Add matrix determinant and inverse methods.

src/Makefile.am

@@ -2,13 +2,14 @@
 noinst_LIBRARIES = liblol.a
 
 liblol_a_SOURCES = \
-    core.h matrix.h tiler.cpp tiler.h dict.cpp dict.h audio.cpp audio.h \
-    scene.cpp scene.h font.cpp font.h layer.cpp layer.h map.cpp map.h \
-    entity.cpp entity.h ticker.cpp ticker.h tileset.cpp tileset.h \
-    forge.cpp forge.h video.cpp video.h timer.cpp timer.h bitfield.h \
-    profiler.cpp profiler.h input.h input.cpp world.cpp world.h \
-    sample.cpp sample.h sampler.cpp sampler.h text.cpp text.h \
-    emitter.cpp emitter.h numeric.h worldentity.cpp worldentity.h \
+    core.h matrix.cpp matrix.h tiler.cpp tiler.h dict.cpp dict.h \
+    audio.cpp audio.h scene.cpp scene.h font.cpp font.h layer.cpp layer.h \
+    map.cpp map.h entity.cpp entity.h ticker.cpp ticker.h \
+    tileset.cpp tileset.h forge.cpp forge.h video.cpp video.h \
+    timer.cpp timer.h bitfield.h profiler.cpp profiler.h input.h input.cpp \
+    world.cpp world.h sample.cpp sample.h sampler.cpp sampler.h \
+    text.cpp text.h emitter.cpp emitter.h numeric.h \
+    worldentity.cpp worldentity.h \
     \
     sdlinput.cpp sdlinput.h \
     \

src/matrix.cpp

@@ -0,0 +1,64 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2011 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include <cstdio>
+#include <cstdlib> /* free() */
+#include <cstring> /* strdup() */
+
+#include "core.h"
+
+static inline float det3(float a, float b, float c,
+                         float d, float e, float f,
+                         float g, float h, float i)
+{
+    return a * (e * i - h * f)
+         + b * (f * g - i * d)
+         + c * (d * h - g * e);
+}
+
+static inline float cofact3(float4x4 const &mat, int i, int j)
+{
+    return det3(mat[(i + 1) & 3][(j + 1) & 3],
+                mat[(i + 2) & 3][(j + 1) & 3],
+                mat[(i + 3) & 3][(j + 1) & 3],
+                mat[(i + 1) & 3][(j + 2) & 3],
+                mat[(i + 2) & 3][(j + 2) & 3],
+                mat[(i + 3) & 3][(j + 2) & 3],
+                mat[(i + 1) & 3][(j + 3) & 3],
+                mat[(i + 2) & 3][(j + 3) & 3],
+                mat[(i + 3) & 3][(j + 3) & 3]) * (((i + j) & 1) ? -1.0f : 1.0f);
+}
+
+template<> float float4x4::det() const
+{
+    float ret = 0;
+    for (int n = 0; n < 4; n++)
+        ret += (*this)[n][0] * cofact3(*this, n, 0);
+    return ret;
+}
+
+template<> float4x4 float4x4::invert() const
+{
+    float4x4 ret;
+    float d = det();
+    if (d)
+    {
+        d = 1.0f / d;
+        for (int j = 0; j < 4; j++)
+            for (int i = 0; i < 4; i++)
+                ret[j][i] = cofact3(*this, i, j) * d;
+    }
+    return ret;
+}
+

src/matrix.h

@@ -175,37 +175,49 @@ GLOBALS(2)
 GLOBALS(3)
 GLOBALS(4)
 
-template <typename T> struct Vec4x4
+template <typename T> struct Mat4
 {
-    inline Vec4x4() { }
-    inline Vec4x4(T val) { v[0] = v[1] = v[2] = v[3] = val; }
-    inline Vec4x4(Vec4<T> v0, Vec4<T> v1, Vec4<T> v2, Vec4<T> v3)
+    inline Mat4() { }
+    inline Mat4(T val) { for (int i = 0; i < 4; i++) v[i] = val; }
+    inline Mat4(Vec4<T> v0, Vec4<T> v1, Vec4<T> v2, Vec4<T> v3)
         { v[0] = v0; v[1] = v1; v[2] = v2; v[3] = v3; }
 
     inline Vec4<T>& operator[](int n) { return v[n]; }
     inline Vec4<T> const& operator[](int n) const { return v[n]; }
 
