From 04f42e0468549829d8ba3dd4163180b816cdc557 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Tue, 9 Nov 2021 11:50:49 -0500
Subject: [PATCH] metal: Deal better with -[CAMetalLayer nextDrawable]
returning nil.
Fixes #4863.
---
include/SDL_render.h | 7 +++-
src/render/metal/SDL_render_metal.m | 65 +++++++++++++++++++++--------
2 files changed, 54 insertions(+), 18 deletions(-)
diff --git a/include/SDL_render.h b/include/SDL_render.h
index 330e4425b8..a74fc129e3 100644
--- a/include/SDL_render.h
+++ b/include/SDL_render.h
@@ -1806,9 +1806,14 @@ extern DECLSPEC void *SDLCALL SDL_RenderGetMetalLayer(SDL_Renderer * renderer);
* This function returns `void *`, so SDL doesn't have to include Metal's
* headers, but it can be safely cast to an `id<MTLRenderCommandEncoder>`.
*
+ * Note that as of SDL 2.0.18, this will return NULL if Metal refuses to
+ * give SDL a drawable to render to, which might happen if the window is
+ * hidden/minimized/offscreen. This doesn't apply to command encoders for
+ * render targets, just the window's backbacker. Check your return values!
+ *
* \param renderer The renderer to query
* \returns an `id<MTLRenderCommandEncoder>` on success, or NULL if the
- * renderer isn't a Metal renderer.
+ * renderer isn't a Metal renderer or there was an error.
*
* \since This function is available since SDL 2.0.8.
*
diff --git a/src/render/metal/SDL_render_metal.m b/src/render/metal/SDL_render_metal.m
index 05d8a944bd..e4dd590f58 100644
--- a/src/render/metal/SDL_render_metal.m
+++ b/src/render/metal/SDL_render_metal.m
@@ -459,7 +459,7 @@ - (void)dealloc
return MakePipelineState(data, cache, [NSString stringWithFormat:@" (blend=custom 0x%x)", blendmode], blendmode);
}
-static void
+static SDL_bool
METAL_ActivateRenderCommandEncoder(SDL_Renderer * renderer, MTLLoadAction load, MTLClearColor *clear_color, id<MTLBuffer> vertex_buffer)
{
METAL_RenderData *data = (__bridge METAL_RenderData *) renderer->driverdata;
@@ -481,10 +481,16 @@ - (void)dealloc
load = MTLLoadActionDontCare;
}
}
- mtltexture = data.mtlbackbuffer.texture;
+ if (data.mtlbackbuffer != nil) {
+ mtltexture = data.mtlbackbuffer.texture;
+ }
}
- SDL_assert(mtltexture);
+ /* mtltexture can be nil here if macOS refused to give us a drawable,
+ which apparently can happen for minimized windows, etc. */
+ if (mtltexture == nil) {
+ return SDL_FALSE;
+ }
if (load == MTLLoadActionClear) {
SDL_assert(clear_color != NULL);
@@ -517,6 +523,8 @@ - (void)dealloc
// or whatever. This means we can _always_ batch rendering commands!
[data.mtlcmdbuffer enqueue];
}
+
+ return SDL_TRUE;
}
static void
@@ -1205,7 +1213,7 @@ - (void)dealloc
size_t color_offset;
} METAL_DrawStateCache;
-static void
+static SDL_bool
SetDrawState(SDL_Renderer *renderer, const SDL_RenderCommand *cmd, const SDL_MetalFragmentFunction shader,
const size_t constants_offset, id<MTLBuffer> mtlbufvertex, METAL_DrawStateCache *statecache)
{
@@ -1214,7 +1222,9 @@ - (void)dealloc
size_t first = cmd->data.draw.first;
id<MTLRenderPipelineState> newpipeline;
- METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, statecache->vertex_buffer);
+ if (!METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, statecache->vertex_buffer)) {
+ return SDL_FALSE;
+ }
if (statecache->viewport_dirty) {
MTLViewport viewport;
@@ -1268,9 +1278,10 @@ - (void)dealloc
}
[data.mtlcmdencoder setVertexBufferOffset:first atIndex:0]; /* position/texcoords */
+ return SDL_TRUE;
}
-static void
+static SDL_bool
SetCopyState(SDL_Renderer *renderer, const SDL_RenderCommand *cmd, const size_t constants_offset,
id<MTLBuffer> mtlbufvertex, METAL_DrawStateCache *statecache)
{
@@ -1278,7 +1289,9 @@ - (void)dealloc
SDL_Texture *texture = cmd->data.draw.texture;
METAL_TextureData *texturedata = (__bridge METAL_TextureData *)texture->driverdata;
- SetDrawState(renderer, cmd, texturedata.fragmentFunction, constants_offset, mtlbufvertex, statecache);
+ if (!SetDrawState(renderer, cmd, texturedata.fragmentFunction, constants_offset, mtlbufvertex, statecache)) {
+ return SDL_FALSE;
+ }
if (texture != statecache->texture) {
METAL_TextureData *oldtexturedata = NULL;
@@ -1296,6 +1309,7 @@ - (void)dealloc
}
statecache->texture = texture;
}
+ return SDL_TRUE;
}
static int
@@ -1393,6 +1407,7 @@ - (void)dealloc
MTLClearColor color = MTLClearColorMake(r / 255.0f, g / 255.0f, b / 255.0f, a / 255.0f);
// get new command encoder, set up with an initial clear operation.
