Method SampleCurve

Source/Engine/Visject/ShaderGraphUtilities.cpp:258–410

template<typename T>
void ShaderGraphUtilities::SampleCurve(TextWriterUnicode& writer, const BezierCurve<T>& curve, const String& time, const String& value)
{
    const auto& keyframes = curve.GetKeyframes();

    if (keyframes.Count() == 0)
    {
        writer.Write(
            TEXT(
                "	{{\n"
                "		// Curve ({1})\n"
                "		{0} = 0;\n"
                "	}}\n"
            ),
            value, // {0}
            GetTypename<T>() // {1}
        );
    }
    else if (keyframes.Count() == 1)
    {
        writer.Write(
            TEXT(
                "	{{\n"
                "		// Curve ({1})\n"
                "		{0} = {2};\n"
                "	}}\n"
            ),
            value, // {0}
            GetTypename<T>(), // {1}
            ShaderGraphValue(keyframes[0].Value).Value // {2}
        );
    }
    else if (keyframes.Count() == 2)
    {
        writer.Write(
            TEXT(
                "	{{\n"
                "		// Curve ({4})\n"
                "		const float leftTime = {3};\n"
                "		const float rightTime = {5};\n"
                "		const float lengthTime = rightTime - leftTime;\n"
                "		float time = clamp({0}, leftTime, rightTime);\n"
                "		float alpha = lengthTime < 0.0000001 ? 0.0f : (time - leftTime) / lengthTime;\n"

                "		const {4} leftValue = {6};\n"
                "		const {4} rightValue = {7};\n"
                "		const float oneThird = 1.0f / 3.0f;\n"
                "		{4} leftTangent = leftValue + {8} * (lengthTime * oneThird);\n"
                "		{4} rightTangent = rightValue + {1} * (lengthTime * oneThird);\n"

                "		{4} p01 = lerp(leftValue, leftTangent, alpha);\n"
                "		{4} p12 = lerp(leftTangent, rightTangent, alpha);\n"
                "		{4} p23 = lerp(rightTangent, rightValue, alpha);\n"
                "		{4} p012 = lerp(p01, p12, alpha);\n"
                "		{4} p123 = lerp(p12, p23, alpha);\n"
                "		{2} = lerp(p012, p123, alpha);\n"
                "	}}\n"
            ),
            time, // {0}