Add a test of drawing mesh instances

Author: Morcki

tests/python/expected/test_draw_mesh_instances.png

@@ -616,3 +616,113 @@ def render():
         verify_image(window.get_image_buffer_as_numpy(),
                      'test_draw_part_of_lines')
     window.destroy()
+
+@pytest.mark.skipif(not _ti_core.GGUI_AVAILABLE, reason="GGUI Not Available")
+@test_utils.test(arch=supported_archs)
+def test_draw_mesh_instances():
+    N = 10
+    NV = (N + 1)**2
+    NT = 2 * N**2
+    NE = 2 * N * (N + 1) + N**2
+    pos = ti.Vector.field(3, ti.f32, shape=NV)
+    tri = ti.field(ti.i32, shape=3 * NT)
+    edge = ti.Vector.field(2, ti.i32, shape=NE)
+
+    # Instance Attribute Information
+    NInstanceRows = 100
+    NInstanceCols = 100
+    NInstance = NInstanceRows * NInstanceCols
+    instances_transforms = ti.Matrix.field(4, 4, ti.f32, shape = (NInstance,))
+
+    @ti.kernel
+    def init_transforms_of_instances():
+        identity = ti.Matrix.identity(ti.f32, 4)
+        for i in range(NInstanceRows):
+            for j in range(NInstanceCols):
+                index = i * NInstanceCols + j
+                instances_transforms[index] = identity
+                translate_matrix = ti.math.translate(1.2 * j, 0, -1.2 * i)
+                instances_transforms[index] = translate_matrix @ instances_transforms[index]
+
+    @ti.kernel
+    def init_pos():
+        for i, j in ti.ndrange(N + 1, N + 1):
+            idx = i * (N + 1) + j
+            pos[idx] = ti.Vector([i / N, 1.0 - j / N, 0.5])
+
+    @ti.kernel
+    def init_tri():
+        for i, j in ti.ndrange(N, N):
+            tri_idx = 6 * (i * N + j)
+            pos_idx = i * (N + 1) + j
+            if (i + j) % 2 == 0:
+                tri[tri_idx + 0] = pos_idx
+                tri[tri_idx + 1] = pos_idx + N + 2
+                tri[tri_idx + 2] = pos_idx + 1
+                tri[tri_idx + 3] = pos_idx
+                tri[tri_idx + 4] = pos_idx + N + 1
+                tri[tri_idx + 5] = pos_idx + N + 2
+            else:
+                tri[tri_idx + 0] = pos_idx
+                tri[tri_idx + 1] = pos_idx + N + 1
+                tri[tri_idx + 2] = pos_idx + 1
+                tri[tri_idx + 3] = pos_idx + 1
+                tri[tri_idx + 4] = pos_idx + N + 1
+                tri[tri_idx + 5] = pos_idx + N + 2
+
+    @ti.kernel
+    def init_edge():
+        for i, j in ti.ndrange(N + 1, N):
+            edge_idx = i * N + j
+            pos_idx = i * (N + 1) + j
+            edge[edge_idx] = ti.Vector([pos_idx, pos_idx + 1])
+        start = N * (N + 1)
+        for i, j in ti.ndrange(N, N + 1):
+            edge_idx = start + j * N + i
+            pos_idx = i * (N + 1) + j
+            edge[edge_idx] = ti.Vector([pos_idx, pos_idx + N + 1])
+        start = 2 * N * (N + 1)
+        for i, j in ti.ndrange(N, N):
+            edge_idx = start + i * N + j
+            pos_idx = i * (N + 1) + j
+            if (i + j) % 2 == 0:
+                edge[edge_idx] = ti.Vector([pos_idx, pos_idx + N + 2])
+            else:
+                edge[edge_idx] = ti.Vector([pos_idx + 1, pos_idx + N + 1])
+
+
+    @ti.kernel
+    def update_transform(t : ti.f32):
+        for i in range(NInstance):
+            rotation_matrix = ti.math.rot_by_axis(ti.math.vec3(0, 1, 0), 0.01 * ti.math.sin(t))
+            instances_transforms[i] = instances_transforms[i] @ rotation_matrix
+
+    init_transforms_of_instances()
+
+    init_pos()
+    init_tri()
+    init_edge()
+
+    window = ti.ui.Window("test", (1024, 1024), vsync=True, show_window=False)
+    canvas = window.get_canvas()
+    scene = ti.ui.Scene()
+    camera = ti.ui.make_camera()
+    camera.position(-1.82731234, 2.26492691, 2.27800684)
+    camera.lookat(-1.13230401, 2.11502124, 1.57480579)
+    camera.fov(90)
+
+    def render():
+        scene.set_camera(camera)
+        scene.point_light(pos=(0.5, 1, 2), color=(1, 1, 1))
+
+        scene.mesh_instance(pos, tri, color=(39/255, 123/255, 192/255), two_sided=True, transforms=instances_transforms)
+        canvas.scene(scene)
+
+    for i in range(30):
+        update_transform(30)
+        render()
+        window.get_image_buffer_as_numpy()
+
+    render()
+    verify_image(window.get_image_buffer_as_numpy(), 'test_draw_mesh_instances')
+    window.destroy()