Migrating shaders to builtins to support M1 #2897

Migrated all shaders from geometry shaders to builtins (all geometry data now calculated in python before passing to shader) to make them more reliable and support Metal backend on Mac M1 (tested that it works - both annotations and gizmo).

The current downside is that there is no more custom frag shaders too - meaning we do not support dashed lines in the annotations (currently Hidden and Grid just use a bit less bright annotation color).

src/blenderbim/blenderbim/bim/module/drawing/gizmos.py

@@ -23,7 +23,7 @@ from bpy import types
 from mathutils import Vector
 from mathutils import geometry
 from bpy_extras import view3d_utils
-from blenderbim.bim.module.drawing.shaders import DotsGizmoShader, ExtrusionGuidesShader, BaseLinesShader
+from blenderbim.bim.module.drawing.shaders import DotsGizmoShader, ExtrusionGuidesShader
 from ifcopenshell.util.unit import si_conversions
 
 
@@ -251,11 +251,12 @@ X3DISC = (
 class CustomGizmo:
     # FIXME: highliting/selection doesnt work
     def draw_very_custom_shape(self, ctx, custom_shape, select_id=None):
-        # similar to draw_custom_shape
-        shape, batch, shader = custom_shape
+        # create shader and batch
+        shader_wrapper, batch = custom_shape
+        shader = shader_wrapper.get_shader()
 
+        # setup params
         shader.bind()
-
         if select_id is not None:
             gpu.select.load_id(select_id)
         else:
@@ -264,13 +265,17 @@ class CustomGizmo:
             else:
                 color = (*self.color, self.alpha)
             shader.uniform_float("color", color)
-            shape.glenable()
+            shader_wrapper.glenable()
+        shader_wrapper.uniform_region(ctx)
 
-        shape.uniform_region(ctx)
-        # shader.uniform_float('modelMatrix', self.matrix_world)
+        # using `with` block to make sure matrix multiplication
+        # won't affect other shaders
         with gpu.matrix.push_pop():
-            gpu.matrix.multiply_matrix(self.matrix_world)
-            batch.draw()
+            # using matrix_world seems to be unaffected by matrix_offset
+            # therefore we use basis @ offset
+            matrix = self.matrix_basis @ self.matrix_offset
+            gpu.matrix.multiply_matrix(matrix)
+            batch.draw(shader)
 
         gpu.state.blend_set("NONE")
 
@@ -360,6 +365,7 @@ class UglyDotGizmo(OffsetHandle, types.Gizmo):
         self.draw_custom_shape(self.custom_shape, select_id=select_id)
 
 
+# TODO: dead code?
 class DotGizmo(CustomGizmo, OffsetHandle, types.Gizmo):
     """Single dot viewport-aligned"""
 
@@ -389,10 +395,6 @@ class DotGizmo(CustomGizmo, OffsetHandle, types.Gizmo):
         self.refresh()
         self.draw_very_custom_shape(ctx, self.custom_shape, select_id=select_id)
 
-    # doesn't get called
-    # def test_select(self, ctx, location):
-    #     pass
-
 
 class ExtrusionGuidesGizmo(CustomGizmo, types.Gizmo):
     """Extrusion guides
@@ -407,19 +409,25 @@ class ExtrusionGuidesGizmo(CustomGizmo, types.Gizmo):
     __slots__ = ("scale_value", "custom_shape")
 
     def setup(self):
-        shader = ExtrusionGuidesShader()
-        self.custom_shape = shader, shader.batch(pos=((0, 0, 0), (0, 0, 1))), shader.prog
-        self.use_draw_scale = False
-
-    def refresh(self):
-        depth = self.target_get_value("depth") / self.scale_value
-        self.matrix_offset.col[2][2] = depth  # z-scaled
+        """setup `custom_shape`"""
+        shader_wrapper = ExtrusionGuidesShader()
+        verts = [Vector((0, 0, 0)), Vector((0, 0, 1))]
+        verts, edges = shader_wrapper.process_geometry(verts)
+        self.custom_shape = shader_wrapper, shader_wrapper.batch(
+            pos=verts,
+            indices=edges,
+        )
 
     def draw(self, ctx):
         self.refresh()
         self.draw_very_custom_shape(ctx, self.custom_shape)
 
+    def refresh(self):
+        depth = self.target_get_value("depth") / self.scale_value
+        self.matrix_offset.col[2][2] = depth  # z-scaled
 
+
+# TODO: dead code?
 class DimensionLabelGizmo(types.Gizmo):
     """Text label for a dimension"""
 
