metal: Don't try to create a zero-byte vertex buffer.

(Which will cause a crash in Metal, or an assert in the validation layer.)
This commit is contained in:
Ryan C. Gordon 2018-10-04 20:21:23 -04:00
parent 1ecf4dfc5f
commit 638d624f5a

View file

@ -1052,6 +1052,7 @@ METAL_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *ver
{ @autoreleasepool {
METAL_RenderData *data = (__bridge METAL_RenderData *) renderer->driverdata;
METAL_DrawStateCache statecache;
id<MTLBuffer> mtlbufvertex = nil;
statecache.pipeline = nil;
statecache.constants_offset = CONSTANTS_OFFSET_INVALID;
@ -1063,24 +1064,26 @@ METAL_RunCommandQueue(SDL_Renderer * renderer, SDL_RenderCommand *cmd, void *ver
statecache.color_offset = 0;
// !!! FIXME: have a ring of pre-made MTLBuffers we cycle through? How expensive is creation?
id<MTLBuffer> mtlbufvertexstaging = [data.mtldevice newBufferWithLength:vertsize options:MTLResourceStorageModeShared];
#if !__has_feature(objc_arc)
[mtlbufvertexstaging autorelease];
#endif
mtlbufvertexstaging.label = @"SDL vertex staging data";
SDL_memcpy([mtlbufvertexstaging contents], vertices, vertsize);
if (vertsize > 0) {
id<MTLBuffer> mtlbufvertexstaging = [data.mtldevice newBufferWithLength:vertsize options:MTLResourceStorageModeShared];
#if !__has_feature(objc_arc)
[mtlbufvertexstaging autorelease];
#endif
mtlbufvertexstaging.label = @"SDL vertex staging data";
SDL_memcpy([mtlbufvertexstaging contents], vertices, vertsize);
// Move our new vertex buffer from system RAM to GPU memory so any draw calls can use it.
id<MTLBuffer> mtlbufvertex = [data.mtldevice newBufferWithLength:vertsize options:MTLResourceStorageModePrivate];
#if !__has_feature(objc_arc)
[mtlbufvertex autorelease];
#endif
mtlbufvertex.label = @"SDL vertex data";
id<MTLCommandBuffer> cmdbuffer = [data.mtlcmdqueue commandBuffer];
id<MTLBlitCommandEncoder> blitcmd = [cmdbuffer blitCommandEncoder];
[blitcmd copyFromBuffer:mtlbufvertexstaging sourceOffset:0 toBuffer:mtlbufvertex destinationOffset:0 size:vertsize];
[blitcmd endEncoding];
[cmdbuffer commit];
// Move our new vertex buffer from system RAM to GPU memory so any draw calls can use it.
mtlbufvertex = [data.mtldevice newBufferWithLength:vertsize options:MTLResourceStorageModePrivate];
#if !__has_feature(objc_arc)
[mtlbufvertex autorelease];
#endif
mtlbufvertex.label = @"SDL vertex data";
id<MTLCommandBuffer> cmdbuffer = [data.mtlcmdqueue commandBuffer];
id<MTLBlitCommandEncoder> blitcmd = [cmdbuffer blitCommandEncoder];
[blitcmd copyFromBuffer:mtlbufvertexstaging sourceOffset:0 toBuffer:mtlbufvertex destinationOffset:0 size:vertsize];
[blitcmd endEncoding];
[cmdbuffer commit];
}
// If there's a command buffer here unexpectedly (app requested one?). Commit it so we can start fresh.
[data.mtlcmdencoder endEncoding];