1b2dd815b4
This adds much more comprehensive support for gobject-introspection based bindings by registering all objects as fundamental types that inherit from CoglObject, and all structs as boxed types. Co-Author: Robert Bragg <robert@linux.intel.com> Reviewed-by: Neil Roberts <neil@linux.intel.com>
646 lines
23 KiB
C
646 lines
23 KiB
C
/*
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* Cogl
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*
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* A Low Level GPU Graphics and Utilities API
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*
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* Copyright (C) 2009,2010,2012 Intel Corporation.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*
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*
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* Authors:
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* Havoc Pennington <hp@pobox.com> for litl
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* Robert Bragg <robert@linux.intel.com>
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*/
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#ifndef _COGL_MATRIX_STACK_H_
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#define _COGL_MATRIX_STACK_H_
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#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
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#error "Only <cogl/cogl.h> can be included directly."
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#endif
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#include "cogl-matrix.h"
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#include "cogl-context.h"
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/**
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* SECTION:cogl-matrix-stack
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* @short_description: Functions for efficiently tracking many
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* related transformations
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*
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* Matrices can be used (for example) to describe the model-view
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* transforms of objects, texture transforms, and projective
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* transforms.
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*
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* The #CoglMatrix api provides a good way to manipulate individual
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* matrices representing a single transformation but if you need to
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* track many-many such transformations for many objects that are
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* organized in a scenegraph for example then using a separate
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* #CoglMatrix for each object may not be the most efficient way.
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*
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* A #CoglMatrixStack enables applications to track lots of
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* transformations that are related to each other in some kind of
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* hierarchy. In a scenegraph for example if you want to know how to
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* transform a particular node then you usually have to walk up
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* through the ancestors and accumulate their transforms before
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* finally applying the transform of the node itself. In this model
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* things are grouped together spatially according to their ancestry
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* and all siblings with the same parent share the same initial
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* transformation. The #CoglMatrixStack API is suited to tracking lots
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* of transformations that fit this kind of model.
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*
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* Compared to using the #CoglMatrix api directly to track many
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* related transforms, these can be some advantages to using a
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* #CoglMatrixStack:
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* <itemizedlist>
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* <listitem>Faster equality comparisons of transformations</listitem>
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* <listitem>Efficient comparisons of the differences between arbitrary
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* transformations</listitem>
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* <listitem>Avoid redundant arithmetic related to common transforms
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* </listitem>
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* <listitem>Can be more space efficient (not always though)</listitem>
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* </itemizedlist>
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*
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* For reference (to give an idea of when a #CoglMatrixStack can
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* provide a space saving) a #CoglMatrix can be expected to take 72
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* bytes whereas a single #CoglMatrixEntry in a #CoglMatrixStack is
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* currently around 32 bytes on a 32bit CPU or 36 bytes on a 64bit
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* CPU. An entry is needed for each individual operation applied to
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* the stack (such as rotate, scale, translate) so if most of your
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* leaf node transformations only need one or two simple operations
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* relative to their parent then a matrix stack will likely take less
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* space than having a #CoglMatrix for each node.
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*
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* Even without any space saving though the ability to perform fast
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* comparisons and avoid redundant arithmetic (especially sine and
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* cosine calculations for rotations) can make using a matrix stack
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* worthwhile.
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*/
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/**
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* CoglMatrixStack:
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*
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* Tracks your current position within a hierarchy and lets you build
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* up a graph of transformations as you traverse through a hierarchy
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* such as a scenegraph.
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*
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* A #CoglMatrixStack always maintains a reference to a single
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* transformation at any point in time, representing the
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* transformation at the current position in the hierarchy. You can
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* get a reference to the current transformation by calling
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* cogl_matrix_stack_get_entry().
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*
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* When a #CoglMatrixStack is first created with
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* cogl_matrix_stack_new() then it is conceptually positioned at the
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* root of your hierarchy and the current transformation simply
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* represents an identity transformation.
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*
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* As you traverse your object hierarchy (your scenegraph) then you
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* should call cogl_matrix_stack_push() whenever you move down one
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* level and call cogl_matrix_stack_pop() whenever you move back up
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* one level towards the root.
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*
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* At any time you can apply a set of operations, such as "rotate",
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* "scale", "translate" on top of the current transformation of a
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* #CoglMatrixStack using functions such as
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* cogl_matrix_stack_rotate(), cogl_matrix_stack_scale() and
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* cogl_matrix_stack_translate(). These operations will derive a new
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* current transformation and will never affect a transformation
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* that you have referenced using cogl_matrix_stack_get_entry().
