Add manual depth test between models

include/openspace/rendering/framebufferrenderer.h

@@ -99,6 +99,43 @@ public:
     void initialize();
     void deinitialize();
 
+    // Functions to access the G-buffer textures
+    /**
+     * Gives access to the color texture of the G-buffer. NOTE: This texture is used for
+     * the majority of rendering the scene and might be already in use. Use CAUTION when
+     * using this function. The size of the texture is the resolution of the viewport.
+     *
+     * \return GLuint identifier of the color texture of the G-buffer
+     */
+    GLuint gBufferColorTexture();
+
+    /**
+     * Gives access to the position texture of the G-buffer. NOTE: This texture is used for
+     * the majority of rendering the scene and might be already in use. Use CAUTION when
+     * using this function. The size of the texture is the resolution of the viewport.
+     *
+     * \return GLuint identifier of the position texture of the G-buffer
+     */
+    GLuint gBufferPositionTexture();
+
+    /**
+     * Gives access to the normal texture of the G-buffer. NOTE: This texture is used for
+     * the majority of rendering the scene and might be already in use. Use CAUTION when
+     * using this function. The size of the texture is the resolution of the viewport.
+     *
+     * \return GLuint identifier of the normal texture of the G-buffer
+     */
+    GLuint gBufferNormalTexture();
+
+    /**
+     * Gives access to the depth texture of the G-buffer. NOTE: This texture is used for
+     * the majority of rendering the scene and might be already in use. Use CAUTION when
+     * using this function. The size of the texture is the resolution of the viewport.
+     *
+     * \return GLuint identifier of the depth texture of the G-buffer
+     */
+    GLuint gBufferDepthTexture();
+
     void updateResolution();
     void updateRaycastData();
     void updateDeferredcastData();