NazaraEngine/src/Nazara/Renderer/RenderTexture.cpp

// Copyright (C) 2015 Jérôme Leclercq
// This file is part of the "Nazara Engine - Renderer module"
// For conditions of distribution and use, see copyright notice in Config.hpp

#include <Nazara/Renderer/RenderTexture.hpp>
#include <Nazara/Core/CallOnExit.hpp>
#include <Nazara/Core/Error.hpp>
#include <Nazara/Renderer/Context.hpp>
#include <Nazara/Renderer/OpenGL.hpp>
#include <Nazara/Renderer/Renderer.hpp>
#include <Nazara/Renderer/RenderBuffer.hpp>
#include <Nazara/Renderer/Texture.hpp>
#include <Nazara/Utility/PixelFormat.hpp>
#include <functional>
#include <limits>
#include <memory>
#include <vector>
#include <Nazara/Renderer/Debug.hpp>

namespace
{
	struct Attachment
	{
		NazaraSlot(NzRenderBuffer, OnRenderBufferDestroy, renderBufferDestroySlot);
		NazaraSlot(NzTexture, OnTextureDestroy, textureDestroySlot);

		NzRenderBufferRef buffer;
		NzTextureRef texture;

		nzAttachmentPoint attachmentPoint;
		bool isBuffer;
		bool isUsed = false;
		unsigned int height;
		unsigned int width;
	};

	unsigned int attachmentIndex[nzAttachmentPoint_Max+1] =
	{
		3, // nzAttachmentPoint_Color
		0, // nzAttachmentPoint_Depth
		1, // nzAttachmentPoint_DepthStencil
		2  // nzAttachmentPoint_Stencil
	};

	nzAttachmentPoint formatTypeToAttachment[nzPixelFormatType_Max+1] =
	{
		nzAttachmentPoint_Color,        // nzPixelFormatType_Color
		nzAttachmentPoint_Depth,        // nzPixelFormatType_Depth
		nzAttachmentPoint_DepthStencil, // nzPixelFormatType_DepthStencil
		nzAttachmentPoint_Stencil       // nzPixelFormatType_Stencil
	};

	GLuint lockedPrevious = 0;
	nzUInt8 lockedLevel = 0;
}

struct NzRenderTextureImpl
{
	NazaraSlot(NzContext, OnContextDestroy, contextDestroySlot);

	GLuint fbo;
	std::vector<Attachment> attachments;
	std::vector<nzUInt8> colorTargets;
	mutable std::vector<GLenum> drawBuffers;
	const NzContext* context;
	bool complete = false;
	bool userDefinedTargets = false;
	unsigned int height;
	unsigned int width;
};

bool NzRenderTexture::AttachBuffer(nzAttachmentPoint attachmentPoint, nzUInt8 index, NzRenderBuffer* buffer)
{
	#if NAZARA_RENDERER_SAFE
	if (!m_impl)
	{
		NazaraError("Render texture not created");
		return false;
	}

	if (attachmentPoint != nzAttachmentPoint_Color)
	{
		if (index > 0)
		{
			NazaraError("Index must be 0 for non-color attachments");
			return false;
		}
	}
	else
	{
		if (index >= NzRenderer::GetMaxColorAttachments())
		{
			NazaraError("Color index is over max color attachments (" + NzString::Number(index) + " >= " + NzString::Number(NzRenderer::GetMaxColorAttachments()) + ")");
			return false;
		}
	}

	if (!buffer || !buffer->IsValid())
	{
		NazaraError("Invalid render buffer");
		return false;
	}

	unsigned int depthStencilIndex = attachmentIndex[nzAttachmentPoint_DepthStencil];
	if (m_impl->attachments.size() > depthStencilIndex && m_impl->attachments[depthStencilIndex].isUsed)
	{
		if (attachmentPoint == nzAttachmentPoint_Depth)
		{
			NazaraError("Depth target already attached by DepthStencil attachment");
			return false;
		}
		else if (attachmentPoint == nzAttachmentPoint_Stencil)
		{
			NazaraError("Stencil target already attached by DepthStencil attachment");
			return false;
		}
	}

	nzAttachmentPoint targetAttachmentPoint = formatTypeToAttachment[NzPixelFormat::GetType(buffer->GetFormat())];
	if (targetAttachmentPoint != attachmentPoint && targetAttachmentPoint != nzAttachmentPoint_DepthStencil &&
	    attachmentPoint != nzAttachmentPoint_Depth && attachmentPoint != nzAttachmentPoint_Stencil)
	{
		NazaraError("Pixel format type does not match attachment point type");
		return false;
	}
	#endif

	if (!Lock())
	{
		NazaraError("Failed to lock render texture");
		return false;
	}

