File indexing completed on 2024-09-15 04:51:15

 /*
     KWin - the KDE window manager
     This file is part of the KDE project.
 
     SPDX-FileCopyrightText: 2006-2007 Rivo Laks <rivolaks@hot.ee>
     SPDX-FileCopyrightText: 2010, 2011 Martin Gräßlin <mgraesslin@kde.org>
     SPDX-FileCopyrightText: 2023 Xaver Hugl <xaver.hugl@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 #include "glframebuffer.h"
 #include "core/rendertarget.h"
 #include "core/renderviewport.h"
 #include "glplatform.h"
 #include "gltexture.h"
 #include "glutils.h"
 #include "utils/common.h"
 
 namespace KWin
 {
 
 void GLFramebuffer::initStatic()
 {
     if (GLPlatform::instance()->isGLES()) {
         s_supported = true;
         s_supportsPackedDepthStencil = hasGLVersion(3, 0) || hasGLExtension(QByteArrayLiteral("GL_OES_packed_depth_stencil"));
         s_supportsDepth24 = hasGLVersion(3, 0) || hasGLExtension(QByteArrayLiteral("GL_OES_depth24"));
         s_blitSupported = hasGLVersion(3, 0);
     } else {
         s_supported = hasGLVersion(3, 0) || hasGLExtension(QByteArrayLiteral("GL_ARB_framebuffer_object")) || hasGLExtension(QByteArrayLiteral("GL_EXT_framebuffer_object"));
         s_supportsPackedDepthStencil = hasGLVersion(3, 0) || hasGLExtension(QByteArrayLiteral("GL_ARB_framebuffer_object")) || hasGLExtension(QByteArrayLiteral("GL_EXT_packed_depth_stencil"));
         s_blitSupported = hasGLVersion(3, 0) || hasGLExtension(QByteArrayLiteral("GL_ARB_framebuffer_object")) || hasGLExtension(QByteArrayLiteral("GL_EXT_framebuffer_blit"));
     }
 }
 
 void GLFramebuffer::cleanup()
 {
     Q_ASSERT(s_fbos.isEmpty());
     s_supported = false;
     s_blitSupported = false;
 }
 
 bool GLFramebuffer::blitSupported()
 {
     return s_blitSupported;
 }
 
 GLFramebuffer *GLFramebuffer::currentFramebuffer()
 {
     return s_fbos.isEmpty() ? nullptr : s_fbos.top();
 }
 
 void GLFramebuffer::pushFramebuffer(GLFramebuffer *fbo)
 {
     fbo->bind();
     s_fbos.push(fbo);
 }
 
 GLFramebuffer *GLFramebuffer::popFramebuffer()
 {
     GLFramebuffer *ret = s_fbos.pop();
     if (!s_fbos.isEmpty()) {
         s_fbos.top()->bind();
     } else {
         glBindFramebuffer(GL_FRAMEBUFFER, 0);
     }
 
     return ret;
 }
 
 GLFramebuffer::GLFramebuffer()
     : m_colorAttachment(nullptr)
 {
 }
 
 static QString formatFramebufferStatus(GLenum status)
 {
     switch (status) {
     case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
         // An attachment is the wrong type / is invalid / has 0 width or height
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT");
     case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
         // There are no images attached to the framebuffer
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT");
     case GL_FRAMEBUFFER_UNSUPPORTED:
         // A format or the combination of formats of the attachments is unsupported
         return QStringLiteral("GL_FRAMEBUFFER_UNSUPPORTED");
     case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
         // Not all attached images have the same width and height
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT");
     case GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
         // The color attachments don't have the same format
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT");
     case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
         // The attachments don't have the same number of samples
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE");
     case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
         // The draw buffer is missing
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER");
     case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
         // The read buffer is missing
         return QStringLiteral("GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER");
     default:
         return QStringLiteral("Unknown (0x") + QString::number(status, 16) + QStringLiteral(")");
     }
 }
 
