From e024b7e72c4170e84e689b530f18f2f03c1f1b35 Mon Sep 17 00:00:00 2001
From: Matthew Turk <matthewturk@gmail.com>
Date: Fri, 16 Dec 2022 14:17:52 -0600
Subject: [PATCH 1/5] First draft of vmcontainer

---
 yt_idv/scene_data/variable_mesh.py | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 yt_idv/scene_data/variable_mesh.py

diff --git a/yt_idv/scene_data/variable_mesh.py b/yt_idv/scene_data/variable_mesh.py
new file mode 100644
index 0000000..20d5842
--- /dev/null
+++ b/yt_idv/scene_data/variable_mesh.py
@@ -0,0 +1,27 @@
+import numpy as np
+import traitlets
+from yt.data_objects.selection_objects.data_selection_objects import (
+    YTSelectionContainer2D,
+)
+from yt_idv.scene_data.base_data import SceneData
+from yt_idv.opengl_support import VertexArray, VertexAttribute
+
+
+class VariableMeshContainer(SceneData):
+    name = "variable_mesh"
+    data_source = traitlets.Instance(YTSelectionContainer2D)
+
+    @traitlets.default("vertex_array")
+    def _default_vertex_array(self):
+        rv = VertexArray(name="vm_positions", each=1)
+
+    def add_data(self, field):
+        if len(self.vertex_array.attributes) > 0:
+            # Has already been initialized, so we just update the data
+            self.vertex_array.attributes[-1].data = self.data_source[field].astype("f4")
+            return
+        for vfield in ("px", "py", "pdx", "pdy"):
+            self.vertex_array.attributes.append(
+                VertexAttribute(name=vfield, data=self.data_source[vfield].astype("f4")
+            )
+        self.vertex_array.attributes.append(VertexAttribute(name = "field", data = self.data_source[field].astype("f4")))

From d4dc21e9d954db6016319f5a6553e43b8d9b1310 Mon Sep 17 00:00:00 2001
From: Matthew Turk <matthewturk@gmail.com>
Date: Mon, 19 Dec 2022 17:00:59 -0600
Subject: [PATCH 2/5] initial ideas for displaying vm

---
 .../scene_components/variable_mesh_display.py | 21 +++++
 yt_idv/shaders/variable_mesh_expand.geom.glsl | 81 +++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 yt_idv/scene_components/variable_mesh_display.py
 create mode 100644 yt_idv/shaders/variable_mesh_expand.geom.glsl