	// Détachement de l'attache précédente (Si il y a)
	Detach(attachmentPoint, index);

	glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, GL_RENDERBUFFER, buffer->GetOpenGLID());

	Unlock();

	unsigned int attachIndex = attachmentIndex[attachmentPoint] + index;
	if (attachIndex >= m_impl->attachments.size())
		m_impl->attachments.resize(attachIndex+1);

	Attachment& attachment = m_impl->attachments[attachIndex];
	attachment.attachmentPoint = attachmentPoint;
	attachment.buffer = buffer;
	attachment.renderBufferDestroySlot.Connect(buffer->OnRenderBufferDestroy, std::bind(&NzRenderTexture::OnRenderBufferDestroy, this, std::placeholders::_1, attachIndex));
	attachment.isBuffer = true;
	attachment.isUsed = true;
	attachment.height = buffer->GetHeight();
	attachment.width = buffer->GetWidth();

	InvalidateSize();
	InvalidateTargets();

	if (attachmentPoint == nzAttachmentPoint_Color && !m_impl->userDefinedTargets)
		m_impl->colorTargets.push_back(index);

	return true;
}

bool NzRenderTexture::AttachBuffer(nzAttachmentPoint attachmentPoint, nzUInt8 index, nzPixelFormat format, unsigned int width, unsigned int height)
{
	NzRenderBufferRef renderBuffer = NzRenderBuffer::New();
	if (!renderBuffer->Create(format, width, height))
	{
		NazaraError("Failed to create RenderBuffer");
		return false;
	}

	if (!AttachBuffer(attachmentPoint, index, renderBuffer))
	{
		NazaraError("Failed to attach buffer");
		return false;
	}

	return true;
}

bool NzRenderTexture::AttachTexture(nzAttachmentPoint attachmentPoint, nzUInt8 index, NzTexture* texture, unsigned int z)
{
	#if NAZARA_RENDERER_SAFE
	if (!m_impl)
	{
		NazaraError("Render texture not created");
		return false;
	}

	if (attachmentPoint != nzAttachmentPoint_Color)
	{
		if (index > 0)
		{
			NazaraError("Index must be 0 for non-color attachments");
			return false;
		}
	}
	else
	{
		if (index >= NzRenderer::GetMaxColorAttachments())
		{
			NazaraError("Color index is over max color attachments (" + NzString::Number(index) + " >= " + NzString::Number(NzRenderer::GetMaxColorAttachments()) + ")");
			return false;
		}
	}

	if (attachmentPoint == nzAttachmentPoint_Stencil)
	{
		NazaraError("Targeting stencil-only textures is not supported");
		return false;
	}

	unsigned int depthStencilIndex = attachmentIndex[nzAttachmentPoint_DepthStencil];
	if (attachmentPoint == nzAttachmentPoint_Depth && m_impl->attachments.size() > depthStencilIndex &&
		m_impl->attachments[depthStencilIndex].isUsed)
	{
		NazaraError("Depth target already attached by DepthStencil attachment");
		return false;
	}

	if (!texture || !texture->IsValid())
	{
		NazaraError("Invalid texture");
		return false;
	}

	unsigned int depth = (texture->GetType() == nzImageType_Cubemap) ? 6 : texture->GetDepth();
	if (z >= depth)
	{
		NazaraError("Z value exceeds depth (" + NzString::Number(z) + " >= (" + NzString::Number(depth) + ')');
		return false;
	}

	nzAttachmentPoint targetAttachmentPoint = formatTypeToAttachment[NzPixelFormat::GetType(texture->GetFormat())];
	if (targetAttachmentPoint != attachmentPoint && targetAttachmentPoint != nzAttachmentPoint_DepthStencil &&
		attachmentPoint != nzAttachmentPoint_Depth && attachmentPoint != nzAttachmentPoint_Stencil)
	{
		NazaraError("Pixel format type does not match attachment point type");
		return false;
	}
	#endif

	if (!Lock())
	{
		NazaraError("Failed to lock render texture");
		return false;
	}

