Added Transform objects to love.math (resolves issue #1228).

- Added love.math.newTransform.
- Added love.graphics.applyTransform and love.graphics.replaceTransform.
- love.graphics.draw/print/printf, Text:add/addf, and SpriteBatch:add can accept a Transform argument.
- love.graphics.push can accept an optional Transform as a second argument, which will apply the Transform after pushing the matrix stack,
- Shader:send can accept Transform objects when sending to a mat4 uniform variable.

--HG--
branch : minor

src/modules/math/Transform.cpp

@@ -0,0 +1,131 @@
+/**
+ * Copyright (c) 2006-2016 LOVE Development Team
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ **/
+
+#include "Transform.h"
+
+namespace love
+{
+namespace math
+{
+
+Transform::Transform()
+	: matrix()
+	, inverseDirty(true)
+	, inverseMatrix()
+{
+}
+
+Transform::Transform(const Matrix4 &m)
+	: matrix(m)
+	, inverseDirty(true)
+	, inverseMatrix()
+{
+}
+
+Transform::Transform(float x, float y, float a, float sx, float sy, float ox, float oy, float kx, float ky)
+	: matrix(x, y, a, sx, sy, ox, oy, kx, ky)
+	, inverseDirty(true)
+	, inverseMatrix()
+{
+}
+
+Transform::~Transform()
+{
+}
+
+Transform *Transform::clone()
+{
+	return new Transform(*this);
+}
+
+Transform *Transform::inverse()
+{
+	return new Transform(getInverseMatrix());
+}
+
+void Transform::apply(Transform *other)
+{
+	matrix *= other->getMatrix();
+	inverseDirty = true;
+}
+
+void Transform::translate(float x, float y)
+{
+	matrix.translate(x, y);
+	inverseDirty = true;
+}
+
+void Transform::rotate(float angle)
+{
+	matrix.rotate(angle);
+	inverseDirty = true;
+}
+
+void Transform::scale(float x, float y)
+{
+	matrix.scale(x, y);
+	inverseDirty = true;
+}
+
+void Transform::shear(float x, float y)
+{
+	matrix.shear(x, y);
+	inverseDirty = true;
+}
+
+void Transform::reset()
+{
+	matrix.setIdentity();
+	inverseDirty = true;
+}
+
+void Transform::setTransformation(float x, float y, float a, float sx, float sy, float ox, float oy, float kx, float ky)
+{
+	matrix.setTransformation(x, y, a, sx, sy, ox, oy, kx, ky);
+	inverseDirty = true;
+}
+
+love::Vector Transform::transformPoint(love::Vector p) const
+{
+	love::Vector result;
+	matrix.transform(&result, &p, 1);
+	return result;
+}
+
+love::Vector Transform::inverseTransformPoint(love::Vector p)
+{
+	love::Vector result;
+	getInverseMatrix().transform(&result, &p, 1);
+	return result;
+}
+
+const Matrix4 &Transform::getMatrix() const
+{
+	return matrix;
+}
+
+void Transform::setMatrix(const Matrix4 &m)
+{
+	matrix = m;
+	inverseDirty = true;
+}
+
+} // math
+} // love