Add a new OpenGL pyramid sample

This sample shows the use of modern OpenGL (3.2).

Closes #16910.

samples/opengl/pyramid/mathstuff.h

@@ -0,0 +1,83 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        mathstuff.h
+// Purpose:     Some maths used for pyramid sample
+// Author:      Manuel Martin
+// Created:     2015/01/31
+// Copyright:   (c) 2015 Manuel Martin
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef MATHSTUFF_H
+  #define MATHSTUFF_H
+
+//NOTE:
+// glm library is great for handling matrices and vectors in a OpenGL style, see
+// http://glm.g-truc.net/
+// But it's too large for this simple sample. I coded on my own the maths needed.
+
+// A vector with 3 components
+class myVec3
+{
+public:
+    myVec3() { x = y = z = 0.0 ;}
+    myVec3(double xd, double yd, double zd) : x(xd), y(yd), z(zd) {}
+    ~myVec3() {}
+
+    double x, y, z;
+};
+
+// A vector with 4 components
+class myVec4
+{
+public:
+    myVec4() { x = y = z = w = 0.0 ;}
+    myVec4(double xd, double yd, double zd, double wd)
+            : x(xd), y(yd), z(zd), w(wd) {}
+    myVec4(const myVec3& v3, double wd = 0.0)
+            : x(v3.x), y(v3.y), z(v3.z), w(wd) {}
+    ~myVec4() {}
+
+    double x, y, z, w;
+};
+
+// Overload of "-" operator
+myVec3 operator- (const myVec3& v1, const myVec3& v2);
+
+// Vector normalization
+myVec3 MyNormalize(const myVec3& v);
+
+// Dot product
+double MyDot(const myVec3& v1, const myVec3& v2);
+
+// Cross product
+myVec3 MyCross(const myVec3& v1, const myVec3& v2);
+
+// Distance between two points
+double MyDistance(const myVec3& v1, const myVec3& v2);
+
+// Angle between two normalized vectors, in radians
+double AngleBetween(myVec3 v1, myVec3 v2);
+
+// Matrix 4x4 by 4x1 multiplication
+myVec4 MyMatMul4x1(const float *m1, const myVec4& v);
+
+// Matrix 4x4 by 4x4 multiplication
+void MyMatMul4x4(const float *m1, const float *m2, float* mm);
+
+// Matrix inverse. Returns the determinant
+double MyMatInverse(const float *m, float *minv);
+
+// Matrix of rotation around an axis in the origin
+void MyRotate(const myVec3& axis, double angle, float *mrot);
+
+// Matrix for defining the viewing transformation
+void MyLookAt(const myVec3& camPos, const myVec3& camUp, const myVec3& targ, float *mt);
+
+// Matrix for defining the perspective projection with symmetric frustum
+void MyPerspective(double fov, double aspect, double zNear, double zFar, float *mp);
+
+// Matrix for defining the orthogonal projection
+void MyOrtho(double left, double right, double bottom, double top,
+             double zNear, double zFar, float *mo);
+
+#endif // MATHSTUFF_H