Automatically transform Skeleton2D calculations so pivots are not needed

4 files changed, 43 insertions, 2 deletions

diff --git a/drivers/gles3/rasterizer_canvas_gles3.cpp b/drivers/gles3/rasterizer_canvas_gles3.cpp
index fbe00d22af..8888d11a24 100644
--- a/drivers/gles3/rasterizer_canvas_gles3.cpp
+++ b/drivers/gles3/rasterizer_canvas_gles3.cpp
@@ -440,6 +440,7 @@ void RasterizerCanvasGLES3::canvas_render_items(RID p_to_render_target, Item *p_
 					const Item::CommandMesh *cm = static_cast<const Item::CommandMesh *>(c);
 					if (cm->mesh_instance.is_valid()) {
 						mesh_storage->mesh_instance_check_for_update(cm->mesh_instance);
+						mesh_storage->mesh_instance_set_canvas_item_transform(cm->mesh_instance, canvas_transform_inverse * ci->final_transform);
 						update_skeletons = true;
 					}
 				}
diff --git a/drivers/gles3/shaders/skeleton.glsl b/drivers/gles3/shaders/skeleton.glsl
index a1e3c098f4..aad856a5a2 100644
--- a/drivers/gles3/shaders/skeleton.glsl
+++ b/drivers/gles3/shaders/skeleton.glsl
@@ -87,6 +87,16 @@ uniform highp float blend_weight;
 uniform lowp float blend_shape_count;
 #endif
 
+#ifdef USE_SKELETON
+uniform mediump vec2 skeleton_transform_x;
+uniform mediump vec2 skeleton_transform_y;
+uniform mediump vec2 skeleton_transform_offset;
+
+uniform mediump vec2 inverse_transform_x;
+uniform mediump vec2 inverse_transform_y;
+uniform mediump vec2 inverse_transform_offset;
+#endif
+
 vec2 signNotZero(vec2 v) {
 	return mix(vec2(-1.0), vec2(1.0), greaterThanEqual(v.xy, vec2(0.0)));
 }
@@ -164,10 +174,13 @@ void main() {
 	m += GET_BONE_MATRIX(bones.z, bones_a.z, in_weight_attrib.z);
 	m += GET_BONE_MATRIX(bones.w, bones_a.w, in_weight_attrib.w);
 
+	mat4 skeleton_matrix = mat4(vec4(skeleton_transform_x, 0.0, 0.0), vec4(skeleton_transform_y, 0.0, 0.0), vec4(0.0, 0.0, 1.0, 0.0), vec4(skeleton_transform_offset, 0.0, 1.0));
+	mat4 inverse_matrix = mat4(vec4(inverse_transform_x, 0.0, 0.0), vec4(inverse_transform_y, 0.0, 0.0), vec4(0.0, 0.0, 1.0, 0.0), vec4(inverse_transform_offset, 0.0, 1.0));
 	mat4 bone_matrix = mat4(m[0], m[1], vec4(0.0, 0.0, 1.0, 0.0), vec4(0.0, 0.0, 0.0, 1.0));
 
-	//reverse order because its transposed
-	out_vertex = (vec4(out_vertex, 0.0, 1.0) * bone_matrix).xy;
+	bone_matrix = skeleton_matrix * transpose(bone_matrix) * inverse_matrix;
+
+	out_vertex = (bone_matrix * vec4(out_vertex, 0.0, 1.0)).xy;
 #endif // USE_SKELETON
 
 #else // MODE_2D
diff --git a/drivers/gles3/storage/mesh_storage.cpp b/drivers/gles3/storage/mesh_storage.cpp
index 71f262af20..5ba0c5a09c 100644
--- a/drivers/gles3/storage/mesh_storage.cpp
+++ b/drivers/gles3/storage/mesh_storage.cpp
@@ -997,6 +997,11 @@ void MeshStorage::mesh_instance_check_for_update(RID p_mesh_instance) {
 	}
 }
 
+void MeshStorage::mesh_instance_set_canvas_item_transform(RID p_mesh_instance, const Transform2D &p_transform) {
+	MeshInstance *mi = mesh_instance_owner.get_or_null(p_mesh_instance);
+	mi->canvas_item_transform_2d = p_transform;
+}
+
 void MeshStorage::_blend_shape_bind_mesh_instance_buffer(MeshInstance *p_mi, uint32_t p_surface) {
 	glBindBuffer(GL_ARRAY_BUFFER, p_mi->surfaces[p_surface].vertex_buffers[0]);
 
