u/mask: Introduce u_visibility_mask

src/xrt/auxiliary/util/CMakeLists.txt

@@ -96,6 +96,8 @@ add_library(
 	u_config_json.c
 	u_config_json.h
 	u_verify.h
+	u_visibility_mask.c
+	u_visibility_mask.h
 	u_win32_com_guard.cpp
 	u_win32_com_guard.hpp
 	u_worker.c

src/xrt/auxiliary/util/u_visibility_mask.c

@@ -0,0 +1,91 @@
+// Copyright 2023, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief Visibility mask utilitary
+ * @author Simon Zeni <simon.zeni@collabora.com>
+ * @ingroup aux_util
+ */
+
+#include "u_misc.h"
+#include "u_visibility_mask.h"
+#include "u_logging.h"
+
+#include <string.h>
+
+static const struct xrt_vec2 vertices_hidden[] = {
+    {1.0, 0.75},   {1.0, 1.0},   {0.75, 1.0},   {-1.0, 1.0},  {-1.0, 0.75}, {-0.75, 1.0},
+    {-1.0, -0.75}, {-1.0, -1.0}, {-0.75, -1.0}, {0.75, -1.0}, {1.0, -1.0},  {1.0, -0.75},
+};
+
+static const uint32_t indices_hidden[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11};
+
+static const struct xrt_vec2 vertices_visible[] = {
+    {1.f, -.75f}, {.75f, -1.f}, {-.75f, -1.f}, {-1.f, -.75f}, {-1.f, .75f},
+    {-.75f, 1.f}, {.75f, 1.f},  {1.f, .75f},   {0.f, 0.f},
+};
+
+static const uint32_t indices_visible[] = {
+    8, 2, 1, 3, 2, 8, 8, 1, 0, 6, 8, 7, 4, 8, 5, 8, 0, 7, 5, 8, 6, 4, 3, 8,
+};
+
+static const struct xrt_vec2 vertices_line[] = {
+    {-.75f, -1.f}, {.75f, -1.f}, {1.f, -.75f}, {1.f, .75f}, {.75f, 1.f}, {-.75f, 1.f}, {-1.f, .75f}, {-1.f, -.75f},
+};
+
+static const uint32_t indices_line[] = {0, 1, 2, 3, 4, 5, 6, 7};
+
+void
+u_visibility_mask_get_default(enum xrt_visibility_mask_type type, struct xrt_visibility_mask **out_mask)
+{
+	uint32_t nvertices, nindices;
+
+	switch (type) {
+	case XRT_VISIBILITY_MASK_TYPE_HIDDEN_TRIANGLE_MESH:
+		nvertices = ARRAY_SIZE(vertices_hidden);
+		nindices = ARRAY_SIZE(indices_hidden);
+		break;
+	case XRT_VISIBILITY_MASK_TYPE_VISIBLE_TRIANGLE_MESH:
+		nvertices = ARRAY_SIZE(vertices_visible);
+		nindices = ARRAY_SIZE(indices_visible);
+		break;
+	case XRT_VISIBILITY_MASK_TYPE_LINE_LOOP:
+		nvertices = ARRAY_SIZE(vertices_line);
+		nindices = ARRAY_SIZE(indices_line);
+		break;
+	}
+
+	const size_t size =
+	    sizeof(struct xrt_visibility_mask) + sizeof(uint32_t) * nindices + sizeof(struct xrt_vec2) * nvertices;
+	*out_mask = U_CALLOC_WITH_CAST(struct xrt_visibility_mask, size);
+	if (*out_mask == NULL) {
+		U_LOG_E("failed to allocate out xrt_visibility_mask");
+		return;
+	}
+
+	struct xrt_visibility_mask *mask = *out_mask;
+
+	mask->index_count = nindices;
+	mask->vertex_count = nvertices;
+
+	const struct xrt_vec2 *vertices;
+	const uint32_t *indices;
+
+	switch (type) {
+	case XRT_VISIBILITY_MASK_TYPE_HIDDEN_TRIANGLE_MESH:
+		vertices = vertices_hidden;
+		indices = indices_hidden;
+		break;
+	case XRT_VISIBILITY_MASK_TYPE_VISIBLE_TRIANGLE_MESH:
+		vertices = vertices_visible;
+		indices = indices_visible;
+		break;
+	case XRT_VISIBILITY_MASK_TYPE_LINE_LOOP:
+		vertices = vertices_line;
+		indices = indices_line;
+		break;
+	}
+
+	memcpy(xrt_visibility_mask_get_indices(mask), indices, sizeof(uint32_t) * nindices);
+	memcpy(xrt_visibility_mask_get_vertices(mask), vertices, sizeof(struct xrt_vec2) * nvertices);
+}

src/xrt/auxiliary/util/u_visibility_mask.h

@@ -0,0 +1,30 @@
+// Copyright 2023, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief Visibility mask utilitary header
+ * @author Simon Zeni <simon.zeni@collabora.com>
+ * @ingroup aux_util
+ */
+
+#include "xrt/xrt_defines.h"
+#include "xrt/xrt_visibility_mask.h"
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*!
+ * Default visibility mask. The caller must take care of de-allocating the mask once done with it.
+ *
+ * @ingroup aux_util
+ */
+void
+u_visibility_mask_get_default(enum xrt_visibility_mask_type type, struct xrt_visibility_mask **out_mask);
+
+
+#ifdef __cplusplus
+}
+#endif