mutter/cogl/cogl-material.h
Emmanuele Bassi 80783abf89 docs: Documentation fixes for CoglMaterial
Clean up the references, the docbook tags, and the style to fit in
with the rest of the API references for Cogl and Clutter.
2009-11-19 13:56:47 +00:00

788 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 {
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
*
* Return value: a handle to the new material
*/
CoglHandle cogl_material_new (void);
#ifndef COGL_DISABLE_DEPRECATED
/**
* cogl_material_ref:
* @handle: a @CoglHandle.
*
* Increment the reference count for a cogl material.
*
* Return value: the @handle.
*
* Since: 1.0
*
* Deprecated: 1.2: Use cogl_handle_ref() instead
*/
CoglHandle cogl_material_ref (CoglHandle handle);
/**
* cogl_material_unref:
* @handle: a @CoglHandle.
*
* Decrement the reference count for a cogl material.
*
* Since: 1.0
*
* Deprecated: 1.2: Use cogl_handle_unref() instead
*/
void cogl_material_unref (CoglHandle handle);
#endif /* COGL_DISABLE_DEPRECATED */
/**
* cogl_is_material:
* @handle: A CoglHandle
*
* Gets whether the given handle references an existing material object.
*
* Return value: %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
*
* Sets 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
*
* Sets 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
*
* Sets 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: (out): The location to store the color
*
* 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
*
* Sets the material's ambient color, in the standard OpenGL lighting
* model. 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 be most apparent 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
*
* Retrieves the current ambient color for @material
*
* 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
*
* Sets the material's diffuse color, in the standard OpenGL lighting
* model. 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
*
* Retrieves the current diffuse color for @material
*
* 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
*
* Conveniently sets the diffuse and ambient color of @material at the same
* time. See cogl_material_set_ambient() and cogl_material_set_diffuse().
*
* 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
*
* Sets the material's specular color, in the standard OpenGL lighting
* model. 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
*
* 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]
*
* Sets the materials shininess, in the standard OpenGL lighting model,
* 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
*
* 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
*
* Sets the material's emissive color, in the standard OpenGL lighting
* model. 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
*
* 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 {
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: return location for 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, don't support this feature. May be %NULL, in which case a
* warning will be printed out using GLib's logging facilities 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 their 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:
*
* |[
* &lt;channel-mask&gt;=ADD(SRC_COLOR*(&lt;factor&gt;), DST_COLOR*(&lt;factor&gt;))
* ]|
*
* <warning>The brackets around blend factors are currently not
* optional!</warning>
*
* This is the list of source-names usable as blend factors:
* <itemizedlist>
* <listitem><para>SRC_COLOR: The color of the in comming fragment</para></listitem>
* <listitem><para>DST_COLOR: The color of the framebuffer</para></listitem>
* <listitem><para>CONSTANT: The constant set via cogl_material_set_blend_constant()</para></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>
*
* <note>Remember; all color components are normalized to the range [0, 1]
* before computing the result of blending.</note>
*
* <example id="cogl-Blend-Strings-blend-unpremul">
* <title>Blend Strings/1</title>
* <para>Blend a non-premultiplied source over a destination with
* premultiplied alpha:</para>
* <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>
* </example>
*
* <example id="cogl-Blend-Strings-blend-premul">
* <title>Blend Strings/2</title>
* <para>Blend a premultiplied source over a destination with
* premultiplied alpha</para>
* <programlisting>
* "RGBA = ADD(SRC_COLOR, DST_COLOR*(1-SRC_COLOR[A]))"
* </programlisting>
* </example>
*
* 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.
*
* Return value: %TRUE if the blend string was successfully parsed, and the
* described blending is supported by the underlying driver/hardware. If
* there was an error, %FALSE is returned and @error is set accordingly (if
* present).
