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mutter/cogl/cogl-material-private.h
Neil Roberts e007bc5358 cogl-material: Add support for setting the wrap mode for a layer 
Previously, Cogl's texture coordinate system was effectively always
GL_REPEAT so that if an application specifies coordinates outside the
range 0→1 it would get repeated copies of the texture. It would
however change the mode to GL_CLAMP_TO_EDGE if all of the coordinates
are in the range 0→1 so that in the common case that the whole texture
is being drawn with linear filtering it will not blend in edge pixels
from the opposite sides.

This patch adds the option for applications to change the wrap mode
per layer. There are now three wrap modes: 'repeat', 'clamp-to-edge'
and 'automatic'. The automatic map mode is the default and it
implements the previous behaviour. The wrap mode can be changed for
the s and t coordinates independently. I've tried to make the
internals support setting the r coordinate but as we don't support 3D
textures yet I haven't exposed any public API for it.

The texture backends still have a set_wrap_mode virtual but this value
is intended to be transitory and it will be changed whenever the
material is flushed (although the backends are expected to cache it so
that it won't use too many GL calls). In my understanding this value
was always meant to be transitory and all primitives were meant to set
the value before drawing. However there were comments suggesting that
this is not the expected behaviour. In particular the vertex buffer
drawing code never set a wrap mode so it would end up with whatever
the texture was previously used for. These issues are now fixed
because the material will always set the wrap modes.

There is code to manually implement clamp-to-edge for textures that
can't be hardware repeated. However this doesn't fully work because it
relies on being able to draw the stretched parts using quads with the
same values for tx1 and tx2. The texture iteration code doesn't
support this so it breaks. This is a separate bug and it isn't
trivially solved.

When flushing a material there are now extra options to set wrap mode
overrides. The overrides are an array of values for each layer that
specifies an override for the s, t or r coordinates. The primitives
use this to implement the automatic wrap mode. cogl_polygon also uses
it to set GL_CLAMP_TO_BORDER mode for its trick to render sliced
textures. Although this code has been added it looks like the sliced
trick has been broken for a while and I haven't attempted to fix it
here.

I've added a constant to represent the maximum number of layers that a
material supports so that I can size the overrides array. I've set it
to 32 because as far as I can tell we have that limit imposed anyway
because the other flush options use a guint32 to store a flag about
each layer. The overrides array ends up adding 32 bytes to each flush
options struct which may be a concern.

