mutter/cogl/cogl-context.h
Neil Roberts 992d5f7fb6 cogl-vertex-buffer: Don't disable layers with no texture coords
It should be quite acceptable to use a texture without defining any
texture coords. For example a shader may be in use that is doing
texture lookups without referencing the texture coordinates. Also it
should be possible to replace the vertex colors using a texture layer
without a texture but with a constant layer color.

enable_state_for_drawing_buffer no longer sets any disabled layers in
the overrides. Instead of counting the number of units with texture
coordinates it now keeps them in a mask. This means there can now be
gaps in the list of enabled texture coordinate arrays. To cope with
this, the Cogl context now also stores a mask to track the enabled
arrays. Instead of code manually iterating each enabled array to
disable them, there is now an internal function called
_cogl_disable_texcoord_arrays which disables a given mask.

I think this could also fix potential bugs when a vertex buffer has
gaps in the texture coordinate attributes that it provides. For
example if the vertex buffer only had texture coordinates for layer 2
then the disabling code would not disable the coordinates for layers 0
and 1 even though they are not used. This could cause a crash if the
previous data for those arrays is no longer valid.

http://bugzilla.openedhand.com/show_bug.cgi?id=2132
2010-05-24 16:10:56 +01:00

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4.1 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*/
#ifndef __COGL_CONTEXT_H
#define __COGL_CONTEXT_H
#include "cogl-internal.h"
#include "cogl-context-driver.h"
#include "cogl-primitives.h"
#include "cogl-clip-stack.h"
#include "cogl-matrix-stack.h"
#include "cogl-material-private.h"
#include "cogl-atlas.h"
#include "cogl-buffer-private.h"
typedef struct
{
GLfloat v[3];
GLfloat t[2];
GLubyte c[4];
} CoglTextureGLVertex;
typedef struct
{
/* Features cache */
CoglFeatureFlags feature_flags;
gboolean features_cached;
CoglHandle default_material;
/* Enable cache */
unsigned long enable_flags;
guint8 color_alpha;
gboolean enable_backface_culling;
CoglFrontWinding flushed_front_winding;
gboolean indirect;
/* A few handy matrix constants */
CoglMatrix identity_matrix;
CoglMatrix y_flip_matrix;
/* Client-side matrix stack or NULL if none */
CoglMatrixMode flushed_matrix_mode;
GList *texture_units;
/* Materials */
CoglHandle simple_material;
CoglHandle source_material;
/* Textures */
CoglHandle default_gl_texture_2d_tex;
CoglHandle default_gl_texture_rect_tex;
/* Batching geometry... */
/* We journal the texture rectangles we want to submit to OpenGL so
* we have an oppertunity to optimise the final order so that we
* can batch things together. */
GArray *journal;
GArray *logged_vertices;
GArray *polygon_vertices;
/* Some simple caching, to minimize state changes... */
CoglHandle current_material;
unsigned long current_material_flags;
CoglMaterialFlushOptions current_material_flush_options;
GArray *current_layers;
/* Bitmask of texture coordinates arrays that are enabled */
unsigned int texcoord_arrays_enabled;
/* PBOs */
/* This can be used to check if a pbo is bound */
CoglBuffer *current_pbo;
/* Framebuffers */
GSList *framebuffer_stack;
CoglHandle window_buffer;
gboolean dirty_bound_framebuffer;
gboolean dirty_gl_viewport;
/* Primitives */
CoglHandle current_path;
CoglHandle stencil_material;
/* Pre-generated VBOs containing indices to generate GL_TRIANGLES
out of a vertex array of quads */
CoglHandle quad_indices_byte;
unsigned int quad_indices_short_len;
CoglHandle quad_indices_short;
gboolean in_begin_gl_block;
CoglHandle texture_download_material;
CoglAtlas *atlas;
CoglHandle atlas_texture;
/* 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 */
guint8 journal_rectangles_color;
/* Cached value for GL_MAX_TEXTURE_UNITS to avoid calling
glGetInteger too often */
GLint max_texture_units;
CoglContextDriver drv;
} CoglContext;
CoglContext *
_cogl_context_get_default ();
/* 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
#endif /* __COGL_CONTEXT_H */