[Bf-extensions-cvs] [dd2126b0] master: Snap utilities: Avoid any OpenGL resources allocations for class members

[Sergey Sharybin]

Commit: dd2126b0988e6efa6a29b47cfefb659ec7952b68
Author: Sergey Sharybin
Date:   Tue Oct 17 10:41:43 2017 +0200
Branches: master
https://developer.blender.org/rBAdd2126b0988e6efa6a29b47cfefb659ec7952b68

Snap utilities: Avoid any OpenGL resources allocations for class members

OpenGL is not available in background mode, which was making unit tests to fail.
Additionally, it will cause some unwanted noise when someone renders his project
from command line, or performs any other command-line operation with Blender.

===================================================================

M	modules/snap_context/mesh_drawing.py

===================================================================

diff --git a/modules/snap_context/mesh_drawing.py b/modules/snap_context/mesh_drawing.py
index 82d87937..c85da506 100644
--- a/modules/snap_context/mesh_drawing.py
+++ b/modules/snap_context/mesh_drawing.py
@@ -156,33 +156,43 @@ class _Mesh_Arrays():
 
 
 class GPU_Indices_Mesh():
-    shader = Shader(
-        load_shader('3D_vert.glsl'),
-        None,
-        load_shader('primitive_id_frag.glsl'),
-    )
+    shader = None
 
-    unif_use_clip_planes = bgl.glGetUniformLocation(shader.program, 'use_clip_planes')
-    unif_clip_plane = bgl.glGetUniformLocation(shader.program, 'clip_plane')
+    @classmethod
+    def init_opengl(cls):
+        # OpenGL was already initialized, nothing to do here.
+        if cls.shader is not None:
+            return
+
+        cls.shader = Shader(
+            load_shader('3D_vert.glsl'),
+            None,
+            load_shader('primitive_id_frag.glsl'),
+        )
 
-    unif_MVP = bgl.glGetUniformLocation(shader.program, 'MVP')
-    unif_MV = bgl.glGetUniformLocation(shader.program, 'MV')
-    unif_offset = bgl.glGetUniformLocation(shader.program, 'offset')
+        cls.unif_use_clip_planes = bgl.glGetUniformLocation(cls.shader.program, 'use_clip_planes')
+        cls.unif_clip_plane = bgl.glGetUniformLocation(cls.shader.program, 'clip_plane')
 
-    attr_pos = bgl.glGetAttribLocation(shader.program, 'pos')
-    attr_primitive_id = bgl.glGetAttribLocation(shader.program, 'primitive_id')
+        cls.unif_MVP = bgl.glGetUniformLocation(cls.shader.program, 'MVP')
+        cls.unif_MV = bgl.glGetUniformLocation(cls.shader.program, 'MV')
+        cls.unif_offset = bgl.glGetUniformLocation(cls.shader.program, 'offset')
 
-    P = bgl.Buffer(bgl.GL_FLOAT, (4, 4))
-    MV = bgl.Buffer(bgl.GL_FLOAT, (4, 4))
+        cls.attr_pos = bgl.glGetAttribLocation(cls.shader.program, 'pos')
+        cls.attr_primitive_id = bgl.glGetAttribLocation(cls.shader.program, 'primitive_id')
 
-    # returns of public API #
-    vert_index = bgl.Buffer(bgl.GL_INT, 1)
+        cls.P = bgl.Buffer(bgl.GL_FLOAT, (4, 4))
+        cls.MV = bgl.Buffer(bgl.GL_FLOAT, (4, 4))
 
-    tri_co = bgl.Buffer(bgl.GL_FLOAT, (3, 3))
-    edge_co = bgl.Buffer(bgl.GL_FLOAT, (2, 3))
-    vert_co = bgl.Buffer(bgl.GL_FLOAT, 3)
+        # returns of public API #
+        cls.vert_index = bgl.Buffer(bgl.GL_INT, 1)
+
+        cls.tri_co = bgl.Buffer(bgl.GL_FLOAT, (3, 3))
+        cls.edge_co = bgl.Buffer(bgl.GL_FLOAT, (2, 3))
+        cls.vert_co = bgl.Buffer(bgl.GL_FLOAT, 3)
 
     def __init__(self, obj, draw_tris, draw_edges, draw_verts):
+        GPU_Indices_Mesh.init_opengl()
+
         self._NULL = gl_buffer_void_as_long(0)
 
         self.MVP = bgl.Buffer(bgl.GL_FLOAT, (4, 4))
@@ -463,6 +473,7 @@ def _restore_shader_state(cls):
 def gpu_Indices_enable_state():
     _store_current_shader_state(PreviousGLState)
 
+    GPU_Indices_Mesh.init_opengl()
     bgl.glUseProgram(GPU_Indices_Mesh.shader.program)
     #bgl.glBindVertexArray(GPU_Indices_Mesh.vao[0])
 
@@ -477,6 +488,7 @@ def gpu_Indices_use_clip_planes(rv3d, value):
         planes = bgl.Buffer(bgl.GL_FLOAT, (6, 4), rv3d.clip_planes)
 
         _store_current_shader_state(PreviousGLState)
+        GPU_Indices_Mesh.init_opengl()
         bgl.glUseProgram(GPU_Indices_Mesh.shader.program)
         bgl.glUniform1i(GPU_Indices_Mesh.unif_use_clip_planes, value)