math::make_loot_at_XX

headers/enduro2d/math/mat4.hpp

@@ -457,6 +457,46 @@ namespace e2d { namespace math
             axis_z);
     }
 
+    //
+    // make_loot_at_lh_matrix4
+    //
+
+    template < typename T >
+    std::enable_if_t<std::is_floating_point<T>::value, mat4<T>>
+    make_loot_at_lh_matrix4(const vec3<T>& eye, const vec3<T>& at, const vec3<T>& up) noexcept {
+        const vec3<T> az = normalized(at - eye);
+        const vec3<T> ax = normalized(math::cross(up, az));
+        const vec3<T> ay = math::cross(az, ax);
+        const T dx = math::dot(ax, eye);
+        const T dy = math::dot(ay, eye);
+        const T dz = math::dot(az, eye);
+        return {
+            ax.x, ay.x, az.x, T(0),
+            ax.y, ay.y, az.y, T(0),
+            ax.z, ay.z, az.z, T(0),
+            -dx,  -dy,  -dz,  T(1)};
+    }
+
+    //
+    // make_loot_at_rh_matrix4
+    //
+
+    template < typename T >
+    std::enable_if_t<std::is_floating_point<T>::value, mat4<T>>
+    make_loot_at_rh_matrix4(const vec3<T>& eye, const vec3<T>& at, const vec3<T>& up) noexcept {
+        const vec3<T> az = normalized(eye - at);
+        const vec3<T> ax = normalized(math::cross(up, az));
+        const vec3<T> ay = math::cross(az, ax);
+        const T dx = math::dot(ax, eye);
+        const T dy = math::dot(ay, eye);
+        const T dz = math::dot(az, eye);
+        return {
+            ax.x, ay.x, az.x, T(0),
+            ax.y, ay.y, az.y, T(0),
+            ax.z, ay.z, az.z, T(0),
+            dx,   dy,   dz,   T(1)};
+    }
+
     //
     // make_orthogonal_lh_matrix4
     //

samples/sources/sample_01/sample_01.cpp

@@ -238,7 +238,8 @@ int e2d_main() {
             math::make_rotation_matrix4(make_rad(game_time) * 0.001f, 1.f, 0.f, 0.f) *
             math::make_rotation_matrix4(make_rad(game_time) * 0.001f, 0.f, 1.f, 0.f) *
             math::make_rotation_matrix4(make_rad(game_time) * 0.001f, 0.f, 0.f, 1.f) *
-            math::make_translation_matrix4(0.f,0.f,3.f) *
+            math::make_translation_matrix4(0.f, 0.f, 0.f) *
+            math::make_loot_at_lh_matrix4({0.f,0.f,-3.f}, v3f::zero(), v3f::unit_y()) *
             projection;
 
         material.properties()