From 916df68f067cc4ebf9c31f43d515c7c2d8464dfe Mon Sep 17 00:00:00 2001
From: Gregory Wells <me@gregorywells.dev>
Date: Mon, 18 Aug 2025 21:13:40 -0400
Subject: [PATCH] OpenGL framebuffer API

---
 .../apis/opengl/loader/opengl_device_loader.c |  5 +--
 .../src/framebuffer/opengl_framebuffer.c      | 35 +++++++++++++++++++
 .../src/framebuffer/opengl_framebuffer.h      | 11 ++++++
 3 files changed, 49 insertions(+), 2 deletions(-)
 create mode 100644 projects/apis/opengl/src/framebuffer/opengl_framebuffer.c
 create mode 100644 projects/apis/opengl/src/framebuffer/opengl_framebuffer.h

diff --git a/projects/apis/opengl/loader/opengl_device_loader.c b/projects/apis/opengl/loader/opengl_device_loader.c
index d3edbce..8828c8a 100644
--- a/projects/apis/opengl/loader/opengl_device_loader.c
+++ b/projects/apis/opengl/loader/opengl_device_loader.c
@@ -8,6 +8,7 @@
 #include "commands/pool/opengl_command_pool.h"
 #include "buffer/opengl_buffer.h"
 #include "textures/opengl_texture.h"
+#include "framebuffer/opengl_framebuffer.h"
 
 gnDeviceFunctions loadOpenGLDeviceFunctions() {
     return (gnDeviceFunctions){
@@ -24,8 +25,8 @@ gnDeviceFunctions loadOpenGLDeviceFunctions() {
         ._gnCreateGraphicsPipeline = NULL,
         ._gnDestroyGraphicsPipeline = NULL,
 
-        ._gnCreateFramebuffer = NULL,
-        ._gnDestroyFramebuffer = NULL,
+        ._gnCreateFramebuffer = openglCreateFramebuffer,
+        ._gnDestroyFramebuffer = openglDestroyFramebuffer,
 
         ._gnCreateCommandPool = openglCreateCommandPool,
         ._gnDestroyCommandPool = openglDestroyCommandPool,
diff --git a/projects/apis/opengl/src/framebuffer/opengl_framebuffer.c b/projects/apis/opengl/src/framebuffer/opengl_framebuffer.c
new file mode 100644
index 0000000..feac3b7
--- /dev/null
+++ b/projects/apis/opengl/src/framebuffer/opengl_framebuffer.c
@@ -0,0 +1,35 @@
+#include "opengl_framebuffer.h"
+#include "stdlib.h"
+#include "renderpass/opengl_render_pass_descriptor.h"
+#include "textures/opengl_texture.h"
+#include "stdio.h"
+#include "core/src/output_device/gryphn_output_device.h"
+#include "core/src/instance/gryphn_instance.h"
+
+gnReturnCode openglCreateFramebuffer(gnFramebuffer framebuffer, gnDevice device, gnFramebufferInfo info) {
+    framebuffer->framebuffer = malloc(sizeof(struct gnPlatformFramebuffer_t));
+    framebuffer->framebuffer->framebufferCount = info.renderPassDescriptor->renderPassDescriptor->subpassCount;
+    framebuffer->framebuffer->framebuffers = malloc(sizeof(GLuint) * info.renderPassDescriptor->renderPassDescriptor->subpassCount);
+    for (int i = 0; i < info.renderPassDescriptor->renderPassDescriptor->subpassCount; i++) {
+        glCreateFramebuffers(1, &framebuffer->framebuffer->framebuffers[i]);
+        for (int c = 0; c < info.renderPassDescriptor->renderPassDescriptor->subpasses[i].colorAttachmentCount; c++)
+            glNamedFramebufferTexture(framebuffer->framebuffer->framebuffers[i], GL_COLOR_ATTACHMENT0 + c, info.attachments[info.renderPassDescriptor->renderPassDescriptor->subpasses[i].colorAttachments[c].attachmentIndex]->texture->id, 0);
+        if (info.renderPassDescriptor->renderPassDescriptor->subpasses[i].depthAttachment.index >= 0)
+            glNamedFramebufferTexture(framebuffer->framebuffer->framebuffers[i], GL_DEPTH_STENCIL_ATTACHMENT, info.attachments[info.renderPassDescriptor->renderPassDescriptor->subpasses[i].depthAttachment.index]->texture->id, 0);
+        if (glCheckNamedFramebufferStatus(framebuffer->framebuffer->framebuffers[i], GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+            char string[500];
+            snprintf(string, 500, "Failed to create OpenGL framebuffer: 0x%x\n", glCheckNamedFramebufferStatus(framebuffer->framebuffer->framebuffers[i], GL_FRAMEBUFFER));
+            gnDebuggerSetErrorMessage(framebuffer->device->instance->debugger, (gnMessageData){
+                .message = gnCreateString(string)
+            });
+            return GN_FAILED_CREATE_OBJECT;
+        }
+
+    }
+    return GN_SUCCESS;
+}
+void openglDestroyFramebuffer(gnFramebuffer framebuffer) {
+    for (int i = 0; i < framebuffer->framebuffer->framebufferCount; i++)
+        glDeleteFramebuffers(1, &framebuffer->framebuffer->framebuffers[i]);
+    free(framebuffer->framebuffer);
+}
diff --git a/projects/apis/opengl/src/framebuffer/opengl_framebuffer.h b/projects/apis/opengl/src/framebuffer/opengl_framebuffer.h
new file mode 100644
index 0000000..5f8f4dc
--- /dev/null
+++ b/projects/apis/opengl/src/framebuffer/opengl_framebuffer.h
@@ -0,0 +1,11 @@
+#pragma once
+#include "glad/glad.h"
+#include "core/src/framebuffer/gryphn_framebuffer.h"
+
+typedef struct gnPlatformFramebuffer_t {
+    uint32_t framebufferCount;
+    GLuint* framebuffers;
+} gnPlatformFramebuffer_t;
+
+gnReturnCode openglCreateFramebuffer(gnFramebuffer framebuffer, gnDevice device, gnFramebufferInfo info);
+void openglDestroyFramebuffer(gnFramebuffer framebuffer);