Documentation and example usage of textures.

Mentions some not-yet-done features such as Vector2i or proper texture
formats.

src/AbstractTexture.h

@@ -28,22 +28,11 @@ namespace Magnum {
 /**
 @brief Base for textures
 
-@attention Don't forget to call @ref Texture::setWrapping() "setWrapping()",
-    setMinificationFilter() and setMagnificationFilter() after creating the
-    texture, otherwise the texture will be incomplete. If you specified
-    @ref Wrapping "Wrapping::ClampToBorder" in @ref Texture::setWrapping() "setWrapping()",
-    be sure to also call setBorderColor(). If you specified mipmap filtering
-    in setMinificationFilter(), be sure to also either explicitly set all mip
-    levels or call generateMipmap().
-
-The texture is bound to shader via bind(). Texture uniform on the shader must
-also be set to particular texture layer using
-AbstractShaderProgram::setUniform(GLint, GLint).
-
 See Texture, CubeMapTexture and CubeMapTextureArray documentation for more
-information.
+information and usage examples.
 
 @section AbstractTexture-performance-optimization Performance optimizations
+
 The engine tracks currently bound textures in all available layers to avoid
 unnecessary calls to @fn_gl{ActiveTexture} and @fn_gl{BindTexture}. %Texture
 configuration functions use dedicated highest available texture layer to not
@@ -639,6 +628,8 @@ class MAGNUM_EXPORT AbstractTexture {
          * Sets filter used when the object pixel size is smaller than the
          * texture size. If @extension{EXT,direct_state_access} is not
          * available, the texture is bound to some layer before the operation.
+         * Initial value is (@ref AbstractTexture::Filter "Filter::NearestNeighbor",
+         * @ref AbstractTexture::Mipmap "Mipmap::Linear").
          * @attention For rectangle textures only some modes are supported,
          *      see @ref AbstractTexture::Filter "Filter" and
          *      @ref AbstractTexture::Mipmap "Mipmap" documentation for more
@@ -657,6 +648,7 @@ class MAGNUM_EXPORT AbstractTexture {
          * Sets filter used when the object pixel size is larger than largest
          * texture size. If @extension{EXT,direct_state_access} is not
          * available, the texture is bound to some layer before the operation.
+         * Initial value is @ref AbstractTexture::Filter "Filter::Linear".
          * @see @fn_gl{ActiveTexture}, @fn_gl{BindTexture} and @fn_gl{TexParameter}
          *      or @fn_gl_extension{TextureParameter,EXT,direct_state_access}
          *      with @def_gl{TEXTURE_MAG_FILTER}
@@ -674,6 +666,7 @@ class MAGNUM_EXPORT AbstractTexture {
          * Border color when @ref AbstractTexture::Wrapping "wrapping" is set
          * to `ClampToBorder`. If @extension{EXT,direct_state_access} is not
          * available, the texture is bound to some layer before the operation.
+         * Initial value is `{0.0f, 0.0f, 0.0f, 0.0f}`.
          * @see @fn_gl{ActiveTexture}, @fn_gl{BindTexture} and @fn_gl{TexParameter}
          *      or @fn_gl_extension{TextureParameter,EXT,direct_state_access}
          *      with @def_gl{TEXTURE_BORDER_COLOR}

src/CubeMapTexture.h

@@ -26,10 +26,9 @@ namespace Magnum {
 /**
 @brief Cube map texture
 
-%Texture used mainly for environemnt maps. See AbstractTexture documentation
-for more information. It consists of 6 square textures generating 6 faces of
-the cube as following. Note that all images must be turned upside down (+Y is
-top):
+%Texture used mainly for environment maps. It consists of 6 square textures
+generating 6 faces of the cube as following. Note that all images must be
+turned upside down (+Y is top):
 
               +----+
               | -Y |
@@ -39,11 +38,29 @@ top):
               | +Y |
               +----+
 
-When using cube map texture in the shader, use `samplerCube`. Unlike classic
-textures, coordinates for cube map textures is signed three-part vector from
-the center of the cube, which intersects one of the six sides of the cube map.
-
-See AbstractTexture documentation for more information about usage.
+@section CubeMapTexture-usage Basic usage
+
+See Texture documentation for introduction.
+
+Common usage is to fully configure all texture parameters and then set the
+data from e.g. set of Image objects:
+@code
+Image2D positiveX({256, 256}, Image2D::Components::RGBA, Image2D::ComponentType::UnsignedByte, dataPositiveX);
+// ...
+
+CubeMapTexture texture;
+texture.setMagnificationFilter(Texture2D::Filter::Linear)
+    // ...
+    ->setData(CubeMapTexture::Coordinate::PositiveX, 0, Texture2D::Format::RGBA8, &positiveX)
+    ->setData(CubeMapTexture::Coordinate::NegativeX, 0, Texture2D::Format::RGBA8, &negativeX)
+    // ...
+@endcode
+
+The texture is bound to layer specified by shader via bind(). In shader, the
+texture is used via `samplerCube`. Unlike classic textures, coordinates for
+cube map textures is signed three-part vector from the center of the cube,
+which intersects one of the six sides of the cube map. See also
+AbstractShaderProgram for more information.
 
