df21e20f65
Although we use GLib internally in Cogl we would rather not leak GLib api through Cogl's own api, except through explicitly namespaced cogl_glib_ / cogl_gtype_ feature apis. One of the benefits we see to not leaking GLib through Cogl's public API is that documentation for Cogl won't need to first introduce the Glib API to newcomers, thus hopefully lowering the barrier to learning Cogl. This patch provides a Cogl specific typedef for reporting runtime errors which by no coincidence matches the typedef for GError exactly. If Cogl is built with --enable-glib (default) then developers can even safely assume that a CoglError is a GError under the hood. This patch also enforces a consistent policy for when NULL is passed as an error argument and an error is thrown. In this case we log the error and abort the application, instead of silently ignoring it. In common cases where nothing has been implemented to handle a particular error and/or where applications are just printing the error and aborting themselves then this saves some typing. This also seems more consistent with language based exceptions which usually cause a program to abort if they are not explicitly caught (which passing a non-NULL error signifies in this case) Since this policy for NULL error pointers is stricter than the standard GError convention, there is a clear note in the documentation to warn developers that are used to using the GError api. Reviewed-by: Neil Roberts <neil@linux.intel.com> (cherry picked from commit b068d5ea09ab32c37e8c965fc8582c85d1b2db46) Note: Since we can't change the Cogl 1.x api the patch was changed to not rename _error_quark() functions to be _error_domain() functions and although it's a bit ugly, instead of providing our own CoglError type that's compatible with GError we simply #define CoglError to GError unless Cogl is built with glib disabled. Note: this patch does technically introduce an API break since it drops the cogl_error_get_type() symbol generated by glib-mkenum (Since the CoglError enum was replaced by a CoglSystemError enum) but for now we are assuming that this will not affect anyone currently using the Cogl API. If this does turn out to be a problem in practice then we would be able to fix this my manually copying an implementation of cogl_error_get_type() generated by glib-mkenum into a compatibility source file and we could also define the original COGL_ERROR_ enums for compatibility too. Note: another minor concern with cherry-picking this patch to the 1.14 branch is that an api scanner would be lead to believe that some APIs have changed, and for example the gobject-introspection parser which understands the semantics of GError will not understand the semantics of CoglError. We expect most people that have tried to use gobject-introspection with Cogl already understand though that it is not well suited to generating bindings of the Cogl api anyway and we aren't aware or anyone depending on such bindings for apis involving GErrors. (GnomeShell only makes very-very minimal use of Cogl via the gjs bindings for the cogl_rectangle and cogl_color apis.) The main reason we have cherry-picked this patch to the 1.14 branch even given the above concerns is that without it it would become very awkward for us to cherry-pick other beneficial patches from master.
369 lines
12 KiB
C
369 lines
12 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2011 Collabora Ltd.
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* Copyright (C) 2012 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see
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* <http://www.gnu.org/licenses/>.
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*
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* Authors:
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* Tomeu Vizoso <tomeu.vizoso@collabora.com>
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* Robert Bragg <robert@linux.intel.com>
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*
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*/
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#ifndef __COGL_GLES2_H__
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#define __COGL_GLES2_H__
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#define __COGL_H_INSIDE__
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#include <cogl/cogl-defines.h>
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#include <cogl/cogl-context.h>
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#include <cogl/cogl-framebuffer.h>
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#include <cogl/cogl-texture.h>
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#include <cogl/cogl-texture-2d.h>
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/* CoglGLES2Vtable depends on GLES 2.0 typedefs being available but we
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* want to be careful that the public api doesn't expose arbitrary
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* system GL headers as part of the Cogl API so although when building
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* internally we consistently refer to the system headers to avoid
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* conflicts we only expose the minimal set of GLES 2.0 types and enums
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* publicly.
