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我正在尝试组合 2 个渲染目标，颜色和法线，用于漫反射闪电并在屏幕上渲染结果。这个想法是使用具有仅包含像素着色器的效果的精灵来组合来自纹理的渲染目标。XNA 代码：

GraphicsDevice.SetRenderTarget(null);
GraphicsDevice.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1.0f, 0);
effect.CurrentTechnique = effect.Techniques["show_buffer"];
effect.Parameters["normalTex"].SetValue(normalRendertarget);
effect.Parameters["colorTex"].SetValue(colorRendertarget);
effect.Parameters["AmbientIntensity"].SetValue(ambientIntesity);
effect.Parameters["LightDirection"].SetValue(lightDirection);
effect.Parameters["DiffuseIntensity"].SetValue(diffuseIntensity);

spriteBatch.Begin(0, BlendState.Opaque, null, null, null,effect);
spriteBatch.Draw(normalRT, Vector2.Zero, Color.White);
spriteBatch.End();

由于某种原因， spriteBatch.Draw() 中使用的渲染目标会影响结果。

像素着色器：

void Tex_PixelShader(float2 texCoord : TEXCOORD0, out float4 color : COLOR0)
{
 float4 normal = tex2D(normalTexSampler, texCoord);
 //tranform normal back into [-1,1] range
 normal.rgb = (normal.rgb*2)-1; 
 float4 baseColor = tex2D(colorTexSampler, texCoord);
 float3 lightDirectionNorm = normalize(LightDirection);
 float diffuse = saturate(dot(-lightDirectionNorm,normal.rgb));

 //only works with normalRT in spriteBatch.Draw()
 //colorRT  in spriteBatch.Draw() gives colorRT but darker as result
 color = float4 (baseColor.rgb * (AmbientIntensity + diffuse*DiffuseIntensity), 1.0f);

 //only works with colorRT in spriteBatch.Draw()
 //normalRT in spriteBatch.Draw() gives normalRT as result
 //color = tex2D(colorTexSampler, texCoord); 

 //only works with NormalRT
 //colorRT in spriteBatch.Draw() gives colorRT as result
 //color=tex2D(normalTexSampler, texCoord);

 // works with any rendertarget in spriteBatch.Draw()
 //color = float4(0.0f,1.0f,0.0f,1.0f);
}

两个渲染目标中的 alpha 值始终为 1。将顶点着色器添加到效果会导致黑色。使用 spriteBatch.Draw() 绘制一个没有任何效果的渲染目标表明每个渲染目标的内容都很好。我无法理解这一点。有任何想法吗？

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1 回答 1

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使用GraphicsDevice.Textures[1]=tex; 设置纹理；而不是effect.Parameters["tex"]=tex; 工作。谢谢安德鲁。

将 xna 代码更改为：

GraphicsDevice.SetRenderTarget(null);
GraphicsDevice.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1.0f, 0);
effect.CurrentTechnique = effect.Techniques["show_buffer"];
GraphicsDevice.Textures[1] = normalRT;   //changed
GraphicsDevice.Textures[2] = colorRT;    //changed
effect.Parameters["AmbientIntensity"].SetValue(ambientIntesity);
effect.Parameters["LightDirection"].SetValue(lightDirection);
effect.Parameters["DiffuseIntensity"].SetValue(diffuseIntensity);

spriteBatch.Begin(0, BlendState.Opaque, null, null, null,effect);
spriteBatch.Draw((Texture2D)colorRT, Vector2.Zero, Color.White);
spriteBatch.End();

以及着色器代码：

sampler normalSampler: register(s1);   //added
sampler colorSampler: register(s2);    //added

void Tex_PixelShader(float2 texCoord : TEXCOORD0, out float4 color : COLOR0)
{
 float4 normal = tex2D(normalSampler, texCoord); //changed
 normal.rgb = (normal.rgb*2)-1;
 float4 baseColor = tex2D(colorSampler, texCoord);  //changed

 float3 lightDirectionNorm = normalize(LightDirection);
 float diffuse = saturate(dot(-lightDirectionNorm,normal.rgb));

 color = float4 (baseColor.rgb * (AmbientIntensity + diffuse*DiffuseIntensity), 1.0f);
}
于 2012-09-17T07:16:08.567 回答