mutter/cogl/cogl-framebuffer.h
Robert Bragg 92c3063014 framebuffer: Add cogl_framebuffer draw methods
This adds cogl_framebuffer_ apis for drawing attributes and primitives
that replace corresponding apis that depend on the default CoglContext.
This is part of the on going effort to adapt the Cogl api so it no
longer depends on a global context variable.

All the new drawing functions also take an explicit pipeline argument
since we are also aiming to avoid being a stateful api like Cairo and
OpenGL. Being stateless makes it easier for orthogonal components to
share access to the GPU. Being stateless should also minimize any
impedance miss-match for those wanting to build higher level stateless
apis on top of Cogl.

Note: none of the legacy, global state options such as
cogl_set_depth_test_enabled(), cogl_set_backface_culling_enabled() or
cogl_program_use() are supported by these new drawing apis and if set
will simply be silently ignored.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
2012-02-09 13:09:15 +00:00

1275 lines
45 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011 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, see
* <http://www.gnu.org/licenses/>.
*
*
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#ifndef __COGL_FRAMEBUFFER_H
#define __COGL_FRAMEBUFFER_H
#include <cogl/cogl.h>
#include <glib.h>
#ifdef COGL_HAS_WIN32_SUPPORT
#include <windows.h>
#endif /* COGL_HAS_WIN32_SUPPORT */
#if defined (COGL_HAS_EGL_PLATFORM_WAYLAND_SUPPORT)
#include <wayland-client.h>
#endif /* COGL_HAS_EGL_PLATFORM_WAYLAND_SUPPORT */
G_BEGIN_DECLS
/**
* SECTION:cogl-framebuffer
* @short_description: A common interface for manipulating framebuffers
*
* Framebuffers are a collection of buffers that can be rendered too.
* A framebuffer may be comprised of one or more color buffers, an
* optional depth buffer and an optional stencil buffer. Other
* configuration parameters are associated with framebuffers too such
* as whether the framebuffer supports multi-sampling (an anti-aliasing
* technique) or dithering.
*
* There are two kinds of framebuffer in Cogl, #CoglOnscreen
* framebuffers and #CoglOffscreen framebuffers. As the names imply
* offscreen framebuffers are for rendering something offscreen
* (perhaps to a texture which is bound as one of the color buffers).
* The exact semantics of onscreen framebuffers depends on the window
* system backend that you are using, but typically you can expect
* rendering to a #CoglOnscreen framebuffer will be immediately
* visible to the user.
*
* If you want to create a new framebuffer then you should start by
* looking at the #CoglOnscreen and #CoglOffscreen constructor
* functions, such as cogl_offscreen_new_to_texture() or
* cogl_onscreen_new(). The #CoglFramebuffer interface deals with
* all aspects that are common between those two types of framebuffer.
*
* Setup of a new CoglFramebuffer happens in two stages. There is a
* configuration stage where you specify all the options and ancillary
* buffers you want associated with your framebuffer and then when you
* are happy with the configuration you can "allocate" the framebuffer
* using cogl_framebuffer_allocate(). Technically explicitly calling
* cogl_framebuffer_allocate() is optional for convenience and the
* framebuffer will automatically be allocated when you first try to
* draw to it, but if you do the allocation manually then you can
* also catch any possible errors that may arise from your
* configuration.
*/
#ifdef COGL_ENABLE_EXPERIMENTAL_API
#define COGL_FRAMEBUFFER(X) ((CoglFramebuffer *)(X))
/**
* cogl_framebuffer_allocate:
* @framebuffer: A #CoglFramebuffer
* @error: A pointer to a #GError for returning exceptions.
*
* Explicitly allocates a configured #CoglFramebuffer allowing developers to
* check and handle any errors that might arise from an unsupported
* configuration so that fallback configurations may be tried.
*
* <note>Many applications don't support any fallback options at least when
* they are initially developed and in that case the don't need to use this API
* since Cogl will automatically allocate a framebuffer when it first gets
* used. The disadvantage of relying on automatic allocation is that the
* program will abort with an error message if there is an error during
* automatic allocation.<note>
*
* Return value: %TRUE if there were no error allocating the framebuffer, else %FALSE.
* Since: 1.8
* Stability: unstable
*/
gboolean
cogl_framebuffer_allocate (CoglFramebuffer *framebuffer,
GError **error);
/**
* cogl_framebuffer_get_width:
* @framebuffer: A #CoglFramebuffer
*
* Queries the current width of the given @framebuffer.
*
* Return value: The width of @framebuffer.
* Since: 1.8
* Stability: unstable
*/
int
cogl_framebuffer_get_width (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_height:
* @framebuffer: A #CoglFramebuffer
*
* Queries the current height of the given @framebuffer.