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*/
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#ifdef COGL_COMPILATION
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#include "cogl-gl-header.h"
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#else
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#include <cogl/cogl-gles2-types.h>
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#endif
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G_BEGIN_DECLS
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/**
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* SECTION:cogl-gles2
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* @short_description: A portable api to access OpenGLES 2.0
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*
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* Cogl provides portable access to the OpenGLES api through a single
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* library that is able to smooth over inconsistencies between the
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* different vendor drivers for OpenGLES in a single place.
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*
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* The api is designed to allow Cogl to transparently implement the
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* api on top of other drivers, such as OpenGL, D3D or on Cogl's own
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* drawing api so even if your platform doesn't come with an
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* OpenGLES 2.0 api Cogl may still be able to expose the api to your
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* application.
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*
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* Since Cogl is a library and not an api specification it is possible
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* to add OpenGLES 2.0 api features to Cogl which can immidiately
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* benefit developers regardless of what platform they are running on.
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*
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* With this api it's possible to re-use existing OpenGLES 2.0 code
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* within applications that are rendering with the Cogl API and also
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* it's possible for applications that render using OpenGLES 2.0 to
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* incorporate content rendered with Cogl.
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*
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* Applications can check for OpenGLES 2.0 api support by checking for
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* %COGL_FEATURE_ID_GLES2_CONTEXT support with cogl_has_feature().
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*
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* Since: 1.12
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* Stability: unstable
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*/
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/**
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* CoglGLES2Context:
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*
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* Represents an OpenGLES 2.0 api context used as a sandbox for
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* OpenGLES 2.0 state. This is comparable to an EGLContext for those
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* who have used OpenGLES 2.0 with EGL before.
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*
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* Since: 1.12
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* Stability: unstable
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*/
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typedef struct _CoglGLES2Context CoglGLES2Context;
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/**
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* CoglGLES2Vtable:
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*
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* Provides function pointers for the full OpenGLES 2.0 api. The
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* api must be accessed this way and not by directly calling
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* symbols of any system OpenGLES 2.0 api.
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*
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* Since: 1.12
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* Stability: unstable
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*/
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typedef struct _CoglGLES2Vtable CoglGLES2Vtable;
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struct _CoglGLES2Vtable
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{
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#define COGL_EXT_BEGIN(name, \
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min_gl_major, min_gl_minor, \
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gles_availability, \
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extension_suffixes, extension_names)
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#define COGL_EXT_FUNCTION(ret, name, args) \
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ret (* name) args;
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#define COGL_EXT_END()
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#include <cogl/gl-prototypes/cogl-gles2-functions.h>
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#undef COGL_EXT_BEGIN
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#undef COGL_EXT_FUNCTION
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#undef COGL_EXT_END
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};
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uint32_t
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_cogl_gles2_context_error_quark (void);
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/**
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* COGL_GLES2_CONTEXT_ERROR:
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*
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* An error domain for runtime exceptions relating to the
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* cogl_gles2_context api.
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*
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* Since: 2.0
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* Stability: unstable
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*/
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#define COGL_GLES2_CONTEXT_ERROR (_cogl_gles2_context_error_quark ())
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/**
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* CoglGLES2ContextError:
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* @COGL_GLES2_CONTEXT_ERROR_UNSUPPORTED: Creating GLES2 contexts
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* isn't supported. Applications should use cogl_has_feature() to
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* check for the %COGL_FEATURE_ID_GLES2_CONTEXT.
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* @COGL_GLES2_CONTEXT_ERROR_DRIVER: An underlying driver error
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* occured.
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*
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* Error codes that relate to the cogl_gles2_context api.
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*/
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typedef enum { /*< prefix=COGL_GLES2_CONTEXT_ERROR >*/
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COGL_GLES2_CONTEXT_ERROR_UNSUPPORTED,
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COGL_GLES2_CONTEXT_ERROR_DRIVER
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} CoglGLES2ContextError;
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/**
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* cogl_gles2_context_new:
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* @ctx: A #CoglContext
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* @error: A pointer to a #CoglError for returning exceptions
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*
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* Allocates a new OpenGLES 2.0 context that can be used to render to
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* #CoglOffscreen framebuffers (Rendering to #CoglOnscreen
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* framebuffers is not currently supported).
