Optimize QMatrix4x4::map() for QVector3D/QPoint/QPointF

Use the matrix "flagBits" to short-cut transformations when the
matrix type is identity/translate/scale.

1 files changed, 90 insertions, 45 deletions

diff --git a/src/gui/math3d/qmatrix4x4.h b/src/gui/math3d/qmatrix4x4.h
index cff4c1e..ba7f67f 100644
--- a/src/gui/math3d/qmatrix4x4.h
+++ b/src/gui/math3d/qmatrix4x4.h
@@ -631,26 +631,43 @@ inline QVector3D operator*(const QVector3D& vector, const QMatrix4x4& matrix)
 inline QVector3D operator*(const QMatrix4x4& matrix, const QVector3D& vector)
 {
     float x, y, z, w;
-    x = vector.xp * matrix.m[0][0] +
-        vector.yp * matrix.m[1][0] +
-        vector.zp * matrix.m[2][0] +
-        matrix.m[3][0];
-    y = vector.xp * matrix.m[0][1] +
-        vector.yp * matrix.m[1][1] +
-        vector.zp * matrix.m[2][1] +
-        matrix.m[3][1];
-    z = vector.xp * matrix.m[0][2] +
-        vector.yp * matrix.m[1][2] +
-        vector.zp * matrix.m[2][2] +
-        matrix.m[3][2];
-    w = vector.xp * matrix.m[0][3] +
-        vector.yp * matrix.m[1][3] +
-        vector.zp * matrix.m[2][3] +
-        matrix.m[3][3];
-    if (w == 1.0f)
-        return QVector3D(x, y, z, 1);
-    else
-        return QVector3D(x / w, y / w, z / w, 1);
+    if (matrix.flagBits == QMatrix4x4::Identity) {
+        return vector;
+    } else if (matrix.flagBits == QMatrix4x4::Translation) {
+        return QVector3D(vector.xp + matrix.m[3][0],
+                         vector.yp + matrix.m[3][1],
+                         vector.zp + matrix.m[3][2], 1);
+    } else if (matrix.flagBits ==
+                    (QMatrix4x4::Translation | QMatrix4x4::Scale)) {
+        return QVector3D(vector.xp * matrix.m[0][0] + matrix.m[3][0],
+                         vector.yp * matrix.m[1][1] + matrix.m[3][1],
+                         vector.zp * matrix.m[2][2] + matrix.m[3][2], 1);
+    } else if (matrix.flagBits == QMatrix4x4::Scale) {
+        return QVector3D(vector.xp * matrix.m[0][0],
+                         vector.yp * matrix.m[1][1],
+                         vector.zp * matrix.m[2][2], 1);
+    } else {
+        x = vector.xp * matrix.m[0][0] +
+            vector.yp * matrix.m[1][0] +
+            vector.zp * matrix.m[2][0] +
+            matrix.m[3][0];
+        y = vector.xp * matrix.m[0][1] +
+            vector.yp * matrix.m[1][1] +
+            vector.zp * matrix.m[2][1] +
+            matrix.m[3][1];
+        z = vector.xp * matrix.m[0][2] +
+            vector.yp * matrix.m[1][2] +
+            vector.zp * matrix.m[2][2] +
+            matrix.m[3][2];
+        w = vector.xp * matrix.m[0][3] +
+            vector.yp * matrix.m[1][3] +
+            vector.zp * matrix.m[2][3] +
+            matrix.m[3][3];
+        if (w == 1.0f)
+            return QVector3D(x, y, z, 1);
+        else
+            return QVector3D(x / w, y / w, z / w, 1);
+    }
 }
 
