NAME¶

al_draw_polyline - Allegro 5 API

SYNOPSIS¶

#include <allegro5/allegro_primitives.h>
void al_draw_polyline(const float* vertices, int vertex_stride,


   int vertex_count, int join_style, int cap_style,


   ALLEGRO_COLOR color, float thickness, float miter_limit)
    

DESCRIPTION¶

Draw a series of line segments.

•

vertices - Interleaved array of (x, y) vertex coordinates

•

vertex_stride - the number of bytes between pairs of vertices (the stride)

•

vertex_count - Number of vertices in the array

•

join_style - Member of ALLEGRO_LINE_JOIN(3) specifying how to render the joins between line segments

•

cap_style - Member of ALLEGRO_LINE_CAP(3) specifying how to render the end caps

•

color - Color of the line

•

thickness - Thickness of the line, pass <= 0 to draw hairline lines

•

miter_limit - Parameter for miter join style

The stride is normally 2 * sizeof(float) but may be more if the vertex coordinates are in an array of some structure type, e.g.

struct VertexInfo {


   float x;


   float y;


   int id;
};
void my_draw(struct VertexInfo verts[], int vertex_count, ALLEGRO_COLOR c)
{


   al_draw_polyline((float *)verts, sizeof(VertexInfo), vertex_count,


      ALLEGRO_LINE_JOIN_NONE, ALLEGRO_LINE_CAP_NONE, c, 1.0, 1.0);
}
    

The stride may also be negative if the vertices are stored in reverse order.

SINCE¶

5.1.0

SEE ALSO¶

al_draw_polygon(3), ALLEGRO_LINE_JOIN(3), ALLEGRO_LINE_CAP(3)