From ec885cf23da36f5c290162ca917846835880f309 Mon Sep 17 00:00:00 2001
From: MazTheMan <me@maztheman.ca>
Date: Tue, 26 Sep 2023 11:59:26 -0600
Subject: [PATCH] get pixel size from fourcc to calculate pixel stride

---
 include/pixels.h |  1 +
 src/buffer.c     |  5 +++--
 src/pixels.c     | 37 +++++++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/include/pixels.h b/include/pixels.h
index 913bbc7..ff334c8 100644
--- a/include/pixels.h
+++ b/include/pixels.h
@@ -22,3 +22,4 @@
 
 enum wl_shm_format fourcc_to_wl_shm(uint32_t in);
 uint32_t fourcc_from_wl_shm(enum wl_shm_format in);
+int pixel_size_from_fourcc(uint32_t fourcc);
diff --git a/src/buffer.c b/src/buffer.c
index 4d80819..3a59dea 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -91,9 +91,10 @@ struct wv_buffer* wv_buffer_create_shm(int width,
 	if (!self->wl_buffer)
 		goto shm_failure;
 
-	// TODO: Get the pixel size from the format instead of assuming it's 4.
+	int bpp = pixel_size_from_fourcc(fourcc);
+	assert(bpp > 0);
 	self->nvnc_fb = nvnc_fb_from_buffer(self->pixels, width, height, fourcc,
-			stride / 4);
+			stride / bpp);
 	if (!self->nvnc_fb) {
 		goto nvnc_fb_failure;
 	}
diff --git a/src/pixels.c b/src/pixels.c
index 29941bf..0c8dc67 100644
--- a/src/pixels.c
+++ b/src/pixels.c
@@ -44,3 +44,40 @@ uint32_t fourcc_from_wl_shm(enum wl_shm_format in)
 
 	return in;
 }
+
+int pixel_size_from_fourcc(uint32_t fourcc)
+{
+	switch (fourcc & ~DRM_FORMAT_BIG_ENDIAN) {
+	case DRM_FORMAT_RGBA1010102:
+	case DRM_FORMAT_RGBX1010102:
+	case DRM_FORMAT_BGRA1010102:
+	case DRM_FORMAT_BGRX1010102:
+	case DRM_FORMAT_ARGB2101010:
+	case DRM_FORMAT_XRGB2101010:
+	case DRM_FORMAT_ABGR2101010:
+	case DRM_FORMAT_XBGR2101010:
+	case DRM_FORMAT_RGBA8888:
+	case DRM_FORMAT_RGBX8888:
+	case DRM_FORMAT_BGRA8888:
+	case DRM_FORMAT_BGRX8888:
+	case DRM_FORMAT_ARGB8888:
+	case DRM_FORMAT_XRGB8888:
+	case DRM_FORMAT_ABGR8888:
+	case DRM_FORMAT_XBGR8888:
+		return 4;
+	case DRM_FORMAT_BGR888:
+	case DRM_FORMAT_RGB888:
+		return 3;
+	case DRM_FORMAT_RGBA4444:
+	case DRM_FORMAT_RGBX4444:
+	case DRM_FORMAT_BGRA4444:
+	case DRM_FORMAT_BGRX4444:
+	case DRM_FORMAT_ARGB4444:
+	case DRM_FORMAT_XRGB4444:
+	case DRM_FORMAT_ABGR4444:
+	case DRM_FORMAT_XBGR4444:
+		return 2;
+	}
+
+	return 0;
+}