build 180923. basic precipitation visualization system, minor bug fixes

precipitation.h

@@ -0,0 +1,59 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#pragma	once
+
+#include "texture.h"
+
+// based on "Rendering Falling Rain and Snow"
+// by Niniane Wang, Bretton Wade
+
+class basic_precipitation {
+
+public:
+// constructors
+    basic_precipitation() = default;
+// destructor
+	~basic_precipitation();
+// methods
+    inline
+    void
+        set_unit( GLint const Textureunit ) {
+            m_textureunit = Textureunit; }
+    bool
+        init();
+    void
+        update();
+	void
+        render();
+
+    glm::dvec3 m_cameramove{ 0.0 };
+
+private:
+// methods
+    void create( int const Tesselation );
+
+// members
+    std::vector<glm::vec3> m_vertices;
+    std::vector<glm::vec2> m_uvs;
+    std::vector<std::uint16_t> m_indices;
+    GLuint m_vertexbuffer { (GLuint)-1 };
+    GLuint m_uvbuffer { (GLuint)-1 };
+    GLuint m_indexbuffer { (GLuint)-1 };
+    GLint m_textureunit { 0 };
+    texture_handle m_texture { -1 };
+    float m_textureoffset { 0.f };
+    float m_moverate { 30 * 0.001f };
+    float m_moverateweathertypefactor { 1.f }; // medium-dependent; 1.0 for snow, faster for rain
+    glm::dvec3 m_camerapos { 0.0 };
+    bool m_freeflymode { true };
+    bool m_windowopen { true };
+    int m_activecab{ 0 };
+    glm::dvec3 m_cabcameramove{ 0.0 };
+};