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*
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* Internally applying operations to a #CoglMatrixStack builds up a
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* graph of #CoglMatrixEntry structures which each represent a single
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* immutable transform.
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*/
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typedef struct _CoglMatrixStack CoglMatrixStack;
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#ifdef COGL_HAS_GTYPE_SUPPORT
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/**
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* cogl_matrix_stack_get_gtype:
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*
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* Returns: a #GType that can be used with the GLib type system.
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*/
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GType cogl_matrix_stack_get_gtype (void);
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#endif
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/**
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* CoglMatrixEntry:
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*
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* Represents a single immutable transformation that was retrieved
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* from a #CoglMatrixStack using cogl_matrix_stack_get_entry().
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*
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* Internally a #CoglMatrixEntry represents a single matrix
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* operation (such as "rotate", "scale", "translate") which is applied
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* to the transform of a single parent entry.
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*
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* Using the #CoglMatrixStack api effectively builds up a graph of
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* these immutable #CoglMatrixEntry structures whereby operations
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* that can be shared between multiple transformations will result
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* in shared #CoglMatrixEntry nodes in the graph.
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*
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* When a #CoglMatrixStack is first created it references one
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* #CoglMatrixEntry that represents a single "load identity"
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* operation. This serves as the root entry and all operations
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* that are then applied to the stack will extend the graph
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* starting from this root "load identity" entry.
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*
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* Given the typical usage model for a #CoglMatrixStack and the way
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* the entries are built up while traversing a scenegraph then in most
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* cases where an application is interested in comparing two
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* transformations for equality then it is enough to simply compare
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* two #CoglMatrixEntry pointers directly. Technically this can lead
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* to false negatives that could be identified with a deeper
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* comparison but often these false negatives are unlikely and
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* don't matter anyway so this enables extremely cheap comparisons.
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*
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* <note>#CoglMatrixEntry<!-- -->s are reference counted using
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* cogl_matrix_entry_ref() and cogl_matrix_entry_unref() not with
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* cogl_object_ref() and cogl_object_unref().</note>
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*/
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typedef struct _CoglMatrixEntry CoglMatrixEntry;
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#ifdef COGL_HAS_GTYPE_SUPPORT
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/**
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* cogl_matrix_entry_get_gtype:
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*
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* Returns: a #GType that can be used with the GLib type system.
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*/
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GType cogl_matrix_entry_get_gtype (void);
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#endif
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/**
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* cogl_matrix_stack_new:
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* @ctx: A #CoglContext
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*
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* Allocates a new #CoglMatrixStack that can be used to build up
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* transformations relating to objects in a scenegraph like hierarchy.
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* (See the description of #CoglMatrixStack and #CoglMatrixEntry for
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* more details of what a matrix stack is best suited for)
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*
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* When a #CoglMatrixStack is first allocated it is conceptually
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* positioned at the root of your scenegraph hierarchy. As you
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* traverse your scenegraph then you should call
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* cogl_matrix_stack_push() whenever you move down a level and
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* cogl_matrix_stack_pop() whenever you move back up a level towards
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* the root.
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*
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* Once you have allocated a #CoglMatrixStack you can get a reference
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* to the current transformation for the current position in the
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* hierarchy by calling cogl_matrix_stack_get_entry().
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*
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* Once you have allocated a #CoglMatrixStack you can apply operations
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* such as rotate, scale and translate to modify the current transform
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* for the current position in the hierarchy by calling
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* cogl_matrix_stack_rotate(), cogl_matrix_stack_scale() and
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* cogl_matrix_stack_translate().
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*
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* Return value: (transfer full): A newly allocated #CoglMatrixStack
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*/
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CoglMatrixStack *
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cogl_matrix_stack_new (CoglContext *ctx);
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/**
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* cogl_matrix_stack_push:
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* @stack: A #CoglMatrixStack
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*
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* Saves the current transform and starts a new transform that derives
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* from the current transform.
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*
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* This is usually called while traversing a scenegraph whenever you
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* traverse one level deeper. cogl_matrix_stack_pop() can then be
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* called when going back up one layer to restore the previous
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* transform of an ancestor.
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*/
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void
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cogl_matrix_stack_push (CoglMatrixStack *stack);
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/**
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* cogl_matrix_stack_pop:
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* @stack: A #CoglMatrixStack
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*
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* Restores the previous transform that was last saved by calling
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* cogl_matrix_stack_push().
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*
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* This is usually called while traversing a scenegraph whenever you
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* return up one level in the graph towards the root node.
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*/
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void
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cogl_matrix_stack_pop (CoglMatrixStack *stack);
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/**
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* cogl_matrix_stack_load_identity:
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* @stack: A #CoglMatrixStack
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*
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* Resets the current matrix to the identity matrix.