 GLFramebuffer::GLFramebuffer(GLTexture *colorAttachment, Attachment attachment)
     : m_size(colorAttachment->size())
     , m_colorAttachment(colorAttachment)
 {
     if (!s_supported) {
         qCCritical(KWIN_OPENGL) << "Framebuffer objects aren't supported!";
         return;
     }
 
     GLuint prevFbo = 0;
     if (const GLFramebuffer *current = currentFramebuffer()) {
         prevFbo = current->handle();
     }
 
     glGenFramebuffers(1, &m_handle);
     glBindFramebuffer(GL_FRAMEBUFFER, m_handle);
 
     initColorAttachment(colorAttachment);
     if (attachment == Attachment::CombinedDepthStencil) {
         initDepthStencilAttachment();
     }
 
     const GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
     glBindFramebuffer(GL_FRAMEBUFFER, prevFbo);
 
     if (status != GL_FRAMEBUFFER_COMPLETE) {
         // We have an incomplete framebuffer, consider it invalid
         qCCritical(KWIN_OPENGL) << "Invalid framebuffer status: " << formatFramebufferStatus(status);
         glDeleteFramebuffers(1, &m_handle);
         return;
     }
 
     m_valid = true;
 }
 
 GLFramebuffer::GLFramebuffer(GLuint handle, const QSize &size)
     : m_handle(handle)
     , m_size(size)
     , m_valid(true)
     , m_foreign(true)
     , m_colorAttachment(nullptr)
 {
 }
 
 GLFramebuffer::~GLFramebuffer()
 {
     if (!m_foreign && m_valid) {
         glDeleteFramebuffers(1, &m_handle);
     }
     if (m_depthBuffer) {
         glDeleteRenderbuffers(1, &m_depthBuffer);
     }
     if (m_stencilBuffer && m_stencilBuffer != m_depthBuffer) {
         glDeleteRenderbuffers(1, &m_stencilBuffer);
     }
 }
 
 bool GLFramebuffer::bind()
 {
     if (!valid()) {
         qCCritical(KWIN_OPENGL) << "Can't enable invalid framebuffer object!";
         return false;
     }
 
     glBindFramebuffer(GL_FRAMEBUFFER, handle());
     glViewport(0, 0, m_size.width(), m_size.height());
 
     return true;
 }
 
 void GLFramebuffer::initColorAttachment(GLTexture *colorAttachment)
 {
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                            colorAttachment->target(), colorAttachment->texture(), 0);
 }
 
 void GLFramebuffer::initDepthStencilAttachment()
 {
     GLuint buffer = 0;
 
     // Try to attach a depth/stencil combined attachment.
     if (s_supportsPackedDepthStencil) {
         glGenRenderbuffers(1, &buffer);
         glBindRenderbuffer(GL_RENDERBUFFER, buffer);
         glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, m_size.width(), m_size.height());
         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, buffer);
         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, buffer);
 
         if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
             glDeleteRenderbuffers(1, &buffer);
         } else {
             m_depthBuffer = buffer;
             m_stencilBuffer = buffer;
             return;
         }
     }
 
     // Try to attach a depth attachment separately.
     GLenum depthFormat;
     if (GLPlatform::instance()->isGLES()) {
         if (s_supportsDepth24) {
             depthFormat = GL_DEPTH_COMPONENT24;
         } else {
             depthFormat = GL_DEPTH_COMPONENT16;
         }
     } else {
         depthFormat = GL_DEPTH_COMPONENT;
     }
 
     glGenRenderbuffers(1, &buffer);
     glBindRenderbuffer(GL_RENDERBUFFER, buffer);
     glRenderbufferStorage(GL_RENDERBUFFER, depthFormat, m_size.width(), m_size.height());
     glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, buffer);
     if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
         glDeleteRenderbuffers(1, &buffer);
     } else {
         m_depthBuffer = buffer;
     }
 