diff --git a/yt_idv/scene_components/variable_mesh_display.py b/yt_idv/scene_components/variable_mesh_display.py
new file mode 100644
index 0000000..ba792e2
--- /dev/null
+++ b/yt_idv/scene_components/variable_mesh_display.py
@@ -0,0 +1,21 @@
+import numpy as np
+import traitlets
+from OpenGL import GL
+
+from yt_idv.scene_components.base_component import SceneComponent
+from yt_idv.scene_data.variable_mesh import VariableMeshContainer
+
+
+class VariableMeshDisplay(SceneComponent):
+    """
+    A class that renders variable mesh datasets.
+    """
+
+    name = "variable_mesh_display"
+    data = traitlets.Instance(VariableMeshContainer)
+    priority = 11
+
+    def draw(self, scene, program):
+        GL.glEnable(GL.GL_CULL_FACE)
+        GL.glCullFace(GL.GL_BACK)
+        GL.glDrawArrays(GL.GL_TRIANGLE_STRIP, 0, 4, self.data.size)
\ No newline at end of file
diff --git a/yt_idv/shaders/variable_mesh_expand.geom.glsl b/yt_idv/shaders/variable_mesh_expand.geom.glsl
new file mode 100644
index 0000000..3a796ee
--- /dev/null
+++ b/yt_idv/shaders/variable_mesh_expand.geom.glsl
@@ -0,0 +1,81 @@
+layout ( points ) in;
+layout ( triangle_strip, max_vertices = 4 ) out;
+
+flat in float vradius[];
+flat in float vfield_value[];
+
+flat out mat4 inverse_proj;
+flat out mat4 inverse_mvm;
+flat out mat4 inverse_pmvm;
+flat out vec4 v_model;
+flat out float field_value;
+flat out float radius;
+
+out vec2 UV;
+
+flat in mat4 vinverse_proj[];
+flat in mat4 vinverse_mvm[];
+flat in mat4 vinverse_pmvm[];
+flat in vec4 vv_model[];
+flat in vec3 vv_camera_pos[];
+
+// https://stackoverflow.com/questions/28375338/cube-using-single-gl-triangle-strip
+// suggests that the triangle strip we want for the cube is
+
+void main() {
+
+    vec4 cornerPos;
+    vec2 cornerFrag;
+    vec4 position = vv_model[0];
+    mat4 pmvm = projection * modelview;
+
+    // This is our inverse projection model view matrix.  That means that if we
+    // move something in clip space and multiply by this, it becomes the world
+    // coordinates of that new thing.
+    //
+    // We want to figure out what the world vectors corresponding to clip space
+    // motion (at the z and w of our current vertex) are.
+    vec4 fragLeftCorner = pmvm * (position + vradius[0] * normalize(vinverse_pmvm[0] * vec4(-1.0, -1.0, gl_in[0].gl_Position.zw)));
+    vec4 fragRightCorner = pmvm * (position + vradius[0] * normalize(vinverse_pmvm[0] * vec4(1.0, 1.0, gl_in[0].gl_Position.zw)));
+
+    // We don't want to allow each particle to be bigger than some maximum size
+    // in clip space coordinates.
+
+    fragLeftCorner.x = max(fragLeftCorner.x, gl_in[0].gl_Position.x - max_particle_size/2.0);
+    fragLeftCorner.y = max(fragLeftCorner.y, gl_in[0].gl_Position.y - max_particle_size/2.0);
+    fragRightCorner.x = min(fragRightCorner.x, gl_in[0].gl_Position.x + max_particle_size/2.0);
+    fragRightCorner.y = min(fragRightCorner.y, gl_in[0].gl_Position.y + max_particle_size/2.0);
+
+    // https://stackoverflow.com/questions/12239876/fastest-way-of-converting-a-quad-to-a-triangle-strip
+    // or: https://en.wikipedia.org/wiki/Triangle_strip
+    // in section "OpenGL implementation" this corresponds to A = 1, B = 2, C = 3, D = 4
+
+    gl_Position = vec4(fragLeftCorner.xy, gl_in[0].gl_Position.zw);
+    field_value = vfield_value[0];
+    v_model = vv_model[0];
+    radius = vradius[0];
+    UV = vec2(-1.0, -1.0);
+    EmitVertex();
+
+    gl_Position = vec4(fragLeftCorner.x, fragRightCorner.y, gl_in[0].gl_Position.zw);
+    field_value = vfield_value[0];
+    v_model = vv_model[0];
+    radius = vradius[0];
+    UV = vec2(-1.0, +1.0);
+    EmitVertex();
+
+    gl_Position = vec4(fragRightCorner.x, fragLeftCorner.y, gl_in[0].gl_Position.zw);
+    field_value = vfield_value[0];
+    v_model = vv_model[0];
+    radius = vradius[0];
+    UV = vec2(+1.0, -1.0);
+    EmitVertex();
+
+    gl_Position = vec4(fragRightCorner.xy, gl_in[0].gl_Position.zw);
+    field_value = vfield_value[0];
+    v_model = vv_model[0];
+    radius = vradius[0];
+    UV = vec2(+1.0, +1.0);
+    EmitVertex();
+
+}

