sun_position/north.py

   1 # SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 import bpy
   4 import math
   5 import gpu
   6 from gpu_extras.batch import batch_for_shader
   7 from mathutils import Vector
   8
   9
  10 if bpy.app.background:  # ignore north line in background mode
  11     def north_update(self, context):
  12         pass
  13 else:
  14     vertex_shader = '''
  15         uniform mat4 u_ViewProjectionMatrix;
  16
  17         in vec3 position;
  18
  19         flat out vec2 v_StartPos;
  20         out vec4 v_VertPos;
  21
  22         void main()
  23         {
  24             vec4 pos    = u_ViewProjectionMatrix * vec4(position, 1.0f);
  25             gl_Position = pos;
  26             v_StartPos    = (pos / pos.w).xy;
  27             v_VertPos     = pos;
  28         }
  29     '''
  30
  31     fragment_shader = '''
  32         uniform vec4 u_Color;
  33
  34         flat in vec2 v_StartPos;
  35         in vec4 v_VertPos;
  36         out vec4 FragColor;
  37
  38         uniform vec2 u_Resolution;
  39
  40         void main()
  41         {
  42             vec4 vertPos_2d = v_VertPos / v_VertPos.w;
  43             vec2 dir  = (vertPos_2d.xy - v_StartPos.xy) * u_Resolution;
  44             float dist = length(dir);
  45
  46             if (step(sin(dist / 5.0f), 0.0) == 1) discard;
  47
  48             FragColor = u_Color;
  49         }
  50     '''
  51
  52     shader = gpu.types.GPUShader(vertex_shader, fragment_shader)
  53
  54     def draw_north_callback():
  55         # ------------------------------------------------------------------
  56         # Set up the compass needle using the current north offset angle
  57         # less 90 degrees.  This forces the unit circle to begin at the
  58         # 12 O'clock instead of 3 O'clock position.
  59         # ------------------------------------------------------------------
  60         sun_props = bpy.context.scene.sun_pos_properties
  61
  62         color = (0.2, 0.6, 1.0, 0.7)
  63         radius = 100
  64         angle = -(sun_props.north_offset - math.pi / 2)
  65         x = math.cos(angle) * radius
  66         y = math.sin(angle) * radius
  67
  68         coords = Vector((x, y, 0)), Vector((0, 0, 0))   # Start & end of needle
  69
  70         batch = batch_for_shader(
  71             shader, 'LINE_STRIP',
  72             {"position": coords},
  73         )
  74         shader.bind()
  75
  76         matrix = bpy.context.region_data.perspective_matrix
  77         shader.uniform_float("u_ViewProjectionMatrix", matrix)
  78         shader.uniform_float("u_Resolution", (bpy.context.region.width, bpy.context.region.height))
  79         shader.uniform_float("u_Color", color)
  80         gpu.state.line_width_set(2.0)
  81         batch.draw(shader)
  82
  83     _handle = None
  84
  85
  86     def north_update(self, context):
  87         global _handle
  88         if self.show_north and _handle is None:
  89             _handle = bpy.types.SpaceView3D.draw_handler_add(draw_north_callback, (), 'WINDOW', 'POST_VIEW')
  90         elif _handle is not None:
  91             bpy.types.SpaceView3D.draw_handler_remove(_handle, 'WINDOW')
  92             _handle = None
  93         context.area.tag_redraw()