     // Try to attach a stencil attachment separately.
     GLenum stencilFormat;
     if (GLPlatform::instance()->isGLES()) {
         stencilFormat = GL_STENCIL_INDEX8;
     } else {
         stencilFormat = GL_STENCIL_INDEX;
     }
 
     glGenRenderbuffers(1, &buffer);
     glBindRenderbuffer(GL_RENDERBUFFER, buffer);
     glRenderbufferStorage(GL_RENDERBUFFER, stencilFormat, m_size.width(), m_size.height());
     glFramebufferRenderbuffer(GL_RENDERBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, buffer);
     if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
         glDeleteRenderbuffers(1, &buffer);
     } else {
         m_stencilBuffer = buffer;
     }
 }
 
 void GLFramebuffer::blitFromFramebuffer(const QRect &source, const QRect &destination, GLenum filter, bool flipX, bool flipY)
 {
     if (!valid()) {
         return;
     }
 
     const GLFramebuffer *top = currentFramebuffer();
     GLFramebuffer::pushFramebuffer(this);
 
     glBindFramebuffer(GL_DRAW_FRAMEBUFFER, handle());
     glBindFramebuffer(GL_READ_FRAMEBUFFER, top->handle());
 
     const QRect s = source.isNull() ? QRect(QPoint(0, 0), top->size()) : source;
     const QRect d = destination.isNull() ? QRect(QPoint(0, 0), size()) : destination;
 
     GLuint srcX0 = s.x();
     GLuint srcY0 = top->size().height() - (s.y() + s.height());
     GLuint srcX1 = s.x() + s.width();
     GLuint srcY1 = top->size().height() - s.y();
     if (flipX) {
         std::swap(srcX0, srcX1);
     }
     if (flipY) {
         std::swap(srcY0, srcY1);
     }
 
     const GLuint dstX0 = d.x();
     const GLuint dstY0 = m_size.height() - (d.y() + d.height());
     const GLuint dstX1 = d.x() + d.width();
     const GLuint dstY1 = m_size.height() - d.y();
 
     glBlitFramebuffer(srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1, GL_COLOR_BUFFER_BIT, filter);
 
     GLFramebuffer::popFramebuffer();
 }
 
 bool GLFramebuffer::blitFromRenderTarget(const RenderTarget &sourceRenderTarget, const RenderViewport &sourceViewport, const QRect &source, const QRect &destination)
 {
     OutputTransform transform = sourceRenderTarget.texture() ? sourceRenderTarget.texture()->contentTransform() : OutputTransform();
 
     // TODO: Also blit if rotated 180 degrees, it's equivalent to flipping both x and y axis
     const bool normal = transform == OutputTransform::Normal;
     const bool mirrorX = transform == OutputTransform::FlipX;
     const bool mirrorY = transform == OutputTransform::FlipY;
     if ((normal || mirrorX || mirrorY) && blitSupported()) {
         // either no transformation or flipping only
         blitFromFramebuffer(sourceViewport.mapToRenderTarget(source), destination, GL_LINEAR, mirrorX, mirrorY);
         return true;
     } else {
         const auto texture = sourceRenderTarget.texture();
         if (!texture) {
             // rotations aren't possible without a texture
             return false;
         }
 
         GLFramebuffer::pushFramebuffer(this);
 
         QMatrix4x4 mat;
         mat.ortho(QRectF(QPointF(), size()));
         // GLTexture::render renders with origin (0, 0), move it to the correct place
         mat.translate(destination.x(), destination.y());
 
         ShaderBinder binder(ShaderTrait::MapTexture);
         binder.shader()->setUniform(GLShader::Mat4Uniform::ModelViewProjectionMatrix, mat);
 
         texture->render(sourceViewport.mapToRenderTargetTexture(source), infiniteRegion(), destination.size(), 1);
 
         GLFramebuffer::popFramebuffer();
         return true;
     }
 }
 
 GLTexture *GLFramebuffer::colorAttachment() const
 {
     return m_colorAttachment;
 }
 
 }