[feat]: reduce renderer abstraction

1 files changed, 240 insertions, 6 deletions

diff --git a/src/rendering/framebuffer.cpp b/src/rendering/framebuffer.cpp
index 089c31e..3da4b48 100644
--- a/src/rendering/framebuffer.cpp
+++ b/src/rendering/framebuffer.cpp
@@ -1,17 +1,251 @@
 #include "framebuffer.h"
-#include "renderer.h"
+#include "core/log.h"
 
-#include "platform/opengl/opengl_framebuffer.h"
+#include <glad/glad.h>
 
 namespace Donut
 {
-    auto Framebuffer::create(const FramebufferSpecification& spec) -> Ref<Framebuffer>
+    namespace Utils
+    {
+        static GLenum TextureTarget(bool multisampled)
+        {
+            return multisampled ? GL_TEXTURE_2D_MULTISAMPLE : GL_TEXTURE_2D;
+        }
+
+        static void bind_texture(bool multisampled, uint32_t id)
+        {
+            glBindTexture(TextureTarget(multisampled), id);
+        }
+
+        static void CreateTextures(bool multisampled, uint32_t* out_id, uint32_t count)
+        {
+            // glCreateTextures is 4.5 DSA; macOS caps at 4.1. Callers bind each
+            // texture (with the correct target) before use.
+            glGenTextures(count, out_id);
+        }
+
+        static void AttachColorTexture(uint32_t id, int samples, GLenum internal_format, GLenum format, uint32_t width, uint32_t height, int index)
+        {
+            bool multisampled = samples > 1;
+            if (multisampled)
+            {
+                glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, internal_format, width, height, GL_FALSE);
+            }
+            else
+            {
+                // Integer color formats require an integer pixel type even when
+                // data is null, or macOS's strict core profile rejects the call.
+                GLenum type = (format == GL_RED_INTEGER) ? GL_INT : GL_UNSIGNED_BYTE;
+                glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, type, nullptr);
+
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+            }
+
+            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + index, TextureTarget(multisampled), id, 0);
+        }
+
+        static void AttachDepthTexture(uint32_t id, int samples, GLenum format, GLenum attachment_type, uint32_t width, uint32_t height)
+        {
+            bool multisampled = samples > 1;
+            if (multisampled)
+            {
+                glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, format, width, height, GL_FALSE);
+            }
+            else
+            {
+                // glTexStorage2D is 4.2; use mutable storage for macOS (4.1).
+                GLenum depth_format = (format == GL_DEPTH24_STENCIL8) ? GL_DEPTH_STENCIL : GL_DEPTH_COMPONENT;
+                GLenum depth_type   = (format == GL_DEPTH24_STENCIL8) ? GL_UNSIGNED_INT_24_8 : GL_FLOAT;
+                glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, depth_format, depth_type, nullptr);
+
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+            }
+
+            glFramebufferTexture2D(GL_FRAMEBUFFER, attachment_type, TextureTarget(multisampled), id, 0);
+        }
+
+        static bool IsDepthFormat(FramebufferTextureFormat format)
+        {
+            switch (format)
+            {
+                case FramebufferTextureFormat::DEPTH24STENCIL8:  return true;
+            }
+            return false;
+        }
+
+        static GLenum DonutFBTextureFormatToGL(FramebufferTextureFormat format)
+        {
+            switch (format)
+            {
+                case FramebufferTextureFormat::RGBA8:       return GL_RGBA8;
+                case FramebufferTextureFormat::RED_INTEGER: return GL_RED_INTEGER;
+            }
+
+            return 0;
+        }
+    }
+
+    Framebuffer::Framebuffer(const FramebufferSpecification& spec)
+        : m_specification(spec)
+    {
+        for (auto spec : m_specification.attachments.attachments)
+        {
+            if (!Utils::IsDepthFormat(spec.texture_format))
+                m_color_attachment_specifications.emplace_back(spec);
+            else
+                m_depth_attachment_specification = spec;
+        }
+
+        invalidate();
+    }
+
+    Framebuffer::~Framebuffer()
+    {
+        glDeleteFramebuffers(1, &m_renderer_id);
+        glDeleteTextures(static_cast<GLsizei>(m_color_attachments.size()), m_color_attachments.data());
+        glDeleteTextures(1, &m_depth_attachment);
+    }
+
+    auto Framebuffer::invalidate() -> void
     {
-        switch (Renderer::get_api())
+        if (m_renderer_id)
+        {
+            glDeleteFramebuffers(1, &m_renderer_id);
+            glDeleteTextures(static_cast<GLsizei>(m_color_attachments.size()), m_color_attachments.data());
+            glDeleteTextures(1, &m_depth_attachment);
+
+            m_color_attachments.clear();
+            m_depth_attachment = 0;
+        }
+
+        glGenFramebuffers(1, &m_renderer_id); // glCreateFramebuffers is 4.5 DSA; unavailable on macOS 4.1
+        glBindFramebuffer(GL_FRAMEBUFFER, m_renderer_id);
+
+        bool multisample = m_specification.Samples > 1;
+
+        if (m_color_attachment_specifications.size())
         {
-            case RendererAPI::API::OpenGL:  return create_ref<OpenGLFramebuffer>(spec);
+            m_color_attachments.resize(m_color_attachment_specifications.size());
+            Utils::CreateTextures(multisample, m_color_attachments.data(), static_cast<uint32_t>(m_color_attachments.size()));
+
+            for (size_t i = 0; i < m_color_attachments.size(); i++)
+            {
+                Utils::bind_texture(multisample, m_color_attachments[i]);
+                switch (m_color_attachment_specifications[i].texture_format)
+                {
+                    case FramebufferTextureFormat::RGBA8:
+                        Utils::AttachColorTexture(m_color_attachments[i], m_specification.Samples, GL_RGBA8, GL_RGBA, m_specification.Width, m_specification.Height, static_cast<int>(i));
+                        break;
+                    case FramebufferTextureFormat::RED_INTEGER:
+                        Utils::AttachColorTexture(m_color_attachments[i], m_specification.Samples, GL_R32I, GL_RED_INTEGER, m_specification.Width, m_specification.Height, static_cast<int>(i));
+                        break;
+                }
+            }
         }
 
