C++ Vector4::GetX方法代码示例

CMatrix4::CMatrix4(const Vector4& v1, const Vector4& v2, const Vector4& v3, const Vector4& v4)
#if 0
    : m{ v1.GetX(), v1.GetY(), v1.GetZ(), v1.GetW(),
         v2.GetX(), v2.GetY(), v2.GetZ(), v2.GetW(),
         v3.GetX(), v3.GetY(), v3.GetZ(), v3.GetW(),
         v4.GetX(), v4.GetY(), v4.GetZ(), v4.GetW() }
{
#else
{
    constexpr std::size_t bytes = sizeof(float) * 4;
    std::memcpy(static_cast<void*>(&m[0]), static_cast<const float*>(v1), bytes);
    std::memcpy(static_cast<void*>(&m[4]), static_cast<const float*>(v2), bytes);
    std::memcpy(static_cast<void*>(&m[8]), static_cast<const float*>(v3), bytes);
    std::memcpy(static_cast<void*>(&m[12]), static_cast<const float*>(v4), bytes);
#endif
}

CMatrix4::CMatrix4(const Array& m)
    : m(m)
{
}

void CMatrix4::SetRow(std::int32_t row, const Vector4& v)
{
    HASENPFOTE_ASSERT_MSG((row >= 0) && (row < order), "Row index out of bounds.");
    m[offset<order>(row, 0)] = v.GetX();
    m[offset<order>(row, 1)] = v.GetY();
    m[offset<order>(row, 2)] = v.GetZ();
    m[offset<order>(row, 3)] = v.GetW();
}

// `計算點光源, 它和頂點位置, 頂點面向, 光源位置, 光源方向, 光柱交角有關.`
void CalculateSpotLight(Vertex_VCN *pVertices, int num_vertices)
{
	float fSpotLightCutoffCos = FastMath::Cos( FastMath::DegreeToRadian(g_fSpotLightCutoff) );

	for ( int i=0; i<num_vertices; i++ )
	{
		// `求出轉換後在世界座標系的頂點位置`
		Vector4 vPosition = pVertices[i].m_Position * g_world_matrix;
		// `求出轉換後在世界座標系的頂點面向, RotateVector函式只做旋轉, 忽略位移.`
		Vector4 vNormal = g_world_matrix.RotateVector(pVertices[i].m_Normal);
		// `計算出頂點位置到光源的方向跟長度`
		Vector4 vVertex_to_Light = g_vLightPosition - vPosition; 
		float light_distance = vVertex_to_Light.NormalizeAndGetLength();
		// `頂點面向跟光線方向的交角, 可以決定反射光的強度.`
		Vector4 vCosine = Vector3Dot(g_vLightDirection, vVertex_to_Light);
		// `把vCosine局限在永遠大於0的范圍`
		vCosine.Clamp_to_0();
		float fCosine = vCosine.GetX();
		if ( fCosine >= fSpotLightCutoffCos )
		{
			// `頂點跟光線的交角小於fSpotightCutoffCos時, 才落在光柱范圍內.`
			Vector4 vDistance(1.0f, light_distance, light_distance * light_distance);
			// `g_vLightAttenuation里記錄了計算衰減公式1/(a + b*d + c*d^2)里的(a,b,c)`
			// `Vector3Dot(vDistance, g_vLightAttenuation) = (a,b,c) dot (1,d,d^2) = (a + b*d + c*d^2)`
			Vector4 vAttenuation = Vector3Dot(vDistance, g_vLightAttenuation);
			// `比較靠近光柱外圍部分的頂點, 光線會衰減.`
			float fFalloff = pow(fCosine, g_fSpotLightExponent);
			Vector4 vIntensity = Vector3Dot(vNormal, vVertex_to_Light);
			pVertices[i].m_Color += fFalloff * vIntensity * g_vLightColor / vAttenuation;
			pVertices[i].m_Color.Clamp_to_1();
		}
	}
}

void ShapeRectangle::Render() const
{
	Vector4 bottomLeft = m_transformComponent->Transformation(m_bottomLeft);
	Vector4 bottomRight = m_transformComponent->Transformation(m_bottomRight);
	Vector4 topLeft = m_transformComponent->Transformation(m_topLeft);
	Vector4 topRight = m_transformComponent->Transformation(m_topRight);

	glBegin(GL_TRIANGLE_STRIP);
	glColor3ub(m_red, m_green, m_blue);

	glVertex2f(bottomLeft.GetX(), bottomLeft.GetY());
	glVertex2f(bottomRight.GetX(), bottomRight.GetY());
	glVertex2f(topLeft.GetX(), topLeft.GetY());
	glVertex2f(topRight.GetX(), topRight.GetY());

	glEnd();
}

void CMatrix4::SetColumn(std::int32_t column, const Vector4& v)
{
    HASENPFOTE_ASSERT_MSG((column >= 0) && (column < order), "Column index out of bounds.");
    m[offset<order>(0, column)] = v.GetX();
    m[offset<order>(1, column)] = v.GetY();
    m[offset<order>(2, column)] = v.GetZ();
    m[offset<order>(3, column)] = v.GetW();
}

void CgEffect::SetVector(const char* name, Vector4& v)
{
    cgSetParameter4f(this->retrieveParameter(name), v.GetX(), v.GetY(), v.GetZ(), v.GetW());
}