Add mat4_projection and mat4_lookat.

cpp/math.cpp

@@ -38,6 +38,22 @@ void rk_mat3_mul_mat3(
     ret = a * b;
 }
 
+void rk_mat4_projection(
+    rk_mat4 & ret,
+    float hfov,
+    float ratio,
+    float near,
+    float far) {
+    ret = glm::perspectiveRH(hfov, ratio, near, far);
+}
+
+void rk_mat4_lookat(
+    rk_mat4 & ret,
+    rk_vec3 const & position,
+    rk_vec3 const & lookat) {
+    ret = glm::lookAtRH(position, lookat, glm::vec3(0.0f, 0.0f, 1.0f));
+}
+
 void rk_mat4_mul_vec4(
     rk_vec4 & ret,
     rk_mat4 const & a,

cpp/math.hpp

@@ -41,6 +41,18 @@ RK_EXPORT void rk_mat3_mul_mat3(
     rk_mat3 const & a,
     rk_mat3 const & b);
 
+RK_EXPORT void rk_mat4_projection(
+    rk_mat4 & ret,
+    float hfov,
+    float ratio,
+    float near,
+    float far);
+
+RK_EXPORT void rk_mat4_lookat(
+    rk_mat4 & ret,
+    rk_vec3 const & position,
+    rk_vec3 const & lookat);
+
 RK_EXPORT void rk_mat4_mul_vec4(
     rk_vec4 & ret,
     rk_mat4 const & a,