mutter/clutter/cogl/cogl-material.h
Robert Bragg 845ff67301 [cogl] Improving Cogl journal to minimize driver overheads + GPU state changes
Previously the journal was always flushed at the end of
_cogl_rectangles_with_multitexture_coords, (i.e.  the end of any
cogl_rectangle* calls) but now we have broadened the potential for batching
geometry.  In ideal circumstances we will only flush once per scene.

In summary the journal works like this:

When you use any of the cogl_rectangle* APIs then nothing is emitted to the
GPU at this point, we just log one or more quads into the journal.  A
journal entry consists of the quad coordinates, an associated material
reference, and a modelview matrix.  Ideally the journal only gets flushed
once at the end of a scene, but in fact there are things to consider that
may cause unwanted flushing, including:

- modifying materials mid-scene
    This is because each quad in the journal has an associated material
    reference (i.e. not copy), so if you try and modify a material that is
    already referenced in the journal we force a flush first)

    NOTE: For now this means you should avoid using cogl_set_source_color()
	      since that currently uses a single shared material. Later we
	  should change it to use a pool of materials that is recycled
	  when the journal is flushed.

- modifying any state that isn't currently logged, such as depth, fog and
  backface culling enables.

The first thing that happens when flushing, is to upload all the vertex data
associated with the journal into a single VBO.

We then go through a process of splitting up the journal into batches that
have compatible state so they can be emitted to the GPU together.  This is
currently broken up into 3 levels so we can stagger the state changes:

1) we break the journal up according to changes in the number of material layers
   associated with logged quads. The number of layers in a material determines
   the stride of the associated vertices, so we have to update our vertex
   array offsets at this level. (i.e. calling gl{Vertex,Color},Pointer etc)
2) we further split batches up according to material compatability. (e.g.
   materials with different textures) We flush material state at this level.
3) Finally we split batches up according to modelview changes. At this level
   we update the modelview matrix and actually emit the actual draw command.

This commit is largely about putting the initial design in-place; this will be
followed by other changes that take advantage of the extended batching.
2009-06-30 17:13:34 +01:00

768 lines
26 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <cogl/cogl.h> can be included directly."
#endif
#ifndef __COGL_MATERIAL_H__
#define __COGL_MATERIAL_H__
G_BEGIN_DECLS
#include <cogl/cogl-types.h>
#include <cogl/cogl-matrix.h>
/**
* SECTION:cogl-material
* @short_description: Fuctions for creating and manipulating materials
*
* COGL allows creating and manipulating materials used to fill in
* geometry. Materials may simply be lighting attributes (such as an
* ambient and diffuse colour) or might represent one or more textures
* blended together.
*/
/**
* CoglMaterialFilter:
* @COGL_MATERIAL_FILTER_NEAREST: Measuring in manhatten distance from the,
* current pixel center, use the nearest texture
* texel.
* @COGL_MATERIAL_FILTER_LINEAR: Use the weighted average of the 4 texels
* nearest the current pixel center.
* @COGL_MATERIAL_FILTER_NEAREST_MIPMAP_NEAREST: Select the mimap level whose
* texel size most closely matches
* the current pixel, and use the
* COGL_MATERIAL_FILTER_NEAREST
* criterion.
* @COGL_MATERIAL_FILTER_LINEAR_MIPMAP_NEAREST: Select the mimap level whose
* texel size most closely matches
* the current pixel, and use the
* COGL_MATERIAL_FILTER_LINEAR
* criterion.
* @COGL_MATERIAL_FILTER_NEAREST_MIPMAP_LINEAR: Select the two mimap levels
* whose texel size most closely
* matches the current pixel, use
* the COGL_MATERIAL_FILTER_NEAREST
* criterion on each one and take
* their weighted average.