From 3c64812f78c33d40eed0dc947bea17b83615e678 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Mon, 19 Dec 2022 23:01:40 +0000
Subject: [PATCH 3/5] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 yt_idv/scene_components/variable_mesh_display.py | 2 +-
 yt_idv/scene_data/variable_mesh.py               | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/yt_idv/scene_components/variable_mesh_display.py b/yt_idv/scene_components/variable_mesh_display.py
index ba792e2..5ecb527 100644
--- a/yt_idv/scene_components/variable_mesh_display.py
+++ b/yt_idv/scene_components/variable_mesh_display.py
@@ -18,4 +18,4 @@ class VariableMeshDisplay(SceneComponent):
     def draw(self, scene, program):
         GL.glEnable(GL.GL_CULL_FACE)
         GL.glCullFace(GL.GL_BACK)
-        GL.glDrawArrays(GL.GL_TRIANGLE_STRIP, 0, 4, self.data.size)
\ No newline at end of file
+        GL.glDrawArrays(GL.GL_TRIANGLE_STRIP, 0, 4, self.data.size)
diff --git a/yt_idv/scene_data/variable_mesh.py b/yt_idv/scene_data/variable_mesh.py
index 20d5842..0819bf3 100644
--- a/yt_idv/scene_data/variable_mesh.py
+++ b/yt_idv/scene_data/variable_mesh.py
@@ -3,8 +3,9 @@
 from yt.data_objects.selection_objects.data_selection_objects import (
     YTSelectionContainer2D,
 )
-from yt_idv.scene_data.base_data import SceneData
+
 from yt_idv.opengl_support import VertexArray, VertexAttribute
+from yt_idv.scene_data.base_data import SceneData
 
 
 class VariableMeshContainer(SceneData):

From 8cb85309d9722045384da57f7cf0b2576aa5af48 Mon Sep 17 00:00:00 2001
From: Matthew Turk <matthewturk@gmail.com>
Date: Tue, 6 Jun 2023 17:06:54 -0500
Subject: [PATCH 4/5] Working on further variable mesh viewer functionality

---
 examples/variable_mesh_viewer.py              | 20 +++++
 .../scene_components/variable_mesh_display.py |  5 +-
 yt_idv/scene_data/variable_mesh.py            |  5 +-
 yt_idv/shaders/shaderlist.yaml                | 23 +++++
 yt_idv/shaders/variable_mesh.frag.glsl        |  8 ++
 yt_idv/shaders/variable_mesh.vert.glsl        | 15 ++++
 yt_idv/shaders/variable_mesh_expand.geom.glsl | 88 +++++++------------
 7 files changed, 105 insertions(+), 59 deletions(-)
 create mode 100644 examples/variable_mesh_viewer.py
 create mode 100644 yt_idv/shaders/variable_mesh.frag.glsl
 create mode 100644 yt_idv/shaders/variable_mesh.vert.glsl

diff --git a/examples/variable_mesh_viewer.py b/examples/variable_mesh_viewer.py
new file mode 100644
index 0000000..158da7b
--- /dev/null
+++ b/examples/variable_mesh_viewer.py
@@ -0,0 +1,20 @@
+import yt
+import yt_idv
+from yt_idv.scene_data.variable_mesh import VariableMeshContainer
+from yt_idv.scene_components.variable_mesh_display import VariableMeshDisplay
+
+ds = yt.load_sample("IsolatedGalaxy")
+
+vm = ds.r[:,:,0.5]
+
+rc = yt_idv.render_context(height=800, width=800, gui=True)
+sg = rc.add_scene(ds, None)
+
+vmc = VariableMeshContainer(data_source = vm)
+vmc.add_data("ones")
+vmd = VariableMeshDisplay(data = vmc)
+
+sg.data_objects.append(vmc)
+sg.components.append(vmd)
+
+rc.run()
diff --git a/yt_idv/scene_components/variable_mesh_display.py b/yt_idv/scene_components/variable_mesh_display.py
index 5ecb527..d52d77c 100644
--- a/yt_idv/scene_components/variable_mesh_display.py
+++ b/yt_idv/scene_components/variable_mesh_display.py
@@ -18,4 +18,7 @@ class VariableMeshDisplay(SceneComponent):
     def draw(self, scene, program):
         GL.glEnable(GL.GL_CULL_FACE)
         GL.glCullFace(GL.GL_BACK)
-        GL.glDrawArrays(GL.GL_TRIANGLE_STRIP, 0, 4, self.data.size)
+        GL.glDrawArraysInstanced(GL.GL_TRIANGLE_STRIP, 0, 4, self.data.size)
+
+    def _set_uniforms(self, scene, program):
+        pass
diff --git a/yt_idv/scene_data/variable_mesh.py b/yt_idv/scene_data/variable_mesh.py
index 0819bf3..fe4da68 100644
--- a/yt_idv/scene_data/variable_mesh.py
+++ b/yt_idv/scene_data/variable_mesh.py
@@ -15,6 +15,7 @@ class VariableMeshContainer(SceneData):
     @traitlets.default("vertex_array")
     def _default_vertex_array(self):
         rv = VertexArray(name="vm_positions", each=1)
+        return rv
 