*
* Return value: The height of @framebuffer.
* Since: 1.8
* Stability: unstable
*/
int
cogl_framebuffer_get_height (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_set_viewport:
* @framebuffer: A #CoglFramebuffer
* @x: The top-left x coordinate of the viewport origin (only integers
* supported currently)
* @y: The top-left y coordinate of the viewport origin (only integers
* supported currently)
* @width: The width of the viewport (only integers supported currently)
* @height: The height of the viewport (only integers supported currently)
*
* Defines a scale and offset for everything rendered relative to the
* top-left of the destination framebuffer.
*
* By default the viewport has an origin of (0,0) and width and height
* that match the framebuffer's size. Assuming a default projection and
* modelview matrix then you could translate the contents of a window
* down and right by leaving the viewport size unchanged by moving the
* offset to (10,10). The viewport coordinates are measured in pixels.
* If you left the x and y origin as (0,0) you could scale the windows
* contents down by specify and width and height that's half the real
* size of the framebuffer.
*
* <note>Although the function takes floating point arguments, existing
* drivers only allow the use of integer values. In the future floating
* point values will be exposed via a checkable feature.</note>
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_set_viewport (CoglFramebuffer *framebuffer,
float x,
float y,
float width,
float height);
/**
* cogl_framebuffer_get_viewport_x:
* @framebuffer: A #CoglFramebuffer
*
* Queries the x coordinate of the viewport origin as set using cogl_framebuffer_set_viewport()
* or the default value which is %0.
*
* Return value: The x coordinate of the viewport origin.
* Since: 1.8
* Stability: unstable
*/
float
cogl_framebuffer_get_viewport_x (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_viewport_y:
* @framebuffer: A #CoglFramebuffer
*
* Queries the y coordinate of the viewport origin as set using cogl_framebuffer_set_viewport()
* or the default value which is %0.
*
* Return value: The y coordinate of the viewport origin.
* Since: 1.8
* Stability: unstable
*/
float
cogl_framebuffer_get_viewport_y (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_viewport_width:
* @framebuffer: A #CoglFramebuffer
*
* Queries the width of the viewport as set using cogl_framebuffer_set_viewport()
* or the default value which is the width of the framebuffer.
*
* Return value: The width of the viewport.
* Since: 1.8
* Stability: unstable
*/
float
cogl_framebuffer_get_viewport_width (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_viewport_height:
* @framebuffer: A #CoglFramebuffer
*
* Queries the height of the viewport as set using cogl_framebuffer_set_viewport()
* or the default value which is the height of the framebuffer.
*
* Return value: The height of the viewport.
* Since: 1.8
* Stability: unstable
*/
float
cogl_framebuffer_get_viewport_height (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_viewport4fv:
* @framebuffer: A #CoglFramebuffer
* @viewport: A pointer to an array of 4 floats to receive the (x, y, width, height)
* components of the current viewport.
*
* Queries the x, y, width and height components of the current viewport as set
* using cogl_framebuffer_set_viewport() or the default values which are 0, 0,
* framebuffer_width and framebuffer_height. The values are written into the
* given @viewport array.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_get_viewport4fv (CoglFramebuffer *framebuffer,
float *viewport);
/**
* cogl_framebuffer_push_matrix:
* @framebuffer: A #CoglFramebuffer pointer
*
* Copies the current model-view matrix onto the matrix stack. The matrix
* can later be restored with cogl_framebuffer_pop_matrix().
*
* Since: 1.10
*/
void
cogl_framebuffer_push_matrix (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_pop_matrix:
* @framebuffer: A #CoglFramebuffer pointer
*
* Restores the model-view matrix on the top of the matrix stack.
