Give passes a weak back-reference to their CommandBuffer

CopyPass, RenderPass, and ComputePass each now hold a non-retaining
CommandBuffer *cmd. CopyPass::uploadData uses self->cmd->device->device
for the SDL device instead of a directly threaded SDL_GPUDevice *.

- Eliminates the SDL_GPUDevice * field on CopyPass
- All three init signatures: init(self, pass, cmd)
- CommandBuffer::begin*Pass passes (CommandBuffer *)self at construction
- Consistent hierarchy: Pass → CommandBuffer → RenderDevice → SDL_GPUDevice

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jdolan

Sources/ObjectivelyGPU/CommandBuffer.c

@@ -57,7 +57,7 @@ static ComputePass *beginComputePass(const CommandBuffer *self, const SDL_GPUSto
   SDL_GPUComputePass *pass = SDL_BeginGPUComputePass(self->cmd, storageTextures, numStorageTextures, storageBuffers, numStorageBuffers);
   GPU_Assert(pass, "SDL_BeginGPUComputePass");
 
-  return $(alloc(ComputePass), init, pass);
+  return $(alloc(ComputePass), init, pass, (CommandBuffer *) self);
 }
 
 /**
@@ -69,7 +69,7 @@ static CopyPass *beginCopyPass(const CommandBuffer *self) {
   SDL_GPUCopyPass *pass = SDL_BeginGPUCopyPass(self->cmd);
   GPU_Assert(pass, "SDL_BeginGPUCopyPass");
 
-  return $(alloc(CopyPass), init, pass, self->device->device);
+  return $(alloc(CopyPass), init, pass, (CommandBuffer *) self);
 }
 
 /**
@@ -81,7 +81,7 @@ static RenderPass *beginRenderPass(const CommandBuffer *self, const SDL_GPUColor
   SDL_GPURenderPass *pass = SDL_BeginGPURenderPass(self->cmd, colorTargets, numColorTargets, depthStencil);
   GPU_Assert(pass, "SDL_BeginGPURenderPass");
 
-  return $(alloc(RenderPass), init, pass);
+  return $(alloc(RenderPass), init, pass, (CommandBuffer *) self);
 }
 
 /**

Sources/ObjectivelyGPU/ComputePass.c

@@ -23,6 +23,7 @@
 
 #include <assert.h>
 
+#include "CommandBuffer.h"
 #include "ComputePass.h"
 
 #define _Class _ComputePass
@@ -93,15 +94,17 @@ static void dispatchComputeIndirect(const ComputePass *self, SDL_GPUBuffer *buff
 }
 
 /**
- * @fn ComputePass *ComputePass::init(ComputePass *self, SDL_GPUComputePass *pass)
+ * @fn ComputePass *ComputePass::init(ComputePass *self, SDL_GPUComputePass *pass, CommandBuffer *cmd)
  * @memberof ComputePass
  */
-static ComputePass *init(ComputePass *self, SDL_GPUComputePass *pass) {
+static ComputePass *init(ComputePass *self, SDL_GPUComputePass *pass, CommandBuffer *cmd) {
 
   self = (ComputePass *) super(Object, self, init);
   if (self) {
     self->pass = pass;
     assert(self->pass);
+    self->cmd = cmd;
+    assert(self->cmd);
   }
 
   return self;

Sources/ObjectivelyGPU/ComputePass.h

@@ -32,6 +32,7 @@
  * @brief ComputePass wraps an `SDL_GPUComputePass` for recording compute dispatches.
  */
 
+typedef struct CommandBuffer CommandBuffer;
 typedef struct ComputePass ComputePass;
 typedef struct ComputePassInterface ComputePassInterface;
 
@@ -64,6 +65,12 @@ struct ComputePass {
    */
   ComputePassInterface *interface;
 
+  /**
+   * @brief The CommandBuffer this pass was begun from.
+   * @private
+   */
+  CommandBuffer *cmd;
+
   /**
    * @brief The underlying SDL compute pass.
    * @details Set to NULL by `dealloc` after `SDL_EndGPUComputePass` is called.
@@ -129,14 +136,15 @@ struct ComputePassInterface {
   void (*dispatchComputeIndirect)(const ComputePass *self, SDL_GPUBuffer *buffer, Uint32 offset);
 
