temp.c

Description

temp.c is a small source code file from the glSeis application. It is not a standalone command-line tool. This file contains a single utility function, draw_axes, which is responsible for rendering a 3D coordinate axis system (X, Y, and Z axes) in the main OpenGL window.

The name “temp.c” suggests it may have been a temporary file for testing drawing functions, but it provides a core piece of the visualization framework.

Functionality

void draw_axes()

  • Purpose: To draw a visual representation of the X, Y, and Z axes at the origin of the 3D world space. This is a common feature in 3D applications to help the user maintain a sense of orientation.
  • Action:
    1. Debug Output: The function first prints the current orientation and position of the “object” (likely the sonar) to the console for debugging purposes.
    2. Draw X-axis: It draws a red cylinder along the positive X-axis, with a red cone at the end to serve as an arrowhead.
    3. Draw Y-axis: It rotates the coordinate system and draws a magenta-colored cylinder and cone along the positive Y-axis.
    4. Draw Z-axis: It rotates again and draws a blue cylinder and cone along the positive Z-axis.
  • Implementation: The function uses OpenGL transformation commands (glPushMatrix, glScalef, glRotatef, glTranslatef) to position and orient each axis. The actual drawing of the shapes is delegated to custom external functions (draw_cylinder_filled and draw_tapered_cylinder_filled).

This function is called whenever the scene needs to be redrawn and the axes_flag is enabled, providing a persistent and helpful reference for navigating the 3D data.