*
* Since: 1.10
*/
void
cogl_framebuffer_pop_matrix (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_identity_matrix:
* @framebuffer: A #CoglFramebuffer pointer
*
* Resets the current model-view matrix to the identity matrix.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_identity_matrix (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_scale:
* @framebuffer: A #CoglFramebuffer pointer
* @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.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_scale (CoglFramebuffer *framebuffer,
float x,
float y,
float z);
/**
* cogl_framebuffer_translate:
* @framebuffer: A #CoglFramebuffer pointer
* @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.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_translate (CoglFramebuffer *framebuffer,
float x,
float y,
float z);
/**
* cogl_framebuffer_rotate:
* @framebuffer: A #CoglFramebuffer pointer
* @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.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_rotate (CoglFramebuffer *framebuffer,
float angle,
float x,
float y,
float z);
/**
* cogl_framebuffer_transform:
* @framebuffer: A #CoglFramebuffer pointer
* @matrix: the matrix to multiply with the current model-view
*
* Multiplies the current model-view matrix by the given matrix.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_transform (CoglFramebuffer *framebuffer,
const CoglMatrix *matrix);
/**
* cogl_framebuffer_get_modelview_matrix:
* @framebuffer: A #CoglFramebuffer pointer
* @matrix: (out): return location for the model-view matrix
*
* Stores the current model-view matrix in @matrix.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_get_modelview_matrix (CoglFramebuffer *framebuffer,
CoglMatrix *matrix);
/**
* cogl_framebuffer_set_modelview_matrix:
* @framebuffer: A #CoglFramebuffer pointer
* @matrix: the new model-view matrix
*
* Sets @matrix as the new model-view matrix.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_set_modelview_matrix (CoglFramebuffer *framebuffer,
CoglMatrix *matrix);
/**
* cogl_framebuffer_perspective:
* @framebuffer: A #CoglFramebuffer pointer
* @fovy: Vertical field of view angle in degrees.
* @aspect: The (width over height) aspect ratio for display
* @z_near: The distance to the near clipping plane (Must be positive,
* and must not be 0)
* @z_far: The distance to the far clipping plane (Must be positive)
*
* Replaces the current projection matrix with a perspective matrix
* based on the provided values.
*
* <note>You should be careful not to have to great a @z_far / @z_near
* ratio since that will reduce the effectiveness of depth testing
* since there wont be enough precision to identify the depth of
* objects near to each other.</note>
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_perspective (CoglFramebuffer *framebuffer,
float fov_y,
float aspect,
float z_near,
float z_far);
/**
* cogl_framebuffer_frustum:
* @framebuffer: A #CoglFramebuffer pointer
* @left: X position of the left clipping plane where it
* intersects the near clipping plane
* @right: X position of the right clipping plane where it
* intersects the near clipping plane
* @bottom: Y position of the bottom clipping plane where it
* intersects the near clipping plane
* @top: Y position of the top clipping plane where it intersects
* the near clipping plane
* @z_near: The distance to the near clipping plane (Must be positive)
* @z_far: The distance to the far clipping plane (Must be positive)
*
* Replaces the current projection matrix with a perspective matrix
* for a given viewing frustum defined by 4 side clip planes that
* all cross through the origin and 2 near and far clip planes.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_frustum (CoglFramebuffer *framebuffer,
float left,
float right,
float bottom,
float top,
float z_near,
float z_far);
/**
* cogl_framebuffer_orthographic:
* @framebuffer: A #CoglFramebuffer pointer
* @x_1: The x coordinate for the first vertical clipping plane
* @y_1: The y coordinate for the first horizontal clipping plane
* @x_2: The x coordinate for the second vertical clipping plane
* @y_2: The y coordinate for the second horizontal clipping plane
* @near: The <emphasis>distance</emphasis> to the near clipping
* plane (will be <emphasis>negative</emphasis> if the plane is
* behind the viewer)
* @far: The <emphasis>distance</emphasis> to the far clipping
* plane (will be <emphasis>negative</emphasis> if the plane is
* behind the viewer)
*
* Replaces the current projection matrix with an orthographic projection
* matrix.
*
* Since: 1.0
* Stability: unstable
*/
void
cogl_framebuffer_orthographic (CoglFramebuffer *framebuffer,
float x_1,
float y_1,
float x_2,
float y_2,
float near,
float far);
/**
* cogl_framebuffer_get_projection_matrix:
* @framebuffer: A #CoglFramebuffer pointer
* @matrix: (out): return location for the projection matrix
*
* Stores the current projection matrix in @matrix.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_get_projection_matrix (CoglFramebuffer *framebuffer,
CoglMatrix *matrix);
/**
* cogl_set_projection_matrix:
* @framebuffer: A #CoglFramebuffer pointer
* @matrix: the new projection matrix
*
* Sets @matrix as the new projection matrix.
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_set_projection_matrix (CoglFramebuffer *framebuffer,
CoglMatrix *matrix);
/**
* cogl_framebuffer_push_scissor_clip:
* @framebuffer: A #CoglFramebuffer pointer
* @x: left edge of the clip rectangle in window coordinates
* @y: 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_framebuffer_pop_clip().
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_push_scissor_clip (CoglFramebuffer *framebuffer,
int x,
int y,
int width,
int height);
/**
* cogl_framebuffer_push_rectangle_clip:
* @framebuffer: A #CoglFramebuffer pointer
* @x_1: x coordinate for top left corner of the clip rectangle
* @y_1: y coordinate for top left corner of the clip rectangle
* @x_2: x coordinate for bottom right corner of the clip rectangle
* @y_2: y coordinate for bottom right corner of the clip rectangle
*
* Specifies a modelview transformed 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_framebuffer_pop_clip().
