std::string DynamicHLSL::generateAttributeConversionHLSL(
gl::VertexFormatType vertexFormatType,
const sh::ShaderVariable &shaderAttrib) const
{
const gl::VertexFormat &vertexFormat = gl::GetVertexFormatFromType(vertexFormatType);
std::string attribString = "input." + decorateVariable(shaderAttrib.name);
// Matrix
if (IsMatrixType(shaderAttrib.type))
{
return "transpose(" + attribString + ")";
}
GLenum shaderComponentType = VariableComponentType(shaderAttrib.type);
int shaderComponentCount = VariableComponentCount(shaderAttrib.type);
// Perform integer to float conversion (if necessary)
bool requiresTypeConversion =
(shaderComponentType == GL_FLOAT && vertexFormat.type != GL_FLOAT);
if (requiresTypeConversion)
{
// TODO: normalization for 32-bit integer formats
ASSERT(!vertexFormat.normalized && !vertexFormat.pureInteger);
return "float" + Str(shaderComponentCount) + "(" + attribString + ")";
}
// No conversion necessary
return attribString;
}
std::string DynamicHLSL::generateVertexShaderForInputLayout(
const std::string &sourceShader,
const InputLayout &inputLayout,
const std::vector<sh::Attribute> &shaderAttributes) const
{
std::stringstream structStream;
std::stringstream initStream;
structStream << "struct VS_INPUT\n"
<< "{\n";
int semanticIndex = 0;
unsigned int inputIndex = 0;
// If gl_PointSize is used in the shader then pointsprites rendering is expected.
// If the renderer does not support Geometry shaders then Instanced PointSprite emulation
// must be used.
bool usesPointSize = sourceShader.find("GL_USES_POINT_SIZE") != std::string::npos;
bool useInstancedPointSpriteEmulation =
usesPointSize && mRenderer->getWorkarounds().useInstancedPointSpriteEmulation;
// Instanced PointSprite emulation requires additional entries in the
// VS_INPUT structure to support the vertices that make up the quad vertices.
// These values must be in sync with the cooresponding values added during inputlayout creation
// in InputLayoutCache::applyVertexBuffers().
//
// The additional entries must appear first in the VS_INPUT layout because
// Windows Phone 8 era devices require per vertex data to physically come
// before per instance data in the shader.
if (useInstancedPointSpriteEmulation)
{
structStream << " float3 spriteVertexPos : SPRITEPOSITION0;\n"
<< " float2 spriteTexCoord : SPRITETEXCOORD0;\n";
}
for (size_t attributeIndex = 0; attributeIndex < shaderAttributes.size(); ++attributeIndex)
{
const sh::Attribute &shaderAttribute = shaderAttributes[attributeIndex];
if (!shaderAttribute.name.empty())
{
ASSERT(inputIndex < MAX_VERTEX_ATTRIBS);
VertexFormatType vertexFormatType =
inputIndex < inputLayout.size() ? inputLayout[inputIndex] : VERTEX_FORMAT_INVALID;
// HLSL code for input structure
if (IsMatrixType(shaderAttribute.type))
{
// Matrix types are always transposed
structStream << " "
<< HLSLMatrixTypeString(TransposeMatrixType(shaderAttribute.type));
}
else
{
GLenum componentType = mRenderer->getVertexComponentType(vertexFormatType);
if (shaderAttribute.name == "gl_InstanceID" ||
shaderAttribute.name == "gl_VertexID")
{
// The input types of the instance ID and vertex ID in HLSL (uint) differs from
// the ones in ESSL (int).
structStream << " uint";
}
else
{
structStream << " " << HLSLComponentTypeString(
componentType,
VariableComponentCount(shaderAttribute.type));
}
}
structStream << " " << decorateVariable(shaderAttribute.name) << " : ";
if (shaderAttribute.name == "gl_InstanceID")
{
structStream << "SV_InstanceID";
}
else if (shaderAttribute.name == "gl_VertexID")
{
structStream << "SV_VertexID";
}
else
{
structStream << "TEXCOORD" << semanticIndex;
semanticIndex += VariableRegisterCount(shaderAttribute.type);
}
structStream << ";\n";
// HLSL code for initialization
initStream << " " << decorateVariable(shaderAttribute.name) << " = ";
// Mismatched vertex attribute to vertex input may result in an undefined
// data reinterpretation (eg for pure integer->float, float->pure integer)
// TODO: issue warning with gl debug info extension, when supported
if (IsMatrixType(shaderAttribute.type) ||
(mRenderer->getVertexConversionType(vertexFormatType) & VERTEX_CONVERT_GPU) != 0)
{
initStream << generateAttributeConversionHLSL(vertexFormatType, shaderAttribute);
}
else
{
initStream << "input." << decorateVariable(shaderAttribute.name);
}
initStream << ";\n";
inputIndex += VariableRowCount(TransposeMatrixType(shaderAttribute.type));
}
}
structStream << "};\n"
"\n"
"void initAttributes(VS_INPUT input)\n"
"{\n"
<< initStream.str() << "}\n";
std::string vertexHLSL(sourceShader);
size_t copyInsertionPos = vertexHLSL.find(VERTEX_ATTRIBUTE_STUB_STRING);
vertexHLSL.replace(copyInsertionPos, VERTEX_ATTRIBUTE_STUB_STRING.length(), structStream.str());
return vertexHLSL;
}
int VariableRegisterCount(GLenum type)
{
return IsMatrixType(type) ? VariableColumnCount(type) : 1;
}
int MatrixComponentCount(GLenum type, bool isRowMajorMatrix)
{
ASSERT(IsMatrixType(type));
return isRowMajorMatrix ? VariableColumnCount(type) : VariableRowCount(type);
}