From 94106858075e77e1b94de2bc6ceab1144146e8b1 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <mclaughc@outlook.com>
Date: Wed, 23 Oct 2019 00:35:08 +1000
Subject: [PATCH] Common: Optionally create framebuffer with GL textures

---
 src/common/gl_texture.cpp | 20 +++++++++++++++++++-
 src/common/gl_texture.h   |  9 ++++++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/common/gl_texture.cpp b/src/common/gl_texture.cpp
index b08072015..efcd2aeb2 100644
--- a/src/common/gl_texture.cpp
+++ b/src/common/gl_texture.cpp
@@ -1,11 +1,12 @@
 #include "gl_texture.h"
+#include "YBaseLib/Assert.h"
 #include "YBaseLib/Log.h"
 Log_SetChannel(GL);
 
 namespace GL {
 
 Texture::Texture(u32 width, u32 height, GLenum format, GLenum type, const void* data /* = nullptr */,
-                 bool linear_filter /* = false */)
+                 bool linear_filter /* = false */, bool create_framebuffer /* = false */)
   : m_width(width), m_height(height)
 {
   glGenTextures(1, &m_id);
@@ -14,10 +15,21 @@ Texture::Texture(u32 width, u32 height, GLenum format, GLenum type, const void*
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, linear_filter ? GL_LINEAR : GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, linear_filter ? GL_LINEAR : GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
+
+  if (create_framebuffer)
+  {
+    glGenFramebuffers(1, &m_fbo_id);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_fbo_id);
+    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_id, 0);
+    Assert(glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
+  }
 }
 
 Texture::~Texture()
 {
+  if (m_fbo_id != 0)
+    glDeleteFramebuffers(1, &m_fbo_id);
+
   glDeleteTextures(1, &m_id);
 }
 
@@ -26,6 +38,12 @@ void Texture::Bind()
   glBindTexture(GL_TEXTURE_2D, m_id);
 }
 
+void Texture::BindFramebuffer(GLenum target /*= GL_DRAW_FRAMEBUFFER*/)
+{
+  DebugAssert(m_fbo_id != 0);
+  glBindFramebuffer(target, m_fbo_id);
+}
+
 void Texture::Unbind()
 {
   glBindTexture(GL_TEXTURE_2D, 0);
diff --git a/src/common/gl_texture.h b/src/common/gl_texture.h
index 4e9bc34b3..638f33079 100644
--- a/src/common/gl_texture.h
+++ b/src/common/gl_texture.h
@@ -6,20 +6,27 @@ namespace GL {
 class Texture
 {
 public:
-  Texture(u32 width, u32 height, GLenum format, GLenum type, const void* data = nullptr, bool linear_filter = false);
+  Texture(u32 width, u32 height, GLenum format, GLenum type, const void* data = nullptr, bool linear_filter = false,
+          bool create_framebuffer = false);
   ~Texture();
 
   GLuint GetGLId() const { return m_id; }
   u32 GetWidth() const { return m_width; }
   u32 GetHeight() const { return m_height; }
 
+  GLuint GetGLFramebufferID() const { return m_fbo_id; }
+
   void Bind();
+  void BindFramebuffer(GLenum target = GL_DRAW_FRAMEBUFFER);
+
   static void Unbind();
 
 private:
   GLuint m_id;
   u32 m_width;
   u32 m_height;
+
+  GLuint m_fbo_id = 0;
 };
 
 } // namespace GL
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