 @see CubeMapTextureArray
 */

src/CubeMapTextureArray.h

@@ -29,12 +29,41 @@ namespace Magnum {
 /**
 @brief Cube map texture array
 
-For information, see CubeMapTexture and AbstractTexture documentation.
+See CubeMapTexture documentation for introduction.
+
+@section CubeMapTextureArray-usage Usage
+
+Common usage is to specify each layer and face separately using setSubData().
+You have to allocate the memory for all layers and faces first, possibly by
+passing properly sized empty Image to setData(). Example: array with 16
+layers of cube map faces, each face consisting of six 64x64 images:
+@code
+Image3D dummy({64, 64, 16*6}, Image3D::Components::RGBA, Image3D::ComponentType::UnsignedByte, nullptr);
+
+CubeMapTextureArray texture;
+texture.setMagnificationFilter(CubeMapTextureArray::Filter::Linear)
+    // ...
+    ->setData(0, CubeMapTextureArray::Format::RGBA8, &dummy);
+
+for(std::size_t i = 0; i != 16; ++i) {
+    void* dataPositiveX = ...;
+    Image2D imagePositiveX({64, 64}, Image3D::Components::RGBA, Image3D::ComponentType::UnsignedByte, imagePositiveX);
+    // ...
+
+    texture->setSubData(i, CubeMapTextureArray::Coordinate::PositiveX, 0, imagePositiveX);
+    texture->setSubData(i, CubeMapTextureArray::Coordinate::NegativeX, 0, imageNegativeX);
+    // ...
+}
+
+// ...
+@endcode
 
-When using cube map texture in the shader, use `samplerCubeArray`. Unlike
-classic textures, coordinates for cube map textures is signed three-part
-vector from the center of the cube, which intersects one of the six sides of
-the cube map.
+The texture is bound to layer specified by shader via bind(). In shader, the
+texture is used via `samplerCubeArray`. Unlike classic textures, coordinates
+for cube map texture arrays is signed four-part vector. First three parts
+define vector from the center of the cube which intersects with one of the six
+sides of the cube map, fourth part is layer in the array. See also
+AbstractShaderProgram for more information.
 
 @see CubeMapTexture::setSeamless()
 @requires_gl40 Extension @extension{ARB,texture_cube_map_array}

src/Texture.h

@@ -27,12 +27,66 @@ namespace Magnum {
 /**
 @brief %Texture
 
-Template class for one- to three-dimensional textures. See AbstractTexture
-documentation for more information.
+Template class for one- to three-dimensional textures. See also
+AbstractTexture documentation for more information.
+
+@section Texture-usage Usage
+
+Common usage is to fully configure all texture parameters and then set the
+data from e.g. Image. Example configuration of high quality texture with
+trilinear anisotropic filtering, i.e. the best you can ask for:
+@code
+void* data;
+Image2D image({4096, 4096}, Image2D::Components::RGBA, Image2D::ComponentType::UnsignedByte, data);
+
+Texture2D texture;
+texture.setMagnificationFilter(Texture2D::Filter::Linear)
+    ->setMinificationFilter(Texture2D::Filter::Linear, Texture2D::Mipmap::Linear)
+    ->setWrapping(Texture2D::Wrapping::ClampToEdge)
+    ->setMaxAnisotropy(Texture2D::maxSupportedAnisotropy)
+    ->setData(0, Texture2D::Format::RGBA8, &image)
+    ->generateMipmap();
+@endcode
+
+@attention Don't forget to fully configure the texture before use. Note that
+    default configuration (if setMinificationFilter() is not called with
+    another value) is to use mipmaps, so be sure to either call setMinificationFilter(),
+    explicitly set all mip levels or call generateMipmap(). If using rectangle
+    texture, you must also call setWrapping(), because the initial value is
+    not supported on rectangle textures. See also setMagnificationFilter() and
+    setBorderColor().
+
+The texture is bound to layer specified by shader via bind(). In shader, the
+texture is used via `sampler1D`, `sampler2D` or `sampler3D` depending on
+dimension count. See also AbstractShaderProgram documentation for more
+information.
+
+@section Texture-array Texture arrays
+
+It is possible to specify each layer separately using setSubData(), but you
+have to allocate the memory for all layers first, possibly by passing properly
+sized empty Image to setData(). Example: 2D texture array with 16 layers of
+64x64 images:
+@code
+Image3D dummy({64, 64, 16}, Image3D::Components::RGBA, Image3D::ComponentType::UnsignedByte, nullptr);
+
+Texture3D texture(Texture3D::Target::Texture2DArray);
+texture.setMagnificationFilter(Texture2D::Filter::Linear)
+    // ...
+    ->setData(0, Texture2D::Format::RGBA8, &dummy);
+
+for(std::size_t i = 0; i != 16; ++i) {
+    void* data = ...;
+    Image2D image({64, 64}, Image3D::Components::RGBA, Image3D::ComponentType::UnsignedByte, image);
+    texture->setSubData(0, Vector3i::zAxis(i), image);
+}
+
+// ...
+@endcode
 
-In shader, the texture is used via `sampler1D`, `sampler2D` or `sampler3D`
-depending on dimension count. Note that you can have more than one texture bound
-to the shader - the only requirement is to have each texture in another layer.
+Similar approach can be used for any other texture types (e.g. setting
+Texture3D data using 2D layers, Texture2D data using one-dimensional chunks
+etc.).
 
 @section Texture-rectangle Rectangle textures
 
@@ -124,7 +178,8 @@ template<std::uint8_t dimensions> class Texture: public AbstractTexture {
          * Sets wrapping type for coordinates out of range (0, 1) for normal
          * textures and (0, textureSizeInGivenDirection-1) for rectangle
          * textures. If @extension{EXT,direct_state_access} is not available,
-         * the texture is bound to some layer before the operation.
+         * the texture is bound to some layer before the operation. Initial
+         * value is @ref AbstractTexture::Wrapping "Wrapping::Repeat".
          * @attention For rectangle textures only some modes are supported,
          *      see @ref AbstractTexture::Wrapping "Wrapping" documentation
          *      for more information.