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_push_rectangle_clip (CoglFramebuffer *framebuffer,
float x_1,
float y_1,
float x_2,
float y_2);
/**
* cogl_framebuffer_push_path_clip:
* @framebuffer: A #CoglFramebuffer pointer
* @path: The path to clip with.
*
* Sets a new clipping area using the silhouette of the specified,
* filled @path. The clipping area is intersected with the previous
* clipping area. To restore the previous clipping area, call
* cogl_framebuffer_pop_clip().
*
* Since: 1.0
* Stability: unstable
*/
void
cogl_framebuffer_push_path_clip (CoglFramebuffer *framebuffer,
CoglPath *path);
/**
* cogl_framebuffer_push_primitive_clip:
* @framebuffer: A #CoglFramebuffer pointer
* @primitive: A #CoglPrimitive describing a flat 2D shape
* @bounds_x1: x coordinate for the top-left corner of the primitives
* bounds
* @bounds_y1: y coordinate for the top-left corner of the primitives
* bounds
* @bounds_x2: x coordinate for the top-left corner of the primitives
* bounds
* @bounds_y2: x coordinate for the bottom-right corner of the
* primitives bounds.
* @bounds_x1: y coordinate for the bottom-right corner of the
* primitives bounds.
*
* Sets a new clipping area using a 2D shaped described with a
* #CoglPrimitive. The shape must not contain self overlapping
* geometry and must lie on a single 2D plane. A bounding box of the
* 2D shape in local coordinates (the same coordinates used to
* describe the shape) must be given. It is acceptable for the bounds
* to be larger than the true bounds but behaviour is undefined if the
* bounds are smaller than the true bounds.
*
* The primitive is transformed by the current model-view matrix and
* the silhouette is intersected with the previous clipping area. To
* restore the previous clipping area, call
* cogl_framebuffer_pop_clip().
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_push_primitive_clip (CoglFramebuffer *framebuffer,
CoglPrimitive *primitive,
float bounds_x1,
float bounds_y1,
float bounds_x2,
float bounds_y2);
/**
* cogl_framebuffer_pop_clip:
* @framebuffer: A #CoglFramebuffer pointer
*
* Reverts the clipping region to the state before the last call to
* cogl_framebuffer_push_clip().
*
* Since: 1.10
* Stability: unstable
*/
void
cogl_framebuffer_pop_clip (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_red_bits:
* @framebuffer: a pointer to a #CoglFramebuffer
*
* Retrieves the number of red bits of @framebuffer
*
* Return value: the number of bits
*
* Since: 1.8
* Stability: unstable
*/
int
cogl_framebuffer_get_red_bits (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_green_bits:
* @framebuffer: a pointer to a #CoglFramebuffer
*
* Retrieves the number of green bits of @framebuffer
*
* Return value: the number of bits
*
* Since: 1.8
* Stability: unstable
*/
int
cogl_framebuffer_get_green_bits (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_blue_bits:
* @framebuffer: a pointer to a #CoglFramebuffer
*
* Retrieves the number of blue bits of @framebuffer
*
* Return value: the number of bits
*
* Since: 1.8
* Stability: unstable
*/
int
cogl_framebuffer_get_blue_bits (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_alpha_bits:
* @framebuffer: a pointer to a #CoglFramebuffer
*
* Retrieves the number of alpha bits of @framebuffer
*
* Return value: the number of bits
*
* Since: 1.8
* Stability: unstable
*/
int
cogl_framebuffer_get_alpha_bits (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_get_dither_enabled:
* @framebuffer: a pointer to a #CoglFramebuffer
*
* Returns whether dithering has been requested for the given @framebuffer.
* See cogl_framebuffer_set_dither_enabled() for more details about dithering.
*
* <note>This may return %TRUE even when the underlying @framebuffer
* display pipeline does not support dithering. This value only represents
* the user's request for dithering.</note>
*
* Return value: %TRUE if dithering has been requested or %FALSE if not.
* Since: 1.8
* Stability: unstable
*/
gboolean
cogl_framebuffer_get_dither_enabled (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_set_dither_enabled:
* @framebuffer: a pointer to a #CoglFramebuffer
* @dither_enabled: %TRUE to enable dithering or %FALSE to disable
*
* Enables or disabled dithering if supported by the hardware.
*
* Dithering is a hardware dependent technique to increase the visible
* color resolution beyond what the underlying hardware supports by playing
* tricks with the colors placed into the framebuffer to give the illusion
* of other colors. (For example this can be compared to half-toning used
* by some news papers to show varying levels of grey even though their may
* only be black and white are available).