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*/
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void
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cogl_matrix_stack_load_identity (CoglMatrixStack *stack);
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/**
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* cogl_matrix_stack_scale:
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* @stack: A #CoglMatrixStack
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* @x: Amount to scale along the x-axis
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* @y: Amount to scale along the y-axis
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* @z: Amount to scale along the z-axis
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*
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* Multiplies the current matrix by one that scales the x, y and z
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* axes by the given values.
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*/
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void
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cogl_matrix_stack_scale (CoglMatrixStack *stack,
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float x,
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float y,
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float z);
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/**
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* cogl_matrix_stack_translate:
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* @stack: A #CoglMatrixStack
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* @x: Distance to translate along the x-axis
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* @y: Distance to translate along the y-axis
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* @z: Distance to translate along the z-axis
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*
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* Multiplies the current matrix by one that translates along all
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* three axes according to the given values.
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*/
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void
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cogl_matrix_stack_translate (CoglMatrixStack *stack,
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float x,
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float y,
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float z);
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/**
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* cogl_matrix_stack_rotate:
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* @stack: A #CoglMatrixStack
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* @angle: Angle in degrees to rotate.
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* @x: X-component of vertex to rotate around.
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* @y: Y-component of vertex to rotate around.
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* @z: Z-component of vertex to rotate around.
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*
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* Multiplies the current matrix by one that rotates the around the
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* axis-vector specified by @x, @y and @z. The rotation follows the
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* right-hand thumb rule so for example rotating by 10 degrees about
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* the axis-vector (0, 0, 1) causes a small counter-clockwise
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* rotation.
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*/
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void
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cogl_matrix_stack_rotate (CoglMatrixStack *stack,
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float angle,
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float x,
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float y,
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float z);
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/**
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* cogl_matrix_stack_rotate_quaternion:
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* @stack: A #CoglMatrixStack
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* @quaternion: A #CoglQuaternion
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*
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* Multiplies the current matrix by one that rotates according to the
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* rotation described by @quaternion.
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*/
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void
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cogl_matrix_stack_rotate_quaternion (CoglMatrixStack *stack,
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const CoglQuaternion *quaternion);
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/**
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* cogl_matrix_stack_rotate_euler:
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* @stack: A #CoglMatrixStack
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* @euler: A #CoglEuler
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*
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* Multiplies the current matrix by one that rotates according to the
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* rotation described by @euler.
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*/
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void
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cogl_matrix_stack_rotate_euler (CoglMatrixStack *stack,
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const CoglEuler *euler);
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/**
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* cogl_matrix_stack_multiply:
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* @stack: A #CoglMatrixStack
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* @matrix: the matrix to multiply with the current model-view
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*
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* Multiplies the current matrix by the given matrix.
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*/
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void
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cogl_matrix_stack_multiply (CoglMatrixStack *stack,
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const CoglMatrix *matrix);
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/**
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* cogl_matrix_stack_frustum:
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* @stack: A #CoglMatrixStack
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* @left: X position of the left clipping plane where it
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* intersects the near clipping plane
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* @right: X position of the right clipping plane where it
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* intersects the near clipping plane
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* @bottom: Y position of the bottom clipping plane where it
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* intersects the near clipping plane
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* @top: Y position of the top clipping plane where it intersects
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* the near clipping plane
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* @z_near: The distance to the near clipping plane (Must be positive)
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* @z_far: The distance to the far clipping plane (Must be positive)
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*
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* Replaces the current matrix with a perspective matrix for a given
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* viewing frustum defined by 4 side clip planes that all cross
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* through the origin and 2 near and far clip planes.
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*/
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void
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cogl_matrix_stack_frustum (CoglMatrixStack *stack,
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float left,
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float right,
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float bottom,
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float top,
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float z_near,
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float z_far);
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/**
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* cogl_matrix_stack_perspective:
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* @stack: A #CoglMatrixStack
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* @fov_y: Vertical field of view angle in degrees.
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* @aspect: The (width over height) aspect ratio for display
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* @z_near: The distance to the near clipping plane (Must be positive,
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* and must not be 0)
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* @z_far: The distance to the far clipping plane (Must be positive)
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*
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* Replaces the current matrix with a perspective matrix based on the
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* provided values.
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*
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* <note>You should be careful not to have too great a @z_far / @z_near
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* ratio since that will reduce the effectiveness of depth testing
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* since there wont be enough precision to identify the depth of
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* objects near to each other.</note>
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*/
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void
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cogl_matrix_stack_perspective (CoglMatrixStack *stack,
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float fov_y,
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float aspect,
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float z_near,
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float z_far);
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/**
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* cogl_matrix_stack_orthographic:
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* @stack: A #CoglMatrixStack
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* @x_1: The x coordinate for the first vertical clipping plane
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* @y_1: The y coordinate for the first horizontal clipping plane
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* @x_2: The x coordinate for the second vertical clipping plane
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* @y_2: The y coordinate for the second horizontal clipping plane
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* @near: The <emphasis>distance</emphasis> to the near clipping
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* plane (will be <emphasis>negative</emphasis> if the plane is
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* behind the viewer)
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* @far: The <emphasis>distance</emphasis> to the far clipping
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* plane (will be <emphasis>negative</emphasis> if the plane is
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* behind the viewer)
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*
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* Replaces the current matrix with an orthographic projection matrix.
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*/
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void
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cogl_matrix_stack_orthographic (CoglMatrixStack *stack,
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float x_1,
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float y_1,
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float x_2,
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float y_2,
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float near,
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float far);
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/**
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* cogl_matrix_stack_get_inverse:
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* @stack: A #CoglMatrixStack
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* @inverse: (out): The destination for a 4x4 inverse transformation matrix
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*
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* Gets the inverse transform of the current matrix and uses it to
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* initialize a new #CoglMatrix.
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*
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* Return value: %TRUE if the inverse was successfully calculated or %FALSE
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* for degenerate transformations that can't be inverted (in this case the
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* @inverse matrix will simply be initialized with the identity matrix)
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*/
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CoglBool
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cogl_matrix_stack_get_inverse (CoglMatrixStack *stack,
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CoglMatrix *inverse);
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/**
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* cogl_matrix_stack_get_entry:
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* @stack: A #CoglMatrixStack
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*
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* Gets a reference to the current transform represented by a
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* #CoglMatrixEntry pointer.
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*
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* <note>The transform represented by a #CoglMatrixEntry is
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* immutable.</note>
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*
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* <note>#CoglMatrixEntry<!-- -->s are reference counted using
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* cogl_matrix_entry_ref() and cogl_matrix_entry_unref() and you
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* should call cogl_matrix_entry_unref() when you are finished with
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* and entry you get via cogl_matrix_stack_get_entry().</note>
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*
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* Return value: (transfer none): A pointer to the #CoglMatrixEntry
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* representing the current matrix stack transform.
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*/
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CoglMatrixEntry *
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cogl_matrix_stack_get_entry (CoglMatrixStack *stack);
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/**
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* cogl_matrix_stack_get:
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* @stack: A #CoglMatrixStack
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* @matrix: (out): The potential destination for the current matrix
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*
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* Resolves the current @stack transform into a #CoglMatrix by
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* combining the operations that have been applied to build up the
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* current transform.
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*
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* There are two possible ways that this function may return its
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* result depending on whether the stack is able to directly point
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* to an internal #CoglMatrix or whether the result needs to be
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* composed of multiple operations.
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*
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* If an internal matrix contains the required result then this
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* function will directly return a pointer to that matrix, otherwise
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* if the function returns %NULL then @matrix will be initialized
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* to match the current transform of @stack.
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*
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* <note>@matrix will be left untouched if a direct pointer is
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* returned.</note>
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*
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* Return value: A direct pointer to the current transform or %NULL
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* and in that case @matrix will be initialized with
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* the value of the current transform.
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*/
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CoglMatrix *
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cogl_matrix_stack_get (CoglMatrixStack *stack,
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CoglMatrix *matrix);
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/**
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* cogl_matrix_entry_get:
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* @entry: A #CoglMatrixEntry
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* @matrix: (out): The potential destination for the transform as
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* a matrix
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*
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* Resolves the current @entry transform into a #CoglMatrix by
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* combining the sequence of operations that have been applied to
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* build up the current transform.
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*
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* There are two possible ways that this function may return its
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* result depending on whether it's possible to directly point
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* to an internal #CoglMatrix or whether the result needs to be
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* composed of multiple operations.
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*
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* If an internal matrix contains the required result then this
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* function will directly return a pointer to that matrix, otherwise
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* if the function returns %NULL then @matrix will be initialized
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* to match the transform of @entry.
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*
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* <note>@matrix will be left untouched if a direct pointer is
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* returned.</note>
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*
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* Return value: A direct pointer to a #CoglMatrix transform or %NULL
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* and in that case @matrix will be initialized with
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* the effective transform represented by @entry.