* @COGL_MATERIAL_FILTER_LINEAR_MIPMAP_LINEAR: Select the two mimap levels
* whose texel size most closely
* matches the current pixel, use
* the COGL_MATERIAL_FILTER_LINEAR
* criterion on each one and take
* their weighted average.
*
* Texture filtering is used whenever the current pixel maps either to more
* than one texture element (texel) or less than one. These filter enums
* correspond to different strategies used to come up with a pixel color, by
* possibly referring to multiple neighbouring texels and taking a weighted
* average or simply using the nearest texel.
*/
typedef enum _CoglMaterialFilter
{
COGL_MATERIAL_FILTER_NEAREST = GL_NEAREST,
COGL_MATERIAL_FILTER_LINEAR = GL_LINEAR,
COGL_MATERIAL_FILTER_NEAREST_MIPMAP_NEAREST = GL_NEAREST_MIPMAP_NEAREST,
COGL_MATERIAL_FILTER_LINEAR_MIPMAP_NEAREST = GL_LINEAR_MIPMAP_NEAREST,
COGL_MATERIAL_FILTER_NEAREST_MIPMAP_LINEAR = GL_NEAREST_MIPMAP_LINEAR,
COGL_MATERIAL_FILTER_LINEAR_MIPMAP_LINEAR = GL_LINEAR_MIPMAP_LINEAR
} CoglMaterialFilter;
/**
* cogl_material_new:
*
* Allocates and initializes a blank white material
*
* Returns: a handle to the new material
*/
CoglHandle cogl_material_new (void);
/**
* cogl_material_ref:
* @handle: a @CoglHandle.
*
* Increment the reference count for a cogl material.
*
* Returns: the @handle.
*
* Since 1.0
*/
CoglHandle cogl_material_ref (CoglHandle handle);
/**
* cogl_material_unref:
* @handle: a @CoglHandle.
*
* Decrement the reference count for a cogl material.
*
* Since 1.0
*/
void cogl_material_unref (CoglHandle handle);
/**
* cogl_is_material:
* @handle: A CoglHandle
*
* Gets whether the given handle references an existing material object.
*
* Returns: %TRUE if the handle references a #CoglMaterial,
* %FALSE otherwise
*/
gboolean cogl_is_material (CoglHandle handle);
/**
* cogl_material_set_color:
* @material: A CoglMaterial object
* @color: The components of the color
*
* This is the basic color of the material, used when no lighting is enabled.
*
* Note that if you don't add any layers to the material then the color
* will be blended unmodified with the destination; the default blend
* expects premultiplied colors: for example, use (0.5, 0.0, 0.0, 0.5) for
* semi-transparent red. See cogl_color_premultiply().
*
* The default value is (1.0, 1.0, 1.0, 1.0)
*
* Since 1.0
*/
void cogl_material_set_color (CoglHandle material, const CoglColor *color);
/**
* cogl_material_set_color4ub:
* @material: A CoglMaterial object
* @red: The red component
* @green: The green component
* @blue: The blue component
* @alpha: The alpha component
*
* This is the basic color of the material, used when no lighting is enabled.
*
* The default value is (0xff, 0xff, 0xff, 0xff)
*
* Since 1.0
*/
void cogl_material_set_color4ub (CoglHandle material,
guint8 red,
guint8 green,
guint8 blue,
guint8 alpha);
/**
* cogl_material_set_color4f:
* @material: A CoglMaterial object
* @red: The red component
* @green: The green component
* @blue: The blue component
* @alpha: The alpha component
*
* This is the basic color of the material, used when no lighting is enabled.
*
* The default value is (1.0, 1.0, 1.0, 1.0)
*
* Since 1.0
*/
void cogl_material_set_color4f (CoglHandle material,
float red,
float green,
float blue,
float alpha);
/**
* cogl_material_get_color:
* @material: A CoglMaterial object
* @color: The location to store the color
*
* This retrieves the current material color.