*
* If the current display pipeline for @framebuffer does not support dithering
* then this has no affect.
*
* Dithering is enabled by default.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_set_dither_enabled (CoglFramebuffer *framebuffer,
gboolean dither_enabled);
/**
* cogl_framebuffer_get_color_mask:
* @framebuffer: a pointer to a #CoglFramebuffer
*
* Gets the current #CoglColorMask of which channels would be written to the
* current framebuffer. Each bit set in the mask means that the
* corresponding color would be written.
*
* Returns: A #CoglColorMask
* Since: 1.8
* Stability: unstable
*/
CoglColorMask
cogl_framebuffer_get_color_mask (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_set_color_mask:
* @framebuffer: a pointer to a #CoglFramebuffer
* @color_mask: A #CoglColorMask of which color channels to write to
* the current framebuffer.
*
* Defines a bit mask of which color channels should be written to the
* given @framebuffer. If a bit is set in @color_mask that means that
* color will be written.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_set_color_mask (CoglFramebuffer *framebuffer,
CoglColorMask color_mask);
/**
* cogl_framebuffer_get_color_format:
* @framebuffer: A #CoglFramebuffer framebuffer
*
* Queries the common #CoglPixelFormat of all color buffers attached
* to this framebuffer. For an offscreen framebuffer created with
* cogl_offscreen_new_to_texture() this will correspond to the format
* of the texture.
*
* Since: 1.8
* Stability: unstable
*/
CoglPixelFormat
cogl_framebuffer_get_color_format (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_set_samples_per_pixel:
* @framebuffer: A #CoglFramebuffer framebuffer
* @n: The minimum number of samples per pixel
*
* Requires that when rendering to @framebuffer then @n point samples
* should be made per pixel which will all contribute to the final
* resolved color for that pixel. The idea is that the hardware aims
* to get quality similar to what you would get if you rendered
* everything twice as big (for 4 samples per pixel) and then scaled
* that image back down with filtering. It can effectively remove the
* jagged edges of polygons and should be more efficient than if you
* were to manually render at a higher resolution and downscale
* because the hardware is often able to take some shortcuts. For
* example the GPU may only calculate a single texture sample for all
* points of a single pixel, and for tile based architectures all the
* extra sample data (such as depth and stencil samples) may be
* handled on-chip and so avoid increased demand on system memory
* bandwidth.
*
* By default this value is usually set to 0 and that is referred to
* as "single-sample" rendering. A value of 1 or greater is referred
* to as "multisample" rendering.
*
* <note>There are some semantic differences between single-sample
* rendering and multisampling with just 1 point sample such as it
* being redundant to use the cogl_framebuffer_resolve_samples() and
* cogl_framebuffer_resolve_samples_region() apis with single-sample
* rendering.</note>
*
* <note>It's recommended that
* cogl_framebuffer_resolve_samples_region() be explicitly used at the
* end of rendering to a point sample buffer to minimize the number of
* samples that get resolved. By default Cogl will implicitly resolve
* all framebuffer samples but if only a small region of a
* framebuffer has changed this can lead to redundant work being
* done.</note>
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_set_samples_per_pixel (CoglFramebuffer *framebuffer,
int samples_per_pixel);
/**
* cogl_framebuffer_get_samples_per_pixel:
* @framebuffer: A #CoglFramebuffer framebuffer
*
* Gets the number of points that are sampled per-pixel when
* rasterizing geometry. Usually by default this will return 0 which
* means that single-sample not multisample rendering has been chosen.
* When using a GPU supporting multisample rendering it's possible to
* increase the number of samples per pixel using
* cogl_framebuffer_set_samples_per_pixel().
*
* Calling cogl_framebuffer_get_samples_per_pixel() before the
* framebuffer has been allocated will simply return the value set
* using cogl_framebuffer_set_samples_per_pixel(). After the
* framebuffer has been allocated the value will reflect the actual
* number of samples that will be made by the GPU.
*
* Returns: The number of point samples made per pixel when
* rasterizing geometry or 0 if single-sample rendering
* has been chosen.
*
* Since: 1.10
* Stability: unstable
*/
int
cogl_framebuffer_get_samples_per_pixel (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_resolve_samples:
* @framebuffer: A #CoglFramebuffer framebuffer
*
* When point sample rendering (also known as multisample rendering)
* has been enabled via cogl_framebuffer_set_samples_per_pixel()
* then you can optionally call this function (or
* cogl_framebuffer_resolve_samples_region()) to explicitly resolve
* the point samples into values for the final color buffer.
*
* Some GPUs will implicitly resolve the point samples during
* rendering and so this function is effectively a nop, but with other
* architectures it is desirable to defer the resolve step until the
* end of the frame.