-        return nullptr;
+        if (m_depth_attachment_specification.texture_format != FramebufferTextureFormat::None)
+        {
+            Utils::CreateTextures(multisample, &m_depth_attachment, 1);
+            Utils::bind_texture(multisample, m_depth_attachment);
+            switch (m_depth_attachment_specification.texture_format)
+            {
+                case FramebufferTextureFormat::DEPTH24STENCIL8:
+                    Utils::AttachDepthTexture(m_depth_attachment, m_specification.Samples, GL_DEPTH24_STENCIL8, GL_DEPTH_STENCIL_ATTACHMENT, m_specification.Width, m_specification.Height);
+                    break;
+            }
+        }
+
+        if (m_color_attachments.size() > 1)
+        {
+            GLenum buffers[4] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3 };
+            glDrawBuffers(static_cast<GLsizei>(m_color_attachments.size()), buffers);
+        }
+        else if (m_color_attachments.empty())
+            glDrawBuffer(GL_NONE);
+
+        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+        {
+            GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+            switch (status)
+            {
+                case GL_FRAMEBUFFER_UNDEFINED:
+                    DONUT_ERROR("Framebuffer is undefined");
+                    break;
+                case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
+                    DONUT_ERROR("Framebuffer has incomplete attachment");
+                    break;
+                case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
+                    DONUT_ERROR("Framebuffer is missing attachment");
+                    break;
+                case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
+                    DONUT_ERROR("Framebuffer has incomplete draw buffer");
+                    break;
+                case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
+                    DONUT_ERROR("Framebuffer has incomplete read buffer");
+                    break;
+                case GL_FRAMEBUFFER_UNSUPPORTED:
+                    DONUT_ERROR("Framebuffer format is unsupported");
+                    break;
+                case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
+                    DONUT_ERROR("Framebuffer has incomplete multisample");
+                    break;
+                case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS:
+                    DONUT_ERROR("Framebuffer has incomplete layer targets");
+                    break;
+                default:
+                    DONUT_ERROR("Framebuffer is incomplete (unknown error: {})", status);
+                    break;
+            }
+        }
+
+        glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    }
+
+    auto Framebuffer::bind() -> void
+    {
+        glBindFramebuffer(GL_FRAMEBUFFER, m_renderer_id);
+        glViewport(0, 0, m_specification.Width, m_specification.Height);
+    }
+
+    auto Framebuffer::unbind() -> void
+    {
+        glBindFramebuffer(GL_FRAMEBUFFER, 0);
+    }
+
+    auto Framebuffer::resize(uint32_t width, uint32_t height) -> void
+    {
+        m_specification.Width = width;
+        m_specification.Height = height;
+
+        invalidate();
+    }
+
+    auto Framebuffer::read_pixel(uint32_t attachment_index, int x, int y) -> int
+    {
+        glReadBuffer(GL_COLOR_ATTACHMENT0 + attachment_index);
+        int pixel_data;
+        glReadPixels(x, y, 1, 1, GL_RED_INTEGER, GL_INT, &pixel_data);
+        return pixel_data;
+    }
+
+    auto Framebuffer::clear_attachment(uint32_t attachment_index, int value) -> void
+    {
+        // glClearTexImage is 4.4 and unavailable on macOS. clear the integer
+        // attachment by binding this framebuffer and clearing its draw buffer.
+        glBindFramebuffer(GL_FRAMEBUFFER, m_renderer_id);
+        glClearBufferiv(GL_COLOR, static_cast<GLint>(attachment_index), &value);
+    }
+
+    auto Framebuffer::create(const FramebufferSpecification& spec) -> Ref<Framebuffer>
+    {
+        return create_ref<Framebuffer>(spec);
     }
 };