*
* Since 1.0
*/
void cogl_material_get_color (CoglHandle material, CoglColor *color);
/**
* cogl_material_set_ambient:
* @material: A CoglMaterial object
* @ambient: The components of the desired ambient color
*
* Exposing the standard OpenGL lighting model; this function sets
* the material's ambient color. The ambient color affects the overall
* color of the object. Since the diffuse color will be intense when
* the light hits the surface directly, the ambient will most aparent
* where the light hits at a slant.
*
* The default value is (0.2, 0.2, 0.2, 1.0)
*
* Since 1.0
*/
void cogl_material_set_ambient (CoglHandle material,
const CoglColor *ambient);
/**
* cogl_material_get_ambient:
* @material: A CoglMaterial object
* @ambient: The location to store the ambient color
*
* This retrieves the materials current ambient color.
*
* Since 1.0
*/
void cogl_material_get_ambient (CoglHandle material, CoglColor *ambient);
/**
* cogl_material_set_diffuse:
* @material: A CoglMaterial object
* @diffuse: The components of the desired diffuse color
*
* Exposing the standard OpenGL lighting model; this function sets
* the material's diffuse color. The diffuse color is most intense
* where the light hits the surface directly; perpendicular to the
* surface.
*
* The default value is (0.8, 0.8, 0.8, 1.0)
*
* Since 1.0
*/
void cogl_material_set_diffuse (CoglHandle material,
const CoglColor *diffuse);
/**
* cogl_material_get_diffuse:
* @material: A CoglMaterial object
* @diffuse: The location to store the diffuse color
*
* This retrieves the materials current diffuse color.
*
* Since 1.0
*/
void cogl_material_get_diffuse (CoglHandle material, CoglColor *diffuse);
/**
* cogl_material_set_ambient_and_diffuse:
* @material: A CoglMaterial object
* @color: The components of the desired ambient and diffuse colors
*
* This is a convenience for setting the diffuse and ambient color
* of the material at the same time.
*
* The default ambient color is (0.2, 0.2, 0.2, 1.0)
* The default diffuse color is (0.8, 0.8, 0.8, 1.0)
*
* Since 1.0
*/
void cogl_material_set_ambient_and_diffuse (CoglHandle material,
const CoglColor *color);
/**
* cogl_material_set_specular:
* @material: A CoglMaterial object
* @specular: The components of the desired specular color
*
* Exposing the standard OpenGL lighting model; this function sets
* the material's specular color. The intensity of the specular color
* depends on the viewport position, and is brightest along the lines
* of reflection.
*
* The default value is (0.0, 0.0, 0.0, 1.0)
*
* Since 1.0
*/
void cogl_material_set_specular (CoglHandle material,
const CoglColor *specular);
/**
* cogl_material_get_specular:
* @material: A CoglMaterial object
* @specular: The location to store the specular color
*
* This retrieves the materials current specular color.
*
* Since 1.0
*/
void cogl_material_get_specular (CoglHandle material, CoglColor *specular);
/**
* cogl_material_set_shininess:
* @material: A CoglMaterial object
* shininess: The desired shininess; range: [0.0, 1.0]
*
* This function sets the materials shininess which determines how
* specular highlights are calculated. A higher shininess will produce
* smaller brigher highlights.
*
* The default value is 0.0
*
* Since 1.0
*/
void cogl_material_set_shininess (CoglHandle material,
float shininess);
/**
* cogl_material_get_shininess:
* @material: A CoglMaterial object
*
* This retrieves the materials current emission color.
*
* Return value: The materials current shininess value
*
* Since 1.0
*/
float cogl_material_get_shininess (CoglHandle material);
/**
* cogl_material_set_emission:
* @material: A CoglMaterial object
* @emission: The components of the desired emissive color
*
* Exposing the standard OpenGL lighting model; this function sets
* the material's emissive color. It will look like the surface is
* a light source emitting this color.
