C++ TType::getOuterArraySize方法代码示例

// Recursively figure out how many bytes of xfb buffer are used by the given type.
// Return the size of type, in bytes.
// Sets containsDouble to true if the type contains a double.
// N.B. Caller must set containsDouble to false before calling.
unsigned int TIntermediate::computeTypeXfbSize(const TType& type, bool& containsDouble) const
{
    // "...if applied to an aggregate containing a double, the offset must also be a multiple of 8, 
    // and the space taken in the buffer will be a multiple of 8.
    // ...within the qualified entity, subsequent components are each 
    // assigned, in order, to the next available offset aligned to a multiple of
    // that component's size.  Aggregate types are flattened down to the component
    // level to get this sequence of components."

    if (type.isArray()) {        
        // TODO: perf: this can be flattened by using getCumulativeArraySize(), and a deref that discards all arrayness
        assert(type.isExplicitlySizedArray());
        TType elementType(type, 0);
        return type.getOuterArraySize() * computeTypeXfbSize(elementType, containsDouble);
    }

    if (type.isStruct()) {
        unsigned int size = 0;
        bool structContainsDouble = false;
        for (int member = 0; member < (int)type.getStruct()->size(); ++member) {
            TType memberType(type, member);
            // "... if applied to 
            // an aggregate containing a double, the offset must also be a multiple of 8, 
            // and the space taken in the buffer will be a multiple of 8."
            bool memberContainsDouble = false;
            int memberSize = computeTypeXfbSize(memberType, memberContainsDouble);
            if (memberContainsDouble) {
                structContainsDouble = true;
                RoundToPow2(size, 8);
            }
            size += memberSize;
        }

        if (structContainsDouble) {
            containsDouble = true;
            RoundToPow2(size, 8);
        }
        return size;
    }

    int numComponents;
    if (type.isScalar())
        numComponents = 1;
    else if (type.isVector())
        numComponents = type.getVectorSize();
    else if (type.isMatrix())
        numComponents = type.getMatrixCols() * type.getMatrixRows();
    else {
        assert(0);
        numComponents = 1;
    }

    if (type.getBasicType() == EbtDouble) {
        containsDouble = true;
        return 8 * numComponents;
    } else
        return 4 * numComponents;
}

// Recursively figure out how many locations are used up by an input or output type.
// Return the size of type, as measured by "locations".
int TIntermediate::computeTypeLocationSize(const TType& type) const
{
    // "If the declared input is an array of size n and each element takes m locations, it will be assigned m * n 
    // consecutive locations..."
    if (type.isArray()) {
        // TODO: perf: this can be flattened by using getCumulativeArraySize(), and a deref that discards all arrayness
        TType elementType(type, 0);
        if (type.isImplicitlySizedArray()) {
            // TODO: are there valid cases of having an implicitly-sized array with a location?  If so, running this code too early.
            return computeTypeLocationSize(elementType);
        } else
            return type.getOuterArraySize() * computeTypeLocationSize(elementType);
    }

    // "The locations consumed by block and structure members are determined by applying the rules above 
    // recursively..."    
    if (type.isStruct()) {
        int size = 0;
        for (int member = 0; member < (int)type.getStruct()->size(); ++member) {
            TType memberType(type, member);
            size += computeTypeLocationSize(memberType);
        }
        return size;
    }

    // ES: "If a shader input is any scalar or vector type, it will consume a single location."

    // Desktop: "If a vertex shader input is any scalar or vector type, it will consume a single location. If a non-vertex 
    // shader input is a scalar or vector type other than dvec3 or dvec4, it will consume a single location, while 
    // types dvec3 or dvec4 will consume two consecutive locations. Inputs of type double and dvec2 will 
    // consume only a single location, in all stages."
    if (type.isScalar())
        return 1;
    if (type.isVector()) {
        if (language == EShLangVertex && type.getQualifier().isPipeInput())
            return 1;
        if (type.getBasicType() == EbtDouble && type.getVectorSize() > 2)
            return 2;
        else
            return 1;
    }

    // "If the declared input is an n x m single- or double-precision matrix, ...
    // The number of locations assigned for each matrix will be the same as 
    // for an n-element array of m-component vectors..."
    if (type.isMatrix()) {
        TType columnType(type, 0);
        return type.getMatrixCols() * computeTypeLocationSize(columnType);
    }

    assert(0);
    return 1;
}

// Ensure index is in bounds, correct if necessary.
// Give an error if not.
void TParseContextBase::checkIndex(const TSourceLoc& loc, const TType& type, int& index)
{
    if (index < 0) {
        error(loc, "", "[", "index out of range '%d'", index);
        index = 0;
    } else if (type.isArray()) {
        if (type.isSizedArray() && index >= type.getOuterArraySize()) {
            error(loc, "", "[", "array index out of range '%d'", index);
            index = type.getOuterArraySize() - 1;
        }
    } else if (type.isVector()) {
        if (index >= type.getVectorSize()) {
            error(loc, "", "[", "vector index out of range '%d'", index);
            index = type.getVectorSize() - 1;
        }
    } else if (type.isMatrix()) {
        if (index >= type.getMatrixCols()) {
            error(loc, "", "[", "matrix index out of range '%d'", index);
            index = type.getMatrixCols() - 1;
        }
    }
}

