From ceeef3567d90798335ca6038258a86704d71878a Mon Sep 17 00:00:00 2001
From: Roman Gilg <subdiff@gmail.com>
Date: Wed, 2 Dec 2020 15:40:04 +0100
Subject: [PATCH] Use DRM_CAP_CURSOR_{WIDTH,HEIGTH} for cursor buffer

Hardware often has cursor plane limitations for the buffer size.

Co-authored-by: Simon Ser <contact@emersion.fr>
---
 src/drm.cpp          |  7 +++++++
 src/drm.hpp          |  2 ++
 src/steamcompmgr.cpp | 17 ++++++++++++-----
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/drm.cpp b/src/drm.cpp
index 0b6f32b..c24f828 100644
--- a/src/drm.cpp
+++ b/src/drm.cpp
@@ -395,6 +395,13 @@ int init_drm(struct drm_t *drm, const char *device, const char *mode_str, unsign
 	drmModeFreeResources(resources);
 	
 	drm->connector_id = connector->connector_id;
+
+	if (drmGetCap(drm->fd, DRM_CAP_CURSOR_WIDTH, &drm->cursor_width) != 0) {
+		drm->cursor_width = 64;
+	}
+	if (drmGetCap(drm->fd, DRM_CAP_CURSOR_HEIGHT, &drm->cursor_height) != 0) {
+		drm->cursor_height = 64;
+	}
 	
 	drmSetClientCap(drm->fd, DRM_CLIENT_CAP_ATOMIC, 1);
 	drmSetClientCap(drm->fd, DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1);
diff --git a/src/drm.hpp b/src/drm.hpp
index b9e12c1..7c3c22d 100644
--- a/src/drm.hpp
+++ b/src/drm.hpp
@@ -50,6 +50,8 @@ struct fb {
 
 struct drm_t {
 	int fd;
+
+	uint64_t cursor_width, cursor_height;
 	
 	/* only used for atomic: */
 	struct plane *plane;
diff --git a/src/steamcompmgr.cpp b/src/steamcompmgr.cpp
index d7878c0..4976815 100644
--- a/src/steamcompmgr.cpp
+++ b/src/steamcompmgr.cpp
@@ -827,6 +827,11 @@ bool MouseCursor::getTexture()
 
 	m_width = image->width;
 	m_height = image->height;
+	if ( BIsNested() == false && alwaysComposite == False )
+	{
+		m_width = g_DRM.cursor_width;
+		m_height = g_DRM.cursor_height;
+	}
 
 	if (m_texture) {
 		vulkan_free_texture(m_texture);
@@ -836,12 +841,14 @@ bool MouseCursor::getTexture()
 	// Assume the cursor is fully translucent unless proven otherwise.
 	bool bNoCursor = true;
 
-	unsigned int cursorDataBuffer[m_width * m_height];
-	for (int i = 0; i < m_width * m_height; i++) {
-		cursorDataBuffer[i] = image->pixels[i];
+	uint32_t cursorDataBuffer[m_width * m_height] = {0};
+	for (int i = 0; i < image->height; i++) {
+		for (int j = 0; j < image->width; j++) {
+			cursorDataBuffer[i * m_width + j] = image->pixels[i * image->width + j];
 
-		if ( cursorDataBuffer[i] & 0x000000ff ) {
-			bNoCursor = false;
+			if ( cursorDataBuffer[i * m_width + j] & 0x000000ff ) {
+				bNoCursor = false;
+			}
 		}
 	}