[Feat] (MG_State/Framebuffer, MG_Impl/Framebuffer): implement glDrawBuffers in the state machine

MobileGL/MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.cpp

@@ -1,6 +1,7 @@
 #include "GL_Framebuffer.h"
 #include "Validators.h"
 #include "Config.h"
+#include "MG_Util/Converters/GLToStr/GLEnumConverter.h"
 #include <MG_Impl/GLImpl/Texture/Validators.h>
 #include <MG_State/GLState/ErrorState/Error.h>
 #include <MG_Util/Converters/GLToMG/FramebufferEnumConverter.h>
@@ -133,7 +134,76 @@ namespace MobileGL {
         }
 
         void DrawBuffers_State(GLsizei n, const GLenum* bufs) {
-            // TODO: implement
+            if (n < 0) {
+                MG_State::pGLContext->RecordError(
+                        ErrorCode::InvalidValue, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                                                              "`n` is less than 0."));
+                return;
+            } else if (n > MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS) {
+                MG_State::pGLContext->RecordError(
+                        ErrorCode::InvalidValue, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                                                              "`n` is greater than `GL_MAX_DRAW_BUFFERS`."));
+                return;
+            }
+
+            // Get bound framebuffer
+            auto& bindingSlot = MG_State::pGLContext->GetFramebufferBindingSlot(FramebufferTarget::Draw);
+            auto fbo = bindingSlot.GetBoundObject();
+            bool isDefaultFBO = (fbo == FramebufferImpl::pDefaultFramebufferInfo->defaultFBO);
+
+            static int existenceMap[(SizeT)FramebufferAttachmentType::FramebufferAttachmentTypeCount] = {
+                    -1
+            };
+            std::fill(existenceMap, existenceMap + (SizeT)FramebufferAttachmentType::FramebufferAttachmentTypeCount, -1);
+
+            for (GLsizei i = 0; i < n; ++i) {
+                auto attType = MG_Util::ConvertGLEnumToFramebufferAttachmentType(bufs[i]);
+
+                // ------------------- Check validity begin ------------------------
+                if (attType == FramebufferAttachmentType::Unknown) {
+                    MG_State::pGLContext->RecordError(
+                            ErrorCode::InvalidEnum, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                                                                  std::format("bufs[{}] = %s is not an accepted value.", i, MG_Util::ConvertGLEnumToString(bufs[i]))));
+                    return;
+                }
+
+                if (isDefaultFBO &&
+                    attType >= FramebufferAttachmentType::Color0 && attType <= FramebufferAttachmentType::Color31) {
+                    MG_State::pGLContext->RecordError(
+                            ErrorCode::InvalidEnum, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                                                                  std::format("FBO is default FBO, but bufs[{}] = {} is one of the `GL_COLOR_ATTACHMENTn` tokens.", i, MG_Util::ConvertGLEnumToString(bufs[i]))));
+                    return;
+                }
+
+                if (!isDefaultFBO &&
+                    attType >= FramebufferAttachmentType::FrontLeft && attType <= FramebufferAttachmentType::BackRight) {
+                    MG_State::pGLContext->RecordError(
+                            ErrorCode::InvalidEnum, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                                                                 std::format("FBO is not default FBO, but bufs[{}] = {} is anything other than `GL_NONE` or one of the `GL_COLOR_ATTACHMENTn` tokens.", i, MG_Util::ConvertGLEnumToString(bufs[i]))));
+                    return;
+                }
+
+                if (attType != FramebufferAttachmentType::None && existenceMap[(SizeT)attType] >= 0) {
+                    MG_State::pGLContext->RecordError(
+                            ErrorCode::InvalidOperation, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                            std::format("a symbolic constant other than `GL_NONE` appears more than once in bufs. bufs[{}] == bufs[{}] == {}.", i, existenceMap[(SizeT)attType], MG_Util::ConvertGLEnumToString(bufs[i]))));
+                    return;
+                }
+
+                existenceMap[(SizeT)attType] = i;
+
+                if ((SizeT)attType > (SizeT)FramebufferAttachmentType::Color0 + MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS) {
+                    MG_State::pGLContext->RecordError(
+                            ErrorCode::InvalidOperation, MakeShared<GenericErrorInfo>("MG_Impl/GLImpl", __func__,
+                                                                                      std::format("bufs[{}] == {} indicates a color buffer that does not exist in the current GL context.", i, MG_Util::ConvertGLEnumToString(bufs[i]))));
+                    return;
+                }
+                // ------------------------- Check validity end ----------------------------------
+                fbo->SetDrawBuffer(i, attType);
+            }
+            for (GLsizei i = n; i < MG_State::GLState::FramebufferObject::MAX_DRAW_BUFFERS; ++i) {
+                fbo->SetDrawBuffer(i, FramebufferAttachmentType::None);
+            }
         }
 