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*/
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CoglMatrix *
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cogl_matrix_entry_get (CoglMatrixEntry *entry,
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CoglMatrix *matrix);
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/**
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* cogl_matrix_stack_set:
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* @stack: A #CoglMatrixStack
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* @matrix: A #CoglMatrix replace the current matrix value with
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*
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* Replaces the current @stack matrix value with the value of @matrix.
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* This effectively discards any other operations that were applied
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* since the last time cogl_matrix_stack_push() was called or since
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* the stack was initialized.
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*/
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void
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cogl_matrix_stack_set (CoglMatrixStack *stack,
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const CoglMatrix *matrix);
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/**
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* cogl_is_matrix_stack:
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* @object: a #CoglObject
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*
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* Determines if the given #CoglObject refers to a #CoglMatrixStack.
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*
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* Return value: %TRUE if @object is a #CoglMatrixStack, otherwise
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* %FALSE.
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*/
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CoglBool
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cogl_is_matrix_stack (void *object);
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/**
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* cogl_matrix_entry_calculate_translation:
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* @entry0: The first reference transform
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* @entry1: A second reference transform
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* @x: (out): The destination for the x-component of the translation
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* @y: (out): The destination for the y-component of the translation
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* @z: (out): The destination for the z-component of the translation
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*
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* Determines if the only difference between two transforms is a
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* translation and if so returns what the @x, @y, and @z components of
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* the translation are.
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*
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* If the difference between the two translations involves anything
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* other than a translation then the function returns %FALSE.
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*
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* Return value: %TRUE if the only difference between the transform of
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* @entry0 and the transform of @entry1 is a translation,
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* otherwise %FALSE.
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*/
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CoglBool
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cogl_matrix_entry_calculate_translation (CoglMatrixEntry *entry0,
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CoglMatrixEntry *entry1,
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float *x,
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float *y,
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float *z);
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/**
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* cogl_matrix_entry_is_identity:
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* @entry: A #CoglMatrixEntry
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*
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* Determines whether @entry is known to represent an identity
|
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* transform.
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*
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* If this returns %TRUE then the entry is definitely the identity
|
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* matrix. If it returns %FALSE it may or may not be the identity
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* matrix but no expensive comparison is performed to verify it.
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*
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* Return value: %TRUE if @entry is definitely an identity transform,
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* otherwise %FALSE.
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*/
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CoglBool
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cogl_matrix_entry_is_identity (CoglMatrixEntry *entry);
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|
/**
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|
* cogl_matrix_entry_equal:
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* @entry0: The first #CoglMatrixEntry to compare
|
|
* @entry1: A second #CoglMatrixEntry to compare
|
|
*
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|
* Compares two arbitrary #CoglMatrixEntry transforms for equality
|
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* returning %TRUE if they are equal or %FALSE otherwise.
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|
*
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|
* <note>In many cases it is unnecessary to use this api and instead
|
|
* direct pointer comparisons of entries are good enough and much
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|
* cheaper too.</note>
|
|
*
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* Return value: %TRUE if @entry0 represents the same transform as
|
|
* @entry1, otherwise %FALSE.
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|
*/
|
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CoglBool
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|
cogl_matrix_entry_equal (CoglMatrixEntry *entry0,
|
|
CoglMatrixEntry *entry1);
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|
|
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/**
|
|
* cogl_debug_matrix_entry_print:
|
|
* @entry: A #CoglMatrixEntry
|
|
*
|
|
* Allows visualizing the operations that build up the given @entry
|
|
* for debugging purposes by printing to stdout.
|
|
*/
|
|
void
|
|
cogl_debug_matrix_entry_print (CoglMatrixEntry *entry);
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|
|
/**
|
|
* cogl_matrix_entry_ref:
|
|
* @entry: A #CoglMatrixEntry
|
|
*
|
|
* Takes a reference on the given @entry to ensure the @entry stays
|
|
* alive and remains valid. When you are finished with the @entry then
|
|
* you should call cogl_matrix_entry_unref().
|
|
*
|
|
* It is an error to pass an @entry pointer to cogl_object_ref() and
|
|
* cogl_object_unref()
|
|
*/
|
|
CoglMatrixEntry *
|
|
cogl_matrix_entry_ref (CoglMatrixEntry *entry);
|
|
|
|
/**
|
|
* cogl_matrix_entry_unref:
|
|
* @entry: A #CoglMatrixEntry
|
|
*
|
|
* Releases a reference on @entry either taken by calling
|
|
* cogl_matrix_entry_unref() or to release the reference given when
|
|
* calling cogl_matrix_stack_get_entry().
|
|
*/
|
|
void
|
|
cogl_matrix_entry_unref (CoglMatrixEntry *entry);
|
|
|
|
#endif /* _COGL_MATRIX_STACK_H_ */
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