Issue with progress bar shader in XNA

问题

I'm create a simple shader for drawing progress bar in XNA.

Idea is simple: there are two textures and value and if X texture coord less then value use pixel from foreground texture, else use background texture.

/* Variables */

texture BackgroundTexture;
sampler2D BackgroundSampler = sampler_state
{
    Texture = (BackgroundTexture);
    MagFilter = Point;
    MinFilter = Point;
    AddressU = Clamp;
    AddressV = Clamp;
};

texture ForegroundTexture;
sampler2D ForegroundSampler = sampler_state
{
    Texture = (ForegroundTexture);
    MagFilter = Point;
    MinFilter = Point;
    AddressU = Clamp;
    AddressV = Clamp;
};

float Value;

/* Pixel shaders */

float4 PixelShader1(float4 pTexCoord : texcoord0) : color0
{
    float4 texColor =
        pTexCoord.x <= Value ?
        tex2D(ForegroundSampler, pTexCoord) :
        tex2D(BackgroundSampler, pTexCoord);

    return texColor;
}

/* Techniques */

technique Technique1
{
    pass Pass1
    {
        PixelShader = compile ps_2_0 PixelShader1();
    }
}

But correct only ForegroundTexture. BackgroundSampler is simply white. I found that correct shown only texture that was declared in shader in last.

Please help me understand why so?

回答1:

I've got it!

There are all correct with shader.

Mistake was heare:

this.progressBarEffect.Parameters["Value"].SetValue(progressBarValue);
            this.progressBarEffect.Parameters["ForegroundTexture"].SetValue(this.progressBarForegroundTexture);
            this.progressBarEffect.Parameters["BackgroundTexture"].SetValue(this.progressBarBackgroundTexture);
            this.spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.Opaque, SamplerState.PointWrap, null, null, this.progressBarEffect);
            this.spriteBatch.Draw(this.pixelTexture, new Rectangle(5, 200, 180, 30), Color.White);
            this.spriteBatch.End();

And correct variant is:

this.progressBarEffect.Parameters["Value"].SetValue(progressBarValue);
            //this.progressBarEffect.Parameters["ForegroundTexture"].SetValue(this.progressBarForegroundTexture);
            this.progressBarEffect.Parameters["BackgroundTexture"].SetValue(this.progressBarBackgroundTexture);
            this.spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.Opaque, SamplerState.PointWrap, null, null, this.progressBarEffect);
            this.spriteBatch.Draw(this.progressBarForegroundTexture, new Rectangle(5, 200, 180, 30), Color.White);
            this.spriteBatch.End();

I've forgot that first declared texture use same index that texture passed to Draw method.

Maybe it will be usefull for somebody.

来源：https://stackoverflow.com/questions/24224977/issue-with-progress-bar-shader-in-xna

标签

xna

progress-bar

hlsl

effect