From: tokyo4j <hrak1529@gmail.com>
Date: Fri, 30 May 2025 11:58:15 +0000 (+0900)
Subject: buffer: add buffer_create_from_wlr_buffer()
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=649773b4f83bee6daa34da7c6ab40b6de2eddc0e;p=proto%2Flabwc.git

buffer: add buffer_create_from_wlr_buffer()
---

diff --git a/include/buffer.h b/include/buffer.h
index a756a7b5..2771334f 100644
--- a/include/buffer.h
+++ b/include/buffer.h
@@ -70,6 +70,13 @@ struct lab_data_buffer *buffer_create_cairo(uint32_t logical_width,
 struct lab_data_buffer *buffer_create_from_data(void *pixel_data, uint32_t width,
 	uint32_t height, uint32_t stride);
 
+/*
+ * Create a lab_data_buffer from a wlr_buffer by copying its content.
+ * The wlr_buffer must be backed by shm.
+ */
+struct lab_data_buffer *buffer_create_from_wlr_buffer(
+	struct wlr_buffer *wlr_buffer);
+
 /*
  * Resize a buffer to the given size. The source buffer is rendered at the
  * center of the output buffer and shrunk if it overflows from the output buffer.
diff --git a/src/buffer.c b/src/buffer.c
index 08560116..1faa4620 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -28,6 +28,7 @@
 #include <stdlib.h>
 #include <drm_fourcc.h>
 #include <wlr/interfaces/wlr_buffer.h>
+#include <wlr/util/log.h>
 #include "buffer.h"
 #include "common/box.h"
 #include "common/mem.h"
@@ -148,6 +149,32 @@ buffer_create_from_data(void *pixel_data, uint32_t width, uint32_t height,
 	return buffer;
 }
 
+struct lab_data_buffer *
+buffer_create_from_wlr_buffer(struct wlr_buffer *wlr_buffer)
+{
+	void *data;
+	uint32_t format;
+	size_t stride;
+	if (!wlr_buffer_begin_data_ptr_access(wlr_buffer,
+			WLR_BUFFER_DATA_PTR_ACCESS_READ, &data, &format, &stride)) {
+		wlr_log(WLR_ERROR, "failed to access wlr_buffer");
+		return NULL;
+	}
+	if (format != DRM_FORMAT_ARGB8888) {
+		/* TODO: support other formats */
+		wlr_buffer_end_data_ptr_access(wlr_buffer);
+		wlr_log(WLR_ERROR, "cannot create buffer: format=%d", format);
+		return NULL;
+	}
+	size_t buffer_size = stride * wlr_buffer->height;
+	void *copied_data = xmalloc(buffer_size);
+	memcpy(copied_data, data, buffer_size);
+	wlr_buffer_end_data_ptr_access(wlr_buffer);
+
+	return buffer_create_from_data(copied_data,
+		wlr_buffer->width, wlr_buffer->height, stride);
+}
+
 struct lab_data_buffer *
 buffer_resize(struct lab_data_buffer *src_buffer, int width, int height,
 		double scale)