RetroGLU Overlay API

Convenience macros for drawing a 2D overlay using transparent textures. More...

Collaboration diagram for RetroGLU Overlay API:

Macros
#define	retroglu_push_overlay(x, y, x_f, y_f, aspect_f)
	Push current projection modelview and prepare useful parameters for drawing a textured overlay.
#define	retroglu_whf(w, h, w_f, h_f, aspect_f)
	Convert width/height in pixels to proportional float values for OpenGL.
#define	retroglu_pop_overlay()
	Restore projection modelview previously pushed using retroglu_push().

Detailed Description

Convenience macros for drawing a 2D overlay using transparent textures.

Macro Definition Documentation

retroglu_pop_overlay

#define retroglu_pop_overlay

(

)

Value:

   glPopMatrix(); \
   glMatrixMode( GL_MODELVIEW );

Restore projection modelview previously pushed using retroglu_push().

retroglu_push_overlay

#define retroglu_push_overlay	(		x,
			y,
			x_f,
			y_f,
			aspect_f )

Value:

   /* Switch to projection setup. */ \
   glMatrixMode( GL_PROJECTION ); \
   glPushMatrix(); \
   /* Lighting makes overlay text hard to see. */ \
   retroglu_disable_lightning(); \
   /* Use ortho for overlay. */ \
   glLoadIdentity(); \
   aspect_f = (float)retroflat_screen_w() / (float)retroflat_screen_h(); \
   /* Switch to ortho projection proportional to screen size. */ \
   glOrtho( -1.0f * aspect_f, aspect_f, -1.0f, 1.0f, 0, 10.0f ); \
   /* -1 to 1 is 2! */ \
   aspect_f *= 2.0f; \
   /* Assuming width > height for aspect ratio. */ \
   x_f = ((x) * aspect_f / retroflat_screen_w()) - (aspect_f / 2); \
   /* Vertical coords also need to be inverted because OpenGL. */ \
   y_f = 1.0f - ((y) * 2.0f / retroflat_screen_h()); \

Push current projection modelview and prepare useful parameters for drawing a textured overlay.

retroglu_whf

#define retroglu_whf	(		w,
			h,
			w_f,
			h_f,
			aspect_f )

Value:

   w_f = ((w) * aspect_f / retroflat_screen_w()); \
   h_f = ((h) * 2.0f / retroflat_screen_h());

Convert width/height in pixels to proportional float values for OpenGL.

Parameters

w	Width of an overlay in pixels (read-only int).
h	Height of an overlay in pixels (read-only int).
w_f	Float to assign proportional width of the overlay.
h_f	Float to assign proportional height of the overlay.