-    inline Vec4x4<T> operator +(Vec4x4<T> const val) const
+    static inline Mat4<T> identity()
     {
-        Vec4x4<T> ret;
+        Mat4<T> ret;
+        for (int j = 0; j < 4; j++)
+            for (int i = 0; i < 4; i++)
+                ret[i][j] = i == j;
+        return ret;
+    }
+
+    T det() const;
+    Mat4<T> invert() const;
+
+    inline Mat4<T> operator +(Mat4<T> const val) const
+    {
+        Mat4<T> ret;
         for (int j = 0; j < 4; j++)
             for (int i = 0; i < 4; i++)
                 ret[i][j] = v[i][j] + val[i][j];
         return ret;
     }
 
-    inline Vec4x4<T> operator -(Vec4x4<T> const val) const
+    inline Mat4<T> operator -(Mat4<T> const val) const
     {
-        Vec4x4<T> ret;
+        Mat4<T> ret;
         for (int j = 0; j < 4; j++)
             for (int i = 0; i < 4; i++)
                 ret[i][j] = v[i][j] - val[i][j];
         return ret;
     }
 
-    inline Vec4x4<T> operator *(Vec4x4<T> const val) const
+    inline Mat4<T> operator *(Mat4<T> const val) const
     {
-        Vec4x4<T> ret;
+        Mat4<T> ret;
         for (int j = 0; j < 4; j++)
             for (int i = 0; i < 4; i++)
             {
@@ -233,8 +245,8 @@ template <typename T> struct Vec4x4
     Vec4<T> v[4];
 };
 
-typedef Vec4x4<float> float4x4;
-typedef Vec4x4<int> int4x4;
+typedef Mat4<float> float4x4;
+typedef Mat4<int> int4x4;
 
 #endif // __DH_MATRIX_H__
 

test/matrix.cpp

@@ -22,31 +22,94 @@
 class MatrixTest : public CppUnit::TestCase
 {
     CPPUNIT_TEST_SUITE(MatrixTest);
+    CPPUNIT_TEST(test_mat_det);
     CPPUNIT_TEST(test_mat_mul);
+    CPPUNIT_TEST(test_mat_inv);
     CPPUNIT_TEST_SUITE_END();
 
 public:
     MatrixTest() : CppUnit::TestCase("Matrix Test") {}
 
-    void setUp() {}
+    void setUp()
+    {
+        identity = float4x4::identity();
+        triangular = float4x4(float4(1.0f, 0.0f, 0.0f, 0.0f),
+                              float4(7.0f, 2.0f, 0.0f, 0.0f),
+                              float4(1.0f, 5.0f, 3.0f, 0.0f),
+                              float4(8.0f, 9.0f, 2.0f, 4.0f));
+        invertible = float4x4(float4( 1.0f,  1.0f,  2.0f, -1.0f),
+                              float4(-2.0f, -1.0f, -2.0f,  2.0f),
+                              float4( 4.0f,  2.0f,  5.0f, -4.0f),
+                              float4( 5.0f, -3.0f, -7.0f, -6.0f));
+    }
 
     void tearDown() {}
 
+    void test_mat_det()
+    {
+        float d1 = triangular.det();
+        CPPUNIT_ASSERT(d1 == 24.0f);
+        float d2 = invertible.det();
+        CPPUNIT_ASSERT(d2 == -1.0f);
+    }
+
     void test_mat_mul()
     {
-        float4 v0(1.0f, 0.0f, 0.0f, 0.0f);
-        float4 v1(0.0f, 1.0f, 0.0f, 0.0f);
-        float4 v2(0.0f, 0.0f, 1.0f, 0.0f);
-        float4 v3(0.0f, 0.0f, 0.0f, 1.0f);
-        float4x4 m0(v0, v1, v2, v3);
-        float4x4 m1(v0, v1, v2, v3);
+        float4x4 m0 = identity;
+        float4x4 m1 = identity;
+        float4x4 m2 = m0 * m1;
+
+        CPPUNIT_ASSERT(m2[0][0] == 1.0f);
+        CPPUNIT_ASSERT(m2[1][0] == 0.0f);
+        CPPUNIT_ASSERT(m2[2][0] == 0.0f);
+        CPPUNIT_ASSERT(m2[3][0] == 0.0f);
+
+        CPPUNIT_ASSERT(m2[0][1] == 0.0f);
+        CPPUNIT_ASSERT(m2[1][1] == 1.0f);
+        CPPUNIT_ASSERT(m2[2][1] == 0.0f);
+        CPPUNIT_ASSERT(m2[3][1] == 0.0f);
+
+        CPPUNIT_ASSERT(m2[0][2] == 0.0f);
+        CPPUNIT_ASSERT(m2[1][2] == 0.0f);
+        CPPUNIT_ASSERT(m2[2][2] == 1.0f);
+        CPPUNIT_ASSERT(m2[3][2] == 0.0f);
+
+        CPPUNIT_ASSERT(m2[0][3] == 0.0f);
+        CPPUNIT_ASSERT(m2[1][3] == 0.0f);
+        CPPUNIT_ASSERT(m2[2][3] == 0.0f);
+        CPPUNIT_ASSERT(m2[3][3] == 1.0f);
+    }
+
+    void test_mat_inv()
+    {
+        float4x4 m0 = invertible;
+        float4x4 m1 = m0.invert();
+
         float4x4 m2 = m0 * m1;
 