// Implement base-alignment and size rules from section 7.6.2.2 Standard Uniform Block Layout
// Operates recursively.
//
// If std140 is true, it does the rounding up to vec4 size required by std140, 
// otherwise it does not, yielding std430 rules.
//
// The size is returned in the 'size' parameter
//
// The stride is only non-0 for arrays or matrices, and is the stride of the
// top-level object nested within the type.  E.g., for an array of matrices,
// it is the distances needed between matrices, despite the rules saying the
// stride comes from the flattening down to vectors.
//
// Return value is the alignment of the type.
int TIntermediate::getBaseAlignment(const TType& type, int& size, int& stride, bool std140, bool rowMajor)
{
    int alignment;

    // When using the std140 storage layout, structures will be laid out in buffer
    // storage with its members stored in monotonically increasing order based on their
    // location in the declaration. A structure and each structure member have a base
    // offset and a base alignment, from which an aligned offset is computed by rounding
    // the base offset up to a multiple of the base alignment. The base offset of the first
    // member of a structure is taken from the aligned offset of the structure itself. The
    // base offset of all other structure members is derived by taking the offset of the
    // last basic machine unit consumed by the previous member and adding one. Each
    // structure member is stored in memory at its aligned offset. The members of a top-
    // level uniform block are laid out in buffer storage by treating the uniform block as
    // a structure with a base offset of zero.
    //
    //   1. If the member is a scalar consuming N basic machine units, the base alignment is N.
    //
    //   2. If the member is a two- or four-component vector with components consuming N basic 
    //      machine units, the base alignment is 2N or 4N, respectively.
    //
    //   3. If the member is a three-component vector with components consuming N
    //      basic machine units, the base alignment is 4N.
    //
    //   4. If the member is an array of scalars or vectors, the base alignment and array
    //      stride are set to match the base alignment of a single array element, according
    //      to rules (1), (2), and (3), and rounded up to the base alignment of a vec4. The
    //      array may have padding at the end; the base offset of the member following
    //      the array is rounded up to the next multiple of the base alignment.
    //
    //   5. If the member is a column-major matrix with C columns and R rows, the
    //      matrix is stored identically to an array of C column vectors with R 
    //      components each, according to rule (4).
    //
    //   6. If the member is an array of S column-major matrices with C columns and
    //      R rows, the matrix is stored identically to a row of S  C column vectors
    //      with R components each, according to rule (4).
    //
    //   7. If the member is a row-major matrix with C columns and R rows, the matrix
    //      is stored identically to an array of R row vectors with C components each,
    //      according to rule (4).
    //
    //   8. If the member is an array of S row-major matrices with C columns and R
    //      rows, the matrix is stored identically to a row of S  R row vectors with C
    //      components each, according to rule (4).
    //
    //   9. If the member is a structure, the base alignment of the structure is N , where
    //      N is the largest base alignment value of any    of its members, and rounded
    //      up to the base alignment of a vec4. The individual members of this substructure 
    //      are then assigned offsets by applying this set of rules recursively,
    //      where the base offset of the first member of the sub-structure is equal to the
    //      aligned offset of the structure. The structure may have padding at the end;
    //      the base offset of the member following the sub-structure is rounded up to
    //      the next multiple of the base alignment of the structure.
    //
    //   10. If the member is an array of S structures, the S elements of the array are laid
    //       out in order, according to rule (9).
    //
    //   Assuming, for rule 10:  The stride is the same as the size of an element.

    stride = 0;
    int dummyStride;

    // rules 4, 6, 8, and 10
    if (type.isArray()) {
        // TODO: perf: this might be flattened by using getCumulativeArraySize(), and a deref that discards all arrayness
        TType derefType(type, 0);
        alignment = getBaseAlignment(derefType, size, dummyStride, std140, rowMajor);
        if (std140)
            alignment = std::max(baseAlignmentVec4Std140, alignment);
        RoundToPow2(size, alignment);
        stride = size;  // uses full matrix size for stride of an array of matrices (not quite what rule 6/8, but what's expected)
                        // uses the assumption for rule 10 in the comment above
        size = stride * type.getOuterArraySize();
        return alignment;
    }

    // rule 9
    if (type.getBasicType() == EbtStruct) {
        const TTypeList& memberList = *type.getStruct();

        size = 0;
        int maxAlignment = std140 ? baseAlignmentVec4Std140 : 0;
        for (size_t m = 0; m < memberList.size(); ++m) {
            int memberSize;
            // modify just the children's view of matrix layout, if there is one for this member
//.........这里部分代码省略.........

// Recursively merge the implicit array sizes through the objects' respective type trees.
void TIntermediate::mergeImplicitArraySizes(TType& type, const TType& unitType)
{
    if (type.isImplicitlySizedArray() && unitType.isArray()) {
        int newImplicitArraySize = unitType.isImplicitlySizedArray() ? unitType.getImplicitArraySize() : unitType.getOuterArraySize();
        if (newImplicitArraySize > type.getImplicitArraySize ())
            type.setImplicitArraySize(newImplicitArraySize);
    }

    // Type mismatches are caught and reported after this, just be careful for now.
    if (! type.isStruct() || ! unitType.isStruct() || type.getStruct()->size() != unitType.getStruct()->size())
        return;

    for (int i = 0; i < (int)type.getStruct()->size(); ++i)
        mergeImplicitArraySizes(*(*type.getStruct())[i].type, *(*unitType.getStruct())[i].type);
}