/*
* 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, see .
*
*
*
* Authors:
* Robert Bragg
*/
#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only can be included directly."
#endif
#ifndef __COGL_VERTEX_BUFFER_H__
#define __COGL_VERTEX_BUFFER_H__
#include
#include
#include
G_BEGIN_DECLS
/**
* SECTION:cogl-vertex-buffer
* @short_description: An API for submitting extensible arrays of vertex
* attributes to be mapped into the GPU for fast drawing.
*
* For example to describe a textured triangle, you could create a new cogl
* vertex buffer with 3 vertices, and then you might add 2 attributes for each
* vertex:
*
*
* a "gl_Position" describing the (x,y,z) position for each vertex.
*
*
* a "gl_MultiTexCoord0" describing the (tx,ty) texture coordinates for each
* vertex.
*
*
*
* The Vertex Buffer API is designed to be a fairly raw mechanism for
* developers to be able to submit geometry to Cogl in a format that can be
* directly consumed by an OpenGL driver and mapped into your GPU for fast
* re-use. It is designed to avoid repeated validation of the attributes by the
* driver; to minimize transport costs (e.g. considering indirect GLX
* use-cases) and to potentially avoid repeated format conversions when
* attributes are supplied in a format that is not natively supported by the
* GPU.
*
* Although this API does allow you to modify attributes after they have been
* submitted to the GPU you should be aware that modification is not that
* cheap, since it implies validating the new data and potentially the
* OpenGL driver will need to reformat it for the GPU.
*
* If at all possible think of tricks that let you re-use static attributes,
* and if you do need to repeatedly update attributes (e.g. for some kind of
* morphing geometry) then only update and re-submit the specific attributes
* that have changed.
*/
/**
* cogl_vertex_buffer_new:
* @n_vertices: The number of vertices that your attributes will correspond to.
*
* Creates a new vertex buffer that you can use to add attributes.
*
* Return value: a new #CoglHandle
*/
CoglHandle
cogl_vertex_buffer_new (unsigned int n_vertices);
/**
* cogl_vertex_buffer_get_n_vertices:
* @handle: A vertex buffer handle
*
* Retrieves the number of vertices that @handle represents
*
* Return value: the number of vertices
*/
unsigned int
cogl_vertex_buffer_get_n_vertices (CoglHandle handle);
/**
* cogl_vertex_buffer_add:
* @handle: A vertex buffer handle
* @attribute_name: The name of your attribute. It should be a valid GLSL
* variable name and standard attribute types must use one of following
* built-in names: (Note: they correspond to the built-in names of GLSL)
*
* "gl_Color"
* "gl_Normal"
* "gl_MultiTexCoord0, gl_MultiTexCoord1, ..."
* "gl_Vertex"
*
* To support adding multiple variations of the same attribute the name
* can have a detail component, E.g. "gl_Color::active" or
* "gl_Color::inactive"
* @n_components: The number of components per attribute and must be 1, 2,
* 3 or 4
* @type: a #CoglAttributeType specifying the data type of each component.
* @normalized: If %TRUE, this specifies that values stored in an integer
* format should be mapped into the range [-1.0, 1.0] or [0.0, 1.0]
* for unsigned values. If %FALSE they are converted to floats
* directly.
* @stride: This specifies the number of bytes from the start of one attribute
* value to the start of the next value (for the same attribute). So, for
* example, with a position interleved with color like this:
* XYRGBAXYRGBAXYRGBA, then if each letter represents a byte, the
* stride for both attributes is 6. The special value 0 means the
* values are stored sequentially in memory.
* @pointer: This addresses the first attribute in the vertex array. This
* must remain valid until you either call cogl_vertex_buffer_submit() or
* issue a draw call.
*
* Adds an attribute to a buffer, or replaces a previously added
* attribute with the same name.
*
* You either can use one of the built-in names such as "gl_Vertex", or
* "gl_MultiTexCoord0" to add standard attributes, like positions, colors
* and normals, or you can add custom attributes for use in shaders.
*
* The number of vertices declared when calling cogl_vertex_buffer_new()
* determines how many attribute values will be read from the supplied
* @pointer.