*
* 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_remove_layer:
* @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>
* <programlisting>
* DOT3_RGB(arg0, arg1) = 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>
* <programlisting>
* DOT3_RGBA(arg0, arg1) = 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:
* <variablelist>
* <varlistentry>
* <term>TEXTURE</term>
* <listitem>Use the color from the current texture layer</listitem>
* </varlistentry>
* <varlistentry>
* <term>TEXTURE_0, TEXTURE_1, etc</term>
* <listitem>Use the color from the specified texture layer</listitem>
* </varlistentry>
* <varlistentry>
* <term>CONSTANT</term>
* <listitem>Use the color from the constant given with
* cogl_material_set_layer_constant()</listitem>
* </varlistentry>
* <varlistentry>
* <term>PRIMARY</term>
* <listitem>Use the color of the material as set with
* cogl_material_set_color()</listitem>
* </varlistentry>
* <varlistentry>
* <term>PREVIOUS</term>
* <listitem>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>
* </varlistentry>
* </variablelist>
*
* <refsect2 id="cogl-Layer-Combine-Examples">
* <title>Layer Combine Examples</title>
* <para>This is effectively what the default blending is:</para>
* <informalexample><programlisting>
* RGBA = MODULATE (PREVIOUS, TEXTURE)
* </programlisting></informalexample>
* <para>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.</para>
* <informalexample><programlisting>
* RGBA = INTERPOLATE (PREVIOUS, TEXTURE, CONSTANT[A])
* </programlisting></informalexample>
* </refsect2>
*
* <note>You can't give a multiplication factor for arguments as you can
* with blending.</note>
*
* Return value: %TRUE if the blend string was successfully parsed, and the
* described texture combining is supported by the underlying driver and
* or hardware. On failure, %FALSE is returned and @error is set
*
* 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
* @layer_index: the index for the layer inside @material
* @matrix: the transformation matrix for the layer
*
* 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 #CoglHandle for a material
*
* This function lets you access a materials internal list of layers
* for iteration.
*
* Return value: (element-type Handle) (transfer none): A list of
* #CoglHandle<!-- -->'s that can be passed to the cogl_material_layer_*
* functions. The list is owned by COGL and it should not be modified or
* freed
*/
G_CONST_RETURN GList *cogl_material_get_layers (CoglHandle material);
/**
* cogl_material_get_n_layers:
* @material: a #CoglHandle for a material
*
* Retrieves the number of layers defined for the given @material
*
* Return value: the number of layers
*
* 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">texture</link>
*
* Available types of layers for a #CoglMaterial. This enumeration
* might be expanded in later versions.
*
* Since: 1.0
*/
typedef enum {
COGL_MATERIAL_LAYER_TYPE_TEXTURE
} CoglMaterialLayerType;
/**
* cogl_material_layer_get_type:
* @layer: A #CoglHandle for a material layer
*
* 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);
/**
* cogl_material_layer_get_texture:
* @layer: A #CoglHandle for a material layer
*
* Extracts a texture handle for a specific layer.
*
* <note>In the future Cogl may support purely GLSL based layers; for those
* layers this function which will likely return %COGL_INVALID_HANDLE if you
* try to get the texture handle from them. Considering this scenario, you
* should call cogl_material_layer_get_type() first in order check it is of
* type %COGL_MATERIAL_LAYER_TYPE_TEXTURE before calling this function.</note>
*
* Return value: a #CoglHandle for the texture inside the layer
*/
CoglHandle cogl_material_layer_get_texture (CoglHandle layer);
/**
* cogl_material_layer_get_min_filter:
* @layer: a #CoglHandle for a material layer
*
* Queries the currently set downscaling filter for a material layer
*
* Return value: the current downscaling filter
*/
CoglMaterialFilter cogl_material_layer_get_min_filter (CoglHandle layer);
/**
* cogl_material_layer_get_mag_filter:
* @layer: a #CoglHandle for a material layer
*
* Queries the currently set downscaling filter for a material later
*
* Return value: the current downscaling filter
*/
CoglMaterialFilter cogl_material_layer_get_mag_filter (CoglHandle layer);
/**
* cogl_material_set_layer_filters:
* @material: 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 material,
gint layer_index,
CoglMaterialFilter min_filter,
CoglMaterialFilter mag_filter);
G_END_DECLS
#endif /* __COGL_MATERIAL_H__ */