Basically the same as before except now the props can't be scaled bec…

…ause our InvertedTR() method doesn't support it. That's okay though, most real world applications won't use it.
hurp · Aug 1, 2013 · a05bf3d · a05bf3d
1 parent 70c1ca8
commit a05bf3d
Show file tree

Hide file tree

Showing 5 changed files with 45 additions and 60 deletions.
diff --git a/game/character.cpp b/game/character.cpp
@@ -72,14 +72,6 @@ void CCharacter::BuildTransform()
 	mRotation.SetRotation(m_flRotationTheta, m_vecRotationAxis);
 	mTranslation.SetTranslation(m_vecTranslation);
 	m_mTransform = mTranslation * mRotation * mScaling;
-
-	// Produce an inverse transformation matrix from three inverse TRS matrices.
-	// Order still matters! http://youtu.be/onSyW44OnxA
-	Matrix4x4 mScalingInverse, mRotationInverse, mTranslationInverse;
-	mScalingInverse.SetScale(1/m_vecScaling);
-	mRotationInverse = mRotation.Transposed();
-	mTranslationInverse.SetTranslation(-m_vecTranslation);
-	m_mTransformInverse = mScalingInverse * mRotationInverse * mTranslationInverse;
 }
 
 void CCharacter::ShotEffect(CRenderingContext* c)
@@ -105,24 +97,24 @@ void CCharacter::ShotEffect(CRenderingContext* c)
 
 void CCharacter::TakeDamage(int iDamage)
 {
+	if (!m_bTakesDamage)
+		return;
+
 	m_iHealth -= iDamage;
 
 	if (m_iHealth <= 0)
 	{
-		if (m_bTakesDamage)
-		{
-			// Spawn another baddy to take this guy's place.
-			CCharacter* pNew = Game()->CreateCharacter();
-
-			// Position the new monster in a random spot near the player.
-			pNew->SetTransform(Vector(1, 1, 1), 0, Vector(0, 1, 0), Vector((float)(rand()%20)-10, 0, (float)(rand()%20)-10));
-
-			pNew->m_aabbSize.vecMin = Vector(-1, 0, -1);
-			pNew->m_aabbSize.vecMax = Vector(1, 2, 1);
-			pNew->m_iBillboardTexture = Game()->GetMonsterTexture();
-			pNew->m_bEnemyAI = true;
-			pNew->m_bTakesDamage = true;
-		}
+		// Spawn another baddy to take this guy's place.
+		CCharacter* pNew = Game()->CreateCharacter();
+
+		// Position the new monster in a random spot near the player.
+		pNew->SetTransform(Vector(1, 1, 1), 0, Vector(0, 1, 0), Vector((float)(rand()%20)-10, 0, (float)(rand()%20)-10));
+
+		pNew->m_aabbSize.vecMin = Vector(-1, 0, -1);
+		pNew->m_aabbSize.vecMax = Vector(1, 2, 1);
+		pNew->m_iBillboardTexture = Game()->GetMonsterTexture();
+		pNew->m_bEnemyAI = true;
+		pNew->m_bTakesDamage = true;
 
 		// We're at zero health, time to die.
 		Game()->RemoveCharacter(this);

diff --git a/game/character.h b/game/character.h
@@ -55,7 +55,6 @@ class CCharacter
 	Vector    m_vecRotationAxis;
 	float     m_flRotationTheta;
 	Matrix4x4 m_mTransform;
-	Matrix4x4 m_mTransformInverse;
 	Vector    m_vecMovement;
 	Vector    m_vecMovementGoal;
 	Vector    m_vecVelocity;

diff --git a/game/game.cpp b/game/game.cpp
@@ -197,10 +197,12 @@ bool CGame::TraceLine(const Vector& v0, const Vector& v1, Vector& vecIntersectio
 		if (!pCharacter->m_bHitByTraces)
 			continue;
 
