randomText As Texture

    Protected rando As Random

    Public Sub New(ByVal displaysettings As DisplaySettings, Optional ByVal WindowedMode As Boolean = False)
        MyBase.New(New Size(displaysettings.xResolution, displaysettings.yResolution), WindowedMode)
        Me.displaySettings = displaysettings
    End Sub

    Public Overrides Sub CreateDeviceResources()
        MyBase.CreateDeviceResources()
        ditherBC = Effect.FromFile(device, Application.StartupPath & "\effects\DitherByChance.fx", ShaderFlags.Debug)
        rando = New Random()

        randomText = New Texture(device, 100, 100, 1, Usage.Dynamic, Format.A32B32G32R32F, Pool.Default)
        Dim data(80000) As Byte
        rando.NextBytes(data)
        Dim dataBox As DataRectangle = randomText.GetSurfaceLevel(0).LockRectangle(LockFlags.None)
        dataBox.Data.Seek(0, IO.SeekOrigin.Begin)
        dataBox.Data.Write(data, 0, data.Length)
        dataBox.Data.Close()
        randomText.GetSurfaceLevel(0).UnlockRectangle()

        device.SetTexture(1, randomText)

        'psByteCode = ShaderBytecode.CompileFromFile(Application.StartupPath & "\effects\DitherByChance.fx", "DitherByChance", "ps_2_0", ShaderFlags.None)
        'ditherByChanceEffect = New PixelShader(device, psByteCode)
        'device.PixelShader = ditherByChanceEffect
        spriteRender = New Sprite(device)
        spriteRender.Transform = Matrix.Identity
        tex = createCharacterTexture()

    End Sub

    Public Overrides Sub ReleaseDeviceResources()
        MyBase.ReleaseDeviceResources()
    End Sub

    Public Overrides Sub RenderScene()
        'ditherBC.Technique = ditherBC.GetTechnique("DitherViaChance")

        Me.device.BeginScene()
        spriteRender.Begin(SpriteFlags.None)
        ditherBC.Begin()
        ditherBC.BeginPass(0)
        spriteRender.Draw(tex, New Rectangle(0, 0, 50, 50), New Color4(1, 1, 1))
        'spriteRender.Draw(randomText, New Rectangle(0, 0, 1000, 1000), New Color4(1, 1, 1))
        spriteRender.End()
        ditherBC.EndPass()
        ditherBC.End()
        Me.device.EndScene()
    End Sub

    Public Function createCharacterTexture() As Texture
        Dim RtsHelper As RenderToSurface = New RenderToSurface(device, 100, 100, Format.A32B32G32R32F)
        Dim texture As Texture = New Texture(device, 100, 100, 1, Usage.RenderTarget, Format.A32B32G32R32F, Pool.Default)

        Dim sloanFont As Font = New Font(device, 98, 98, FontWeight.Normal, 1, False, CharacterSet.Default, Precision.Default,
                                         FontQuality.ClearTypeNatural, PitchAndFamily.Default, "Sloan")


        RtsHelper.BeginScene(texture.GetSurfaceLevel(0), New Viewport(0, 0, 100, 100))



        sloanFont.DrawString(Nothing, "A", 1, 1, New SlimDX.Color4())
        RtsHelper.EndScene(Filter.None)

        Font.Dispose()
        RtsHelper.Dispose()

        Return texture
    End Function
End Class

为什么这个128Bit颜色格式被转换为32Bit

0 个答案: