From 33a0b14e0ad70b30bf4c57ec085cb9921b2b97f5 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 9 Sep 2024 17:14:51 +0300 Subject: qcam: viewfinder_gl: Fix binding of vertex buffer and shader program Starting in Qt 6.7.0, vertex buffers and shader programs are unbound just before calling QOpenGLWidget::paintGL(). This breaks rendering in the GL viewfinder in two ways. First, we bind the vertex buffer only once at initialization time. There is therefore no vertex buffer mapped at rendering time, preventing both the vertex shader from having access to the vertex and texture coordinates. Then, we bind the shader program only when rendering the first frame. There is thus no shader program bound for all subsequent frames, breaking rendering. Fix this by binding the vertex buffer where needed, when setting attribute buffers for the shader program, and binding the shader program for every frame. As we use a single vertex buffer, we could bind it at the beginning of paintGL() and keep it bound indefinitely. That would however fail to clearly indicate in the source code where the vertex buffer is needed, making the code more difficult to understand as it would rely on implicit assumptions. Release the vertex buffer explicitly when we don't need it anymore to avoid this. While at it, fix a coding style violation by adding missing curly brackets. Signed-off-by: Laurent Pinchart Tested-by: Kieran Bingham Reviewed-by: Kieran Bingham --- src/apps/qcam/viewfinder_gl.cpp | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/src/apps/qcam/viewfinder_gl.cpp b/src/apps/qcam/viewfinder_gl.cpp index 9d2a6960..5be7bec5 100644 --- a/src/apps/qcam/viewfinder_gl.cpp +++ b/src/apps/qcam/viewfinder_gl.cpp @@ -443,15 +443,11 @@ bool ViewFinderGL::createFragmentShader() close(); } - /* Bind shader pipeline for use */ - if (!shaderProgram_.bind()) { - qWarning() << "[ViewFinderGL]:" << shaderProgram_.log(); - close(); - } - attributeVertex = shaderProgram_.attributeLocation("vertexIn"); attributeTexture = shaderProgram_.attributeLocation("textureIn"); + vertexBuffer_.bind(); + shaderProgram_.enableAttributeArray(attributeVertex); shaderProgram_.setAttributeBuffer(attributeVertex, GL_FLOAT, @@ -466,6 +462,8 @@ bool ViewFinderGL::createFragmentShader() 2, 2 * sizeof(GLfloat)); + vertexBuffer_.release(); + textureUniformY_ = shaderProgram_.uniformLocation("tex_y"); textureUniformU_ = shaderProgram_.uniformLocation("tex_u"); textureUniformV_ = shaderProgram_.uniformLocation("tex_v"); @@ -809,11 +807,18 @@ void ViewFinderGL::doRender() void ViewFinderGL::paintGL() { - if (!fragmentShader_) + if (!fragmentShader_) { if (!createFragmentShader()) { qWarning() << "[ViewFinderGL]:" << "create fragment shader failed."; } + } + + /* Bind shader pipeline for use. */ + if (!shaderProgram_.bind()) { + qWarning() << "[ViewFinderGL]:" << shaderProgram_.log(); + close(); + } if (image_) { glClearColor(0.0, 0.0, 0.0, 1.0); -- cgit v1.2.1