	// Détachement de l'attache précédente (Si il y a)
	Detach(attachmentPoint, index);

	switch (texture->GetType())
	{
		case nzImageType_1D:
			glFramebufferTexture1D(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, GL_TEXTURE_1D, texture->GetOpenGLID(), 0);
			break;

		case nzImageType_1D_Array:
		case nzImageType_2D_Array:
			glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, texture->GetOpenGLID(), 0, z);
			break;

		case nzImageType_2D:
			glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, GL_TEXTURE_2D, texture->GetOpenGLID(), 0);
			break;

		case nzImageType_3D:
			glFramebufferTexture3D(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, GL_TEXTURE_3D, texture->GetOpenGLID(), 0, z);
			break;

		case nzImageType_Cubemap:
			glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, NzOpenGL::CubemapFace[z], texture->GetOpenGLID(), 0);
			break;
	}

	Unlock();

	unsigned int attachIndex = attachmentIndex[attachmentPoint] + index;
	if (attachIndex >= m_impl->attachments.size())
		m_impl->attachments.resize(attachIndex+1);

	Attachment& attachment = m_impl->attachments[attachIndex];
	attachment.attachmentPoint = attachmentPoint;
	attachment.isBuffer = false;
	attachment.isUsed = true;
	attachment.height = texture->GetHeight();
	attachment.texture = texture;
	attachment.textureDestroySlot.Connect(texture->OnTextureDestroy, std::bind(&NzRenderTexture::OnTextureDestroy, this, std::placeholders::_1, attachIndex));
	attachment.width = texture->GetWidth();

	InvalidateSize();
	InvalidateTargets();

	if (attachmentPoint == nzAttachmentPoint_Color && !m_impl->userDefinedTargets)
		m_impl->colorTargets.push_back(index);

	return true;
}

bool NzRenderTexture::Create(bool lock)
{
	if (!IsSupported())
	{
		NazaraError("Render textures not supported");
		return false;
	}

	Destroy();

	#if NAZARA_RENDERER_SAFE
	if (NzContext::GetCurrent() == nullptr)
	{
		NazaraError("No active context");
		return false;
	}
	#endif

	std::unique_ptr<NzRenderTextureImpl> impl(new NzRenderTextureImpl);

	impl->fbo = 0;
	glGenFramebuffers(1, &impl->fbo);

	if (!impl->fbo)
	{
		NazaraError("Failed to create framebuffer");
		return false;
	}

	m_impl = impl.release();
	m_impl->context = NzContext::GetCurrent();
	m_impl->contextDestroySlot.Connect(m_impl->context->OnContextDestroy, this, &NzRenderTexture::OnContextDestroy);

	m_checked = false;
	m_drawBuffersUpdated = true;
	m_sizeUpdated = false;
	m_targetsUpdated = true;

	if (lock)
	{
		// En cas d'exception, la ressource sera quand même libérée
		NzCallOnExit onExit([this] ()
		{
			Destroy();
		});

		if (!Lock())
		{
			NazaraError("Failed to lock render texture");
			return false;
		}

		onExit.Reset();
	}

	OnRenderTargetParametersChange(this);
	OnRenderTargetSizeChange(this);

	return true;
}

void NzRenderTexture::Destroy()
{
	if (m_impl)
	{
		if (IsActive())
			NzRenderer::SetTarget(nullptr);

