/// <summary>
/// Creates a new instance of the Shader class.
/// </summary>
/// <param name="shaderBytecode">Byte array containing the compiled shader bytecode.</param>
public Shader(byte[] shaderBytecode)
{
var bytecodeContainer = new BytecodeContainer(shaderBytecode);
var programType = bytecodeContainer.Shader.Version.ProgramType;
switch (programType)
{
case ProgramType.GeometryShader:
case ProgramType.HullShader:
case ProgramType.DomainShader:
case ProgramType.ComputeShader:
throw new NotSupportedException(string.Format(
"The '{0}' shader type is not yet supported.",
bytecodeContainer.Shader.Version.ProgramType));
}
_constantBuffers = bytecodeContainer.ResourceDefinition.ConstantBuffers;
_resourceBindings = bytecodeContainer.ResourceDefinition.ResourceBindings;
_inputSignature = bytecodeContainer.InputSignature;
_inputSignatureSize = _inputSignature.Parameters.Sum(x => x.ByteCount);
_outputSignature = bytecodeContainer.OutputSignature;
_outputSignatureSize = _outputSignature.Parameters.Sum(x => x.ByteCount);
var numContexts = (programType == ProgramType.PixelShader) ? 4 : 1;
_virtualMachine = new VirtualMachine(bytecodeContainer, numContexts);
}
internal IEnumerable <FragmentQuad> Execute(
IEnumerable <InputAssemblerPrimitiveOutput> inputs,
PrimitiveTopology primitiveTopology,
OutputSignatureChunk previousStageOutputSignature,
BytecodeContainer pixelShader,
int multiSampleCount)
{
// TODO: Allow selection of different viewport.
var viewport = _viewports[0];
var outputInputBindings = ShaderOutputInputBindings.FromShaderSignatures(
previousStageOutputSignature, pixelShader);
var rasterizer = PrimitiveRasterizerFactory.CreateRasterizer(
primitiveTopology, State.Description, multiSampleCount,
outputInputBindings, ref viewport, FragmentFilter);
foreach (var primitive in inputs)
{
// Frustum culling.
if (ViewportCuller.ShouldCullTriangle(primitive.Vertices))
{
continue;
}
// TODO: Clipping.
// http://simonstechblog.blogspot.tw/2012/04/software-rasterizer-part-2.html#softwareRasterizerDemo
// Perspective divide.
for (int i = 0; i < primitive.Vertices.Length; i++)
{
PerspectiveDivide(ref primitive.Vertices[i].Position);
}
// Backface culling.
if (State.Description.CullMode != CullMode.None && rasterizer.ShouldCull(primitive.Vertices))
{
continue;
}
// Transform from clip space to screen space.
for (int i = 0; i < primitive.Vertices.Length; i++)
{
viewport.MapClipSpaceToScreenSpace(ref primitive.Vertices[i].Position);
}
// Rasterize.
foreach (var fragmentQuad in rasterizer.Rasterize(primitive))
{
yield return(fragmentQuad);
}
}
}
/// <summary>
/// Registers are effectively shared between outputs of the previous stage
/// and inputs of the next stage, so we don't need to do any mapping. We only
/// need to keep track of the interpolation mode, and system value semantic,
/// of the inputs.
/// <seealso cref="http://msdn.microsoft.com/en-us/library/windows/desktop/bb509650(v=vs.85).aspx"/>
///
/// TODO: Add some sort of runtime validation that signatures match. Direct3D
/// does this, but only when debugging.
/// </summary>
public static ShaderOutputInputBindings FromShaderSignatures(
OutputSignatureChunk outputSignature,
BytecodeContainer inputShader)
{
var inputRegisterDeclarations = inputShader.Shader.DeclarationTokens
.OfType <PixelShaderInputRegisterDeclarationToken>()
.ToList();
// Only create a binding if the value is actually used in the next shader.
// We can gather this information from the declaration tokens. If there is
// no declaration token for an item, then it isn't used.
var bindings = new List <ShaderOutputInputBinding>();
foreach (var inputParameter in inputShader.InputSignature.Parameters)
{
// Get register declaration for this parameter. If there is no register
// declaration, then it isn't used, and we can move on.
var inputRegisterDeclaration = FindInputRegisterDeclaration(
inputRegisterDeclarations, inputParameter);
if (inputRegisterDeclaration == null)
{
continue;
}
bindings.Add(new ShaderOutputInputBinding
{
Register = (int)inputParameter.Register,
ComponentMask = inputParameter.Mask,
InterpolationMode = inputRegisterDeclaration.InterpolationMode,
SystemValueType = inputParameter.SystemValueType
});
}
return(new ShaderOutputInputBindings
{
Bindings = bindings.ToArray()
});
}
