light/Engine/src/Platform/GraphicsAPI/OpenGL/glFramebuffer.cpp

#include "glFramebuffer.h"

#include <glad/glad.h>

#include <glm/glm.hpp>

namespace Light {

	glFramebuffer::glFramebuffer(const FramebufferSpecification& specification)
		: m_Specification(specification),
		  m_BufferID(NULL),
		  m_ColorAttachmentID(NULL),
		  m_DepthStencilAttachmentID(NULL)
	{
		Resize({ specification.width, specification.height });
	}

	glFramebuffer::~glFramebuffer()
	{
		glDeleteFramebuffers(1, &m_BufferID);
		glDeleteTextures(1, &m_ColorAttachmentID);
		// glDeleteTextures(1, &m_DepthStencilAttachmentID);
	}

	void glFramebuffer::BindAsTarget(const glm::vec4& clearColor)
	{
		// #todo: use viewport instead of default x=0, y=0
		glBindFramebuffer(GL_FRAMEBUFFER, m_BufferID);
		glViewport(0, 0, m_Specification.width, m_Specification.height);

		glClearColor(clearColor.r, clearColor.g, clearColor.b, clearColor.a);
		glClear(GL_COLOR_BUFFER_BIT);
	}

	void glFramebuffer::BindAsResource()
	{
		LT_ENGINE_ERROR("glFramebuffer::BindAsResource: NO_IMPLEMENT!");
	}

	void glFramebuffer::Resize(const glm::uvec2& size)
	{
		if (m_BufferID)
		{
			glDeleteFramebuffers(1, &m_BufferID);
			glDeleteTextures(1, &m_ColorAttachmentID);
			// glDeleteTextures(1, &m_DepthStencilAttachmentID);
		}

		m_Specification.width = std::clamp(size.x, 1u, (unsigned int)GL_MAX_TEXTURE_SIZE);
		m_Specification.height = std::clamp(size.y, 1u, (unsigned int)GL_MAX_TEXTURE_SIZE);

		glCreateFramebuffers(1, &m_BufferID);
		glBindFramebuffer(GL_FRAMEBUFFER, m_BufferID);

		// create color attachment
		glCreateTextures(GL_TEXTURE_2D, 1, &m_ColorAttachmentID);
		glBindTexture(GL_TEXTURE_2D, m_ColorAttachmentID);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, m_Specification.width, m_Specification.height, NULL, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
		glTextureParameteri(m_ColorAttachmentID, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		glTextureParameteri(m_ColorAttachmentID, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_ColorAttachmentID, 0);

		// glTextureStorage2D(m_ColorAttachmentID, 0, GL_RGBA8, m_Specification.width, m_Specification.height);

		//	glCreateTextures(GL_TEXTURE_2D, 1, &m_DepthStencilAttachmentID);
		//	glBindTexture(GL_TEXTURE_2D, m_DepthStencilAttachmentID);
		//	glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8, m_Specification.width, m_Specification.height, NULL, GL_DEPTH_STENCIL, GL_UNSIGNED_INT_24_8, nullptr);
		//	// glTextureStorage2D(m_DepthStencilAttachmentID, 0, GL_DEPTH24_STENCIL8, m_Specification.width, m_Specification.height);
		//	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, m_DepthStencilAttachmentID, 0);

		LT_ENGINE_ASSERT((glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE), "glFramebuffer::Validate: framebuffer is incomplete");

		glBindFramebuffer(GL_FRAMEBUFFER, 0);
	}

}