Add perspective support to SkMatrix44 initializers.

tests/Matrix44Test.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
 #include "SkMatrix44.h"
 
@@ skipping 453 matching lines @@
     b.transpose();
     REPORTER_ASSERT(reporter, nearly_equal(a, b));
     a.asColMajorf(bufferf);
     b.setColMajorf(bufferf);
     REPORTER_ASSERT(reporter, nearly_equal(a, b));
     b.setRowMajorf(bufferf);
     b.transpose();
     REPORTER_ASSERT(reporter, nearly_equal(a, b));
 }
 
+static void test_3x3_conversion(skiatest::Reporter* reporter) {
+    SkMScalar values4x4[16] = { 1, 2, 3, 4,
+                             5, 6, 7, 8,
+                             9, 10, 11, 12,
+                             13, 14, 15, 16 };
+    SkMScalar values3x3[9] = { 1, 2, 4,
+                            5, 6, 8,
+                            13, 14, 16 };
+    SkMScalar values4x4flattened[16] = { 1, 2, 0, 4,
+                                         5, 6, 0, 8,
+                                         0, 0, 1, 0,
+                                         13, 14, 0, 16 };
+    SkMatrix44 a44;
+    a44.setRowMajor(values4x4);
+
+    SkMatrix a33 = a44;
+    SkMatrix expected33;
+    for (int i = 0; i < 9; i++) expected33[i] = values3x3[i];
+    REPORTER_ASSERT(reporter, expected33 == a33);
+
+    SkMatrix44 a44flattened = a33;
+    SkMatrix44 expected44flattened;
+    expected44flattened.setRowMajor(values4x4flattened);
+    REPORTER_ASSERT(reporter, nearly_equal(a44flattened, expected44flattened));
+
+    // Test that a point with a Z value of 0 is transformed the same way.
+    SkScalar vec4[4] = { 2, 4, 0, 8 };
+    SkScalar vec3[3] = { 2, 4, 8 };
+
+    SkScalar vec4transformed[4];
+    SkScalar vec3transformed[3];
+    SkScalar vec4transformed2[4];
+    a44.mapScalars(vec4, vec4transformed);
+    a33.mapHomogeneousPoints(vec3transformed, vec3, 1);
+    a44flattened.mapScalars(vec4, vec4transformed2);
+    REPORTER_ASSERT(reporter, vec4transformed[0] == vec3transformed[0]);
+    REPORTER_ASSERT(reporter, vec4transformed[1] == vec3transformed[1]);
+    REPORTER_ASSERT(reporter, vec4transformed[3] == vec3transformed[2]);
+    REPORTER_ASSERT(reporter, vec4transformed[0] == vec4transformed2[0]);
+    REPORTER_ASSERT(reporter, vec4transformed[1] == vec4transformed2[1]);
+    REPORTER_ASSERT(reporter, vec4transformed[2] != vec4transformed2[2]);
+    REPORTER_ASSERT(reporter, vec4transformed[3] == vec4transformed2[3]);
+}
+
 static void TestMatrix44(skiatest::Reporter* reporter) {
     SkMatrix44 mat, inverse, iden1, iden2, rot;
 
     mat.reset();
     mat.setTranslate(1, 1, 1);
     mat.invert(&inverse);
     iden1.setConcat(mat, inverse);
     REPORTER_ASSERT(reporter, is_identity(iden1));
 
     mat.setScale(2, 2, 2);
@@ skipping 81 matching lines @@
     test_constructor(reporter);
     test_gettype(reporter);
     test_determinant(reporter);
     test_invert(reporter);
     test_transpose(reporter);
     test_get_set_double(reporter);
     test_set_row_col_major(reporter);
     test_translate(reporter);
     test_scale(reporter);
     test_map2(reporter);
+    test_3x3_conversion(reporter);
 }
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("Matrix44", Matrix44TestClass, TestMatrix44)