   /**
-   * @fn ComputePass *ComputePass::init(ComputePass *self, SDL_GPUComputePass *pass)
+   * @fn ComputePass *ComputePass::init(ComputePass *self, SDL_GPUComputePass *pass, CommandBuffer *cmd)
    * @brief Initializes this ComputePass wrapping the given SDL compute pass.
    * @param self The ComputePass.
    * @param pass The SDL compute pass to wrap. Must not be NULL.
+   * @param cmd The CommandBuffer this pass was begun from.
    * @return The initialized ComputePass, or NULL on failure.
    * @memberof ComputePass
    */
-  ComputePass *(*init)(ComputePass *self, SDL_GPUComputePass *pass);
+  ComputePass *(*init)(ComputePass *self, SDL_GPUComputePass *pass, CommandBuffer *cmd);
 };
 
 /**

Sources/ObjectivelyGPU/CopyPass.c

@@ -24,7 +24,9 @@
 #include <assert.h>
 #include <string.h>
 
+#include "CommandBuffer.h"
 #include "CopyPass.h"
+#include "RenderDevice.h"
 
 #define _Class _CopyPass
 
@@ -78,17 +80,17 @@ static void downloadTexture(const CopyPass *self, const SDL_GPUTextureRegion *sr
 }
 
 /**
- * @fn CopyPass *CopyPass::init(CopyPass *self, SDL_GPUCopyPass *pass, SDL_GPUDevice *device)
+ * @fn CopyPass *CopyPass::init(CopyPass *self, SDL_GPUCopyPass *pass, CommandBuffer *cmd)
  * @memberof CopyPass
  */
-static CopyPass *init(CopyPass *self, SDL_GPUCopyPass *pass, SDL_GPUDevice *device) {
+static CopyPass *init(CopyPass *self, SDL_GPUCopyPass *pass, CommandBuffer *cmd) {
 
   self = (CopyPass *) super(Object, self, init);
   if (self) {
     self->pass = pass;
     assert(self->pass);
-    self->device = device;
-    assert(self->device);
+    self->cmd = cmd;
+    assert(self->cmd);
   }
 
   return self;
@@ -112,24 +114,24 @@ static void uploadData(const CopyPass *self, SDL_GPUBuffer *dst, const void *dat
   assert(data);
   assert(size);
 
-  SDL_GPUTransferBuffer *tbuf = SDL_CreateGPUTransferBuffer(self->device, &(SDL_GPUTransferBufferCreateInfo) {
+  SDL_GPUTransferBuffer *tbuf = SDL_CreateGPUTransferBuffer(self->cmd->device->device, &(SDL_GPUTransferBufferCreateInfo) {
     .usage = SDL_GPU_TRANSFERBUFFERUSAGE_UPLOAD,
     .size = size,
   });
   GPU_Assert(tbuf, "SDL_CreateGPUTransferBuffer");
 
-  void *mapped = SDL_MapGPUTransferBuffer(self->device, tbuf, cycle);
+  void *mapped = SDL_MapGPUTransferBuffer(self->cmd->device->device, tbuf, cycle);
   GPU_Assert(mapped, "SDL_MapGPUTransferBuffer");
 
   memcpy(mapped, data, size);
-  SDL_UnmapGPUTransferBuffer(self->device, tbuf);
+  SDL_UnmapGPUTransferBuffer(self->cmd->device->device, tbuf);
 
   SDL_UploadToGPUBuffer(self->pass,
     &(SDL_GPUTransferBufferLocation) { .transfer_buffer = tbuf },
     &(SDL_GPUBufferRegion) { .buffer = dst, .offset = offset, .size = size },
     cycle);
 
-  SDL_ReleaseGPUTransferBuffer(self->device, tbuf);
+  SDL_ReleaseGPUTransferBuffer(self->cmd->device->device, tbuf);
 }
 
 /**

Sources/ObjectivelyGPU/CopyPass.h

@@ -32,6 +32,7 @@
  * @brief CopyPass wraps an `SDL_GPUCopyPass` for uploading and copying GPU resources.
  */
 
+typedef struct CommandBuffer CommandBuffer;
 typedef struct CopyPass CopyPass;
 typedef struct CopyPassInterface CopyPassInterface;
 
@@ -71,10 +72,10 @@ struct CopyPass {
   SDL_GPUCopyPass *pass;
 
   /**
-   * @brief The GPU device, used by `uploadData` to manage transfer buffers.
+   * @brief The CommandBuffer this pass was begun from.
    * @private
    */
-  SDL_GPUDevice *device;
+  CommandBuffer *cmd;
 };
 