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*
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* To actually access the OpenGLES 2.0 api itself you need to use
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* cogl_gles2_context_get_vtable(). You should not try to directly link
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* to and use the symbols provided by the a system OpenGLES 2.0
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* driver.
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*
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* Once you have allocated an OpenGLES 2.0 context you can make it
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* current using cogl_push_gles2_context(). For those familiar with
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* using the EGL api, this serves a similar purpose to eglMakeCurrent.
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*
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* <note>Before using this api applications can check for OpenGLES 2.0
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* api support by checking for %COGL_FEATURE_ID_GLES2_CONTEXT support
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* with cogl_has_feature(). This function will return %FALSE and
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* return an %COGL_GLES2_CONTEXT_ERROR_UNSUPPORTED error if the
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* feature isn't available.</note>
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*
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* Since: 2.0
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* Return value: A newly allocated #CoglGLES2Context or %NULL if there
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* was an error and @error will be updated in that case.
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* Stability: unstable
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*/
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CoglGLES2Context *
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cogl_gles2_context_new (CoglContext *ctx, CoglError **error);
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/**
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* cogl_gles2_context_get_vtable:
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* @gles2_ctx: A #CoglGLES2Context allocated with
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* cogl_gles2_context_new()
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*
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* Queries the OpenGLES 2.0 api function pointers that should be
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* used for rendering with the given @gles2_ctx.
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*
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* <note>You should not try to directly link to and use the symbols
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* provided by any system OpenGLES 2.0 driver.</note>
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*
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* Since: 2.0
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* Return value: A pointer to a #CoglGLES2Vtable providing pointers
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* to functions for the full OpenGLES 2.0 api.
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* Stability: unstable
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*/
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const CoglGLES2Vtable *
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cogl_gles2_context_get_vtable (CoglGLES2Context *gles2_ctx);
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/**
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* cogl_push_gles2_context:
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* @ctx: A #CoglContext
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* @gles2_ctx: A #CoglGLES2Context allocated with
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* cogl_gles2_context_new()
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* @read_buffer: A #CoglFramebuffer to access to read operations
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* such as glReadPixels. (must be a #CoglOffscreen
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* framebuffer currently)
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* @write_buffer: A #CoglFramebuffer to access for drawing operations
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* such as glDrawArrays. (must be a #CoglOffscreen
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* framebuffer currently)
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* @error: A pointer to a #CoglError for returning exceptions
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*
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* Pushes the given @gles2_ctx onto a stack associated with @ctx so
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* that the OpenGLES 2.0 api can be used instead of the Cogl
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* rendering apis to read and write to the specified framebuffers.
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*
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* Usage of the api available through a #CoglGLES2Vtable is only
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* allowed between cogl_push_gles2_context() and
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* cogl_pop_gles2_context() calls.
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*
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* If there is a runtime problem with switching over to the given
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* @gles2_ctx then this function will return %FALSE and return
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* an error through @error.
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*
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* Since: 2.0
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* Return value: %TRUE if operation was successfull or %FALSE
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* otherwise and @error will be updated.
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* Stability: unstable
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*/
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CoglBool
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cogl_push_gles2_context (CoglContext *ctx,
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CoglGLES2Context *gles2_ctx,
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CoglFramebuffer *read_buffer,
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CoglFramebuffer *write_buffer,
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CoglError **error);
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/**
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* cogl_pop_gles2_context:
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* @ctx: A #CoglContext
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*
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* Restores the previously active #CoglGLES2Context if there
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* were nested calls to cogl_push_gles2_context() or otherwise
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* restores the ability to render with the Cogl api instead
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* of OpenGLES 2.0.
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*
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* The behaviour is undefined if calls to cogl_pop_gles2_context()
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* are not balenced with the number of corresponding calls to
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* cogl_push_gles2_context().
