From e9e36229633164c1133915c4fe73469fae6b65ab Mon Sep 17 00:00:00 2001
From: Brett <brettmaster1@gmail.com>
Date: Tue, 16 Apr 2024 16:07:46 -0400
Subject: [PATCH] framebuffers

---
 CMakeLists.txt                |   2 +-
 README.md                     |   8 ++-
 examples/basic/basic.cpp      |   4 +-
 include/blt/gfx/framebuffer.h |  73 ++++++++++++++++++++++--
 include/blt/gfx/model.h       |   2 +-
 include/blt/gfx/texture.h     |  16 +++++-
 include/blt/gfx/window.h      |   8 +--
 src/blt/gfx/framebuffer.cpp   | 102 ++++++++++++++++++++++++++++++++--
 src/blt/gfx/model.cpp         |   3 +-
 src/blt/gfx/window.cpp        |   6 +-
 10 files changed, 200 insertions(+), 24 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0b998ea..9aac8ba 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.25)
 
-set(BLT_GRAPHICS_VERSION 0.9.13)
+set(BLT_GRAPHICS_VERSION 0.9.14)
 set(BLT_GRAPHICS_TEST_VERSION 0.0.1)
 
 project(BLT_WITH_GRAPHICS VERSION ${BLT_GRAPHICS_VERSION})
diff --git a/README.md b/README.md
index 9803eb3..7cab401 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,9 @@
 # BLT-With-Graphics-Template
 
-BLT + Graphics + Emscripten
\ No newline at end of file
+BLT + Graphics + Emscripten
+
+TODO: some of the API is inconsistent.
+
+Textures bind themselves but FBOs do not.
+
+make more use of factory functions
\ No newline at end of file
diff --git a/examples/basic/basic.cpp b/examples/basic/basic.cpp
index 9deb172..5d6b2d3 100644
--- a/examples/basic/basic.cpp
+++ b/examples/basic/basic.cpp
@@ -25,7 +25,7 @@ blt::gfx::resource_manager resources;
 blt::gfx::batch_renderer_2d renderer_2d(resources);
 blt::gfx::first_person_camera camera;
 
-void init(blt::gfx::window_context& context)
+void init(const blt::gfx::window_context& context)
 {
     using namespace blt::gfx;
     
@@ -35,7 +35,7 @@ void init(blt::gfx::window_context& context)
     renderer_2d.create();
 }
 
-void update(blt::gfx::window_context& context, std::int32_t width, std::int32_t height)
+void update(const blt::gfx::window_context& context, std::int32_t width, std::int32_t height)
 {
     global_matrices.update_perspectives(width, height, 90, 0.1, 2000);
     
diff --git a/include/blt/gfx/framebuffer.h b/include/blt/gfx/framebuffer.h
index 3c75463..e60f09a 100644
--- a/include/blt/gfx/framebuffer.h
+++ b/include/blt/gfx/framebuffer.h
@@ -20,31 +20,94 @@
 #define BLT_WITH_GRAPHICS_FRAMEBUFFER_H
 
 #include "blt/gfx/gl_includes.h"
+#include <blt/gfx/texture.h>
+#include <vector>
+#include "blt/std/types.h"
 
 namespace blt::gfx
 {
+
+#define C(num) COLOR##num = GL_COLOR_ATTACHMENT##num,
+
+#define COLOR_LIST \
+    C(0) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14) C(15) C(16) \
+    C(17) C(18) C(19) C(20) C(21) C(22) C(23) C(24) C(25) C(26) C(27) C(28) C(29) C(30) C(31)
+    
+    class fbo_t;
+    
+    class rbo_t
+    {
+            friend fbo_t;
+        private:
+            GLuint rboID;
+            GLuint storage_type;
+        public:
+            rbo_t(): rboID(0), storage_type(0)
+            {}
+            
+            void create();
+            
+            void bind() const;
+            
+            void setStorage(GLuint storage_type, blt::i32 width, blt::i32 height);
+            
+            void updateStorage(blt::i32 width, blt::i32 height) const;
+            
+            static void unbind();
+            
+            void destroy();
+            
+            static rbo_t make_render_buffer(GLuint storage_type, blt::i32 width, blt::i32 height);
+    };
+    
     class fbo_t
     {
         public:
-            enum class fbo_draw_t : GLuint
+            enum class draw_t : GLuint
             {
                 DRAW = GL_DRAW_FRAMEBUFFER,
                 READ = GL_READ_FRAMEBUFFER,
                 BOTH = GL_FRAMEBUFFER
             };
+            enum class attachment_t : GLuint
+            {
+                COLOR_LIST
+                DEPTH_STENCIL = GL_DEPTH_STENCIL_ATTACHMENT,
+                DEPTH = GL_DEPTH_ATTACHMENT,
+                STENCIL = GL_STENCIL_ATTACHMENT
+            };
+        
         private:
-            GLuint fboID;
+            GLuint fboID = 0;
+            GLuint generic_bind_type = GL_FRAMEBUFFER;
+            std::vector<blt::gfx::texture_gl*> texture_buffers;
+            std::vector<rbo_t> render_buffers;
         public:
-            void create();
+            // default used for fbo binding
+            void create(draw_t bind_type = draw_t::BOTH);
             