*
* Since Cogl will automatically ensure samples are resolved if the
* target color buffer is used as a source this API only needs to be
* used if explicit control is desired - perhaps because you want to
* ensure that the resolve is completed in advance to avoid later
* having to wait for the resolve to complete.
*
* If you are performing incremental updates to a framebuffer you
* should consider using cogl_framebuffer_resolve_samples_region()
* instead to avoid resolving redundant pixels.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_resolve_samples (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_resolve_samples_region:
* @framebuffer: A #CoglFramebuffer framebuffer
* @x: top-left x coordinate of region to resolve
* @y: top-left y coordinate of region to resolve
* @width: width of region to resolve
* @height: height of region to resolve
*
* When point sample rendering (also known as multisample rendering)
* has been enabled via cogl_framebuffer_set_samples_per_pixel()
* then you can optionally call this function (or
* cogl_framebuffer_resolve_samples()) to explicitly resolve the point
* samples into values for the final color buffer.
*
* Some GPUs will implicitly resolve the point samples during
* rendering and so this function is effectively a nop, but with other
* architectures it is desirable to defer the resolve step until the
* end of the frame.
*
* Use of this API is recommended if incremental, small updates to
* a framebuffer are being made because by default Cogl will
* implicitly resolve all the point samples of the framebuffer which
* can result in redundant work if only a small number of samples have
* changed.
*
* Because some GPUs implicitly resolve point samples this function
* only guarantees that at-least the region specified will be resolved
* and if you have rendered to a larger region then it's possible that
* other samples may be implicitly resolved.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_resolve_samples_region (CoglFramebuffer *framebuffer,
int x,
int y,
int width,
int height);
/**
* @framebuffer: A #CoglFramebuffer
*
* Can be used to query the #CoglContext a given @framebuffer was
* instantiated within. This is the #CoglContext that was passed to
* cogl_onscreen_new() for example.
*
* Return value: The #CoglContext that the given @framebuffer was
* instantiated within.
* Since: 1.8
* Stability: unstable
*/
CoglContext *
cogl_framebuffer_get_context (CoglFramebuffer *framebuffer);
/**
* cogl_framebuffer_clear:
* @framebuffer: A #CoglFramebuffer
* @buffers: A mask of #CoglBufferBit<!-- -->'s identifying which auxiliary
* buffers to clear
* @color: The color to clear the color buffer too if specified in
* @buffers.
*
* Clears all the auxiliary buffers identified in the @buffers mask, and if
* that includes the color buffer then the specified @color is used.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_clear (CoglFramebuffer *framebuffer,
unsigned long buffers,
const CoglColor *color);
/**
* cogl_framebuffer_clear4f:
* @framebuffer: A #CoglFramebuffer
* @buffers: A mask of #CoglBufferBit<!-- -->'s identifying which auxiliary
* buffers to clear
* @red: The red component of color to clear the color buffer too if
* specified in @buffers.
* @green: The green component of color to clear the color buffer too if
* specified in @buffers.
* @blue: The blue component of color to clear the color buffer too if
* specified in @buffers.
* @alpha: The alpha component of color to clear the color buffer too if
* specified in @buffers.
*
* Clears all the auxiliary buffers identified in the @buffers mask, and if
* that includes the color buffer then the specified @color is used.
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_clear4f (CoglFramebuffer *framebuffer,
unsigned long buffers,
float red,
float green,
float blue,
float alpha);
/**
* cogl_framebuffer_draw_primitive:
* @framebuffer: A destination #CoglFramebuffer
* @pipeline: A #CoglPipeline state object
* @primitive: A #CoglPrimitive geometry object
*
* Draws the given @primitive geometry to the specified destination
* @framebuffer using the graphics processing pipeline described by @pipeline.
*
* <note>This api doesn't support any of the legacy global state options such
* as cogl_set_depth_test_enabled(), cogl_set_backface_culling_enabled() or
* cogl_program_use()</note>
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_framebuffer_draw_primitive (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglPrimitive *primitive);
/**
* cogl_framebuffer_vdraw_attributes:
* @framebuffer: A destination #CoglFramebuffer
* @pipeline: A #CoglPipeline state object
* @mode: The #CoglVerticesMode defining the topology of vertices
* @first_vertex: The vertex offset within the given attributes to draw from
* @n_vertices: The number of vertices to draw from the given attributes
* @...: A set of vertex #CoglAttribute<!-- -->s defining vertex geometry
*
* First defines a geometry primitive by grouping a set of vertex attributes;
* specifying a @first_vertex; a number of vertices (@n_vertices) and
* specifying what kind of topology the vertices have via @mode.
