ios - 在 Metal Shader Vertex 函数中出错

Question

代码库有点旧，正在努力支持最新的 iOS 版本。它过去工作正常，但现在出现以下错误。

vertex function has invalid return type 'ColorInOut'

下面是 Metal 着色器代码的一部分。您可以获得完整代码 here .

typedef struct
{
    packed_float3 position;
    packed_float3 normal;
    packed_float2 texCoord1;
    packed_float3 tangent;
    packed_float3 bitagent;
    packed_float4 vertColor;
} vertex_t;

typedef struct
{
    float4 position [[position]] , vertexPosition_ws;
    float2 uv,texture2UV;
    float hasLighting;
    float pointSize [[point_size]];
    float vertexDepth, reflection;
    float hasMeshColor;
    float shadowDarkness, transparency;
    float2 pointCoord [[ point_coord ]];
    float4 eyeVec, lightDir, lightColor;
    float3 meshColor;
    float3 T;
    float3 B;
    float3 N;
} ColorInOut;

vertex ColorInOut Mesh_Vertex(device vertex_t* vertex_array [[ buffer(0) ]],
                                constant float4x4& vp [[ buffer(SHADER_MESH_mvp) ]],
                                constant MatArray* model [[ buffer(SHADER_MESH_model) ]],
                                constant float4x4& lvp [[ buffer(SHADER_MESH_lightViewProjMatrix) ]],
                                constant packed_float3& eyePos [[ buffer(SHADER_MESH_eyePos) ]],
                                constant float& shadowDarkness [[ buffer(SHADER_MESH_shadowDarkness) ]],
                                constant float *hasMeshColor [[ buffer(SHADER_MESH_hasMeshColor) ]],
                                constant float *reflectionValue [[ buffer(SHADER_MESH_reflectionValue) ]],
                                constant float *transparency [[ buffer(SHADER_MESH_transparency) ]],
                                constant float *hasLighting [[ buffer(SHADER_MESH_hasLighting) ]],
                                constant float *uvScaleValue [[ buffer(SHADER_MESH_uvScale) ]],
                                constant float3Struct *meshColor [[buffer(SHADER_MESH_meshColor)]],
                                unsigned int vid [[ vertex_id ]],
                                unsigned int iId [[ instance_id ]]
                                )
{

    float4 vertexPosition_ws = model[iId].data * float4(float3(vertex_array[vid].position), 1.0);
    float4 vertColor = float4(vertex_array[vid].vertColor);
    float3 tangent = float3(vertex_array[vid].tangent);
    float3 bitangent = float3(vertex_array[vid].bitagent);
    float3 normal = float3(vertex_array[vid].normal);

    ColorInOut out;
    out.hasMeshColor = hasMeshColor[iId];
    out.meshColor = (meshColor[iId].data[0] == -1.0) ? vertColor.xyz : float3(meshColor[iId].data);
    out.reflection = reflectionValue[iId];

    out.T = normalize(float3(model[iId].data * float4(tangent, 0.0)));
    out.B = normalize(float3(model[iId].data * float4(bitangent, 0.0)));
    out.N = normalize(float3(model[iId].data * float4(normal,  0.0)));

    out.vertexPosition_ws = vertexPosition_ws;
    out.transparency = transparency[iId];
    out.hasLighting = hasLighting[iId];
    out.position = vp * vertexPosition_ws;
    out.uv = vertex_array[vid].texCoord1 * uvScaleValue[iId];
    out.shadowDarkness = 0.0;

    if(bool(hasLighting[iId])) {
        float4 vertexLightCoord = lvp * vertexPosition_ws;
        float4 texCoords = vertexLightCoord/vertexLightCoord.w;
        out.texture2UV = float4((texCoords / 2.0) + 0.5).xy;
        out.texture2UV.y = (1.0 - out.texture2UV.y); // need to flip metal texture vertically
        out.vertexDepth = texCoords.z;
        out.shadowDarkness = shadowDarkness;
    }

    float4 eye_position_ws = vertexPosition_ws - float4(float3(eyePos), 1.0);
    out.eyeVec = normalize(eye_position_ws);

    return out;
}

Answer 1

我怀疑你引用的是整个错误信息。在询问错误消息时，请始终包括完整的逐字消息。

也就是说，我最好的猜测是 [[ point_coord ]] 不是顶点函数输出的有效属性。

另一件事是你应该将输入参数 vertex_array 声明为 const 以便 Metal 知道你不会写入它:

device const vertex_t* vertex_array [[ buffer(0) ]]

写入缓冲区或纹理的顶点着色器只能返回 void。