@@ -1163,6 +1168,16 @@ void MeshStorage::update_mesh_instances() {
 				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::BLEND_SHAPE_COUNT, float(mi->mesh->blend_shape_count), skeleton_shader.shader_version, variant, specialization);
 
 				if (can_use_skeleton) {
+					Transform2D transform = mi->canvas_item_transform_2d.affine_inverse() * sk->base_transform_2d;
+					skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::SKELETON_TRANSFORM_X, transform[0], skeleton_shader.shader_version, variant, specialization);
+					skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::SKELETON_TRANSFORM_Y, transform[1], skeleton_shader.shader_version, variant, specialization);
+					skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::SKELETON_TRANSFORM_OFFSET, transform[2], skeleton_shader.shader_version, variant, specialization);
+
+					Transform2D inverse_transform = transform.affine_inverse();
+					skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::INVERSE_TRANSFORM_X, inverse_transform[0], skeleton_shader.shader_version, variant, specialization);
+					skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::INVERSE_TRANSFORM_Y, inverse_transform[1], skeleton_shader.shader_version, variant, specialization);
+					skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::INVERSE_TRANSFORM_OFFSET, inverse_transform[2], skeleton_shader.shader_version, variant, specialization);
+
 					// Do last blendshape in the same pass as the Skeleton.
 					_compute_skeleton(mi, sk, i);
 					can_use_skeleton = false;
@@ -1201,6 +1216,16 @@ void MeshStorage::update_mesh_instances() {
 					continue;
 				}
 
+				Transform2D transform = mi->canvas_item_transform_2d.affine_inverse() * sk->base_transform_2d;
+				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::SKELETON_TRANSFORM_X, transform[0], skeleton_shader.shader_version, variant, specialization);
+				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::SKELETON_TRANSFORM_Y, transform[1], skeleton_shader.shader_version, variant, specialization);
+				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::SKELETON_TRANSFORM_OFFSET, transform[2], skeleton_shader.shader_version, variant, specialization);
+
+				Transform2D inverse_transform = transform.affine_inverse();
+				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::INVERSE_TRANSFORM_X, inverse_transform[0], skeleton_shader.shader_version, variant, specialization);
+				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::INVERSE_TRANSFORM_Y, inverse_transform[1], skeleton_shader.shader_version, variant, specialization);
+				skeleton_shader.shader.version_set_uniform(SkeletonShaderGLES3::INVERSE_TRANSFORM_OFFSET, inverse_transform[2], skeleton_shader.shader_version, variant, specialization);
+
 				glBindVertexArray(mi->mesh->surfaces[i]->skeleton_vertex_array);
 				_compute_skeleton(mi, sk, i);
 			}
diff --git a/drivers/gles3/storage/mesh_storage.h b/drivers/gles3/storage/mesh_storage.h
index 2efc57462b..e1c2bc3f63 100644
--- a/drivers/gles3/storage/mesh_storage.h
+++ b/drivers/gles3/storage/mesh_storage.h
@@ -163,6 +163,7 @@ struct MeshInstance {
 	bool weights_dirty = false;
 	SelfList<MeshInstance> weight_update_list;
 	SelfList<MeshInstance> array_update_list;
+	Transform2D canvas_item_transform_2d;
 	MeshInstance() :
 			weight_update_list(this), array_update_list(this) {}
 };
@@ -423,6 +424,7 @@ public:
 	virtual void mesh_instance_set_skeleton(RID p_mesh_instance, RID p_skeleton) override;
 	virtual void mesh_instance_set_blend_shape_weight(RID p_mesh_instance, int p_shape, float p_weight) override;
 	virtual void mesh_instance_check_for_update(RID p_mesh_instance) override;
+	virtual void mesh_instance_set_canvas_item_transform(RID p_mesh_instance, const Transform2D &p_transform) override;
 	virtual void update_mesh_instances() override;
 
 	// TODO: considering hashing versions with multimesh buffer RID.