mutter/cogl/cogl-context-private.h
Neil Roberts 52a646abc5 Use the EGL_KHR_surfacless_context extension
The surfaceless context extension can be used to bind a context
without a surface. We can use this to avoid creating a dummy surface
when the CoglContext is first created. Otherwise we have to have the
dummy surface so that we can bind it before the first onscreen is
created.

The main awkward part of this patch is that theoretically according to
the GL and GLES spec if you first bind a context without a surface
then the default state for glDrawBuffers is GL_NONE instead of
GL_BACK. In practice Mesa doesn't seem to do this but we need to be
robust against a GL implementation that does. Therefore we track when
the CoglContext is first used with a CoglOnscreen and force the
glDrawBuffers state to be GL_BACK.

There is a further awkward part in that GLES2 doesn't actually have a
glDrawBuffers state but GLES3 does. GLES3 also defaults to GL_NONE in
this case so if GLES3 is available then we have to be sure to set the
state to GL_BACK. As far as I can tell that actually makes GLES3
incompatible with GLES2 because in theory if the application is not
aware of GLES3 then it should be able to assume the draw buffer is
always GL_BACK.

Reviewed-by: Robert Bragg <robert.bragg@intel.com>
(cherry picked from commit e5f28f1e75db9bdc4f2688f420a74f908f96cf76)

Conflicts:
	cogl/winsys/cogl-winsys-egl-kms.c
	cogl/winsys/cogl-winsys-egl-x11.c
2014-06-17 13:31:03 +01:00