         CPPUNIT_ASSERT(m2[0][0] == 1.0f);
+        CPPUNIT_ASSERT(m2[1][0] == 0.0f);
+        CPPUNIT_ASSERT(m2[2][0] == 0.0f);
+        CPPUNIT_ASSERT(m2[3][0] == 0.0f);
+
+        CPPUNIT_ASSERT(m2[0][1] == 0.0f);
         CPPUNIT_ASSERT(m2[1][1] == 1.0f);
+        CPPUNIT_ASSERT(m2[2][1] == 0.0f);
+        CPPUNIT_ASSERT(m2[3][1] == 0.0f);
+
+        CPPUNIT_ASSERT(m2[0][2] == 0.0f);
+        CPPUNIT_ASSERT(m2[1][2] == 0.0f);
         CPPUNIT_ASSERT(m2[2][2] == 1.0f);
+        CPPUNIT_ASSERT(m2[3][2] == 0.0f);
+
+        CPPUNIT_ASSERT(m2[0][3] == 0.0f);
+        CPPUNIT_ASSERT(m2[1][3] == 0.0f);
+        CPPUNIT_ASSERT(m2[2][3] == 0.0f);
         CPPUNIT_ASSERT(m2[3][3] == 1.0f);
     }
+
+private:
+    float4x4 triangular, identity, invertible;
 };
 
 CPPUNIT_TEST_SUITE_REGISTRATION(MatrixTest);

win32/deushax.vcxproj

@@ -61,6 +61,7 @@
     <ClCompile Include="..\src\input.cpp" />
     <ClCompile Include="..\src\layer.cpp" />
     <ClCompile Include="..\src\map.cpp" />
+    <ClCompile Include="..\src\matrix.cpp" />
     <ClCompile Include="..\src\profiler.cpp" />
     <ClCompile Include="..\src\sample.cpp" />
     <ClCompile Include="..\src\sampler.cpp" />

win32/deushax.vcxproj.filters

@@ -136,6 +136,9 @@
     <ClCompile Include="..\src\map.cpp">
       <Filter>lolengine</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\matrix.cpp">
+      <Filter>lolengine</Filter>
+    </ClCompile>
     <ClCompile Include="..\src\profiler.cpp">
       <Filter>lolengine</Filter>
     </ClCompile>

win32/editor.vcxproj

@@ -61,6 +61,7 @@
     <ClCompile Include="..\src\input.cpp" />
     <ClCompile Include="..\src\layer.cpp" />
     <ClCompile Include="..\src\map.cpp" />
+    <ClCompile Include="..\src\matrix.cpp" />
     <ClCompile Include="..\src\profiler.cpp" />
     <ClCompile Include="..\src\sample.cpp" />
     <ClCompile Include="..\src\sampler.cpp" />

win32/editor.vcxproj.filters

@@ -136,6 +136,9 @@
     <ClCompile Include="..\src\map.cpp">
       <Filter>lolengine</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\matrix.cpp">
+      <Filter>lolengine</Filter>
+    </ClCompile>
     <ClCompile Include="..\src\profiler.cpp">
       <Filter>lolengine</Filter>
     </ClCompile>
@@ -182,4 +185,4 @@
     <ClCompile Include="..\deushax\gtk\glmapview.cpp" />
     <ClCompile Include="..\deushax\mapviewer.cpp" />
   </ItemGroup>
-</Project>
+</Project>

win32/monsterz.vcxproj

@@ -70,6 +70,7 @@
     <ClCompile Include="..\src\input.cpp" />
     <ClCompile Include="..\src\layer.cpp" />
     <ClCompile Include="..\src\map.cpp" />
+    <ClCompile Include="..\src\matrix.cpp" />
     <ClCompile Include="..\src\profiler.cpp" />
     <ClCompile Include="..\src\sample.cpp" />
     <ClCompile Include="..\src\sampler.cpp" />

win32/monsterz.vcxproj.filters

@@ -141,6 +141,9 @@
     <ClCompile Include="..\src\map.cpp">
       <Filter>lolengine</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\matrix.cpp">
+      <Filter>lolengine</Filter>
+    </ClCompile>
     <ClCompile Include="..\src\profiler.cpp">
       <Filter>lolengine</Filter>
     </ClCompile>