mutter/cogl.h.in
Robert Bragg c52eda6715 Bug 1406 - Handling of premultiplication in clutter
Merge branch 'premultiplication'

[cogl-texture docs] Improves the documentation of the internal_format args
[test-premult] Adds a unit test for texture upload premultiplication semantics
[fog] Document that fogging only works with opaque or unmultipled colors
[test-blend-strings] Explicitly request RGBA_888 tex format for test textures
[premultiplication] Be more conservative with what data gets premultiplied
[bitmap] Fixes _cogl_bitmap_fallback_unpremult
[cogl-bitmap] Fix minor copy and paste error in _cogl_bitmap_fallback_premult
Avoid unnecesary unpremultiplication when saving to local data
Don't unpremultiply Cairo data
Default to a blend function that expects premultiplied colors
Implement premultiplication for CoglBitmap
Use correct texture format for pixmap textures and FBO's
Add cogl_color_premultiply()
2009-06-11 16:00:28 +01:00

735 lines
25 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 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.
*/
#ifndef __COGL_H__
#define __COGL_H__
#include <glib.h>
#define __COGL_H_INSIDE__
#include <cogl/cogl-defines-@CLUTTER_COGL@.h>
#include <cogl/cogl-vertex-buffer.h>
#include <cogl/cogl-matrix.h>
#include <cogl/cogl-vertex-buffer.h>
#include <cogl/cogl-fixed.h>
#include <cogl/cogl-color.h>
#include <cogl/cogl-offscreen.h>
#include <cogl/cogl-material.h>
#include <cogl/cogl-path.h>
#include <cogl/cogl-shader.h>
#include <cogl/cogl-bitmap.h>
#include <cogl/cogl-texture.h>
#include <cogl/cogl-types.h>
#include <cogl/cogl-debug.h>
#include <cogl/cogl-deprecated.h>
#include <cogl/cogl-enum-types.h>
G_BEGIN_DECLS
/**
* SECTION:cogl
* @short_description: General purpose API
*
* General utility functions for COGL.
*/
/**
* cogl_get_option_group:
*
* Retrieves the #GOptionGroup used by COGL to parse the command
* line options. Clutter uses this to handle the COGL command line
* options during its initialization process.
*
* Return value: a #GOptionGroup
*
* Since: 1.0
*/
GOptionGroup * cogl_get_option_group (void);
/* Misc */
/**
* cogl_get_features:
*
* Returns all of the features supported by COGL.
*
* Return value: A logical OR of all the supported COGL features.
*
* Since: 0.8
*/
CoglFeatureFlags cogl_get_features (void);
/**
* cogl_features_available:
* @features: A bitmask of features to check for
*
* Checks whether the given COGL features are available. Multiple
* features can be checked for by or-ing them together with the '|'
* operator. %TRUE is only returned if all of the requested features
* are available.
*
* Return value: %TRUE if the features are available, %FALSE otherwise.
*/
gboolean cogl_features_available (CoglFeatureFlags features);
/**
* cogl_get_proc_address:
* @name: the name of the function.
*
* Gets a pointer to a given GL or GL ES extension function. This acts
* as a wrapper around glXGetProcAddress() or whatever is the
* appropriate function for the current backend.
*
* Return value: a pointer to the requested function or %NULL if the
* function is not available.
*/
CoglFuncPtr cogl_get_proc_address (const gchar *name);
/**
* cogl_check_extension:
* @name: extension to check for
* @ext: list of extensions
*
* Check whether @name occurs in list of extensions in @ext.
*
* Returns: %TRUE if the extension occurs in the list, %FALSE otherwize.
*/
gboolean cogl_check_extension (const gchar *name,
const gchar *ext);
/**
* cogl_get_bitmasks:
* @red: Return location for the number of red bits or %NULL
* @green: Return location for the number of green bits or %NULL
* @blue: Return location for the number of blue bits or %NULL
* @alpha: Return location for the number of alpha bits or %NULL
*
* Gets the number of bitplanes used for each of the color components
* in the color buffer. Pass %NULL for any of the arguments if the
* value is not required.
*/
void cogl_get_bitmasks (gint *red,
gint *green,
gint *blue,
gint *alpha);
/**
* cogl_perspective:
* @fovy: Vertical of view angle in degrees.