*
* Then the function draws the given @primitive geometry to the specified
* destination @framebuffer using the graphics processing pipeline described by
* @pipeline.
*
* The list of #CoglAttribute<!-- -->s define the attributes of the vertices to
* be drawn, such as positions, colors and normals and should be %NULL
* terminated.
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_framebuffer_vdraw_attributes (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglVerticesMode mode,
int first_vertex,
int n_vertices,
...) G_GNUC_NULL_TERMINATED;
/**
* cogl_framebuffer_draw_attributes:
* @framebuffer: A destination #CoglFramebuffer
* @pipeline: A #CoglPipeline state object
* @mode: The #CoglVerticesMode defining the topology of vertices
* @first_vertex: The vertex offset within the given attributes to draw from
* @n_vertices: The number of vertices to draw from the given attributes
* @attributes: An array of pointers to #CoglAttribute<-- -->s defining vertex
* geometry
* @n_attributes: The number of attributes in the @attributes array.
*
* First defines a geometry primitive by grouping a set of vertex @attributes;
* specifying a @first_vertex; a number of vertices (@n_vertices) and
* specifying what kind of topology the vertices have via @mode.
*
* Then the function draws the given @primitive geometry to the specified
* destination @framebuffer using the graphics processing pipeline described by
* @pipeline.
*
* The list of #CoglAttribute<!-- -->s define the attributes of the vertices to
* be drawn, such as positions, colors and normals and the number of attributes
* is given as @n_attributes.
*
* <note>This api doesn't support any of the legacy global state options such
* as cogl_set_depth_test_enabled(), cogl_set_backface_culling_enabled() or
* cogl_program_use()</note>
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_framebuffer_draw_attributes (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglVerticesMode mode,
int first_vertex,
int n_vertices,
CoglAttribute **attributes,
int n_attributes);
/**
* cogl_framebuffer_vdraw_indexed_attributes:
* @framebuffer: A destination #CoglFramebuffer
* @pipeline: A #CoglPipeline state object
* @mode: The #CoglVerticesMode defining the topology of vertices
* @first_vertex: The vertex offset within the given attributes to draw from
* @n_vertices: The number of vertices to draw from the given attributes
* @indices: The array of indices used by the GPU to lookup attribute
* data for each vertex.
* @...: A set of vertex #CoglAttribute<!-- -->s defining vertex geometry
*
* Behaves the same as cogl_framebuffer_vdraw_attributes() except that
* instead of reading vertex data sequentially from the specified
* attributes the @indices provide an indirection for how the data
* should be indexed allowing a random access order to be
* specified.
*
* For example an indices array of [0, 1, 2, 0, 2, 3] could be used
* used to draw two triangles (@mode = %COGL_VERTICES_MODE_TRIANGLES +
* @n_vertices = 6) but only provide attribute data for the 4 corners
* of a rectangle. When the GPU needs to read in each of the 6
* vertices it will read the @indices array for each vertex in
* sequence and use the index to look up the vertex attribute data. So
* here you can see that first and fourth vertex will point to the
* same data and third and fifth vertex will also point to shared
* data.
*
* Drawing with indices can be a good way of minimizing the size of a
* mesh by allowing you to avoid data for duplicate vertices because
* multiple entries in the index array can refer back to a single
* shared vertex.
*
* <note>The @indices array must at least be as long @first_vertex +
* @n_vertices otherwise the GPU will overrun the indices array when
* looking up vertex data.</note>
*
* Since it's very common to want to draw a run of rectangles using
* indices to avoid duplicating vertex data you can use
* cogl_get_rectangle_indices() to get a set of indices that can be
* shared.
*
* <note>This api doesn't support any of the legacy global state
* options such as cogl_set_depth_test_enabled(),
* cogl_set_backface_culling_enabled() or cogl_program_use()</note>
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_framebuffer_vdraw_indexed_attributes (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglVerticesMode mode,
int first_vertex,
int n_vertices,
CoglIndices *indices,
...) G_GNUC_NULL_TERMINATED;
/**
* cogl_framebuffer_draw_indexed_attributes:
* @framebuffer: A destination #CoglFramebuffer
* @pipeline: A #CoglPipeline state object
* @mode: The #CoglVerticesMode defining the topology of vertices
* @first_vertex: The vertex offset within the given attributes to draw from
* @n_vertices: The number of vertices to draw from the given attributes
* @indices: The array of indices used by the GPU to lookup attribute
* data for each vertex.
* @attributes: An array of pointers to #CoglAttribute<-- -->s defining vertex
* geometry
* @n_attributes: The number of attributes in the @attributes array.