-            void bind(fbo_draw_t type = fbo_draw_t::BOTH) const;
+            void bind(draw_t type = draw_t::BOTH) const;
             
-            bool validate();
+            // this function takes ownership of the pointer.
+            void attachTexture(blt::gfx::texture_gl* texture, attachment_t attachment, int level = 0);
+            
+            void updateBuffersStorage(blt::i32 width, blt::i32 height);
+            
+            // this function takes ownership of the render buffer
+            void attachRenderBuffer(rbo_t rbo, attachment_t attachment);
+            
+            static bool validate();
             
             static void unbind();
             
             void destroy();
+        
+        public:
+            static fbo_t make_render_texture(blt::i32 width, blt::i32 height);
     };
+
+#undef C
+#undef COLOR_LIST
 }
 
 #endif //BLT_WITH_GRAPHICS_FRAMEBUFFER_H
diff --git a/include/blt/gfx/model.h b/include/blt/gfx/model.h
index 53db22a..f82ebc3 100644
--- a/include/blt/gfx/model.h
+++ b/include/blt/gfx/model.h
@@ -227,7 +227,7 @@ namespace blt::gfx
                 glBindVertexArray(0);
             }
             
-            static inline std::shared_ptr<vbo_t_owner> createSharedVBO(const vbo_t& vbo)
+            static inline static_dynamic_array::vbo_type createSharedVBO(const vbo_t& vbo)
             {
                 return std::make_shared<vbo_t_owner>(vbo);
             }
diff --git a/include/blt/gfx/texture.h b/include/blt/gfx/texture.h
index 82f02b5..6020451 100644
--- a/include/blt/gfx/texture.h
+++ b/include/blt/gfx/texture.h
@@ -24,6 +24,7 @@
 #include <string>
 #include <vector>
 #include <utility>
+#include "blt/std/types.h"
 
 namespace blt::gfx
 {
@@ -157,6 +158,14 @@ namespace blt::gfx
                 return textureID;
             }
             
+            [[nodiscard]] inline GLint getBindType() const
+            {
+                return textureBindType;
+            }
+            
+            virtual void updateSize(blt::i32, blt::i32)
+            {}
+            
             virtual ~texture_gl()
             {
                 glDeleteTextures(1, &textureID);
@@ -177,10 +186,15 @@ namespace blt::gfx
             
             void upload(const texture_data& file_data) const;
             
+            inline void updateSize(blt::i32 width, blt::i32 height) final
+            {
+                resize(width, height);
+            }
+            
             /**
              * Resizes the internal memory for the texture but does NOT resize the texture image stored
              */
-            inline void resize(int width, int height);
+            void resize(int width, int height);
     };
     
     struct gl_texture2D_array : public texture_gl
diff --git a/include/blt/gfx/window.h b/include/blt/gfx/window.h
index df2a758..44bc732 100644
--- a/include/blt/gfx/window.h
+++ b/include/blt/gfx/window.h
@@ -31,14 +31,14 @@ namespace blt::gfx
         std::string title;
         std::int32_t width;
         std::int32_t height;
-        std::function<void(window_context&)> init;
-        std::function<void(window_context&, std::int32_t, std::int32_t)> update;
+        std::function<void(const window_context&)> init;
+        std::function<void(const window_context&, std::int32_t, std::int32_t)> update;
         
         window_context context{};
         std::int32_t sync_interval = 0;
         
-        window_data(std::string title, std::function<void(window_context&)> init,
-                    std::function<void(window_context&, std::int32_t, std::int32_t)> update, std::int32_t width = 640,
+        window_data(std::string title, std::function<void(const window_context&)> init,
+                    std::function<void(const window_context&, std::int32_t, std::int32_t)> update, std::int32_t width = 640,
                     std::int32_t height = 480):
                 title(std::move(title)), width(width), height(height), init(std::move(init)), update(std::move(update))
         {}
diff --git a/src/blt/gfx/framebuffer.cpp b/src/blt/gfx/framebuffer.cpp
index a82e647..65caba8 100644
--- a/src/blt/gfx/framebuffer.cpp
+++ b/src/blt/gfx/framebuffer.cpp
@@ -18,13 +18,54 @@
 