     def add_data(self, field):
         if len(self.vertex_array.attributes) > 0:
@@ -22,7 +23,9 @@ def add_data(self, field):
             self.vertex_array.attributes[-1].data = self.data_source[field].astype("f4")
             return
         for vfield in ("px", "py", "pdx", "pdy"):
+            f = self.data_source[vfield].in_units('unitary').astype("f4")
             self.vertex_array.attributes.append(
-                VertexAttribute(name=vfield, data=self.data_source[vfield].astype("f4")
+                VertexAttribute(name=vfield, data=f)
             )
         self.vertex_array.attributes.append(VertexAttribute(name = "field", data = self.data_source[field].astype("f4")))
+        self.size = self.data_source['px'].size
diff --git a/yt_idv/shaders/shaderlist.yaml b/yt_idv/shaders/shaderlist.yaml
index 52f52eb..19fea8a 100644
--- a/yt_idv/shaders/shaderlist.yaml
+++ b/yt_idv/shaders/shaderlist.yaml
@@ -133,6 +133,13 @@ shader_definitions:
       - one
       - zero
       blend_equation: func add
+    variable_mesh:
+      info: Sample a flat field value
+      source: variable_mesh.frag.glsl
+      depth_test: less
+      blend_func:
+      - one
+      - zero
   vertex:
     default:
       info: A first pass vertex shader that tranlates the location of vertices from
@@ -160,6 +167,9 @@ shader_definitions:
     octree_position:
       info: Expect instanced rendering of octree nodes
       source: octree_position.vert.glsl
+    variable_mesh:
+      info: Billboard some variable mesh values
+      source: variable_mesh.vert.glsl
   geometry:
     grid_expand:
       info: Expand grid left and right edges into a set of triangles
@@ -167,6 +177,9 @@ shader_definitions:
     particle_expand:
       info: Expand particles from points to triangulated quads
       source: particle_expand.geom.glsl
+    variable_mesh_expand:
+      info: Expand variable mesh points to quads
+      source: variable_mesh_expand.geom.glsl
 component_shaders:
   curve_rendering:
       default_value: default
@@ -315,3 +328,13 @@ component_shaders:
       first_fragment: field_value
       second_vertex: passthrough
       second_fragment: apply_colormap
+  variable_mesh_display:
+    default_value: default
+    default:
+      description: Display variable mesh as quads
+      first_vertex: variable_mesh
+      first_geometry: variable_mesh_expand
+      first_fragment: variable_mesh
+      second_vertex: passthrough
+      second_fragment: apply_colormap
+
diff --git a/yt_idv/shaders/variable_mesh.frag.glsl b/yt_idv/shaders/variable_mesh.frag.glsl
new file mode 100644
index 0000000..3e4b03d
--- /dev/null
+++ b/yt_idv/shaders/variable_mesh.frag.glsl
@@ -0,0 +1,8 @@
+flat in vec4 v_model;
+flat in float field_value;
+out vec4 output_color;
+
+void main()
+{
+    output_color = vec4(field_value);
+}
diff --git a/yt_idv/shaders/variable_mesh.vert.glsl b/yt_idv/shaders/variable_mesh.vert.glsl
new file mode 100644
index 0000000..ec2434c
--- /dev/null
+++ b/yt_idv/shaders/variable_mesh.vert.glsl
@@ -0,0 +1,15 @@
+in float px;
+in float py;
+in float pdx;
+in float pdy;
+in float field_value;
+
+flat out vec4 vv_model;
+flat out float vv_field_value;
+
+void main()
+{
+    vv_model = vec4(px, py, pdx, pdy);
+    vv_field_value = field_value;
+    gl_Position = vec4(px, py, 0.0, 0.0);
+}
diff --git a/yt_idv/shaders/variable_mesh_expand.geom.glsl b/yt_idv/shaders/variable_mesh_expand.geom.glsl
index 3a796ee..dda4464 100644
--- a/yt_idv/shaders/variable_mesh_expand.geom.glsl
+++ b/yt_idv/shaders/variable_mesh_expand.geom.glsl
@@ -1,81 +1,55 @@
 layout ( points ) in;
 layout ( triangle_strip, max_vertices = 4 ) out;
 