*
* The default value is (0.0, 0.0, 0.0, 1.0)
*
* Since 1.0
*/
void cogl_material_set_emission (CoglHandle material,
const CoglColor *emission);
/**
* cogl_material_get_emission:
* @material: A CoglMaterial object
* @emission: The location to store the emission color
*
* This retrieves the materials current emission color.
*
* Since 1.0
*/
void cogl_material_get_emission (CoglHandle material, CoglColor *emission);
/**
* CoglMaterialAlphaFunc:
* @COGL_MATERIAL_ALPHA_FUNC_NEVER: Never let the fragment through.
* @COGL_MATERIAL_ALPHA_FUNC_LESS: Let the fragment through if the incoming
* alpha value is less than the reference alpha
* value.
* @COGL_MATERIAL_ALPHA_FUNC_EQUAL: Let the fragment through if the incoming
* alpha value equals the reference alpha
* value.
* @COGL_MATERIAL_ALPHA_FUNC_LEQUAL: Let the fragment through if the incoming
* alpha value is less than or equal to the
* reference alpha value.
* @COGL_MATERIAL_ALPHA_FUNC_GREATER: Let the fragment through if the incoming
* alpha value is greater than the reference
* alpha value.
* @COGL_MATERIAL_ALPHA_FUNC_NOTEQUAL: Let the fragment through if the incoming
* alpha value does not equal the reference
* alpha value.
* @COGL_MATERIAL_ALPHA_FUNC_GEQUAL: Let the fragment through if the incoming
* alpha value is greater than or equal to the
* reference alpha value.
* @COGL_MATERIAL_ALPHA_FUNC_ALWAYS: Always let the fragment through.
*
* Alpha testing happens before blending primitives with the framebuffer and
* gives an opportunity to discard fragments based on a comparison with the
* incoming alpha value and a reference alpha value. The #CoglMaterialAlphaFunc
* determines how the comparison is done.
*/
typedef enum _CoglMaterialAlphaFunc
{
COGL_MATERIAL_ALPHA_FUNC_NEVER = GL_NEVER,
COGL_MATERIAL_ALPHA_FUNC_LESS = GL_LESS,
COGL_MATERIAL_ALPHA_FUNC_EQUAL = GL_EQUAL,
COGL_MATERIAL_ALPHA_FUNC_LEQUAL = GL_LEQUAL,
COGL_MATERIAL_ALPHA_FUNC_GREATER = GL_GREATER,
COGL_MATERIAL_ALPHA_FUNC_NOTEQUAL = GL_NOTEQUAL,
COGL_MATERIAL_ALPHA_FUNC_GEQUAL = GL_GEQUAL,
COGL_MATERIAL_ALPHA_FUNC_ALWAYS = GL_ALWAYS
} CoglMaterialAlphaFunc;
/**
* cogl_material_set_alpha_test_function:
* @material: A CoglMaterial object
* @alpha_func: A @CoglMaterialAlphaFunc constant
* @alpha_reference: A reference point that the chosen alpha function uses
* to compare incoming fragments to.
*
* Before a primitive is blended with the framebuffer, it goes through an
* alpha test stage which lets you discard fragments based on the current
* alpha value. This function lets you change the function used to evaluate
* the alpha channel, and thus determine which fragments are discarded
* and which continue on to the blending stage.
*
* The default is COGL_MATERIAL_ALPHA_FUNC_ALWAYS
*
* Since 1.0
*/
void cogl_material_set_alpha_test_function (CoglHandle material,
CoglMaterialAlphaFunc alpha_func,
float alpha_reference);
/**
* cogl_material_set_blend:
* @material: A CoglMaterial object
* @blend_string: A <link linkend="cogl-Blend-Strings">Cogl blend string</link>
* describing the desired blend function.
* @error: A GError that may report lack of driver support if you give
* separate blend string statements for the alpha channel and RGB
* channels since some drivers or backends such as GLES 1.1 dont
* support this. May be %NULL, in which case a warning will be
* printed out if an error is encountered.