 #endif
@@ -752,19 +769,33 @@ inline QPoint operator*(const QMatrix4x4& matrix, const QPoint& point)
     float x, y, w;
     xin = point.x();
     yin = point.y();
-    x = xin * matrix.m[0][0] +
-        yin * matrix.m[1][0] +
-        matrix.m[3][0];
-    y = xin * matrix.m[0][1] +
-        yin * matrix.m[1][1] +
-        matrix.m[3][1];
-    w = xin * matrix.m[0][3] +
-        yin * matrix.m[1][3] +
-        matrix.m[3][3];
-    if (w == 1.0f)
-        return QPoint(qRound(x), qRound(y));
-    else
-        return QPoint(qRound(x / w), qRound(y / w));
+    if (matrix.flagBits == QMatrix4x4::Identity) {
+        return point;
+    } else if (matrix.flagBits == QMatrix4x4::Translation) {
+        return QPoint(qRound(xin + matrix.m[3][0]),
+                      qRound(yin + matrix.m[3][1]));
+    } else if (matrix.flagBits ==
+                    (QMatrix4x4::Translation | QMatrix4x4::Scale)) {
+        return QPoint(qRound(xin * matrix.m[0][0] + matrix.m[3][0]),
+                      qRound(yin * matrix.m[1][1] + matrix.m[3][1]));
+    } else if (matrix.flagBits == QMatrix4x4::Scale) {
+        return QPoint(qRound(xin * matrix.m[0][0]),
+                      qRound(yin * matrix.m[1][1]));
+    } else {
+        x = xin * matrix.m[0][0] +
+            yin * matrix.m[1][0] +
+            matrix.m[3][0];
+        y = xin * matrix.m[0][1] +
+            yin * matrix.m[1][1] +
+            matrix.m[3][1];
+        w = xin * matrix.m[0][3] +
+            yin * matrix.m[1][3] +
+            matrix.m[3][3];
+        if (w == 1.0f)
+            return QPoint(qRound(x), qRound(y));
+        else
+            return QPoint(qRound(x / w), qRound(y / w));
+    }
 }
 
 inline QPointF operator*(const QMatrix4x4& matrix, const QPointF& point)
@@ -773,19 +804,33 @@ inline QPointF operator*(const QMatrix4x4& matrix, const QPointF& point)
     float x, y, w;
     xin = point.x();
     yin = point.y();
-    x = xin * matrix.m[0][0] +
-        yin * matrix.m[1][0] +
-        matrix.m[3][0];
-    y = xin * matrix.m[0][1] +
-        yin * matrix.m[1][1] +
-        matrix.m[3][1];
-    w = xin * matrix.m[0][3] +
-        yin * matrix.m[1][3] +
-        matrix.m[3][3];
-    if (w == 1.0f) {
-        return QPointF(qreal(x), qreal(y));
+    if (matrix.flagBits == QMatrix4x4::Identity) {
+        return point;
+    } else if (matrix.flagBits == QMatrix4x4::Translation) {
+        return QPointF(xin + matrix.m[3][0],
+                       yin + matrix.m[3][1]);
+    } else if (matrix.flagBits ==
+                    (QMatrix4x4::Translation | QMatrix4x4::Scale)) {
+        return QPointF(xin * matrix.m[0][0] + matrix.m[3][0],
+                       yin * matrix.m[1][1] + matrix.m[3][1]);
+    } else if (matrix.flagBits == QMatrix4x4::Scale) {
+        return QPointF(xin * matrix.m[0][0],
+                       yin * matrix.m[1][1]);
     } else {
-        return QPointF(qreal(x / w), qreal(y / w));
+        x = xin * matrix.m[0][0] +
+            yin * matrix.m[1][0] +
+            matrix.m[3][0];
+        y = xin * matrix.m[0][1] +
+            yin * matrix.m[1][1] +
+            matrix.m[3][1];
+        w = xin * matrix.m[0][3] +
+            yin * matrix.m[1][3] +
+            matrix.m[3][3];
+        if (w == 1.0f) {
+            return QPointF(qreal(x), qreal(y));
+        } else {
+            return QPointF(qreal(x / w), qreal(y / w));
+        }
     }
 }