+		Matrix4x4 mInverse = pCharacter->m_mTransform.InvertedTR();
+
 		// The v0 and v1 are in the global coordinate system and we need to transform it to the target's
 		// local coordinate system to use axis-aligned intersection. We do so using the inverse transform matrix.
 		// http://youtu.be/-Fn4atv2NsQ
-		if (LineAABBIntersection(pCharacter->m_aabbSize, pCharacter->m_mTransformInverse*v0, pCharacter->m_mTransformInverse*v1, vecTestIntersection, flTestFraction) && flTestFraction < flLowestFraction)
+		if (LineAABBIntersection(pCharacter->m_aabbSize, mInverse*v0, mInverse*v1, vecTestIntersection, flTestFraction) && flTestFraction < flLowestFraction)
 		{
 			// Once we have the result we can use the regular transform matrix to get it back in
 			// global coordinates. http://youtu.be/-Fn4atv2NsQ
@@ -276,7 +278,6 @@ void CGame::Update(float dt)
 	// Produce a transformation matrix from our three TRS matrices.
 	// Order matters! http://youtu.be/7pe1xYzFCvA
 	m_hPlayer->m_mTransform = mPlayerTranslation * mPlayerRotation * mPlayerScaling;
-	m_hPlayer->m_mTransformInverse = m_hPlayer->m_mTransform.InvertedRT();
 
 	float flMonsterSpeed = 0.5f;
 	for (size_t i = 0; i < MAX_CHARACTERS; i++)
@@ -594,13 +595,13 @@ void CGame::GameLoop()
 	m_hPlayer->m_bTakesDamage = true;
 
 	m_hPropEuler = CreateCharacter();
-	m_hPropEuler->SetTransform(Vector(2, 0.5f, 0.5f), 0, Vector(0, 1, 0), Vector(0, 3, 4));
+	m_hPropEuler->SetTransform(Vector(1, 1, 1), 0, Vector(0, 1, 0), Vector(0, 3, 4));
 	m_hPropEuler->m_aabbSize.vecMin = Vector(-1, -1, -1);
 	m_hPropEuler->m_aabbSize.vecMax = Vector(1, 1, 1);
 	m_hPropEuler->m_clrRender = Color(0.4f, 0.8f, 0.2f, 1.0f);
 
 	m_hPropQuaternion = CreateCharacter();
-	m_hPropQuaternion->SetTransform(Vector(2, 0.5f, 0.5f), 0, Vector(0, 1, 0), Vector(0, 3, -4));
+	m_hPropQuaternion->SetTransform(Vector(1, 1, 1), 0, Vector(0, 1, 0), Vector(0, 3, -4));
 	m_hPropQuaternion->m_aabbSize.vecMin = Vector(-1, -1, -1);
 	m_hPropQuaternion->m_aabbSize.vecMax = Vector(1, 1, 1);
 	m_hPropQuaternion->m_clrRender = Color(0.4f, 0.8f, 0.2f, 1.0f);
@@ -609,13 +610,13 @@ void CGame::GameLoop()
 	Vector vecPropMax = Vector(1, 2, 1);
 
 	CCharacter* pProp1 = CreateCharacter();
-	pProp1->SetTransform(Vector(2, 1, 4), 20, Vector(0, 1, 0), Vector(18, 0, 10));
+	pProp1->SetTransform(Vector(1, 1, 1), 20, Vector(0, 1, 0), Vector(18, 0, 10));
 	pProp1->m_aabbSize.vecMin = vecPropMin;
 	pProp1->m_aabbSize.vecMax = vecPropMax;
 	pProp1->m_clrRender = Color(0.4f, 0.8f, 0.2f, 1.0f);
 
 	CCharacter* pProp2 = CreateCharacter();
-	pProp2->SetTransform(Vector(1, 2, 3), 30, Vector(0, 1, 0), Vector(10, 0, 15));
+	pProp2->SetTransform(Vector(1, 1, 1), 30, Vector(0, 1, 0), Vector(10, 0, 15));
 	pProp2->m_aabbSize.vecMin = vecPropMin;
 	pProp2->m_aabbSize.vecMax = vecPropMax;
 	pProp2->m_clrRender = Color(0.4f, 0.8f, 0.2f, 1.0f);
@@ -627,7 +628,7 @@ void CGame::GameLoop()
 	pProp3->m_clrRender = Color(0.4f, 0.8f, 0.2f, 1.0f);
 