*
* If not already familiar; please refer
* <link linkend="cogl-Blend-Strings">here</link> for an overview of what blend
* strings are and there syntax.
*
* Blending occurs after the alpha test function, and combines fragments with
* the framebuffer.
* Currently the only blend function Cogl exposes is ADD(). So any valid
* blend statements will be of the form:
*
* <programlisting>
* &lt;channel-mask&gt;=ADD(SRC_COLOR*(&lt;factor&gt;), DST_COLOR*(&lt;factor&gt;))
* </programlisting>
*
* <b>NOTE: The brackets around blend factors are currently not optional!</b>
*
* This is the list of source-names usable as blend factors:
* <itemizedlist>
* <listitem>SRC_COLOR: The color of the in comming fragment</listitem>
* <listitem>DST_COLOR: The color of the framebuffer</listitem>
* <listitem>
* CONSTANT: The constant set via cogl_material_set_blend_constant()</listitem>
* </itemizedlist>
* The source names can be used according to the
* <link linkend="cogl-Blend-String-syntax">color-source and factor syntax</link>,
* so for example "(1-SRC_COLOR[A])" would be a valid factor, as would
* "(CONSTANT[RGB])"
*
* These can also be used as factors:
* <itemizedlist>
* <listitem>0: (0, 0, 0, 0)</listitem>
* <listitem>1: (1, 1, 1, 1)</listitem>
* <listitem>SRC_ALPHA_SATURATE_FACTOR: (f,f,f,1)
* where f=MIN(SRC_COLOR[A],1-DST_COLOR[A])</listitem>
* </itemizedlist>
* <para>
* Remember; all color components are normalized to the range [0, 1] before
* computing the result of blending.
* </para>
* <section>
* <title>Examples</title>
* Blend a non-premultiplied source over a destination with
* premultiplied alpha:
* <programlisting>
* "RGB = ADD(SRC_COLOR*(SRC_COLOR[A]), DST_COLOR*(1-SRC_COLOR[A]))"
* "A = ADD(SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
* </programlisting>
* Blend a premultiplied source over a destination with premultiplied alpha:
* <programlisting>
* "RGBA = ADD(SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
* </programlisting>
* </section>
*
* The default blend string is:
* "RGBA = ADD (SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
* That gives normal alpha-blending when the calculated color for the material
* is in premultiplied form.
*
* Returns: TRUE if the blend string was successfully parsed, and the described
* blending is supported by the underlying driver/hardware. If there
* was an error, it returns FALSE.
*
* Since: 1.0
*/
gboolean cogl_material_set_blend (CoglHandle material,
const char *blend_string,
GError **error);
/**
* cogl_material_set_blend_constant:
* @material: A CoglMaterial object
* @constant_color: The constant color you want
*
* When blending is setup to reference a CONSTANT blend factor then
* blending will depend on the constant set with this function.
*
* Since: 1.0
*/
void cogl_material_set_blend_constant (CoglHandle material,
CoglColor *constant_color);
/**
* cogl_material_set_layer:
* @material: A #CoglHandle for a material object
* @layer_index: the index of the layer
* @texture: a #CoglHandle for the layer object
*
* In addition to the standard OpenGL lighting model a Cogl material may have
* one or more layers comprised of textures that can be blended together in
* order, with a number of different texture combine modes. This function
* defines a new texture layer.
*
* The index values of multiple layers do not have to be consecutive; it is
* only their relative order that is important.
*
* <note>In the future, we may define other types of material layers, such
* as purely GLSL based layers.</note>
*
* Since 1.0
*/
void cogl_material_set_layer (CoglHandle material,
int layer_index,
CoglHandle texture);
/**
* cogl_material_add_texture:
* @material: A CoglMaterial object
* @layer_index: Specifies the layer you want to remove
*
* This function removes a layer from your material
*/
void cogl_material_remove_layer (CoglHandle material,
gint layer_index);
/**
* cogl_material_set_layer_combine:
* @material: A CoglMaterial object
* @layer_index: Specifies the layer you want define a combine function for
* @blend_string: A <link linkend="cogl-Blend-Strings">Cogl blend string</link>
* describing the desired texture combine function.