@@ -486,6 +494,7 @@ class ExtrusionWidget(types.GizmoGroup):
         theme = ctx.preferences.themes[0].user_interface
         scale_value = self.get_scale_value(ctx.scene.unit_settings.system, ctx.scene.unit_settings.length_unit)
 
+        # setup handle
         gz = self.handle = self.gizmos.new("BIM_GT_uglydot_3d")
         gz.matrix_basis = basis
         gz.scale_basis = 0.1
@@ -496,6 +505,7 @@ class ExtrusionWidget(types.GizmoGroup):
         gz.target_set_prop("offset", prop, "value")
         gz.scale_value = scale_value
 
+        # setup guides
         gz = self.guides = self.gizmos.new("BIM_GT_extrusion_guides")
         gz.matrix_basis = basis
         gz.color = gz.color_highlight = tuple(theme.gizmo_secondary)

src/blenderbim/blenderbim/bim/module/drawing/shaders.py

@@ -16,9 +16,23 @@
 # You should have received a copy of the GNU General Public License
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
-from gpu.types import GPUShader
 from gpu_extras.batch import batch_for_shader
 import gpu
+from mathutils import Vector
+
+
+# NOTES:
+# Since Metal doesn't support geometry shaders we stick to builtin shaders
+# and generate all geometry data in python before passing it to the shader.
+# This way was considered to be the most reliable atm.
+# More: https://blender.stackexchange.com/questions/291674/migrating-geometry-shaders-to-metal
+#
+# BGL deprecation:
+# since `bgl` is deprecated, creating smoothing lines became tricky
+# Notes for creating shaders with smoothed lines:
+# in geom shader - use triangle_strip, DEFAULT_SETUP, do_edge_verts or do_vertex to emit vertices
+# in frag shader - use lineWidth uniform, smoothline flaot in, smoothing shader code from base shader
+# mind the vertex limit since emitting vertices for smoothed lines produces twice as much vertices
 
 
 BASE_DEF_GLSL = """
@@ -29,12 +43,6 @@ BASE_DEF_GLSL = """
 #define lineSmooth true
 """
 
-# since `bgl` is deprecated, creating smoothing lines became tricky
-# Notes for creating shaders with smoothed lines:
-# in geom shader - use triangle_strip, DEFAULT_SETUP, do_edge_verts or do_vertex to emit vertices
-# in frag shader - use lineWidth uniform, smoothline flaot in, smoothing shader code from base shader
-# mind the vertex limit since emitting vertices for smoothed lines produces twice as much vertices
-
 BASE_LIB_GLSL = """
 // TODO: redefine as macor instead
 uniform vec2 winsize;
@@ -160,12 +168,11 @@ void do_vertex_util(vec4 pos, vec2 ofs)
 
 // geometry utils
 void triangle_head(in vec4 side, in vec4 dir, in float length, in float width, in float radius, out vec4 head[5]) {
-    vec4 nose = side * length;
-    vec4 ear = dir * width;
+    // TODO: radius is unnecessary?
     head[0] = side * -radius;
-    head[1] = nose * -.5;
-    head[2] = vec4(0) + ear;
-    head[3] = nose * .5;
+    head[1] = side * length * -.5;
+    head[2] = dir * width;
+    head[3] = side * length * .5;
     head[4] = side * radius;
 }
 
@@ -189,6 +196,22 @@ void do_circle_head(vec4 pos_w, vec4 head[CIRCLE_SEGS]) {
 """
 
 
+def add_verts_sequence(verts, start_i, output_verts, output_edges, closed=False):
+    """Add sequence of verts to output lists, returns next vertex index"""
+    for i, v in enumerate(verts[:-1], start_i):
+        output_verts.append(v)
+        output_edges.append((i, i + 1))
+    output_verts.append(verts[-1])
+    if closed:
+        output_edges.append((i + 1, start_i))
+    return i + 2
+
+
+def add_offsets(v, offsets):
+    """returns list of verts with offsets added"""
+    return [v + offset for offset in offsets]
+
+
 class BaseShader:
     """Wrapper for GPUShader
     To use for viewport decorations with geometry generated on GPU side.
@@ -265,48 +288,49 @@ class BaseShader:
     """
 
