// Vector by matrix multiplication has a pattern of:
// float2(dot(m_row1, v), dot(m_row2, v))
// float3(dot(m_row1, v), dot(m_row2, v), dot(m_row3, v))
// float4(dot(m_row1, v), dot(m_row2, v), dot(m_row3, v), dot(m_row4, v))
public MatrixMultiplicationContext TryGetMultiplicationGroup(IList <HlslTreeNode> components)
{
const bool allowMatrix = true;
if (!(components[0] is DotProductOperation firstDot))
{
return(null);
}
int dimension = firstDot.X.Length;
if (components.Count < dimension)
{
return(null);
}
GroupNode firstMatrixRow = TryGetMatrixRow(firstDot, firstDot, 0);
if (firstMatrixRow == null)
{
return(null);
}
GroupNode vector = firstDot.X == firstMatrixRow
? firstDot.Y
: firstDot.X;
var matrixRows = new List <GroupNode>();
matrixRows.Add(firstMatrixRow);
for (int i = 1; i < components.Count; i++)
{
if (!(components[i] is DotProductOperation nextDot))
{
break;
}
GroupNode matrixRow = TryGetMatrixRow(nextDot, firstDot, i);
if (matrixRow == null)
{
break;
}
GroupNode nextVector = nextDot.X == matrixRow
? nextDot.Y
: nextDot.X;
if (!NodeGrouper.AreNodesEquivalent(vector, nextVector))
{
break;
}
matrixRows.Add(matrixRow);
}
if (matrixRows.Count < 2)
{
return(null);
}
ConstantDeclaration matrix = TryGetMatrixDeclaration(matrixRows);
if (matrix == null)
{
return(null);
}
bool matrixByVector = firstMatrixRow.Inputs
.Cast <RegisterInputNode>()
.All(row => row.ComponentIndex == 0);
vector = SwizzleVector(vector, firstMatrixRow, matrixByVector);
return(new MatrixMultiplicationContext(vector, matrix, matrixByVector, matrixRows.Count));
}