 	CCharacter* pProp4 = CreateCharacter();
-	pProp4->SetTransform(Vector(2, 2, 2), 40, Vector(0, 1, 0), Vector(-2, 0, 14));
+	pProp4->SetTransform(Vector(1, 1, 1), 40, Vector(0, 1, 0), Vector(-2, 0, 14));
 	pProp4->m_aabbSize.vecMin = vecPropMin;
 	pProp4->m_aabbSize.vecMax = vecPropMax;
 	pProp4->m_clrRender = Color(0.4f, 0.8f, 0.2f, 1.0f);

diff --git a/math/matrix.cpp b/math/matrix.cpp
@@ -537,41 +537,30 @@ void Matrix4x4::SetRightVector(const Vector& v)
 	m[2][2] = v.z;
 }
 
-// Not a true inversion, only works if the matrix is a translation/rotation matrix.
-void Matrix4x4::InvertRT()
+// Use the information embedded in a matrix to create its inverse.
+// http://youtu.be/7CxKAtWqHC8
+Matrix4x4 Matrix4x4::InvertedTR() const
 {
-	TAssert(fabs(GetForwardVector().LengthSqr() - 1) < 0.00001f);
+	// This method can only be used if the matrix is a translation/rotation matrix.
+	// The below asserts will trigger if this is not the case.
+	TAssert(fabs(GetForwardVector().LengthSqr() - 1) < 0.00001f);   // Each basis vector should be length 1.
 	TAssert(fabs(GetUpVector().LengthSqr() - 1) < 0.00001f);
 	TAssert(fabs(GetRightVector().LengthSqr() - 1) < 0.00001f);
+	TAssert(fabs(GetForwardVector().Dot(GetUpVector())) < 0.0001f); // All vectors should be orthogonal.
+	TAssert(fabs(GetForwardVector().Dot(GetRightVector())) < 0.0001f);
+	TAssert(fabs(GetRightVector().Dot(GetUpVector())) < 0.0001f);
 
-	Matrix4x4 t;
+	Matrix4x4 M;
 
-	for (int h = 0; h < 3; h++)
-		for (int v = 0; v < 3; v++)
-			t.m[h][v] = m[v][h];
+	// Create the transposed upper 3x3 matrix
+	for (int i = 0; i < 3; i++)
+		for (int j = 0; j < 3; j++)
+			M.m[i][j] = m[j][i];
 
-	Vector vecTranslation = GetTranslation();
+	// The new matrix translation = -Rt
+	M.SetTranslation(-(M*GetTranslation()));
 
-	Init(t);
-
-	SetTranslation(t*(-vecTranslation));
-}
-
-Matrix4x4 Matrix4x4::InvertedRT() const
-{
-	TAssert(fabs(GetForwardVector().LengthSqr() - 1) < 0.00001f);
-	TAssert(fabs(GetUpVector().LengthSqr() - 1) < 0.00001f);
-	TAssert(fabs(GetRightVector().LengthSqr() - 1) < 0.00001f);
-
-	Matrix4x4 r;
-
-	for (int h = 0; h < 3; h++)
-		for (int v = 0; v < 3; v++)
-			r.m[h][v] = m[v][h];
-
-	r.SetTranslation(r*(-GetTranslation()));
-
-	return r;
+	return M;
 }
 
 float Matrix4x4::Trace() const

diff --git a/math/matrix.h b/math/matrix.h
@@ -118,8 +118,7 @@ class Matrix4x4
 	Vector		GetUpVector() const { return Vector(m[1][0], m[1][1], m[1][2]); }
 	Vector		GetRightVector() const { return Vector(m[2][0], m[2][1], m[2][2]); }
 
-	void		InvertRT();
-	Matrix4x4	InvertedRT() const;
+	Matrix4x4	InvertedTR() const;
 
 	float		Trace() const;
 
@@ -136,6 +135,11 @@ class Matrix4x4
 	struct MVector4D
 	{
 		float x, y, z, w;
+
+		float Length() const
+		{
+			return sqrt(x*x + y*y + z*z + w*w);
+		}
 	};
 
 	union {