RmlUi/Source/Core/DecoratorShader.cpp

#include "DecoratorShader.h"
#include "../../Include/RmlUi/Core/ComputedValues.h"
#include "../../Include/RmlUi/Core/Element.h"
#include "../../Include/RmlUi/Core/Geometry.h"
#include "../../Include/RmlUi/Core/MeshUtilities.h"
#include "../../Include/RmlUi/Core/PropertyDefinition.h"
#include "../../Include/RmlUi/Core/RenderManager.h"

namespace Rml {

Pool<ShaderElementData>& GetShaderElementDataPool()
{
	static Pool<ShaderElementData> gradient_element_data_pool(20, true);
	return gradient_element_data_pool;
}

DecoratorShader::DecoratorShader() {}

DecoratorShader::~DecoratorShader() {}

bool DecoratorShader::Initialise(String&& in_value)
{
	value = std::move(in_value);
	return true;
}

DecoratorDataHandle DecoratorShader::GenerateElementData(Element* element, BoxArea paint_area) const
{
	RenderManager* render_manager = element->GetRenderManager();
	if (!render_manager)
		return INVALID_DECORATORDATAHANDLE;

	const RenderBox render_box = element->GetRenderBox(paint_area);
	const Vector2f dimensions = render_box.GetFillSize();
	CompiledShader shader = render_manager->CompileShader("shader", Dictionary{{"value", Variant(value)}, {"dimensions", Variant(dimensions)}});
	if (!shader)
		return INVALID_DECORATORDATAHANDLE;

	Mesh mesh;

	const ComputedValues& computed = element->GetComputedValues();
	const byte alpha = byte(computed.opacity() * 255.f);
	MeshUtilities::GenerateBackground(mesh, render_box, ColourbPremultiplied(alpha, alpha));

	const Vector2f offset = render_box.GetFillOffset();
	for (Vertex& vertex : mesh.vertices)
		vertex.tex_coord = (vertex.position - offset) / dimensions;

	ShaderElementData* element_data =
		GetShaderElementDataPool().AllocateAndConstruct(render_manager->MakeGeometry(std::move(mesh)), std::move(shader));

	return reinterpret_cast<DecoratorDataHandle>(element_data);
}

void DecoratorShader::ReleaseElementData(DecoratorDataHandle handle) const
{
	ShaderElementData* element_data = reinterpret_cast<ShaderElementData*>(handle);
	GetShaderElementDataPool().DestroyAndDeallocate(element_data);
}

void DecoratorShader::RenderElement(Element* element, DecoratorDataHandle handle) const
{
	ShaderElementData* element_data = reinterpret_cast<ShaderElementData*>(handle);
	element_data->geometry.Render(element->GetAbsoluteOffset(BoxArea::Border), {}, element_data->shader);
}

DecoratorShaderInstancer::DecoratorShaderInstancer()
{
	ids.value = RegisterProperty("value", String()).AddParser("string").GetId();
	RegisterShorthand("decorator", "value", ShorthandType::FallThrough);
}

DecoratorShaderInstancer::~DecoratorShaderInstancer() {}

SharedPtr<Decorator> DecoratorShaderInstancer::InstanceDecorator(const String& /*name*/, const PropertyDictionary& properties_,
	const DecoratorInstancerInterface& /*interface_*/)
{
	const Property* p_value = properties_.GetProperty(ids.value);
	if (!p_value)
		return nullptr;

	String value = p_value->Get<String>();

	auto decorator = MakeShared<DecoratorShader>();
	if (decorator->Initialise(std::move(value)))
		return decorator;

	return nullptr;
}

} // namespace Rml