         void DeleteRenderbuffers_State(GLsizei n, const GLuint* renderbuffers) {

MobileGL/MG_State/GLState/FramebufferState/FramebufferObject.cpp

@@ -63,8 +63,10 @@ namespace MobileGL {
             }
 
             // FramebufferObject
-            FramebufferObject::FramebufferObject(Uint externalIndex) : m_externalIndex(externalIndex) {
+            FramebufferObject::FramebufferObject(Uint externalIndex) :
+                m_externalIndex(externalIndex) {
                 m_attachments.fill(FramebufferAttachment(false));
+                m_drawBuffers.fill(FramebufferAttachmentType::None);
             }
 
             void FramebufferObject::AttachTexture(FramebufferAttachmentType type, SharedPtr<ITextureObject> texture,
@@ -126,12 +128,22 @@ namespace MobileGL {
                 return true;
             }
 
-            void FramebufferObject::SetDrawBuffers(const std::vector<FramebufferAttachmentType>& buffers) {
+            void FramebufferObject::SetDrawBuffer(Uint index, FramebufferAttachmentType buffer) {
-                m_drawBuffers = buffers;
+                if (m_drawBuffers[index] == buffer)
+                    return;
                 m_drawBuffersDirty = true;
+                m_drawBuffers[index] = buffer;
             }
 
-            const Vector<FramebufferAttachmentType>& FramebufferObject::GetDrawBuffers() const {
+//            void FramebufferObject::SetDrawBuffers(const Vector<FramebufferAttachmentType>& buffers) {
+//                m_drawBuffers = buffers;
+//                m_drawBuffersDirty = true;
+//            }
+//            void SetDrawBuffer(Uint index, FramebufferAttachmentType buffer) {
+//
+//            }
+
+            const auto& FramebufferObject::GetDrawBuffers() const {
                 return m_drawBuffers;
             }
 

MobileGL/MG_State/GLState/FramebufferState/FramebufferObject.h

@@ -12,6 +12,16 @@ namespace MobileGL {
     };
 
     enum class FramebufferAttachmentType {
+        None,
+
+        FrontLeft,
+        FrontRight,
+        BackLeft,
+        BackRight,
+
+        Depth,
+        Stencil,
+
         Color0,
         Color1,
         Color2,
@@ -44,8 +54,7 @@ namespace MobileGL {
         Color29,
         Color30,
         Color31,
-        Depth,
+
-        Stencil,
         FramebufferAttachmentTypeCount,
         Unknown = -1
     };
@@ -81,6 +90,7 @@ namespace MobileGL {
             class FramebufferObject {
             public:
                 using TargetEnum = FramebufferTarget;
+                static constexpr uint MAX_DRAW_BUFFERS = 8;
 
                 FramebufferObject(Uint externalIndex);
 
@@ -93,8 +103,9 @@ namespace MobileGL {
                             static_cast<SizeT>(FramebufferAttachmentType::FramebufferAttachmentTypeCount)>&
                 GetAllAttachments() const;
                 Bool CheckCompleteness() const;
-                void SetDrawBuffers(const std::vector<FramebufferAttachmentType>& buffers);
+//                void SetDrawBuffers(const Vector<FramebufferAttachmentType>& buffers);
-                const Vector<FramebufferAttachmentType>& GetDrawBuffers() const;
+                void SetDrawBuffer(Uint index, FramebufferAttachmentType buffer);
+                const auto& GetDrawBuffers() const;
                 Uint GetExternalIndex() const;
 
             private:
@@ -103,7 +114,7 @@ namespace MobileGL {
                       static_cast<SizeT>(FramebufferAttachmentType::FramebufferAttachmentTypeCount)>
                     m_attachments;
                 Bool m_drawBuffersDirty = true;
-                Vector<FramebufferAttachmentType> m_drawBuffers;
+                Array<FramebufferAttachmentType, MAX_DRAW_BUFFERS> m_drawBuffers;
             };
 
         } // namespace GLState