* @aspect: Aspect ratio of diesplay
* @z_near: Nearest visible point
* @z_far: Furthest visible point along the z-axis
*
* Replaces the current projection matrix with a perspective matrix
* based on the provided values.
*/
void cogl_perspective (float fovy,
float aspect,
float z_near,
float z_far);
/**
* cogl_frustum:
* @left: Left clipping plane
* @right: Right clipping plane
* @bottom: Bottom clipping plane
* @top: Top clipping plane
* @z_near: Nearest visible point
* @z_far: Furthest visible point along the z-axis
*
* Replaces the current projection matrix with a perspective matrix
* for the given viewing frustum.
*
* Since: 0.8.2
*/
void cogl_frustum (float left,
float right,
float bottom,
float top,
float z_near,
float z_far);
/**
* cogl_ortho:
* @left: The coordinate for the left clipping plane
* @right: The coordinate for the right clipping plane
* @bottom: The coordinate for the bottom clipping plane
* @top: The coordinate for the top clipping plane
* @near: The coordinate for the near clipping plane (may be negative if
* the plane is behind the viewer)
* @far: The coordinate for the far clipping plane (may be negative if
* the plane is behind the viewer)
*
* Replaces the current projection matrix with a parallel projection
* matrix.
*
* Since: 1.0
*/
void cogl_ortho (float left,
float right,
float bottom,
float top,
float near,
float far);
/*
* _cogl_setup_viewport:
* @width: Width of the viewport
* @height: Height of the viewport
* @fovy: Field of view angle in degrees
* @aspect: Aspect ratio to determine the field of view along the x-axis
* @z_near: Nearest visible point along the z-axis
* @z_far: Furthest visible point along the z-axis
*
* Replaces the current viewport and projection matrix with the given
* values. The viewport is placed at the top left corner of the window
* with the given width and height. The projection matrix is replaced
* with one that has a viewing angle of @fovy along the y-axis and a
* view scaled according to @aspect along the x-axis. The view is
* clipped according to @z_near and @z_far on the z-axis.
*
* This function is used only by Clutter.
*/
void _cogl_setup_viewport (guint width,
guint height,
float fovy,
float aspect,
float z_near,
float z_far);
/**
* cogl_viewport:
* @width: Width of the viewport
* @height: Height of the viewport
*
* Replace the current viewport with the given values.
*
* Since: 0.8.2
*/
void cogl_viewport (guint width,
guint height);
/**
* cogl_push_matrix:
*
* Store the current model-view matrix on the matrix stack. The matrix
* can later be restored with cogl_pop_matrix().
*/
void cogl_push_matrix (void);
/**
* cogl_pop_matrix:
*
* Restore the current model-view matrix from the matrix stack.
*/
void cogl_pop_matrix (void);
/**
* cogl_scale:
* @x: Amount to scale along the x-axis
* @y: Amount to scale along the y-axis
* @z: Amount to scale along the z-axis
*
* Multiplies the current model-view matrix by one that scales the x,
* y and z axes by the given values.
*/
void cogl_scale (float x,
float y,
float z);
/**
* cogl_translate:
* @x: Distance to translate along the x-axis
* @y: Distance to translate along the y-axis
* @z: Distance to translate along the z-axis
*
* Multiplies the current model-view matrix by one that translates the
* model along all three axes according to the given values.
*/
void cogl_translate (float x,
float y,
float z);
/**
* cogl_rotate:
* @angle: Angle in degrees to rotate.
* @x: X-component of vertex to rotate around.
* @y: Y-component of vertex to rotate around.
* @z: Z-component of vertex to rotate around.
*
* Multiplies the current model-view matrix by one that rotates the
* model around the vertex specified by @x, @y and @z. The rotation
* follows the right-hand thumb rule so for example rotating by 10
* degrees about the vertex (0, 0, 1) causes a small counter-clockwise
* rotation.
*/
void cogl_rotate (float angle,
float x,
float y,
float z);
/**
* cogl_get_modelview_matrix:
* @matrix: pointer to a CoglMatrix to recieve the matrix
*
* Stores the current model-view matrix in @matrix.
*/
void cogl_get_modelview_matrix (CoglMatrix *matrix);
/**
* cogl_set_modelview_matrix:
* @matrix: pointer to a CoglMatrix to set as the new model-view matrix
*
* Loads matrix as the new model-view matrix.