+ // (this might fail, and future draw operations will notice.)
METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionClear, &color, mtlbufvertex);
break;
}
@@ -1401,8 +1416,9 @@ - (void)dealloc
case SDL_RENDERCMD_DRAW_LINES: {
const size_t count = cmd->data.draw.count;
const MTLPrimitiveType primtype = (cmd->command == SDL_RENDERCMD_DRAW_POINTS) ? MTLPrimitiveTypePoint : MTLPrimitiveTypeLineStrip;
- SetDrawState(renderer, cmd, SDL_METAL_FRAGMENT_SOLID, CONSTANTS_OFFSET_HALF_PIXEL_TRANSFORM, mtlbufvertex, &statecache);
- [data.mtlcmdencoder drawPrimitives:primtype vertexStart:0 vertexCount:count];
+ if (SetDrawState(renderer, cmd, SDL_METAL_FRAGMENT_SOLID, CONSTANTS_OFFSET_HALF_PIXEL_TRANSFORM, mtlbufvertex, &statecache)) {
+ [data.mtlcmdencoder drawPrimitives:primtype vertexStart:0 vertexCount:count];
+ }
break;
}
@@ -1420,11 +1436,13 @@ - (void)dealloc
SDL_Texture *texture = cmd->data.draw.texture;
if (texture) {
- SetCopyState(renderer, cmd, CONSTANTS_OFFSET_IDENTITY, mtlbufvertex, &statecache);
- [data.mtlcmdencoder drawPrimitives:MTLPrimitiveTypeTriangle vertexStart:0 vertexCount:count];
+ if (SetCopyState(renderer, cmd, CONSTANTS_OFFSET_IDENTITY, mtlbufvertex, &statecache)) {
+ [data.mtlcmdencoder drawPrimitives:MTLPrimitiveTypeTriangle vertexStart:0 vertexCount:count];
+ }
} else {
- SetDrawState(renderer, cmd, SDL_METAL_FRAGMENT_SOLID, CONSTANTS_OFFSET_IDENTITY, mtlbufvertex, &statecache);
- [data.mtlcmdencoder drawPrimitives:MTLPrimitiveTypeTriangle vertexStart:0 vertexCount:count];
+ if (SetDrawState(renderer, cmd, SDL_METAL_FRAGMENT_SOLID, CONSTANTS_OFFSET_IDENTITY, mtlbufvertex, &statecache)) {
+ [data.mtlcmdencoder drawPrimitives:MTLPrimitiveTypeTriangle vertexStart:0 vertexCount:count];
+ }
}
break;
}
@@ -1443,7 +1461,9 @@ - (void)dealloc
Uint32 pixel_format, void * pixels, int pitch)
{ @autoreleasepool {
METAL_RenderData *data = (__bridge METAL_RenderData *) renderer->driverdata;
- METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil);
+ if (!METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil)) {
+ return SDL_SetError("Failed to activate render command encoder (is your window in the background?");
+ }
[data.mtlcmdencoder endEncoding];
id<MTLTexture> mtltexture = data.mtlpassdesc.colorAttachments[0].texture;
@@ -1488,20 +1508,28 @@ - (void)dealloc
METAL_RenderPresent(SDL_Renderer * renderer)
{ @autoreleasepool {
METAL_RenderData *data = (__bridge METAL_RenderData *) renderer->driverdata;
+ SDL_bool ready = SDL_TRUE;
// If we don't have a command buffer, we can't present, so activate to get one.
if (data.mtlcmdencoder == nil) {
// We haven't even gotten a backbuffer yet? Clear it to black. Otherwise, load the existing data.
if (data.mtlbackbuffer == nil) {
MTLClearColor color = MTLClearColorMake(0.0f, 0.0f, 0.0f, 1.0f);
- METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionClear, &color, nil);
+ ready = METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionClear, &color, nil);
} else {
- METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil);
+ ready = METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil);
}
}
[data.mtlcmdencoder endEncoding];
- [data.mtlcmdbuffer presentDrawable:data.mtlbackbuffer];
+
+ // If we don't have a drawable to present, don't try to present it.
+ // But we'll still try to commit the command buffer in case it was already enqueued.
+ if (ready) {
+ SDL_assert(data.mtlbackbuffer != nil);
+ [data.mtlcmdbuffer presentDrawable:data.mtlbackbuffer];
+ }
+
[data.mtlcmdbuffer commit];
data.mtlcmdencoder = nil;
@@ -1544,6 +1572,9 @@ - (void)dealloc
static void *
METAL_GetMetalCommandEncoder(SDL_Renderer * renderer)
{ @autoreleasepool {
+ // note that data.mtlcmdencoder can be nil if METAL_ActivateRenderCommandEncoder fails.
+ // Before SDL 2.0.18, it might have returned a non-nil encoding that might not have been
+ // usable for presentation. Check your return values!
METAL_ActivateRenderCommandEncoder(renderer, MTLLoadActionLoad, NULL, nil);
METAL_RenderData *data = (__bridge METAL_RenderData *) renderer->driverdata;
return (__bridge void*)data.mtlcmdencoder;