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/*
* Cogl
*
* A Low Level GPU Graphics and Utilities API
*
* Copyright (C) 2007,2008,2009,2013 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*
*/
#ifndef __COGL_CONTEXT_PRIVATE_H
#define __COGL_CONTEXT_PRIVATE_H
#include "cogl-context.h"
#include "cogl-winsys-private.h"
#include "cogl-flags.h"
#ifdef COGL_HAS_XLIB_SUPPORT
#include "cogl-xlib-private.h"
#endif
#include "cogl-display-private.h"
#include "cogl-primitives.h"
#include "cogl-clip-stack.h"
#include "cogl-matrix-stack.h"
#include "cogl-pipeline-private.h"
#include "cogl-buffer-private.h"
#include "cogl-bitmask.h"
#include "cogl-atlas.h"
#include "cogl-driver.h"
#include "cogl-texture-driver.h"
#include "cogl-pipeline-cache.h"
#include "cogl-texture-2d.h"
#include "cogl-texture-3d.h"
#include "cogl-texture-rectangle.h"
#include "cogl-sampler-cache-private.h"
#include "cogl-gpu-info-private.h"
#include "cogl-gl-header.h"
#include "cogl-framebuffer-private.h"
#include "cogl-onscreen-private.h"
#include "cogl-fence-private.h"
#include "cogl-poll-private.h"
#include "cogl-path/cogl-path-types.h"
#include "cogl-private.h"
typedef struct
{
GLfloat v[3];
GLfloat t[2];
GLubyte c[4];
} CoglTextureGLVertex;
struct _CoglContext
{
CoglObject _parent;
CoglDisplay *display;
CoglDriver driver;
/* Information about the GPU and driver which we can use to
determine certain workarounds */
CoglGpuInfo gpu;
/* vtables for the driver functions */
const CoglDriverVtable *driver_vtable;
const CoglTextureDriver *texture_driver;
int glsl_major;
int glsl_minor;
/* This is the GLSL version that we will claim that snippets are
* written against using the #version pragma. This will be the
* largest version that is less than or equal to the version
* provided by the driver without massively altering the syntax. Eg,
* we wouldn't use version 1.3 even if it is available because that
* removes the attribute and varying keywords. */
int glsl_version_to_use;
/* Features cache */
unsigned long features[COGL_FLAGS_N_LONGS_FOR_SIZE (_COGL_N_FEATURE_IDS)];
CoglFeatureFlags feature_flags; /* legacy/deprecated feature flags */
unsigned long private_features
[COGL_FLAGS_N_LONGS_FOR_SIZE (COGL_N_PRIVATE_FEATURES)];
CoglBool needs_viewport_scissor_workaround;
CoglFramebuffer *viewport_scissor_workaround_framebuffer;
CoglPipeline *default_pipeline;
CoglPipelineLayer *default_layer_0;
CoglPipelineLayer *default_layer_n;
CoglPipelineLayer *dummy_layer_dependant;
GHashTable *attribute_name_states_hash;
GArray *attribute_name_index_map;
int n_attribute_names;
CoglBitmask enabled_builtin_attributes;
CoglBitmask enabled_texcoord_attributes;
CoglBitmask enabled_custom_attributes;
/* These are temporary bitmasks that are used when disabling
* builtin,texcoord and custom attribute arrays. They are here just
* to avoid allocating new ones each time */
CoglBitmask enable_builtin_attributes_tmp;
CoglBitmask enable_texcoord_attributes_tmp;
CoglBitmask enable_custom_attributes_tmp;
CoglBitmask changed_bits_tmp;
CoglBool legacy_backface_culling_enabled;
/* A few handy matrix constants */
CoglMatrix identity_matrix;
CoglMatrix y_flip_matrix;
/* Value that was last used when calling glMatrixMode to avoid
calling it multiple times */
CoglMatrixMode flushed_matrix_mode;
/* The matrix stack entries that should be flushed during the next
* pipeline state flush */
CoglMatrixEntry *current_projection_entry;
CoglMatrixEntry *current_modelview_entry;
CoglMatrixEntry identity_entry;
/* A cache of the last (immutable) matrix stack entries that were
* flushed to the GL matrix builtins */
CoglMatrixEntryCache builtin_flushed_projection;
CoglMatrixEntryCache builtin_flushed_modelview;
GArray *texture_units;
int active_texture_unit;
CoglPipelineFogState legacy_fog_state;
/* Pipelines */
CoglPipeline *opaque_color_pipeline; /* used for set_source_color */
CoglPipeline *blended_color_pipeline; /* used for set_source_color */
CoglPipeline *texture_pipeline; /* used for set_source_texture */
GString *codegen_header_buffer;
GString *codegen_source_buffer;
GString *codegen_boilerplate_buffer;
GList *source_stack;
int legacy_state_set;
CoglPipelineCache *pipeline_cache;
/* Textures */
CoglTexture2D *default_gl_texture_2d_tex;
CoglTexture3D *default_gl_texture_3d_tex;
CoglTextureRectangle *default_gl_texture_rect_tex;
/* Central list of all framebuffers so all journals can be flushed
* at any time. */
GList *framebuffers;
/* Global journal buffers */
GArray *journal_flush_attributes_array;
GArray *journal_clip_bounds;
GArray *polygon_vertices;
/* Some simple caching, to minimize state changes... */
CoglPipeline *current_pipeline;
unsigned long current_pipeline_changes_since_flush;
CoglBool current_pipeline_with_color_attrib;
CoglBool current_pipeline_unknown_color_alpha;
unsigned long current_pipeline_age;
CoglBool gl_blend_enable_cache;
CoglBool depth_test_enabled_cache;
CoglDepthTestFunction depth_test_function_cache;
CoglBool depth_writing_enabled_cache;
float depth_range_near_cache;
float depth_range_far_cache;
CoglBool legacy_depth_test_enabled;
CoglBuffer *current_buffer[COGL_BUFFER_BIND_TARGET_COUNT];
/* Framebuffers */
GSList *framebuffer_stack;
CoglFramebuffer *window_buffer;
unsigned long current_draw_buffer_state_flushed;
unsigned long current_draw_buffer_changes;
CoglFramebuffer *current_draw_buffer;
CoglFramebuffer *current_read_buffer;
gboolean have_last_offscreen_allocate_flags;
CoglOffscreenAllocateFlags last_offscreen_allocate_flags;
GHashTable *swap_callback_closures;
int next_swap_callback_id;
CoglList onscreen_events_queue;
CoglList onscreen_dirty_queue;
CoglClosure *onscreen_dispatch_idle;
CoglGLES2Context *current_gles2_context;
GQueue gles2_context_stack;
/* This becomes TRUE the first time the context is bound to an
* onscreen buffer. This is used by cogl-framebuffer-gl to determine
* when to initialise the glDrawBuffer state */
CoglBool was_bound_to_onscreen;