http://bugzilla.openedhand.com/show_bug.cgi?id=2063
2010-04-12 15:44:23 +01:00

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/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 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/>.
*
*
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#ifndef __COGL_MATERIAL_PRIVATE_H
#define __COGL_MATERIAL_PRIVATE_H
#include "cogl-material.h"
#include "cogl-matrix.h"
#include "cogl-handle.h"
#include <glib.h>
typedef struct _CoglMaterial CoglMaterial;
typedef struct _CoglMaterialLayer CoglMaterialLayer;
typedef enum _CoglMaterialEqualFlags
{
/* Return FALSE if any component of either material isn't set to its
* default value. (Note: if the materials have corresponding flush
* options indicating that e.g. the material color won't be flushed then
* this will not assert a default color value.) */
COGL_MATERIAL_EQUAL_FLAGS_ASSERT_ALL_DEFAULTS = 1L<<0,
} CoglMaterialEqualFlags;
/* XXX: I don't think gtk-doc supports having private enums so these aren't
* bundled in with CoglMaterialLayerFlags */
typedef enum _CoglMaterialLayerPrivFlags
{
/* Ref: CoglMaterialLayerFlags
COGL_MATERIAL_LAYER_FLAG_HAS_USER_MATRIX = 1L<<0
*/
COGL_MATERIAL_LAYER_FLAG_DIRTY = 1L<<1,
COGL_MATERIAL_LAYER_FLAG_DEFAULT_COMBINE = 1L<<2
} CoglMaterialLayerPrivFlags;
/* For tracking the state of a layer that's been flushed to OpenGL */
typedef struct _CoglLayerInfo
{
CoglHandle handle;
unsigned long flags;
GLenum gl_target;
GLuint gl_texture;
gboolean fallback;
gboolean disabled;
gboolean layer0_overridden;
} CoglLayerInfo;
struct _CoglMaterialLayer
{
CoglHandleObject _parent;
unsigned int index; /*!< lowest index is blended first then others on
top */
unsigned long flags;
CoglHandle texture; /*!< The texture for this layer, or
COGL_INVALID_HANDLE for an empty layer */
CoglMaterialFilter mag_filter;
CoglMaterialFilter min_filter;
CoglMaterialWrapMode wrap_mode_s;
CoglMaterialWrapMode wrap_mode_t;
CoglMaterialWrapMode wrap_mode_r;
/* Determines how the color of individual texture fragments
* are calculated. */
GLint texture_combine_rgb_func;
GLint texture_combine_rgb_src[3];
GLint texture_combine_rgb_op[3];
GLint texture_combine_alpha_func;
GLint texture_combine_alpha_src[3];
GLint texture_combine_alpha_op[3];
GLfloat texture_combine_constant[4];
/* TODO: Support purely GLSL based material layers */
CoglMatrix matrix;
};
typedef enum _CoglMaterialFlags
{
COGL_MATERIAL_FLAG_SHOWN_SAMPLER_WARNING = 1L<<0,
COGL_MATERIAL_FLAG_DEFAULT_COLOR = 1L<<1,
COGL_MATERIAL_FLAG_DEFAULT_GL_MATERIAL = 1L<<2,
COGL_MATERIAL_FLAG_DEFAULT_ALPHA_FUNC = 1L<<3,
COGL_MATERIAL_FLAG_ENABLE_BLEND = 1L<<4,
COGL_MATERIAL_FLAG_DEFAULT_BLEND = 1L<<5
} CoglMaterialFlags;
struct _CoglMaterial
{
CoglHandleObject _parent;
unsigned long journal_ref_count;
unsigned long flags;
/* If no lighting is enabled; this is the basic material color */
GLubyte unlit[4];
/* Standard OpenGL lighting model attributes */
GLfloat ambient[4];
GLfloat diffuse[4];
GLfloat specular[4];
GLfloat emission[4];
GLfloat shininess;
/* Determines what fragments are discarded based on their alpha */
CoglMaterialAlphaFunc alpha_func;
GLfloat alpha_func_reference;
/* Determines how this material is blended with other primitives */
#ifndef HAVE_COGL_GLES
GLenum blend_equation_rgb;
GLenum blend_equation_alpha;
GLint blend_src_factor_alpha;
GLint blend_dst_factor_alpha;
GLfloat blend_constant[4];
#endif
GLint blend_src_factor_rgb;
GLint blend_dst_factor_rgb;
GList *layers;
unsigned int n_layers;
};
/*
* SECTION:cogl-material-internals
* @short_description: Functions for creating custom primitives that make use
* of Cogl materials for filling.
*
* Normally you shouldn't need to use this API directly, but if you need to
* developing a custom/specialised primitive - probably using raw OpenGL - then
* this API aims to expose enough of the material internals to support being
* able to fill your geometry according to a given Cogl material.
*/
/*
* _cogl_material_init_default_material:
*
* This initializes the first material owned by the Cogl context. All
* subsequently instantiated materials created via the cogl_material_new()
* API will initially be a copy of this material.
*/
void
_cogl_material_init_default_material (void);
/*
* cogl_material_get_cogl_enable_flags:
* @material: A CoglMaterial object
*
* This determines what flags need to be passed to cogl_enable before this
* material can be used. Normally you shouldn't need to use this function