 namespace blt::gfx
 {
-    
-    void fbo_t::create()
+    void rbo_t::create()
     {
+        glGenRenderbuffers(1, &rboID);
+    }
+    
+    void rbo_t::bind() const
+    {
+        glBindRenderbuffer(GL_RENDERBUFFER, rboID);
+    }
+    
+    void rbo_t::unbind()
+    {
+        glBindRenderbuffer(GL_RENDERBUFFER, 0);
+    }
+    
+    void rbo_t::destroy()
+    {
+        glDeleteRenderbuffers(1, &rboID);
+    }
+    
+    void rbo_t::updateStorage(blt::i32 width, blt::i32 height) const
+    {
+        glRenderbufferStorage(GL_RENDERBUFFER, storage_type, width, height);
+    }
+    
+    void rbo_t::setStorage(GLuint s_type, blt::i32 width, blt::i32 height)
+    {
+        storage_type = s_type;
+        updateStorage(width, height);
+    }
+    
+    rbo_t rbo_t::make_render_buffer(GLuint storage_type, blt::i32 width, blt::i32 height)
+    {
+        rbo_t rbo{};
+        rbo.create();
+        rbo.bind();
+        rbo.setStorage(storage_type, width, height);
+        rbo_t::unbind();
+        return rbo;
+    }
+    
+    void fbo_t::create(fbo_t::draw_t type)
+    {
+        generic_bind_type = static_cast<GLuint>(type);
         glGenFramebuffers(1, &fboID);
     }
     
-    void fbo_t::bind(fbo_draw_t type) const
+    void fbo_t::bind(draw_t type) const
     {
         glBindFramebuffer(static_cast<GLuint>(type), fboID);
     }
@@ -36,11 +77,64 @@ namespace blt::gfx
     
     void fbo_t::destroy()
     {
-    
+        glDeleteFramebuffers(1, &fboID);
+        for (auto& v : render_buffers)
+            v.destroy();
+        for (auto* texture : texture_buffers)
+            delete texture;
     }
     
     bool fbo_t::validate()
     {
         return glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE;
     }
+    
+    void fbo_t::attachTexture(blt::gfx::texture_gl* texture, attachment_t attachment, int level)
+    {
+        texture_buffers.push_back(texture);
+        glFramebufferTexture2D(generic_bind_type, static_cast<GLuint>(attachment), texture->getBindType(), texture->getTextureID(), level);
+    }
+    
+    void fbo_t::attachRenderBuffer(rbo_t rbo, fbo_t::attachment_t attachment)
+    {
+        rbo.bind();
+        glFramebufferRenderbuffer(generic_bind_type, static_cast<GLuint>(attachment), GL_RENDERBUFFER, rbo.rboID);
+        render_buffers.push_back(rbo);
+    }
+    
+    void fbo_t::updateBuffersStorage(blt::i32 width, blt::i32 height)
+    {
+        for (auto& rbo : render_buffers)
+        {
+            rbo.bind();
+            rbo.updateStorage(width, height);
+        }
+        
+        for (auto& texture : texture_buffers)
+            texture->updateSize(width, height);
+    }
+    
+    fbo_t fbo_t::make_render_texture(blt::i32 width, blt::i32 height)
+    {
+        fbo_t fbo;
+        
+        fbo.create();
+        fbo.bind();
+        
+        auto* texture = new texture_gl2D(width, height);
+        fbo.attachTexture(texture, attachment_t::COLOR0);
+        
+        rbo_t depth_rbo;
+        depth_rbo.create();
+        depth_rbo.bind();
+        depth_rbo.setStorage(GL_DEPTH24_STENCIL8, width, height);
+        
+        fbo.attachRenderBuffer(depth_rbo, attachment_t::DEPTH_STENCIL);
+        
+        if (!fbo_t::validate())
+            BLT_ERROR("Failed to create render texture framebuffer!");
+        fbo_t::unbind();
+        
+        return fbo;
+    }
 }
\ No newline at end of file
diff --git a/src/blt/gfx/model.cpp b/src/blt/gfx/model.cpp
index fa3c511..dfbed18 100644
--- a/src/blt/gfx/model.cpp
+++ b/src/blt/gfx/model.cpp
@@ -43,8 +43,7 @@ namespace blt::gfx
         size_ = next_size;
     }
     
-    static_dynamic_array::static_dynamic_array()
-    {}
+    static_dynamic_array::static_dynamic_array() = default;
     
     static_dynamic_array::vbo_type& static_dynamic_array::operator[](size_t index)
     {
diff --git a/src/blt/gfx/window.cpp b/src/blt/gfx/window.cpp
index c1f33a7..366175c 100644
--- a/src/blt/gfx/window.cpp
+++ b/src/blt/gfx/window.cpp
@@ -143,7 +143,7 @@ namespace blt::gfx
     
     void loop(void* arg)
     {
-        const auto& data = *((const window_data*) arg);
+        const auto& data = *((window_data*) arg);
         /* -- Get the current framebuffer size, update the global width/height state, along with OpenGL viewport -- */
         glfwGetFramebufferSize(window_state.window, &window_state.width, &window_state.height);
         glViewport(0, 0, window_state.width, window_state.height);
@@ -156,7 +156,7 @@ namespace blt::gfx
         ImGui::NewFrame();
         
         /* -- Call user update function -- */
-        data.update(window_state.width, window_state.height);
+        data.update(data.context, window_state.width, window_state.height);
         
         /* -- Render the ImGUI frame -- */
         ImGui::Render();
@@ -209,7 +209,7 @@ namespace blt::gfx
             glEnable(GL_MULTISAMPLE);
         
         /* -- Call User Provided post-window-init function  -- */
-        data.init();
+        data.init(data.context);
 
 #ifdef __EMSCRIPTEN__
         /*