		// Le FBO devant être supprimé dans son contexte d'origine, nous déléguons sa suppression à la classe OpenGL
		// Celle-ci va libérer le FBO dès que possible (la prochaine fois que son contexte d'origine sera actif)
		NzOpenGL::DeleteFrameBuffer(m_impl->context, m_impl->fbo);

		delete m_impl; // Enlève également une références sur les Texture/RenderBuffer
		m_impl = nullptr;
	}
}

void NzRenderTexture::Detach(nzAttachmentPoint attachmentPoint, nzUInt8 index)
{
	#if NAZARA_RENDERER_SAFE
	if (!m_impl)
	{
		NazaraError("Render texture not created");
		return;
	}

	if (attachmentPoint != nzAttachmentPoint_Color && index > 0)
	{
		NazaraError("Index must be 0 for non-color attachments");
		return;
	}
	#endif

	unsigned int attachIndex = attachmentIndex[attachmentPoint] + index;
	if (attachIndex >= m_impl->attachments.size())
		return;

	Attachment& attachement = m_impl->attachments[attachIndex];
	if (!attachement.isUsed)
		return;

	if (!Lock())
	{
		NazaraError("Failed to lock render texture");
		return;
	}

	attachement.isUsed = false;

	if (attachement.isBuffer)
	{
		glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, GL_RENDERBUFFER, 0);

		attachement.buffer = nullptr;
		attachement.renderBufferDestroySlot.Disconnect();
	}
	else
	{
		if (glFramebufferTexture)
			glFramebufferTexture(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, 0, 0);
		else
			glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, NzOpenGL::Attachment[attachmentPoint]+index, 0, 0, 0);

		attachement.texture = nullptr;
		attachement.textureDestroySlot.Disconnect();
	}

	InvalidateSize();

	if (attachement.attachmentPoint == nzAttachmentPoint_Color)
		InvalidateTargets();

	Unlock();

	m_checked = false;
}

unsigned int NzRenderTexture::GetHeight() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	if (!m_sizeUpdated)
		UpdateSize();

	return m_impl->height;
}

NzRenderTargetParameters NzRenderTexture::GetParameters() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	///TODO
	return NzRenderTargetParameters();
}

NzVector2ui NzRenderTexture::GetSize() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	if (!m_sizeUpdated)
		UpdateSize();

	return NzVector2ui(m_impl->width, m_impl->height);
}

unsigned int NzRenderTexture::GetWidth() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	if (!m_sizeUpdated)
		UpdateSize();

	return m_impl->width;
}

bool NzRenderTexture::IsComplete() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	if (!m_checked)
	{
		if (!Lock())
		{
			NazaraError("Failed to lock render texture");
			return false;
		}

		GLenum status = glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER);
		Unlock();

		m_impl->complete = false;

		switch (status)
		{
			case GL_FRAMEBUFFER_COMPLETE:
				m_impl->complete = true;
				break;

			case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
				NazaraError("Incomplete attachment");
				break;

			case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
				NazaraInternalError("Incomplete draw buffer");
				break;

			case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
				NazaraInternalError("Incomplete read buffer");
				break;

			case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
				NazaraError("Incomplete missing attachment");
				break;

			case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
				NazaraError("Incomplete multisample");
				break;

			case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS:
				NazaraError("Incomplete layer targets");
				break;

			case GL_FRAMEBUFFER_UNSUPPORTED:
				NazaraError("Render texture has unsupported attachments");
				break;

			default:
				NazaraInternalError("Unknown error");
		}

		m_checked = true;
	}

	return m_impl->complete;
}

bool NzRenderTexture::IsRenderable() const
{
	return IsComplete() && !m_impl->attachments.empty();
}

bool NzRenderTexture::Lock() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	if (NzContext::GetCurrent() != m_impl->context)
	{
		NazaraError("RenderTexture cannot be used with this context");
		return false;
	}
	#endif

	if (lockedLevel++ == 0)
	{
		GLint previous;
		glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &previous);

		lockedPrevious = previous;

		if (lockedPrevious != m_impl->fbo)
			glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_impl->fbo);
	}

	return true;
}

void NzRenderTexture::SetColorTargets(const nzUInt8* targets, unsigned int targetCount) const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	for (unsigned int i = 0; i < targetCount; ++i)
	{
		unsigned int index = attachmentIndex[nzAttachmentPoint_Color] + targets[i];
		if (index >= m_impl->attachments.size() || !m_impl->attachments[index].isUsed)
		{
			NazaraError("Target " + NzString::Number(targets[i]) + " not attached");
			return;
		}
	}
	#endif