 /**
@@ -116,15 +117,15 @@ struct CopyPassInterface {
   void (*downloadTexture)(const CopyPass *self, const SDL_GPUTextureRegion *src, const SDL_GPUTextureTransferInfo *dst);
 
   /**
-   * @fn CopyPass *CopyPass::init(CopyPass *self, SDL_GPUCopyPass *pass, SDL_GPUDevice *device)
+   * @fn CopyPass *CopyPass::init(CopyPass *self, SDL_GPUCopyPass *pass, CommandBuffer *cmd)
    * @brief Initializes this CopyPass wrapping the given SDL copy pass.
    * @param self The CopyPass.
    * @param pass The SDL copy pass to wrap. Must not be NULL.
-   * @param device The SDL GPU device, used by `uploadData` to manage transfer buffers.
+   * @param cmd The CommandBuffer this pass was begun from.
    * @return The initialized CopyPass, or NULL on failure.
    * @memberof CopyPass
    */
-  CopyPass *(*init)(CopyPass *self, SDL_GPUCopyPass *pass, SDL_GPUDevice *device);
+  CopyPass *(*init)(CopyPass *self, SDL_GPUCopyPass *pass, CommandBuffer *cmd);
 
   /**
    * @fn void CopyPass::uploadBuffer(const CopyPass *self, const SDL_GPUTransferBufferLocation *src, const SDL_GPUBufferRegion *dst, bool cycle)

Sources/ObjectivelyGPU/RenderPass.c

@@ -23,6 +23,7 @@
 
 #include <assert.h>
 
+#include "CommandBuffer.h"
 #include "RenderPass.h"
 
 #define _Class _RenderPass
@@ -150,15 +151,17 @@ static void drawPrimitivesIndirect(const RenderPass *self, SDL_GPUBuffer *buffer
 }
 
 /**
- * @fn RenderPass *RenderPass::init(RenderPass *self, SDL_GPURenderPass *pass)
+ * @fn RenderPass *RenderPass::init(RenderPass *self, SDL_GPURenderPass *pass, CommandBuffer *cmd)
  * @memberof RenderPass
  */
-static RenderPass *init(RenderPass *self, SDL_GPURenderPass *pass) {
+static RenderPass *init(RenderPass *self, SDL_GPURenderPass *pass, CommandBuffer *cmd) {
 
   self = (RenderPass *) super(Object, self, init);
   if (self) {
     self->pass = pass;
     assert(self->pass);
+    self->cmd = cmd;
+    assert(self->cmd);
   }
 
   return self;

Sources/ObjectivelyGPU/RenderPass.h

@@ -32,6 +32,7 @@
  * @brief RenderPass wraps an `SDL_GPURenderPass` for recording draw commands.
  */
 
+typedef struct CommandBuffer CommandBuffer;
 typedef struct RenderPass RenderPass;
 typedef struct RenderPassInterface RenderPassInterface;
 
@@ -64,6 +65,12 @@ struct RenderPass {
    */
   RenderPassInterface *interface;
 
+  /**
+   * @brief The CommandBuffer this pass was begun from.
+   * @private
+   */
+  CommandBuffer *cmd;
+
   /**
    * @brief When true, the render pass clears to @c clear_color before drawing.
    * @details Defaults to `true` (clear to opaque black).
@@ -186,14 +193,15 @@ struct RenderPassInterface {
   void (*drawPrimitivesIndirect)(const RenderPass *self, SDL_GPUBuffer *buffer, Uint32 offset, Uint32 drawCount);
 
   /**
-   * @fn RenderPass *RenderPass::init(RenderPass *self, SDL_GPURenderPass *pass)
+   * @fn RenderPass *RenderPass::init(RenderPass *self, SDL_GPURenderPass *pass, CommandBuffer *cmd)
    * @brief Initializes this RenderPass wrapping the given SDL render pass.
    * @param self The RenderPass.
    * @param pass The SDL render pass to wrap. Must not be NULL.
+   * @param cmd The CommandBuffer this pass was begun from.
    * @return The initialized RenderPass, or NULL on failure.
    * @memberof RenderPass
    */
-  RenderPass *(*init)(RenderPass *self, SDL_GPURenderPass *pass);
+  RenderPass *(*init)(RenderPass *self, SDL_GPURenderPass *pass, CommandBuffer *cmd);
 
   /**
    * @fn void RenderPass::setBlendConstants(const RenderPass *self, SDL_FColor blendConstants)