imageSampleImplicitLod

pub fn imageSampleImplicitLod(
    sampled_image: anytype,
    coordinate: ImageCoordinate(std.meta.Child(@TypeOf(sampled_image)), f32),
) @Vector(4, ImageSampledType(std.meta.Child(@TypeOf(sampled_image))))

File

Code

pub fn imageSampleImplicitLod(
    sampled_image: anytype,
    coordinate: ImageCoordinate(std.meta.Child(@TypeOf(sampled_image)), f32),
) @Vector(4, ImageSampledType(std.meta.Child(@TypeOf(sampled_image)))) {
    const SampledImage = switch (@typeInfo(@TypeOf(sampled_image))) {
        .pointer => |pointer| pointer.child,
        else => @compileError("Expected a pointer to SPIR-V sampled image type, found '" ++ @typeName(@TypeOf(sampled_image)) ++ "'"),
    };
    const Result = @Vector(4, ImageSampledType(SampledImage));

    const image_info = switch (@typeInfo(SampledImage)) {
        .spirv => |spirv| switch (spirv) {
            .sampled_image => |sampled_image_info| @typeInfo(sampled_image_info).spirv.image,
            else => @compileError("Expected SPIR-V sampled image type, found '" ++ @typeName(SampledImage) ++ "'"),
        },
        else => @compileError("Expected SPIR-V sampled image type, found '" ++ @typeName(SampledImage) ++ "'"),
    };

    if (image_info.multisampled)
        @compileError("Can not implicitly sample a sampled image that was multisampled");

    // TOOD: If buffer dim is added, throw a compile error if the dimension is a buffer.

    return asm volatile (
        \\%loaded_sampler = OpLoad %SampledImage %sampled_image
        \\%ret            = OpImageSampleImplicitLod %Result %loaded_sampler %coordinate
        : [ret] "" (-> Result),
        : [SampledImage] "t" (SampledImage),
          [sampled_image] "" (sampled_image),
          [Result] "t" (Result),
          [coordinate] "" (coordinate),
    );
}