*/
void cogl_set_modelview_matrix (CoglMatrix *matrix);
/**
* cogl_get_projection_matrix:
* @matrix: pointer to a CoglMatrix to recieve the matrix
*
* Stores the current projection matrix in @matrix.
*/
void cogl_get_projection_matrix (CoglMatrix *matrix);
/**
* cogl_set_projection_matrix:
* @matrix: pointer to a CoglMatrix to set as the new projection matrix
*
* Loads matrix as the new projection matrix.
*/
void cogl_set_projection_matrix (CoglMatrix *matrix);
/**
* cogl_get_viewport:
* @v: pointer to a 4 element array of #float<!-- -->s to
* receive the viewport dimensions.
*
* Stores the current viewport in @v. @v[0] and @v[1] get the x and y
* position of the viewport and @v[2] and @v[3] get the width and
* height.
*/
void cogl_get_viewport (float v[4]);
/**
* cogl_set_depth_test_enabled:
* @setting: %TRUE to enable depth testing or %FALSE to disable.
*
* Sets whether depth testing is enabled. If it is disabled then the
* order that actors are layered on the screen depends solely on the
* order specified using clutter_actor_raise() and
* clutter_actor_lower(), otherwise it will also take into account the
* actor's depth. Depth testing is disabled by default.
*/
void cogl_set_depth_test_enabled (gboolean setting);
/**
* cogl_get_depth_test_enable:
*
* Queries if depth testing has been enabled via cogl_set_depth_test_enable()
*
* Returns: TRUE if depth testing is enabled else FALSE
*/
gboolean cogl_get_depth_test_enabled (void);
/**
* cogl_set_backface_culling_enabled:
* @setting: %TRUE to enable backface culling or %FALSE to disable.
*
* Sets whether textures positioned so that their backface is showing
* should be hidden. This can be used to efficiently draw two-sided
* textures or fully closed cubes without enabling depth testing. This
* only affects calls to the cogl_rectangle* family of functions and
* cogl_vertex_buffer_draw*. Backface culling is disabled by default.
*/
void cogl_set_backface_culling_enabled (gboolean setting);
/**
* cogl_get_backface_culling_enabled:
*
* Queries if backface culling has been enabled via
* cogl_set_backface_culling_enabled()
*
* Returns: TRUE if backface culling is enabled else FALSE
*/
gboolean cogl_get_backface_culling_enabled (void);
/**
* cogl_set_fog:
* @fog_color: The color of the fog
* @mode: A CoglFogMode that determines the equation used to calculate the
* fogging blend factor.
* @density: Used by the EXPONENTIAL and EXPONENTIAL_SQUARED CoglFogMode
* equations.
* @z_near: Position along z-axis where no fogging should be applied
* @z_far: Position along z-axes where full fogging should be applied
*
* Enables fogging. Fogging causes vertices that are further away from the eye
* to be rendered with a different color. The color is determined according to
* the chosen fog mode; at it's simplest the color is linearly interpolated so
* that vertices at @z_near are drawn fully with their original color and
* vertices at @z_far are drawn fully with @fog_color. Fogging will remain
* enabled until you call cogl_disable_fog().
*
* Note: The fogging functions only work correctly when primitives use
* unmultiplied alpha colors. By default Cogl will premultiply textures
* and cogl_set_source_color will premultiply colors, so unless you
* explicitly load your textures requesting an unmultiplied
* internal_format and use cogl_material_set_color you can only use
* fogging with fully opaque primitives.
*
* We can look to improve this in the future when we can depend on
* fragment shaders.
*/
void cogl_set_fog (const CoglColor *fog_color,
CoglFogMode mode,
float density,
float z_near,
float z_far);
/**
* cogl_disable_fog:
*
* This function disables fogging, so primitives drawn afterwards will not be
* blended with any previously set fog color.
*/
void cogl_disable_fog (void);
/**
* CoglBufferBit:
* @COGL_BUFFER_BIT_COLOR: Selects the primary color buffer
* @COGL_BUFFER_BIT_DEPTH: Selects the depth buffer
* @COGL_BUFFER_BIT_STENCIL: Selects the stencil buffer
*
* Types of auxiliary buffers
*
* Since: 1.0
*/
typedef enum {
COGL_BUFFER_BIT_COLOR = 1L<<0,
COGL_BUFFER_BIT_DEPTH = 1L<<1,
COGL_BUFFER_BIT_STENCIL = 1L<<2
} CoglBufferBit;
/**
* cogl_clear:
* @color: Background color to clear to
* @buffers: A mask of #CoglBufferBit<!-- -->'s identifying which auxiliary
* buffers to clear
*
* Clears all the auxiliary buffers identified in the @buffers mask, and if
* that includes the color buffer then the specified @color is used.
