draw_lines.py

# Draw Lines

import harfang as hg
from math import sin, cos

hg.InputInit()
hg.WindowSystemInit()

res_x, res_y = 1280, 720
win = hg.RenderInit('Harfang - Draw Lines', res_x, res_y, hg.RF_VSync | hg.RF_MSAA4X)

line_count = 1000

shader = hg.LoadProgramFromFile('resources_compiled/shaders/white')

# vertices
vtx_layout = hg.VertexLayout()
vtx_layout.Begin()
vtx_layout.Add(hg.A_Position, 3, hg.AT_Float)
vtx_layout.End()

vtx = hg.Vertices(vtx_layout, line_count * 2)

# main loop
angle = 0

while not hg.ReadKeyboard().Key(hg.K_Escape) and hg.IsWindowOpen(win):
	hg.SetViewClear(0, hg.CF_Color | hg.CF_Depth, hg.ColorI(64, 64, 64), 1, 0)
	hg.SetViewRect(0, 0, 0, res_x, res_y)

	vtx.Clear()
	for i in range(0, line_count):
		vtx.Begin(2 * i).SetPos(hg.Vec3(sin(angle + i * 0.005), cos(angle + i * 0.01), 0)).End()
		vtx.Begin(2 * i + 1).SetPos(hg.Vec3(sin(angle + i * -0.005), cos(angle + i * 0.005), 0)).End()

	hg.DrawLines(0, vtx, shader)  # submit all lines in a single call

	angle = angle + hg.time_to_sec_f(hg.TickClock())

	hg.Frame()
	hg.UpdateWindow(win)

hg.RenderShutdown()
hg.DestroyWindow(win)