* @error: A GError that may report parse errors or lack of GPU/driver support.
* May be %NULL, in which case a warning will be printed out if an
* error is encountered.
*
* If not already familiar; you can refer
* <link linkend="cogl-Blend-Strings">here</link> for an overview of what blend
* strings are and there syntax.
*
* These are all the functions available for texture combining:
* <itemizedlist>
* <listitem>REPLACE(arg0) = arg0</listitem>
* <listitem>MODULATE(arg0, arg1) = arg0 x arg1</listitem>
* <listitem>ADD(arg0, arg1) = arg0 + arg1</listitem>
* <listitem>ADD_SIGNED(arg0, arg1) = arg0 + arg1 - 0.5</listitem>
* <listitem>INTERPOLATE(arg0, arg1, arg2) =
* arg0 x arg2 + arg1 x (1 - arg2)</listitem>
* <listitem>SUBTRACT(arg0, arg1) = arg0 - arg1</listitem>
* <listitem>
* DOT3_RGB(arg0, arg1) =
* <programlisting>
* 4 x ((arg0[R] - 0.5)) * (arg1[R] - 0.5) +
* (arg0[G] - 0.5)) * (arg1[G] - 0.5) +
* (arg0[B] - 0.5)) * (arg1[B] - 0.5))
* </programlisting>
* </listitem>
* <listitem>DOT3_RGBA(arg0, arg1) =
* <programlisting>
* 4 x ((arg0[R] - 0.5)) * (arg1[R] - 0.5) +
* (arg0[G] - 0.5)) * (arg1[G] - 0.5) +
* (arg0[B] - 0.5)) * (arg1[B] - 0.5))
* </programlisting>
* </listitem>
* </itemizedlist>
*
* Refer to the
* <link linkend="cogl-Blend-String-syntax">color-source syntax</link> for
* describing the arguments. The valid source names for texture combining
* are:
* <itemizedlist>
* <listitem>
* TEXTURE: Use the color from the current texture layer
* </listitem>
* <listitem>
* TEXTURE_0, TEXTURE_1, etc: Use the color from the specified texture layer
* </listitem>
* <listitem>
* CONSTANT: Use the color from the constant given with
* cogl_material_set_layer_constant()
* </listitem>
* <listitem>
* PRIMARY: Use the color of the material as set with cogl_material_set_color()
* </listitem>
* <listitem>
* PREVIOUS: Either use the texture color from the previous layer, or if this
* is layer 0, use the color of the material as set with
* cogl_material_set_color()
* </listitem>
* </itemizedlist>
* <section>
* <title>Example</title>
* This is effectively what the default blending is:
* <programlisting>
* "RGBA = MODULATE (PREVIOUS, TEXTURE)"
* </programlisting>
* This could be used to cross-fade between two images, using the alpha
* component of a constant as the interpolator. The constant color
* is given by calling cogl_material_set_layer_constant.
* <programlisting>
* RGBA = INTERPOLATE (PREVIOUS, TEXTURE, CONSTANT[A])
* </programlisting>
* </section>
* <b>Note: you can't give a multiplication factor for arguments as you can
* with blending.</b>
*
* Returns: TRUE if the blend string was successfully parsed, and the described
* texture combining is supported by the underlying driver/hardware.
* If there was an error, it returns FALSE.
*
* Since: 1.0
*/
gboolean
cogl_material_set_layer_combine (CoglHandle material,
gint layer_index,
const char *blend_string,
GError **error);
/**
* cogl_material_set_layer_combine_constant:
* @material: A CoglMaterial object
* @layer_index: Specifies the layer you want to specify a constant used
* for texture combining
* @constant: The constant color you want
*
* When you are using the 'CONSTANT' color source in a layer combine
* description then you can use this function to define its value.