*
* The data for your attribute isn't copied anywhere until you call
* cogl_vertex_buffer_submit(), or issue a draw call which automatically
* submits pending attribute changes. so the supplied pointer must remain
* valid until then. If you are updating an existing attribute (done by
* re-adding it) then you still need to re-call cogl_vertex_buffer_submit()
* to commit the changes to the GPU. Be carefull to minimize the number
* of calls to cogl_vertex_buffer_submit(), though.
*
* If you are interleving attributes it is assumed that each interleaved
* attribute starts no farther than +- stride bytes from the other attributes
* it is interleved with. I.e. this is ok:
*
* |-0-0-0-0-0-0-0-0-0-0|
*
* This is not ok:
*
* |- - - - -0-0-0-0-0-0 0 0 0 0|
*
* (Though you can have multiple groups of interleved attributes)
*/
void
cogl_vertex_buffer_add (CoglHandle handle,
const char *attribute_name,
guint8 n_components,
CoglAttributeType type,
gboolean normalized,
guint16 stride,
const void *pointer);
/**
* cogl_vertex_buffer_delete:
* @handle: A vertex buffer handle
* @attribute_name: The name of a previously added attribute
*
* Deletes an attribute from a buffer. You will need to call
* cogl_vertex_buffer_submit() or issue a draw call to commit this
* change to the GPU.
*/
void
cogl_vertex_buffer_delete (CoglHandle handle,
const char *attribute_name);
/**
* cogl_vertex_buffer_submit:
* @handle: A vertex buffer handle
*
* Submits all the user added attributes to the GPU; once submitted, the
* attributes can be used for drawing.
*
* You should aim to minimize calls to this function since it implies
* validating your data; it potentially incurs a transport cost (especially if
* you are using GLX indirect rendering) and potentially a format conversion
* cost if the GPU doesn't natively support any of the given attribute formats.
*/
void
cogl_vertex_buffer_submit (CoglHandle handle);
/**
* cogl_vertex_buffer_disable:
* @handle: A vertex buffer handle
* @attribute_name: The name of the attribute you want to disable
*
* Disables a previosuly added attribute.
*
* Since it can be costly to add and remove new attributes to buffers; to make
* individual buffers more reuseable it is possible to enable and disable
* attributes before using a buffer for drawing.
*
* You don't need to call cogl_vertex_buffer_submit() after using this
* function.
*/
void
cogl_vertex_buffer_disable (CoglHandle handle,
const char *attribute_name);
/**
* cogl_vertex_buffer_enable:
* @handle: A vertex buffer handle
* @attribute_name: The name of the attribute you want to enable
*
* Enables a previosuly disabled attribute.
*
* Since it can be costly to add and remove new attributes to buffers; to make
* individual buffers more reuseable it is possible to enable and disable
* attributes before using a buffer for drawing.
*
* You don't need to call cogl_vertex_buffer_submit() after using this function
*/
void
cogl_vertex_buffer_enable (CoglHandle handle,
const char *attribute_name);
/**
* cogl_vertex_buffer_draw:
* @handle: A vertex buffer handle
* @mode: A #CoglVerticesMode specifying how the vertices should be
* interpreted.
* @first: Specifies the index of the first vertex you want to draw with
* @count: Specifies the number of vertices you want to draw.
*
* Allows you to draw geometry using all or a subset of the
* vertices in a vertex buffer.
*
* Any un-submitted attribute changes are automatically submitted before
* drawing.
*/
void
cogl_vertex_buffer_draw (CoglHandle handle,
CoglVerticesMode mode,
int first,
int count);
/**
* cogl_vertex_buffer_indices_new:
* @indices_type: a #CoglIndicesType specifying the data type used for
* the indices.
* @indices_array: (array length=indices_len): Specifies the address of
* your array of indices
* @indices_len: The number of indices in indices_array
*
* Depending on how much geometry you are submitting it can be worthwhile
* optimizing the number of redundant vertices you submit. Using an index
* array allows you to reference vertices multiple times, for example
* during triangle strips.
