From 41fea4472dec859ddec76bdfa7108ebec71de1e3 Mon Sep 17 00:00:00 2001 From: marha Date: Fri, 21 Mar 2014 19:36:05 +0100 Subject: xserver fontconfig libX11 libXext libxcb mesa git update 21 Mar 2014 xserver commit 4fb31e4824d46edc80bb49b4065152899faa5ac6 libxcb commit cb686b576739deea00180c54697c8b62b8419ae0 libX11 commit 8be4610939b833587954957f5963eb4191b43d19 libXext commit 11aad96bd689d54156064d2e81213dc827a689d1 fontconfig commit 5478192f379d784b421329e4bf72cc780818e467 mesa commit 8d8d0cb09eb8735a04fc36cc4d0e2dc9f9d460eb --- mesalib/docs/specs/MESA_configless_context.spec | 125 ++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 mesalib/docs/specs/MESA_configless_context.spec (limited to 'mesalib/docs/specs') diff --git a/mesalib/docs/specs/MESA_configless_context.spec b/mesalib/docs/specs/MESA_configless_context.spec new file mode 100644 index 000000000..f2fafb35a --- /dev/null +++ b/mesalib/docs/specs/MESA_configless_context.spec @@ -0,0 +1,125 @@ +Name + + MESA_configless_context + +Name Strings + + EGL_MESA_configless_context + +Contact + + Neil Roberts + +Status + + Proposal + +Version + + Version 1, February 28, 2014 + +Number + + EGL Extension #not assigned + +Dependencies + + Requires EGL 1.4 or later. This extension is written against the + wording of the EGL 1.4 specification. + +Overview + + This extension provides a means to use a single context to render to + multiple surfaces which have different EGLConfigs. Without this extension + the EGLConfig for every surface used by the context must be compatible + with the one used by the context. The only way to render to surfaces with + different formats would be to create multiple contexts but this is + inefficient with modern GPUs where this restriction is unnecessary. + +IP Status + + Open-source; freely implementable. + +New Procedures and Functions + + None. + +New Tokens + + Accepted as in eglCreateContext + + EGL_NO_CONFIG_MESA ((EGLConfig)0) + +Additions to the EGL Specification section "2.2 Rendering Contexts and Drawing +Surfaces" + + Add the following to the 3rd paragraph: + + "EGLContexts can also optionally be created with respect to an EGLConfig + depending on the parameters used at creation time. If a config is provided + then additional restrictions apply on what surfaces can be used with the + context." + + Replace the last sentence of the 6th paragraph with: + + "In order for a context to be compatible with a surface they both must have + been created with respect to the same EGLDisplay. If the context was + created without respect to an EGLConfig then there are no further + constraints. Otherwise they are only compatible if:" + + Remove the last bullet point in the list of constraints. + +Additions to the EGL Specification section "3.7.1 Creating Rendering Contexts" + + Replace the paragraph starting "If config is not a valid EGLConfig..." + with + + "The config argument can either be a valid EGLConfig or EGL_NO_CONFIG_MESA. + If it is neither of these then an EGL_BAD_CONFIG error is generated. If a + valid config is passed then the error will also be generated if the config + does not support the requested client API (this includes requesting + creation of an OpenGL ES 1.x context when the EGL_RENDERABLE_TYPE + attribute of config does not contain EGL_OPENGL_ES_BIT, or creation of an + OpenGL ES 2.x context when the attribute does not contain + EGL_OPENGL_ES2_BIT). + + Passing EGL_NO_CONFIG_MESA will create a configless context. When a + configless context is used with the OpenGL API it can be assumed that the + initial values of the context's state will be decided when the context is + first made current. In particular this means that the decision of whether + to use GL_BACK or GL_FRONT for the initial value of the first output in + glDrawBuffers will be decided based on the config of the draw surface when + it is first bound." + +Additions to the EGL Specification section "3.7.3 Binding Contexts and +Drawables" + + Replace the first bullet point with the following: + + "* If draw or read are not compatible with ctx as described in section 2.2, + then an EGL_BAD_MATCH error is generated." + + Add a second bullet point after that: + + "* If draw and read are not compatible with each other as described in + section 2.2, then an EGL_BAD_MATCH error is generated." + +Issues + + 1. What happens when an OpenGL context with a double-buffered surface and + draw buffer set to GL_BACK is made current with a single-buffered + surface? + + NOT RESOLVED: There are a few options here. An implementation can + raise an error, change the drawbuffer state to GL_FRONT or just do + nothing, expecting the application to set GL_FRONT drawbuffer before + drawing. However, this extension deliberately does not specify any + required behavior in this corner case and applications should avoid + mixing single- and double-buffered surfaces with configless contexts. + + Future extensions may specify required behavior in this case. + +Revision History + + Version 1, February 28, 2014 + Initial draft (Neil Roberts) -- cgit v1.2.3