	m_impl->colorTargets.resize(targetCount);
	std::memcpy(&m_impl->colorTargets[0], targets, targetCount*sizeof(nzUInt8));

	m_impl->userDefinedTargets = true;
	InvalidateDrawBuffers();
}

void NzRenderTexture::SetColorTargets(const std::initializer_list<nzUInt8>& targets) const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	for (nzUInt8 target : targets)
	{
		unsigned int index = attachmentIndex[nzAttachmentPoint_Color] + target;
		if (index >= m_impl->attachments.size() || !m_impl->attachments[index].isUsed)
		{
			NazaraError("Target " + NzString::Number(target) + " not attached");
			return;
		}
	}
	#endif

	m_impl->colorTargets.resize(targets.size());

	nzUInt8* ptr = &m_impl->colorTargets[0];
	for (nzUInt8 index : targets)
		*ptr++ = index;

	m_impl->userDefinedTargets = true;
	InvalidateDrawBuffers();
}

void NzRenderTexture::Unlock() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	if (NzContext::GetCurrent() != m_impl->context)
	{
		NazaraError("RenderTexture cannot be used with this context");
		return;
	}

	if (lockedLevel == 0)
	{
		NazaraWarning("Unlock called on non-locked texture");
		return;
	}
	#endif

	if (--lockedLevel == 0 && lockedPrevious != m_impl->fbo) // Ici, il est important qu'un FBO soit débindé si l'ancien était 0
		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, lockedPrevious);
}

unsigned int NzRenderTexture::GetOpenGLID() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	if (NzContext::GetCurrent() != m_impl->context)
	{
		NazaraError("RenderTexture cannot be used with this context");
		return 0;
	}
	#endif

	return m_impl->fbo;
}

bool NzRenderTexture::HasContext() const
{
	return false;
}

bool NzRenderTexture::IsSupported()
{
	return NzOpenGL::IsSupported(nzOpenGLExtension_FrameBufferObject);
}

void NzRenderTexture::Blit(NzRenderTexture* src, NzRectui srcRect, NzRenderTexture* dst, NzRectui dstRect, nzUInt32 buffers, bool bilinearFilter)
{
	NazaraAssert(src && src->IsValid(), "Invalid source render texture");
	NazaraAssert(dst && dst->IsValid(), "Invalid destination render texture");

	#if NAZARA_RENDERER_SAFE
	if (srcRect.x+srcRect.width > src->GetWidth() || srcRect.y+srcRect.height > src->GetHeight())
	{
		NazaraError("Source rectangle dimensions are out of bounds");
		return;
	}

	if (dstRect.x+dstRect.width > dst->GetWidth() || dstRect.y+dstRect.height > dst->GetHeight())
	{
		NazaraError("Destination rectangle dimensions are out of bounds");
		return;
	}

	if (bilinearFilter && (buffers & nzRendererBuffer_Depth || buffers & nzRendererBuffer_Stencil))
	{
		NazaraError("Filter cannot be bilinear when blitting depth/stencil buffers");
		return;
	}
	#endif

	GLbitfield mask = 0;
	if (buffers & nzRendererBuffer_Color)
		mask |= GL_COLOR_BUFFER_BIT;

	if (buffers & nzRendererBuffer_Depth)
		mask |= GL_DEPTH_BUFFER_BIT;

	if (buffers & nzRendererBuffer_Stencil)
		mask |= GL_STENCIL_BUFFER_BIT;

	GLint previousDrawBuffer, previousReadBuffer;
	glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &previousDrawBuffer);
	glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &previousReadBuffer);

	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, dst->GetOpenGLID());
	glBindFramebuffer(GL_READ_FRAMEBUFFER, src->GetOpenGLID());

	glBlitFramebuffer(srcRect.x, srcRect.y, srcRect.x + srcRect.width, srcRect.y + srcRect.height,
	                  dstRect.x, dstRect.y, dstRect.x + dstRect.width, dstRect.y + dstRect.height,
	                  mask, (bilinearFilter) ? GL_LINEAR : GL_NEAREST);

