SYNOPSIS

#include <allegro5/allegro_primitives.h>
void al_draw_soft_line(ALLEGRO_VERTEX* v1, ALLEGRO_VERTEX* v2, uintptr_t state,
   void (*first)(uintptr_t, int, int, ALLEGRO_VERTEX*, ALLEGRO_VERTEX*),
   void (*step)(uintptr_t, int),
   void (*draw)(uintptr_t, int, int))

DESCRIPTION

Draws a line using the software rasterizer and user supplied pixel functions. For help in understanding what these functions do, see the implementation of the various shading routines in addons/primitives/line_soft.c. The line is drawn top to bottom.

Parameters:

• v1, v2 - The two vertices of the line
• state - A pointer to a user supplied struct, this struct will be passed to all the pixel functions
• first - Called before drawing the first pixel of the line. It is passed the coordinates of this pixel, as well as the two vertices above. The passed vertices may have been altered by clipping.
• step - Called once per pixel. The second parameter is set to 1 if the step is a minor step, and 0 if this step is a major step. Minor steps are taken only either in x or y directions. Major steps are taken in both directions diagonally. In all cases, the absolute value of the change in coordinate is at most 1 in either direction.
• draw - Called once per pixel. The function is expected to draw the pixel at the coordinates passed to it.