-flat in float vradius[];
-flat in float vfield_value[];
-
-flat out mat4 inverse_proj;
-flat out mat4 inverse_mvm;
-flat out mat4 inverse_pmvm;
 flat out vec4 v_model;
 flat out float field_value;
-flat out float radius;
-
-out vec2 UV;
 
-flat in mat4 vinverse_proj[];
-flat in mat4 vinverse_mvm[];
-flat in mat4 vinverse_pmvm[];
 flat in vec4 vv_model[];
-flat in vec3 vv_camera_pos[];
+flat in float vv_field_value[];
 
-// https://stackoverflow.com/questions/28375338/cube-using-single-gl-triangle-strip
-// suggests that the triangle strip we want for the cube is
 
 void main() {
 
-    vec4 cornerPos;
-    vec2 cornerFrag;
-    vec4 position = vv_model[0];
-    mat4 pmvm = projection * modelview;
-
-    // This is our inverse projection model view matrix.  That means that if we
-    // move something in clip space and multiply by this, it becomes the world
-    // coordinates of that new thing.
-    //
-    // We want to figure out what the world vectors corresponding to clip space
-    // motion (at the z and w of our current vertex) are.
-    vec4 fragLeftCorner = pmvm * (position + vradius[0] * normalize(vinverse_pmvm[0] * vec4(-1.0, -1.0, gl_in[0].gl_Position.zw)));
-    vec4 fragRightCorner = pmvm * (position + vradius[0] * normalize(vinverse_pmvm[0] * vec4(1.0, 1.0, gl_in[0].gl_Position.zw)));
-
-    // We don't want to allow each particle to be bigger than some maximum size
-    // in clip space coordinates.
-
-    fragLeftCorner.x = max(fragLeftCorner.x, gl_in[0].gl_Position.x - max_particle_size/2.0);
-    fragLeftCorner.y = max(fragLeftCorner.y, gl_in[0].gl_Position.y - max_particle_size/2.0);
-    fragRightCorner.x = min(fragRightCorner.x, gl_in[0].gl_Position.x + max_particle_size/2.0);
-    fragRightCorner.y = min(fragRightCorner.y, gl_in[0].gl_Position.y + max_particle_size/2.0);
-
-    // https://stackoverflow.com/questions/12239876/fastest-way-of-converting-a-quad-to-a-triangle-strip
-    // or: https://en.wikipedia.org/wiki/Triangle_strip
-    // in section "OpenGL implementation" this corresponds to A = 1, B = 2, C = 3, D = 4
-
-    gl_Position = vec4(fragLeftCorner.xy, gl_in[0].gl_Position.zw);
-    field_value = vfield_value[0];
+    // This is considerably simpler because we will just be doing things based
+    // on the positions in clip space
+    gl_Position = vec4(
+            vv_model[0].x - vv_model[0].z,
+            vv_model[0].y - vv_model[0].w,
+            0.0,
+            0.0
+    );
+    field_value = vv_field_value[0];
     v_model = vv_model[0];
-    radius = vradius[0];
-    UV = vec2(-1.0, -1.0);
     EmitVertex();
 
-    gl_Position = vec4(fragLeftCorner.x, fragRightCorner.y, gl_in[0].gl_Position.zw);
-    field_value = vfield_value[0];
+    gl_Position = vec4(
+            vv_model[0].x - vv_model[0].z,
+            vv_model[0].y + vv_model[0].w,
+            0.0,
+            0.0
+    );
+    field_value = vv_field_value[0];
     v_model = vv_model[0];
-    radius = vradius[0];
-    UV = vec2(-1.0, +1.0);
     EmitVertex();
 