	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, previousDrawBuffer);
	glBindFramebuffer(GL_READ_FRAMEBUFFER, previousReadBuffer);
}

bool NzRenderTexture::Activate() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	if (NzContext::GetCurrent() != m_impl->context)
	{
		NazaraError("RenderTexture cannot be used with this context");
		return false;
	}
	#endif

	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_impl->fbo);

	m_drawBuffersUpdated = false;

	return true;
}

void NzRenderTexture::Desactivate() const
{
	NazaraAssert(m_impl, "Invalid render texture");

	#if NAZARA_RENDERER_SAFE
	if (NzContext::GetCurrent() != m_impl->context)
	{
		NazaraError("RenderTexture cannot be used with this context");
		return;
	}
	#endif

	glFlush();

	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
}

void NzRenderTexture::EnsureTargetUpdated() const
{
	if (!m_drawBuffersUpdated)
		UpdateDrawBuffers();

	for (nzUInt8 index : m_impl->colorTargets)
	{
		Attachment& attachment = m_impl->attachments[attachmentIndex[nzAttachmentPoint_Color] + index];
		if (!attachment.isBuffer)
			attachment.texture->InvalidateMipmaps();
	}
}

void NzRenderTexture::OnContextDestroy(const NzContext* context)
{
	NazaraAssert(m_impl, "Invalid internal state");
	NazaraUnused(context);

	#ifdef NAZARA_DEBUG
	if (m_impl->context != context)
	{
		NazaraInternalError("Not listening to " + NzString::Pointer(context));
		return;
	}
	#endif

	Destroy();
}

void NzRenderTexture::OnRenderBufferDestroy(const NzRenderBuffer* renderBuffer, unsigned int attachmentIndex)
{
	NazaraAssert(m_impl, "Invalid internal state");
	NazaraAssert(attachmentIndex < m_impl->attachments.size(), "Invalid attachment index");
	NazaraAssert(m_impl->attachments[attachmentIndex].isBuffer, "Invalid attachment state");
	NazaraUnused(renderBuffer);

	Attachment& attachment = m_impl->attachments[attachmentIndex];
	attachment.buffer = nullptr;
	attachment.isUsed = false;
	attachment.renderBufferDestroySlot.Disconnect();

	InvalidateTargets();
}

void NzRenderTexture::OnTextureDestroy(const NzTexture* texture, unsigned int attachmentIndex)
{
	NazaraAssert(m_impl, "Invalid internal state");
	NazaraAssert(attachmentIndex < m_impl->attachments.size(), "Invalid attachment index");
	NazaraAssert(!m_impl->attachments[attachmentIndex].isBuffer, "Invalid attachment state");
	NazaraUnused(texture);

	InvalidateTargets();
}

void NzRenderTexture::UpdateDrawBuffers() const
{
	if (!m_targetsUpdated)
		UpdateTargets();

	glDrawBuffers(m_impl->drawBuffers.size(), &m_impl->drawBuffers[0]);

	m_drawBuffersUpdated = true;
}

void NzRenderTexture::UpdateSize() const
{
	m_impl->width = 0;
	m_impl->height = 0;
	for (Attachment& attachment : m_impl->attachments)
	{
		if (attachment.isUsed)
		{
			m_impl->height = std::max(m_impl->height, attachment.height);
			m_impl->width = std::max(m_impl->width, attachment.width);
		}
	}

	m_sizeUpdated = true;
}

void NzRenderTexture::UpdateTargets() const
{
	if (m_impl->colorTargets.empty())
	{
		m_impl->drawBuffers.resize(1);
		m_impl->drawBuffers[0] = GL_NONE;
	}
	else
	{
		m_impl->drawBuffers.resize(m_impl->colorTargets.size());
		GLenum* ptr = &m_impl->drawBuffers[0];
		for (nzUInt8 index : m_impl->colorTargets)
			*ptr++ = GL_COLOR_ATTACHMENT0 + index;
	}

	m_targetsUpdated = true;
}