     def __init__(self):
-        # NB: libcode arg doesn't work
-        # TODO: rename to .shader
-        self.prog = GPUShader(
-            vertexcode=self.VERT_GLSL,
-            fragcode=self.FRAG_GLSL,
-            geocode=self.LIB_GLSL + self.GEOM_GLSL,
-            defines=self.DEF_GLSL,
-        )
+        # 3D_POLYLINE_UNIFORM_COLOR is good for smoothed lines since `bgl.enable(GL_LINE_SMOOTH)` is deprecated
+        self.line_shader = gpu.shader.from_builtin("3D_POLYLINE_UNIFORM_COLOR")
+        self.base_shader = gpu.shader.from_builtin("3D_UNIFORM_COLOR")
+
+    def get_shader(self):
+        """Returns shader for this type"""
+        return self.line_shader if self.TYPE == "LINES" else self.base_shader
 
     def batch(self, indices=None, **data):
         """Returns automatic GPUBatch filled with provided parameters"""
-        batch = batch_for_shader(self.prog, self.TYPE, data, indices=indices)
-        batch.program_set(self.prog)
+        shader = self.get_shader()
+        batch = batch_for_shader(shader, self.TYPE, data, indices=indices)
         return batch
 
     def bind(self):
-        self.prog.bind()
+        """need to bind shader before changing it's uniforms"""
+        shader = self.get_shader()
+        shader.bind()
+        return shader
 
     def glenable(self):
         gpu.state.blend_set("ALPHA")
         gpu.state.depth_test_set("LESS_EQUAL")
 
     def uniform_region(self, ctx):
+        shader = self.bind()
+
         region = ctx.region
         region3d = ctx.region_data
 
         uniform_floats = {
-            "viewMatrix": region3d.perspective_matrix,
-            "winsize": (region.width, region.height),
+            "ModelViewProjectionMatrix": region3d.perspective_matrix,
+            # POLYLINE_UNIFORM_COLOR specific uniforms
+            "viewportSize": (region.width, region.height),
             "lineWidth": 2.5,
         }
 
         for name, value in uniform_floats.items():
-            try:
-                self.prog.uniform_float(name, value)
-                # TODO: shouldn't just try'n'catch them
-                # because they may indicate errors in code
-            except ValueError:  # unused uniform
-                pass
+            shader.uniform_float(name, value)
 
 
-# TODO: add smoothing if this shades is going to be used
+# TODO: add smoothing if this shader is going to be used
+# TODO: dead code?
 class BaseLinesShader(BaseShader):
     """Draws line segments with gaps around vertices at endpoints"""
 
@@ -429,37 +453,24 @@ class ExtrusionGuidesShader(GizmoShader):
 
     TYPE = "LINES"
 
-    DEF_GLSL = (
-        BaseShader.DEF_GLSL
-        + """
-    #define CROSS_SIZE .5
-    """
-    )
+    def process_geometry(self, verts):
+        CROSS_SIZE = 0.5
 
-    GEOM_GLSL = """
-    uniform mat4 ModelViewProjectionMatrix;
+        p0, p1 = verts
+        bx = Vector((1, 0, 0)) * CROSS_SIZE
+        by = Vector((0, 1, 0)) * CROSS_SIZE
 
-    layout(lines) in;
-    layout(triangle_strip, max_vertices=MAX_POINTS) out;
+        output_verts = []
+        output_edges = []
+        out_kwargs = {
+            "output_verts": output_verts,
+            "output_edges": output_edges,
+        }
 
-    void main() {
-        // default setup for macro to work
-        vec2 EDGE_DIR;
+        start_i = 0
+        start_i = add_verts_sequence(add_offsets(p0, [-bx, bx]), start_i, **out_kwargs)
+        start_i = add_verts_sequence(add_offsets(p0, [-by, by]), start_i, **out_kwargs)
+        start_i = add_verts_sequence(add_offsets(p1, [-bx, bx]), start_i, **out_kwargs)
+        start_i = add_verts_sequence(add_offsets(p1, [-by, by]), start_i, **out_kwargs)
 
-        vec4 p0 = gl_in[0].gl_Position, p1 = gl_in[1].gl_Position;
-        do_edge_verts(p0, p1);
-        EndPrimitive();
-
-        vec4 bx = ModelViewProjectionMatrix[0] * CROSS_SIZE;
-        vec4 by = ModelViewProjectionMatrix[1] * CROSS_SIZE;
-
-        do_edge_verts(p0 - bx, p0 + bx);
-        EndPrimitive();
-        do_edge_verts(p0 - by, p0 + by);
-        EndPrimitive();
-        do_edge_verts(p1 - bx, p1 + bx);
-        EndPrimitive();
-        do_edge_verts(p1 - by, p1 + by);
-        EndPrimitive();
-    }
-    """
+        return output_verts, output_edges