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*
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* Since: 2.0
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* Stability: unstable
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*/
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void
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cogl_pop_gles2_context (CoglContext *ctx);
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/**
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* cogl_gles2_get_current_vtable:
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*
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* Returns the OpenGL ES 2.0 api vtable for the currently pushed
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* #CoglGLES2Context (last pushed with cogl_push_gles2_context()) or
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* %NULL if no #CoglGLES2Context has been pushed.
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*
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* Return value: The #CoglGLES2Vtable for the currently pushed
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* #CoglGLES2Context or %NULL if none has been pushed.
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* Since: 2.0
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* Stability: unstable
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*/
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CoglGLES2Vtable *
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cogl_gles2_get_current_vtable (void);
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/**
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* cogl_gles2_texture_2d_new_from_handle:
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* @ctx: A #CoglContext
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* @gles2_ctx: A #CoglGLES2Context allocated with
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* cogl_gles2_context_new()
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* @handle: An OpenGL ES 2.0 texture handle created with
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* glGenTextures()
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*
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* Creates a #CoglTexture2D from an OpenGL ES 2.0 texture handle that
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* was created within the given @gles2_ctx via glGenTextures(). The
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* texture needs to have been associated with the GL_TEXTURE_2D target.
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*
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* <note>This interface is only intended for sharing textures to read
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* from. The behaviour is undefined if the texture is modified using
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* the Cogl api.</note>
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*
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* <note>Applications should only pass this function handles that were
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* created via a #CoglGLES2Vtable or via libcogl-gles2 and not pass
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* handles created directly using the system's native libGLESv2
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* api.</note>
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*
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* Since: 2.0
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* Stability: unstable
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*/
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CoglTexture2D *
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cogl_gles2_texture_2d_new_from_handle (CoglContext *ctx,
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CoglGLES2Context *gles2_ctx,
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unsigned int handle,
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int width,
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int height,
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CoglPixelFormat internal_format,
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CoglError **error);
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/**
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* cogl_gles2_texture_get_handle:
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* @handle: A return location for an OpenGL ES 2.0 texture handle
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* @target: A return location for an OpenGL ES 2.0 texture target
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*
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* Gets an OpenGL ES 2.0 texture handle for a #CoglTexture that can
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* then be referenced by a #CoglGLES2Context. As well as returning
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* a texture handle the texture's target (such as GL_TEXTURE_2D) is
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* also returned.
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*
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* If the #CoglTexture can not be shared with a #CoglGLES2Context then
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* this function will return %FALSE.
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*
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* This api does not affect the lifetime of the CoglTexture and you
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* must take care not to reference the returned handle after the
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* original texture has been freed.
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*
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* <note>This interface is only intended for sharing textures to read
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* from. The behaviour is undefined if the texture is modified by a
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* GLES2 context.</note>
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*
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* <note>This function will only return %TRUE for low-level
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* #CoglTexture<!-- -->s such as #CoglTexture2D or #CoglTexture3D but
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* not for high level meta textures such as
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* #CoglTexture2DSliced</note>
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*
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* <note>The handle returned should not be passed directly to a system
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* OpenGL ES 2.0 library, the handle is only intended to be used via
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* a #CoglGLES2Vtable or via libcogl-gles2.</note>
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*
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* Return value: %TRUE if a handle and target could be returned
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* otherwise %FALSE is returned.
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* Since: 2.0
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* Stability: unstable
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*/
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CoglBool
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cogl_gles2_texture_get_handle (CoglTexture *texture,
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unsigned int *handle,
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unsigned int *target);
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/**
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* cogl_is_gles2_context:
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* @object: A #CoglObject pointer
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*
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* Gets whether the given object references a #CoglGLES2Context.
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*
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* Return value: %TRUE if the object references a #CoglGLES2Context
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* and %FALSE otherwise.
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* Since: 2.0
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* Stability: unstable
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*/
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CoglBool
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cogl_is_gles2_context (void *object);
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G_END_DECLS
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#endif /* __COGL_GLES2_H__ */
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