* directly since Cogl will do this internally, but if you are developing
* custom primitives directly with OpenGL you may want to use this.
*
* Note: This API is hopfully just a stop-gap solution. Ideally cogl_enable
* will be replaced.
*/
/* TODO: find a nicer solution! */
unsigned long
_cogl_material_get_cogl_enable_flags (CoglHandle handle);
/*
* CoglMaterialLayerFlags:
* @COGL_MATERIAL_LAYER_FLAG_USER_MATRIX: Means the user has supplied a
* custom texture matrix.
*/
typedef enum _CoglMaterialLayerFlags
{
COGL_MATERIAL_LAYER_FLAG_HAS_USER_MATRIX = 1L<<0
} CoglMaterialLayerFlags;
/* XXX: NB: if you add flags here you will need to update
* CoglMaterialLayerPrivFlags!!! */
/*
* cogl_material_layer_get_flags:
* @layer_handle: A CoglMaterialLayer layer handle
*
* This lets you get a number of flag attributes about the layer. Normally
* you shouldn't need to use this function directly since Cogl will do this
* internally, but if you are developing custom primitives directly with
* OpenGL you may need this.
*/
unsigned long
_cogl_material_layer_get_flags (CoglHandle layer_handle);
/*
* Ensures the mipmaps are available for the texture in the layer if
* the filter settings would require it
*/
void
_cogl_material_layer_ensure_mipmaps (CoglHandle layer_handler);
/*
* CoglMaterialFlushFlag:
* @COGL_MATERIAL_FLUSH_FALLBACK_MASK: The fallback_layers member is set to
* a guint32 mask of the layers that can't be supported with the user
* supplied texture and need to be replaced with fallback textures. (1 =
* fallback, and the least significant bit = layer 0)
* @COGL_MATERIAL_FLUSH_DISABLE_MASK: The disable_layers member is set to
* a guint32 mask of the layers that you want to completly disable
* texturing for (1 = fallback, and the least significant bit = layer 0)
* @COGL_MATERIAL_FLUSH_LAYER0_OVERRIDE: The layer0_override_texture member is
* set to a GLuint OpenGL texture name to override the texture used for
* layer 0 of the material. This is intended for dealing with sliced
* textures where you will need to point to each of the texture slices in
* turn when drawing your geometry. Passing a value of 0 is the same as
* not passing the option at all.
* @COGL_MATERIAL_FLUSH_SKIP_GL_COLOR: When flushing the GL state for the
* material don't call glColor.
* @COGL_MATERIAL_FLUSH_WRAP_MODE_OVERRIDES: Specifies that a bitmask
* of overrides for the wrap modes for some or all layers is
* given.
*/
typedef enum _CoglMaterialFlushFlag
{
COGL_MATERIAL_FLUSH_FALLBACK_MASK = 1L<<0,
COGL_MATERIAL_FLUSH_DISABLE_MASK = 1L<<1,
COGL_MATERIAL_FLUSH_LAYER0_OVERRIDE = 1L<<2,
COGL_MATERIAL_FLUSH_SKIP_GL_COLOR = 1L<<3,
COGL_MATERIAL_FLUSH_WRAP_MODE_OVERRIDES = 1L<<4
} CoglMaterialFlushFlag;
/* These constants are used to fill in wrap_mode_overrides */
#define COGL_MATERIAL_WRAP_MODE_OVERRIDE_NONE 0 /* no override */
#define COGL_MATERIAL_WRAP_MODE_OVERRIDE_REPEAT 1
#define COGL_MATERIAL_WRAP_MODE_OVERRIDE_CLAMP_TO_EDGE 2
#define COGL_MATERIAL_WRAP_MODE_OVERRIDE_CLAMP_TO_BORDER 3
/* There can't be more than 32 layers because we need to fit a bitmask
of the layers into a guint32 */
#define COGL_MATERIAL_MAX_LAYERS 32
typedef struct _CoglMaterialWrapModeOverrides
{
struct
{
unsigned long s : 2;
unsigned long t : 2;
unsigned long r : 2;
} values[COGL_MATERIAL_MAX_LAYERS];
} CoglMaterialWrapModeOverrides;
/*
* CoglMaterialFlushOptions:
*
*/
typedef struct _CoglMaterialFlushOptions
{
CoglMaterialFlushFlag flags;
guint32 fallback_layers;
guint32 disable_layers;
GLuint layer0_override_texture;
CoglMaterialWrapModeOverrides wrap_mode_overrides;
} CoglMaterialFlushOptions;
void
_cogl_material_get_colorubv (CoglHandle handle,
guint8 *color);
void
_cogl_material_flush_gl_state (CoglHandle material,
CoglMaterialFlushOptions *options);
gboolean
_cogl_material_equal (CoglHandle material0_handle,
CoglMaterialFlushOptions *material0_flush_options,
CoglHandle material1_handle,
CoglMaterialFlushOptions *material1_flush_options);
CoglHandle
_cogl_material_journal_ref (CoglHandle material_handle);
void
_cogl_material_journal_unref (CoglHandle material_handle);
/* TODO: These should be made public once we add support for 3D
textures in Cogl */
void
_cogl_material_set_layer_wrap_mode_r (CoglHandle material,
int layer_index,
CoglMaterialWrapMode mode);
CoglMaterialWrapMode
_cogl_material_layer_get_wrap_mode_r (CoglHandle layer);
#endif /* __COGL_MATERIAL_PRIVATE_H */
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