/* Primitives */
CoglPath *current_path;
CoglPipeline *stencil_pipeline;
/* Pre-generated VBOs containing indices to generate GL_TRIANGLES
out of a vertex array of quads */
CoglIndices *quad_buffer_indices_byte;
unsigned int quad_buffer_indices_len;
CoglIndices *quad_buffer_indices;
CoglIndices *rectangle_byte_indices;
CoglIndices *rectangle_short_indices;
int rectangle_short_indices_len;
CoglBool in_begin_gl_block;
CoglPipeline *texture_download_pipeline;
CoglPipeline *blit_texture_pipeline;
GSList *atlases;
GHookList atlas_reorganize_callbacks;
/* This debugging variable is used to pick a colour for visually
displaying the quad batches. It needs to be global so that it can
be reset by cogl_clear. It needs to be reset to increase the
chances of getting the same colour during an animation */
uint8_t journal_rectangles_color;
/* Cached values for GL_MAX_TEXTURE_[IMAGE_]UNITS to avoid calling
glGetInteger too often */
GLint max_texture_units;
GLint max_texture_image_units;
GLint max_activateable_texture_units;
/* Fragment processing programs */
CoglHandle current_program;
CoglPipelineProgramType current_fragment_program_type;
CoglPipelineProgramType current_vertex_program_type;
GLuint current_gl_program;
CoglBool current_gl_dither_enabled;
CoglColorMask current_gl_color_mask;
/* Clipping */
/* TRUE if we have a valid clipping stack flushed. In that case
current_clip_stack will describe what the current state is. If
this is FALSE then the current clip stack is completely unknown
so it will need to be reflushed. In that case current_clip_stack
doesn't need to be a valid pointer. We can't just use NULL in
current_clip_stack to mark a dirty state because NULL is a valid
stack (meaning no clipping) */
CoglBool current_clip_stack_valid;
/* The clip state that was flushed. This isn't intended to be used
as a stack to push and pop new entries. Instead the current stack
that the user wants is part of the framebuffer state. This is
just used to record the flush state so we can avoid flushing the
same state multiple times. When the clip state is flushed this
will hold a reference */
CoglClipStack *current_clip_stack;
/* Whether the stencil buffer was used as part of the current clip
state. If TRUE then any further use of the stencil buffer (such
as for drawing paths) would need to be merged with the existing
stencil buffer */
CoglBool current_clip_stack_uses_stencil;
/* This is used as a temporary buffer to fill a CoglBuffer when
cogl_buffer_map fails and we only want to map to fill it with new
data */
GByteArray *buffer_map_fallback_array;
CoglBool buffer_map_fallback_in_use;
size_t buffer_map_fallback_offset;
CoglWinsysRectangleState rectangle_state;
CoglSamplerCache *sampler_cache;
/* FIXME: remove these when we remove the last xlib based clutter
* backend. they should be tracked as part of the renderer but e.g.
* the eglx backend doesn't yet have a corresponding Cogl winsys
* and so we wont have a renderer in that case. */
#ifdef COGL_HAS_XLIB_SUPPORT
int damage_base;
/* List of callback functions that will be given every Xlib event */
GSList *event_filters;
/* Current top of the XError trap state stack. The actual memory for
these is expected to be allocated on the stack by the caller */
CoglXlibTrapState *trap_state;
#endif
unsigned long winsys_features
[COGL_FLAGS_N_LONGS_FOR_SIZE (COGL_WINSYS_FEATURE_N_FEATURES)];
void *winsys;
/* Array of names of uniforms. These are used like quarks to give a
unique number to each uniform name except that we ensure that
they increase sequentially so that we can use the id as an index
into a bitfield representing the uniforms that a pipeline
overrides from its parent. */
GPtrArray *uniform_names;
/* A hash table to quickly get an index given an existing name. The
name strings are owned by the uniform_names array. The values are
the uniform location cast to a pointer. */
GHashTable *uniform_name_hash;
int n_uniform_names;
CoglPollSource *fences_poll_source;
CoglList fences;
/* This defines a list of function pointers that Cogl uses from
either GL or GLES. All functions are accessed indirectly through
these pointers rather than linking to them directly */
#ifndef APIENTRY
#define APIENTRY
#endif
#define COGL_EXT_BEGIN(name, \
min_gl_major, min_gl_minor, \
gles_availability, \
extension_suffixes, extension_names)
#define COGL_EXT_FUNCTION(ret, name, args) \
ret (APIENTRY * name) args;
#define COGL_EXT_END()
#include "gl-prototypes/cogl-all-functions.h"
#undef COGL_EXT_BEGIN
#undef COGL_EXT_FUNCTION
#undef COGL_EXT_END
};
CoglContext *
_cogl_context_get_default ();
const CoglWinsysVtable *
_cogl_context_get_winsys (CoglContext *context);
/* Query the GL extensions and lookup the corresponding function
* pointers. Theoretically the list of extensions can change for
* different GL contexts so it is the winsys backend's responsiblity
* to know when to re-query the GL extensions. The backend should also
* check whether the GL context is supported by Cogl. If not it should
* return FALSE and set @error */
CoglBool
_cogl_context_update_features (CoglContext *context,
CoglError **error);
/* Obtains the context and returns retval if NULL */
#define _COGL_GET_CONTEXT(ctxvar, retval) \
CoglContext *ctxvar = _cogl_context_get_default (); \
if (ctxvar == NULL) return retval;
#define NO_RETVAL
void
_cogl_context_set_current_projection_entry (CoglContext *context,
CoglMatrixEntry *entry);
void
_cogl_context_set_current_modelview_entry (CoglContext *context,
CoglMatrixEntry *entry);
/*
* _cogl_context_get_gl_extensions:
* @context: A CoglContext
*
* Return value: a NULL-terminated array of strings representing the
* supported extensions by the current driver. This array is owned
* by the caller and should be freed with g_strfreev().
*/
char **
_cogl_context_get_gl_extensions (CoglContext *context);
const char *
_cogl_context_get_gl_version (CoglContext *context);
#endif /* __COGL_CONTEXT_PRIVATE_H */