*
* Since 1.0
*/
void cogl_material_set_layer_combine_constant (CoglHandle material,
int layer_index,
CoglColor *constant);
/**
* cogl_material_set_layer_matrix:
* @material: A CoglMaterial object
*
* This function lets you set a matrix that can be used to e.g. translate
* and rotate a single layer of a material used to fill your geometry.
*/
void cogl_material_set_layer_matrix (CoglHandle material,
int layer_index,
CoglMatrix *matrix);
/**
* cogl_material_get_layers:
* @material: A CoglMaterial object
*
* This function lets you access a materials internal list of layers
* for iteration.
*
* Returns: A list of #CoglHandle<!-- -->'s that can be passed to the
* cogl_material_layer_* functions.
*/
const GList *cogl_material_get_layers (CoglHandle material);
/**
* cogl_material_get_n_layers:
* @material: A CoglMaterial object
*
* Returns: The number of layers defined for the given material
*
* Since: 1.0
*/
int cogl_material_get_n_layers (CoglHandle material);
/**
* CoglMaterialLayerType:
* @COGL_MATERIAL_LAYER_TYPE_TEXTURE: The layer represents a
* <link linkend="cogl-Textures">Cogl texture</link>
*
* Available types of layers for a #CoglMaterial. This enumeration
* might be expanded in later versions.
*
* Since: 1.0
*/
typedef enum _CoglMaterialLayerType
{
COGL_MATERIAL_LAYER_TYPE_TEXTURE
} CoglMaterialLayerType;
/**
* cogl_material_layer_get_type:
* @layer_handle: A Cogl material layer handle
*
* Retrieves the type of the layer
*
* Currently there is only one type of layer defined:
* %COGL_MATERIAL_LAYER_TYPE_TEXTURE, but considering we may add purely GLSL
* based layers in the future, you should write code that checks the type
* first.
*
* Return value: the type of the layer
*/
CoglMaterialLayerType cogl_material_layer_get_type (CoglHandle layer_handle);
/**
* cogl_material_layer_get_texture:
* @layer_handle: A CoglMaterialLayer handle
*
* This lets you extract a CoglTexture handle for a specific layer.
*
* Note: In the future, we may support purely GLSL based layers which will
* likely return COGL_INVALID_HANDLE if you try to get the texture.
* Considering this, you can call cogl_material_layer_get_type first,
* to check it is of type COGL_MATERIAL_LAYER_TYPE_TEXTURE.
*/
CoglHandle cogl_material_layer_get_texture (CoglHandle layer_handle);
/**
* cogl_material_layer_get_min_filter:
* @layer_handle: a #CoglHandle for a material layer.
*
* Query the currently set downscaling filter for a cogl material layer.
*
* Returns: the current downscaling filter for a cogl material layer.
*/
CoglMaterialFilter cogl_material_layer_get_min_filter (CoglHandle layer_handle);
/**
* cogl_material_layer_get_mag_filter:
* @layer_handle: a #CoglHandle for a material layer.
*
* Query the currently set downscaling filter for a cogl material layer.
*
* Returns: the current downscaling filter for a cogl material layer.
*/
CoglMaterialFilter cogl_material_layer_get_mag_filter (CoglHandle layer_handle);
/**
* cogl_material_set_layer_filters:
* @handle: a #CoglHandle to a material.
* @layer_index: the layer number to change.
* @min_filter: the filter used when scaling a texture down.
* @mag_filter: the filter used when magnifying a texture.
*
* Changes the decimation and interpolation filters used when a texture is
* drawn at other scales than 100%.
*/
void cogl_material_set_layer_filters (CoglHandle handle,
gint layer_index,
CoglMaterialFilter min_filter,
CoglMaterialFilter mag_filter);
G_END_DECLS
#endif /* __COGL_MATERIAL_H__ */