Cogl.Pipeline.prototype.set_layer_combine

function set_layer_combine(layer_index: Number(gint), blend_string: String): Cogl.Bool {
    // Gjs wrapper for cogl_pipeline_set_layer_combine()
}
  

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.Pipeline.prototype.set_layer_combine_constant</listitem> </varlistentry> <varlistentry> <term>PRIMARY</term> <listitem>Use the color of the pipeline as set with Cogl.Pipeline.prototype.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 pipeline as set with Cogl.Pipeline.prototype.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.Pipeline.prototype.set_layer_combine_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>

Since 2.0