From 32f49ebe974b1f14f9081196acceb95610949d5a Mon Sep 17 00:00:00 2001
From: Greg Wells <gregory@Gregs-MacBook-Pro.local>
Date: Thu, 29 May 2025 13:05:54 -0400
Subject: [PATCH] metal framebuffers

---
 .../src/core/framebuffers/metal_framebuffer.h |  8 ++
 .../src/core/framebuffers/metal_framebuffer.m | 74 +++++++++++++++++++
 src/utils/gryphn_error_code.h                 |  4 +-
 3 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 rendering_api/metal/src/core/framebuffers/metal_framebuffer.h
 create mode 100644 rendering_api/metal/src/core/framebuffers/metal_framebuffer.m

diff --git a/rendering_api/metal/src/core/framebuffers/metal_framebuffer.h b/rendering_api/metal/src/core/framebuffers/metal_framebuffer.h
new file mode 100644
index 0000000..519a6ad
--- /dev/null
+++ b/rendering_api/metal/src/core/framebuffers/metal_framebuffer.h
@@ -0,0 +1,8 @@
+#pragma once
+#include "core/framebuffer/gryphn_framebuffer.h"
+#import <Metal/Metal.h>
+#import <Metal/MTLRenderPass.h>
+
+typedef struct gnPlatformFramebuffer_t {
+    MTLRenderPassDescriptor* framebuffer;
+} gnPlatformFramebuffer;
diff --git a/rendering_api/metal/src/core/framebuffers/metal_framebuffer.m b/rendering_api/metal/src/core/framebuffers/metal_framebuffer.m
new file mode 100644
index 0000000..ad45fb1
--- /dev/null
+++ b/rendering_api/metal/src/core/framebuffers/metal_framebuffer.m
@@ -0,0 +1,74 @@
+#include "metal_framebuffer.h"
+#include "core/debugger/gryphn_debugger.h"
+#include "core/texture/metal_texture.h"
+
+gnBool isDepthFormat(gnImageFormat format) {
+    return gnFalse;
+}
+
+gnBool isStencilFormat(gnImageFormat format) {
+    return gnFalse;
+}
+
+MTLLoadAction mtlGryphnLoadOperation(enum gnLoadOperation_e loadOperation) {
+    switch(loadOperation) {
+    case GN_LOAD_OPERATION_LOAD: return MTLLoadActionLoad;
+    case GN_LOAD_OPERATION_CLEAR: return MTLLoadActionClear;
+    case GN_LOAD_OPERATION_DONT_CARE: return MTLLoadActionDontCare;
+    }
+}
+
+MTLStoreAction mtlGryphnStoreOperation(enum gnStoreOperation_e storeOperation) {
+    switch (storeOperation) {
+    case GN_STORE_OPERATION_STORE: return MTLStoreActionStore;
+    case GN_STORE_OPERATION_DONT_CARE: return MTLStoreActionDontCare;
+    }
+}
+
+gnReturnCode gnCreateFramebufferFn(struct gnFramebuffer_t* framebuffer, struct gnOutputDevice_t* device, struct gnFramebufferInfo_t info) {
+    framebuffer->framebuffer = malloc(sizeof(struct gnPlatformFramebuffer_t));
+    if (info.attachmentCount != info.renderPassDescriptor->info.attachmentCount) {
+        gnDebuggerSetErrorMessage(device->instance->debugger, (gnMessageData){
+            .message = gnCreateString("Attachment count on framebuffer does not equal attachment count on render pass descriptor")
+        });
+        return GN_DIVERGENT_RENDERPASS;
+    }
+
+    framebuffer->framebuffer->framebuffer = [[MTLRenderPassDescriptor alloc] init];
+    [framebuffer->framebuffer->framebuffer setRenderTargetWidth:info.size.x];
+    [framebuffer->framebuffer->framebuffer setRenderTargetHeight:info.size.y];
+
+    for (int i = 0; i < info.renderPassDescriptor->info.attachmentCount; i++) {
+        gnBool wasDepthStencil = gnFalse;
+        if (isDepthFormat(info.renderPassDescriptor->info.attachmentInfos[i].format)) {
+            gnDebuggerSetErrorMessage(device->instance->debugger, (gnMessageData){
+                .message = gnCreateString("Depth attachments are not currently supported in metal (get on this)")
+            });
+            wasDepthStencil = gnTrue;
+        }
+        if (isStencilFormat(info.renderPassDescriptor->info.attachmentInfos[i].format)) {
+            gnDebuggerSetErrorMessage(device->instance->debugger, (gnMessageData){
+                .message = gnCreateString("Stencil attachments are not currently supported in metal (get on this)")
+            });
+            wasDepthStencil = gnTrue;
+        }
+
+        if(!wasDepthStencil) {
+            MTLRenderPassColorAttachmentDescriptor* color = framebuffer->framebuffer->framebuffer.colorAttachments[i];
+            color.texture = info.attachments[i].texture->texture;
+
+            color.loadAction  = mtlGryphnLoadOperation(info.renderPassDescriptor->info.attachmentInfos[i].loadOperation);
+            color.storeAction = mtlGryphnStoreOperation(info.renderPassDescriptor->info.attachmentInfos[i].storeOperation);
+
+            if (color.loadAction == MTLLoadActionClear)
+                color.clearColor = MTLClearColorMake(0.0, 0.0, 0.0, 1.0);
+        }
+    }
+
+    return GN_SUCCESS;
+}
+
+void gnDestroyFramebufferFn(struct gnFramebuffer_t* framebuffer) {
+    [framebuffer->framebuffer->framebuffer release];
+    free(framebuffer->framebuffer);
+}
diff --git a/src/utils/gryphn_error_code.h b/src/utils/gryphn_error_code.h
index aed17a4..faa96ee 100644
--- a/src/utils/gryphn_error_code.h
+++ b/src/utils/gryphn_error_code.h
@@ -25,7 +25,8 @@ typedef enum gnReturnCode_t {
     GN_FAILED_TO_CREATE_GRAPHICS_PIPELINE,
     GN_UNSUPPORTED_SHADER_MODULE,
     GN_UNKNOWN_SUBPASS,
-    GN_FAILED_TO_CREATE_FRAMEBUFFER
+    GN_FAILED_TO_CREATE_FRAMEBUFFER,
+    GN_DIVERGENT_RENDERPASS
 } gnReturnCode;
 
 typedef gnReturnCode gnErrorCode;
@@ -56,5 +57,6 @@ static const char* gnErrorCodeToCString(enum gnReturnCode_t returnCode) {
     case GN_UNSUPPORTED_SHADER_MODULE: return "GN_UNSUPPORTED_SHADER_MODULE";
     case GN_UNKNOWN_SUBPASS: return "GN_UNKNOWN_SUBPASS";
     case GN_FAILED_TO_CREATE_FRAMEBUFFER: return "GN_FAILED_TO_CREATE_FRAMEBUFFER";
+    case GN_DIVERGENT_RENDERPASS: return "GN_DIVERGENT_RENDERPASS";
     }
 }