*
* Return value: A CoglHandle for the indices which you can pass to
* cogl_vertex_buffer_draw_elements().
*/
CoglHandle
cogl_vertex_buffer_indices_new (CoglIndicesType indices_type,
const void *indices_array,
int indices_len);
/**
* cogl_vertex_buffer_indices_get_type:
* @indices: An indices handle
*
* Queries back the data type used for the given indices
*
* Returns: The CoglIndicesType used
*/
CoglIndicesType
cogl_vertex_buffer_indices_get_type (CoglHandle indices);
/**
* cogl_vertex_buffer_draw_elements:
* @handle: A vertex buffer handle
* @mode: A #CoglVerticesMode specifying how the vertices should be
* interpreted.
* @indices: A CoglHandle for a set of indices allocated via
* cogl_vertex_buffer_indices_new ()
* @min_index: Specifies the minimum vertex index contained in indices
* @max_index: Specifies the maximum vertex index contained in indices
* @indices_offset: An offset into named indices. The offset marks the first
* index to use for drawing.
* @count: Specifies the number of vertices you want to draw.
*
* This function lets you use an array of indices to specify the vertices
* within your vertex buffer that you want to draw. The indices themselves
* are created by calling cogl_vertex_buffer_indices_new ()
*
* Any un-submitted attribute changes are automatically submitted before
* drawing.
*/
void
cogl_vertex_buffer_draw_elements (CoglHandle handle,
CoglVerticesMode mode,
CoglHandle indices,
int min_index,
int max_index,
int indices_offset,
int count);
#ifndef COGL_DISABLE_DEPRECATED
/**
* cogl_vertex_buffer_ref:
* @handle: a @CoglHandle.
*
* Increment the reference count for a vertex buffer
*
* Return value: the @handle.
*
* Deprecated: 1.2: Use cogl_handle_ref() instead
*/
CoglHandle
cogl_vertex_buffer_ref (CoglHandle handle) G_GNUC_DEPRECATED;
/**
* cogl_vertex_buffer_unref:
* @handle: a @CoglHandle.
*
* Decrement the reference count for a vertex buffer
*
* Deprecated: 1.2: Use cogl_handle_unref() instead
*/
void
cogl_vertex_buffer_unref (CoglHandle handle) G_GNUC_DEPRECATED;
#endif /* COGL_DISABLE_DEPRECATED */
/**
* cogl_vertex_buffer_indices_get_for_quads:
* @n_indices: the number of indices in the vertex buffer.
*
* Creates a vertex buffer containing the indices needed to draw pairs
* of triangles from a list of vertices grouped as quads. There will
* be at least @n_indices entries in the buffer (but there may be
* more).
*
* The indices will follow this pattern:
*
* 0, 1, 2, 0, 2, 3, 4, 5, 6, 4, 6, 7 ... etc
*
* For example, if you submit vertices for a quad like like that shown
* in then you can request 6
* indices to render two triangles like those shown in .
*
*
* Example of vertices submitted to form a quad
*
*
*
*
* Illustration of the triangle indices that will be generated
*
*
*
* Returns: A %CoglHandle containing the indices. The handled is
* owned by Cogl and should not be modified or unref'd.
*/
CoglHandle
cogl_vertex_buffer_indices_get_for_quads (unsigned int n_indices);
/**
* cogl_is_vertex_buffer:
* @handle: a #CoglHandle for a vertex buffer object
*
* Checks whether @handle is a Vertex Buffer Object
*
* Return value: %TRUE if the handle is a VBO, and %FALSE
* otherwise
*
* Since: 1.0
*/
gboolean
cogl_is_vertex_buffer (CoglHandle handle);
/**
* cogl_is_vertex_buffer_indices:
* @handle: a #CoglHandle
*
* Checks whether @handle is a handle to the indices for a vertex
* buffer object
*
* Return value: %TRUE if the handle is indices, and %FALSE
* otherwise
*
* Since: 1.4
*/
gboolean
cogl_is_vertex_buffer_indices (CoglHandle handle);
G_END_DECLS
#endif /* __COGL_VERTEX_BUFFER_H__ */