可以更改金属材质球中采样器的边界吗?

不知道,但如果知道要从中采样的区域,则很容易在着色器中进行一些数学运算以修复采样坐标。这通常与 texture atlases .

float4 ,将边界存储为(左、上、宽、高) xyzw

fragment float4 fragment_main(FragmentParams in [[stage_in]],
                              texture2d<float, access::sample> tex2d [[texture(0)]],
                              sampler sampler2d [[sampler(0)]],
                              // ...
                              constant float4 &spriteBounds [[buffer(0)]])
{
    // original coordinates, normalized with respect to subimage
    float2 texCoords = in.texCoords;

    // texture dimensions
    float2 texSize = float2(tex2d.get_width(), tex2d.get_height());

    // adjusted texture coordinates, normalized with respect to full texture
    texCoords = (texCoords * spriteBounds.zw + spriteBounds.xy) / texSize;

    // sample color at modified coordinates
    float4 color = tex2d.sample(sampler2d, texCoords);
    // ...
}