*/
void cogl_clear (const CoglColor *color,
gulong buffers);
/**
* cogl_set_source:
* @material: A CoglMaterial object
*
* This function sets the source material that will be used to fill subsequent
* geometry emitted via the cogl API.
*
* Note: in the future we may add the ability to set a front facing material,
* and a back facing material, in which case this function will set both to the
* same.
*
* Since 1.0
*/
void cogl_set_source (CoglHandle material);
/**
* cogl_set_source_color:
* @color: a #CoglColor
*
* This is a convenience function for creating a solid fill source material
* from the given color. This color will be used for any subsequent drawing
* operation.
*
* The color will be premultiplied by Cogl, so the color should be
* non-premultiplied. For example: use (1.0, 0.0, 0.0, 0.5) for
* semi-transparent red.
*
* See also cogl_set_source_color4ub() and cogl_set_source_color4f()
* if you already have the color components.
*
* Since: 1.0
*/
void cogl_set_source_color (const CoglColor *color);
/**
* cogl_set_source_color4ub:
* @red: value of the red channel, between 0 and 255
* @green: value of the green channel, between 0 and 255
* @blue: value of the blue channel, between 0 and 255
* @alpha: value of the alpha channel, between 0 and 255
*
* This is a convenience function for creating a solid fill source material
* from the given color using unsigned bytes for each component. This
* color will be used for any subsequent drawing operation.
*
* The value for each component is an unsigned byte in the range
* between 0 and 255.
*
* Since: 1.0
*/
void cogl_set_source_color4ub (guint8 red,
guint8 green,
guint8 blue,
guint8 alpha);
/**
* cogl_set_source_color4f:
* @red: value of the red channel, between 0 and %1.0
* @green: value of the green channel, between 0 and %1.0
* @blue: value of the blue channel, between 0 and %1.0
* @alpha: value of the alpha channel, between 0 and %1.0
*
* This is a convenience function for creating a solid fill source material
* from the given color using normalized values for each component. This color
* will be used for any subsequent drawing operation.
*
* The value for each component is a fixed point number in the range
* between 0 and %1.0. If the values passed in are outside that
* range, they will be clamped.
*
* Since: 1.0
*/
void cogl_set_source_color4f (float red,
float green,
float blue,
float alpha);
/**
* cogl_set_source_texture:
* @texture_handle: The Cogl texture you want as your source
*
* This is a convenience function for creating a material with the first
* layer set to #texture_handle and setting that material as the source with
* cogl_set_source.
*
* Note: There is no interaction between calls to cogl_set_source_color
* and cogl_set_source_texture. If you need to blend a texture with a color then
* you can create a simple material like this:
* <programlisting>
* material = cogl_material_new ();
* cogl_material_set_color4ub (material, 0xff, 0x00, 0x00, 0x80);
* cogl_material_set_layer (material, 0, tex_handle);
* cogl_set_source (material);
* </programlisting>
*
* Since 1.0
*/
void cogl_set_source_texture (CoglHandle texture_handle);
/**
* SECTION:cogl-clipping
* @short_description: Fuctions for manipulating a stack of clipping regions
*
* To support clipping your geometry to rectangles or paths Cogl exposes a
* stack based API whereby each clip region you push onto the stack is
* intersected with the previous region.
*/
/**
* cogl_clip_push_window_rect:
* @x_offset: left edge of the clip rectangle in window coordinates
* @y_offset: top edge of the clip rectangle in window coordinates
* @width: width of the clip rectangle
* @height: height of the clip rectangle
*
* Specifies a rectangular clipping area for all subsequent drawing
* operations. Any drawing commands that extend outside the rectangle
* will be clipped so that only the portion inside the rectangle will
* be displayed. The rectangle dimensions are not transformed by the
* current model-view matrix.
*
* The rectangle is intersected with the current clip region. To undo
* the effect of this function, call cogl_clip_pop().