*
* Behaves the same as cogl_framebuffer_draw_attributes() except that
* instead of reading vertex data sequentially from the specified
* @attributes the @indices provide an indirection for how the data
* should be indexed allowing a random access order to be
* specified.
*
* For example an indices array of [0, 1, 2, 0, 2, 3] could be used
* used to draw two triangles (@mode = %COGL_VERTICES_MODE_TRIANGLES +
* @n_vertices = 6) but only provide attribute data for the 4 corners
* of a rectangle. When the GPU needs to read in each of the 6
* vertices it will read the @indices array for each vertex in
* sequence and use the index to look up the vertex attribute data. So
* here you can see that first and fourth vertex will point to the
* same data and third and fifth vertex will also point to shared
* data.
*
* Drawing with indices can be a good way of minimizing the size of a
* mesh by allowing you to avoid data for duplicate vertices because
* multiple entries in the index array can refer back to a single
* shared vertex.
*
* <note>The @indices array must at least be as long @first_vertex +
* @n_vertices otherwise the GPU will overrun the indices array when
* looking up vertex data.</note>
*
* Since it's very common to want to draw a run of rectangles using
* indices to avoid duplicating vertex data you can use
* cogl_get_rectangle_indices() to get a set of indices that can be
* shared.
*
* <note>This api doesn't support any of the legacy global state
* options such as cogl_set_depth_test_enabled(),
* cogl_set_backface_culling_enabled() or cogl_program_use()</note>
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_framebuffer_draw_indexed_attributes (CoglFramebuffer *framebuffer,
CoglPipeline *pipeline,
CoglVerticesMode mode,
int first_vertex,
int n_vertices,
CoglIndices *indices,
CoglAttribute **attributes,
int n_attributes);
/* XXX: Should we take an n_buffers + buffer id array instead of using
* the CoglBufferBits type which doesn't seem future proof? */
/**
* cogl_framebuffer_discard_buffers:
* @framebuffer: A #CoglFramebuffer
* @buffers: A #CoglBufferBit mask of which ancillary buffers you want
* to discard.
*
* Declares that the specified @buffers no longer need to be referenced
* by any further rendering commands. This can be an important
* optimization to avoid subsequent frames of rendering depending on
* the results of a previous frame.
*
* For example; some tile-based rendering GPUs are able to avoid allocating and
* accessing system memory for the depth and stencil buffer so long as these
* buffers are not required as input for subsequent frames and that can save a
* significant amount of memory bandwidth used to save and restore their
* contents to system memory between frames.
*
* It is currently considered an error to try and explicitly discard the color
* buffer by passing %COGL_BUFFER_BIT_COLOR. This is because the color buffer is
* already implicitly discard when you finish rendering to a #CoglOnscreen
* framebuffer, and it's not meaningful to try and discard the color buffer of
* a #CoglOffscreen framebuffer since they are single-buffered.
*
*
* Since: 1.8
* Stability: unstable
*/
void
cogl_framebuffer_discard_buffers (CoglFramebuffer *framebuffer,
unsigned long buffers);
/**
* cogl_framebuffer_finish:
* @framebuffer: A #CoglFramebuffer pointer
*
* This blocks the CPU until all pending rendering associated with the
* specified framebuffer has completed. It's very rare that developers should
* ever need this level of synchronization with the GPU and should never be
* used unless you clearly understand why you need to explicitly force
* synchronization.
*
* One example might be for benchmarking purposes to be sure timing
* measurements reflect the time that the GPU is busy for not just the time it
* takes to queue rendering commands.
*
* Stability: unstable
* Since: 1.10
*/
void
cogl_framebuffer_finish (CoglFramebuffer *framebuffer);
/**
* cogl_get_draw_framebuffer:
*
* Gets the current #CoglFramebuffer as set using
* cogl_push_framebuffer()
*
* Return value: The current #CoglFramebuffer
* Stability: unstable
* Since: 1.8
*/
CoglFramebuffer *
cogl_get_draw_framebuffer (void);
#endif /* COGL_ENABLE_EXPERIMENTAL_API */
/* XXX: Note these are defined outside the COGL_ENABLE_EXPERIMENTAL_API guard since
* otherwise the glib-mkenums stuff will get upset. */
GQuark
cogl_framebuffer_error_quark (void);
/**
* COGL_FRAMEBUFFER_ERROR:
*
* An error domain for reporting #CoglFramebuffer exceptions
*/
#define COGL_FRAMEBUFFER_ERROR (cogl_framebuffer_error_quark ())
typedef enum { /*< prefix=COGL_FRAMEBUFFER_ERROR >*/
COGL_FRAMEBUFFER_ERROR_ALLOCATE
} CoglFramebufferError;
G_END_DECLS
#endif /* __COGL_FRAMEBUFFER_H */