Add a substructure for shader states

src/renderer.h

@@ -3,20 +3,26 @@
 
 #include <GLFW/glfw3.h>
 
+/**
+ * Structure representing the state of a shader.
+ */
+struct shader_state {
+  unsigned int program; /**< Shader program ID. */
+  const char *filename; /**< Shader file name. */
+};
+
 /**
  * Structure representing the state of the renderer and associated
  * shaders.
  */
 struct renderer_state {
-  GLFWwindow *window;             /**< GLFW window where the shaders are rendered. */
-  unsigned int screen_shader;     /**< Shader for the main screen. */
-  const char *screen_shader_file; /**< Screen shader file name. */
-  unsigned int buffer_shader;     /**< Shader for the background framebuffer. */
-  const char *buffer_shader_file; /**< Buffer shader file name. */
-  size_t frame_count;		  /**< Frame count since the beginning of the render loop. */
-  size_t prev_frame_count;	  /**< Frame count at the last log. */
-  double time;			  /**< Time in seconds since the beginning of the render loop. */
-  double prev_time;		  /**< Time in seconds at the last log. */
+  GLFWwindow *window; /**< GLFW window where the shaders are rendered. */
+  struct shader_state screen_shader; /**< Shader for the main screen. */
+  struct shader_state buffer_shader; /**< Shader for the framebuffer. */
+  size_t frame_count; /**< Frame count since the start of the render loop. */
+  size_t prev_frame_count; /**< Frame count at the last log. */
+  double time; /**< Time in seconds since the beginning of the render loop. */
+  double prev_time; /**< Time in seconds at the last log. */
 };
 
 GLFWwindow *initialize_window(int width, int height);