*/
void cogl_clip_push_window_rect (float x_offset,
float y_offset,
float width,
float height);
/**
* cogl_clip_push:
* @x_offset: left edge of the clip rectangle
* @y_offset: top edge of the clip rectangle
* @width: width of the clip rectangle
* @height: height of the clip rectangle
*
* Specifies a rectangular clipping area for all subsequent drawing
* operations. Any drawing commands that extend outside the rectangle
* will be clipped so that only the portion inside the rectangle will
* be displayed. The rectangle dimensions are transformed by the
* current model-view matrix.
*
* The rectangle is intersected with the current clip region. To undo
* the effect of this function, call cogl_clip_pop().
*/
void cogl_clip_push (float x_offset,
float y_offset,
float width,
float height);
/**
* cogl_clip_push_from_path:
*
* Sets a new clipping area using the current path. The current path
* is then cleared. The clipping area is intersected with the previous
* clipping area. To restore the previous clipping area, call
* cogl_clip_pop().
*
* Since: 1.0
*/
void cogl_clip_push_from_path (void);
/**
* cogl_clip_push_from_path_preserve:
*
* Sets a new clipping area using the current path. The current path
* is then cleared. The clipping area is intersected with the previous
* clipping area. To restore the previous clipping area, call
* cogl_clip_pop().
*
* Since: 1.0
*/
void cogl_clip_push_from_path_preserve (void);
/**
* cogl_clip_pop:
*
* Reverts the clipping region to the state before the last call to
* cogl_clip_push().
*/
void cogl_clip_pop (void);
/**
* cogl_clip_ensure:
*
* Ensures that the current clipping region has been set in GL. This
* will automatically be called before any Cogl primitives but it
* maybe be neccessary to call if you are using raw GL calls with
* clipping.
*
* Since: 1.0
*/
void cogl_clip_ensure (void);
/**
* cogl_clip_stack_save:
*
* Save the entire state of the clipping stack and then clear all
* clipping. The previous state can be returned to with
* cogl_clip_stack_restore(). Each call to cogl_clip_push() after this
* must be matched by a call to cogl_clip_pop() before calling
* cogl_clip_stack_restore().
*
* Since: 0.8.2
*/
void cogl_clip_stack_save (void);
/**
* cogl_clip_stack_restore:
*
* Restore the state of the clipping stack that was previously saved
* by cogl_clip_stack_save().
*
* Since: 0.8.2
*/
void cogl_clip_stack_restore (void);
/**
* cogl_set_draw_buffer:
* @target: A #CoglBufferTarget that specifies what kind of draw buffer you
* are setting as the render target.
* @offscreen: If you are setting a draw buffer of type COGL_OFFSCREEN_BUFFER
* then this is a CoglHandle for the offscreen buffer.
*
* This redirects all subsequent drawing to the specified draw buffer. This
* can either be an offscreen buffer created with
* cogl_offscreen_new_to_texture () or you can revert to your original
* on screen window buffer.
*/
void cogl_set_draw_buffer (CoglBufferTarget target,
CoglHandle offscreen);
/**
* cogl_push_draw_buffer:
*
* Save cogl_set_draw_buffer() state.
*/
void cogl_push_draw_buffer (void);
/**
* cogl_pop_draw_buffer:
*
* Restore cogl_set_draw_buffer() state.
*/
void cogl_pop_draw_buffer (void);
/*
* Internal API available only to Clutter.
*
* These are typically only to deal with the poor seperation of
* responsabilities that currently exists between Clutter and Cogl.
* Eventually a lot of the backend code currently in Clutter will
* move down into Cogl and these functions will be removed.
*/
void _cogl_destroy_context (void);
/* XXX: Removed before we release Clutter 1.0 since the implementation
* wasn't complete, and so we assume no one is using this yet. Util we
* have some one with a good usecase, we can't pretend to support breaking
* out into raw OpenGL. */
#if 0
/*
* cogl_flush_gl_state:
* @flags: flags controlling what is flushed; currently unused, pass in 0
*
* As an optimization, COGL functions may not immediately modify GL's
* state, instead batching up changes and applying them "just in
* time." Unapplied state could include glEnable() flags and the
* current transformation matrix among other examples. If you want to
* use GL directly, you need to flush any state COGL may have kept
* around. cogl_flush_gl_state() syncs all of COGL's state to GL.
*
* Since: 1.0
*/
void cogl_flush_gl_state (int flags);
#endif
/* private */
void _cogl_set_indirect_context (gboolean indirect);
G_END_DECLS
#undef __COGL_H_INSIDE__
#endif /* __COGL_H__ */