-    gl_Position = vec4(fragRightCorner.x, fragLeftCorner.y, gl_in[0].gl_Position.zw);
-    field_value = vfield_value[0];
+    gl_Position = vec4(
+            vv_model[0].x + vv_model[0].z,
+            vv_model[0].y + vv_model[0].w,
+            0.0,
+            0.0
+    );
+    field_value = vv_field_value[0];
     v_model = vv_model[0];
-    radius = vradius[0];
-    UV = vec2(+1.0, -1.0);
     EmitVertex();
 
-    gl_Position = vec4(fragRightCorner.xy, gl_in[0].gl_Position.zw);
-    field_value = vfield_value[0];
+    gl_Position = vec4(
+            vv_model[0].x + vv_model[0].z,
+            vv_model[0].y - vv_model[0].w,
+            0.0,
+            0.0
+    );
+    field_value = vv_field_value[0];
     v_model = vv_model[0];
-    radius = vradius[0];
-    UV = vec2(+1.0, +1.0);
     EmitVertex();
 
 }

From 1c20dfedafa08531544b64a6025d64a590934c1a Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Tue, 6 Jun 2023 22:07:19 +0000
Subject: [PATCH 5/5] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 examples/variable_mesh_viewer.py   |  9 +++++----
 yt_idv/scene_data/variable_mesh.py | 12 ++++++------
 yt_idv/shaders/shaderlist.yaml     |  1 -
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/examples/variable_mesh_viewer.py b/examples/variable_mesh_viewer.py
index 158da7b..f433899 100644
--- a/examples/variable_mesh_viewer.py
+++ b/examples/variable_mesh_viewer.py
@@ -1,18 +1,19 @@
 import yt
+
 import yt_idv
-from yt_idv.scene_data.variable_mesh import VariableMeshContainer
 from yt_idv.scene_components.variable_mesh_display import VariableMeshDisplay
+from yt_idv.scene_data.variable_mesh import VariableMeshContainer
 
 ds = yt.load_sample("IsolatedGalaxy")
 
-vm = ds.r[:,:,0.5]
+vm = ds.r[:, :, 0.5]
 
 rc = yt_idv.render_context(height=800, width=800, gui=True)
 sg = rc.add_scene(ds, None)
 
-vmc = VariableMeshContainer(data_source = vm)
+vmc = VariableMeshContainer(data_source=vm)
 vmc.add_data("ones")
-vmd = VariableMeshDisplay(data = vmc)
+vmd = VariableMeshDisplay(data=vmc)
 
 sg.data_objects.append(vmc)
 sg.components.append(vmd)
diff --git a/yt_idv/scene_data/variable_mesh.py b/yt_idv/scene_data/variable_mesh.py
index fe4da68..7a37e92 100644
--- a/yt_idv/scene_data/variable_mesh.py
+++ b/yt_idv/scene_data/variable_mesh.py
@@ -23,9 +23,9 @@ def add_data(self, field):
             self.vertex_array.attributes[-1].data = self.data_source[field].astype("f4")
             return
         for vfield in ("px", "py", "pdx", "pdy"):
-            f = self.data_source[vfield].in_units('unitary').astype("f4")
-            self.vertex_array.attributes.append(
-                VertexAttribute(name=vfield, data=f)
-            )
-        self.vertex_array.attributes.append(VertexAttribute(name = "field", data = self.data_source[field].astype("f4")))
-        self.size = self.data_source['px'].size
+            f = self.data_source[vfield].in_units("unitary").astype("f4")
+            self.vertex_array.attributes.append(VertexAttribute(name=vfield, data=f))
+        self.vertex_array.attributes.append(
+            VertexAttribute(name="field", data=self.data_source[field].astype("f4"))
+        )
+        self.size = self.data_source["px"].size
diff --git a/yt_idv/shaders/shaderlist.yaml b/yt_idv/shaders/shaderlist.yaml
index 19fea8a..64a081f 100644
--- a/yt_idv/shaders/shaderlist.yaml
+++ b/yt_idv/shaders/shaderlist.yaml
@@ -337,4 +337,3 @@ component_shaders:
       first_fragment: variable_mesh
       second_vertex: passthrough
       second_fragment: apply_colormap
-