309 lines
11 KiB
C
309 lines
11 KiB
C
/*
|
|
* Cogl.
|
|
*
|
|
* An OpenGL/GLES Abstraction/Utility Layer
|
|
*
|
|
* Vertex Buffer API: Handle extensible arrays of vertex attributes
|
|
*
|
|
* Copyright (C) 2008 Intel Corporation.
|
|
*
|
|
* Authored by: Robert Bragg <robert@linux.intel.com>
|
|
*
|
|
* 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/>.
|
|
*/
|
|
|
|
#if !defined(__COGL_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
|
|
#error "Only <cogl/cogl.h> can be included directly."
|
|
#endif
|
|
|
|
#ifndef __COGL_VERTEX_BUFFER_H__
|
|
#define __COGL_VERTEX_BUFFER_H__
|
|
|
|
#include <glib.h>
|
|
#include <cogl/cogl-types.h>
|
|
|
|
G_BEGIN_DECLS
|
|
|
|
/**
|
|
* SECTION:cogl-vertex-buffer
|
|
* @short_description: An API for submitting extensible arrays of vertex
|
|
* attributes to OpenGL in a way that aims to minimise
|
|
* copying or reformatting of the original data.
|
|
*
|
|
* The Attributes 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 with awareness of the specific
|
|
* hardware being used then costly format conversion can also be avoided.
|
|
*
|
|
* They are designed to work on top of buffer objects and developers should
|
|
* understand that attribute buffers are not that cheap to create but once they
|
|
* have been submitted they can be stored in GPU addressable memory and can
|
|
* be quickly reused.
|
|
*
|
|
* Although this API does allow you to modify attribute buffers after they have
|
|
* been submitted to the GPU you must note that modification is also not that
|
|
* cheap, so if at all possible think of tricks that let you reuse a static
|
|
* buffer. To help with this, it is possible to enable and disable individual
|
|
* attributes cheaply.
|
|
*
|
|
* Take for example attributes representing an elipse. If you were to submit
|
|
* color attributes, texture coordinates and normals, then you would be able
|
|
* to draw an elipses in the following different ways without modifying
|
|
* the vertex buffer, only by changing your source material.
|
|
* <itemizedlist>
|
|
* <listitem>Flat colored elipse</listitem>
|
|
* <listitem>Textured elipse</listitem>
|
|
* <listitem>Smoothly lit textured elipse blended with the color.</listitem>
|
|
* </itemizedlist>
|
|
*
|
|
* Another trick that can be used is submitting highly detailed vertices and
|
|
* then using cogl_vertex_buffer_draw_range_elements to sample sub-sets of
|
|
* the geometry or lower resolution geometry out from a fixed buffer.
|
|
*
|
|
* The API doesn't currently give you any control over the actual OpenGL buffer
|
|
* objects that are created, but you can expect that when you first submit
|
|
* your attributes they start off in one or more GL_STATIC_DRAW buffers.
|
|
* If you then update some of your attributes; then these attributes will
|
|
* normally be moved into new GL_DYNAMIC_DRAW draw buffers.
|
|
*/
|
|
|
|
/**
|
|
* cogl_vertex_buffer_new:
|
|
* @n_vertices: The number of vertices that your attributes will correspond to.
|
|
*
|
|
* This creates a Cogl handle for a new vertex buffer that you can then start
|
|
* to add attributes too.
|
|
*/
|
|
CoglHandle
|
|
cogl_vertex_buffer_new (guint n_vertices);
|
|
|
|
/**
|
|
* 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 in GLSL)
|
|
* <itemizedlist>
|
|
* <listitem>"gl_Color"</listitem>
|
|
* <listitem>"gl_Normal"</listitem>
|
|
* <listitem>"gl_MultiTexCoord0, gl_MultiTexCoord1, ..."</listitem>
|
|
* <listitem>"gl_Vertex"</listitem>
|
|
* </itemizedlist>
|
|
* 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
|
|
* @gl_type: Specifies the data type of each component (GL_BYTE, GL_UNSIGNED_BYTE,
|
|
* GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT or
|
|
* GL_DOUBLE)
|
|
* @normalized: If GL_TRUE, this specifies that values stored in an integer
|
|
* format should be mapped into the range [-1.0, 1.0] or [0.1, 1.0]
|
|
* for unsigned values. If GL_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 call cogl_vertex_buffer_submit)
|
|
*
|
|
* This function lets you add an attribute to a buffer. You either use one
|
|
* of the built-in names to add standard attributes, like positions, colors
|
|
* and normals or you can add custom attributes for use in shaders.
|
|
*
|
|
* Note: The number of vertices declared when first creating the vertex
|
|
* buffer is used to determine how many attribute values will be read from the
|
|
* supplied pointer.
|
|
*
|
|
* Note: the data supplied here isn't copied anywhere until you call
|
|
* cogl_vertex_buffer_submit, so the supplied pointer must remain valid
|
|
* until then.
|
|
* (This is an important optimisation since we can't create the underlying
|
|
* OpenGL buffer object until we know about all the attributes, and repeatedly
|
|
* copying large buffers of vertex data may be very costly) If you add
|
|
* attributes after submitting then you will 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)
|
|
*
|
|
* Note: If you are interleving attributes it is assumed that 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,
|
|
GLenum gl_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
|
|
*
|
|
* This function deletes an attribute from a buffer. You will need to
|
|
* call cogl_vertex_buffer_submit to commit this change to the GPU.
|
|
*/
|
|
void
|
|
cogl_vertex_buffer_delete (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
|
|
*
|
|
* This function enables 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.
|
|
*
|
|
* Note: 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_submit:
|
|
* @handle: A vertex buffer handle
|
|
*
|
|
* This function copies all the user added attributes into buffer objects
|
|
* managed by the OpenGL driver.
|
|
*
|
|
* You should aim to minimize calls to this function.
|
|
*/
|
|
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
|
|
*
|
|
* This function 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.
|
|
*
|
|
* Note: 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_draw:
|
|
* @handle: A vertex buffer handle
|
|
* @mode: Specifies how the vertices should be interpreted, and should be
|
|
* a valid GL primitive type:
|
|
* <itemizedlist>
|
|
* <listitem>GL_POINTS</listitem>
|
|
* <listitem>GL_LINE_STRIP</listitem>
|
|
* <listitem>GL_LINE_LOOP</listitem>
|
|
* <listitem>GL_LINES</listitem>
|
|
* <listitem>GL_TRIANGLE_STRIP</listitem>
|
|
* <listitem>GL_TRIANGLE_FAN</listitem>
|
|
* <listitem>GL_TRIANGLES</listitem>
|
|
* </itemizedlist>
|
|
* (Note: only types available in GLES are listed)
|
|
* @first: Specifies the index of the first vertex you want to draw with
|
|
* @count: Specifies the number of vertices you want to draw.
|
|
*
|
|
* This function lets you draw geometry using all or a subset of the
|
|
* vertices in a vertex buffer.
|
|
*/
|
|
void
|
|
cogl_vertex_buffer_draw (CoglHandle handle,
|
|
GLenum mode,
|
|
GLint first,
|
|
GLsizei count);
|
|
|
|
/**
|
|
* cogl_vertex_buffer_draw_range_elements:
|
|
* @handle: A vertex buffer handle
|
|
* @mode: Specifies how the vertices should be interpreted, and should be
|
|
* a valid GL primitive type:
|
|
* <itemizedlist>
|
|
* <listitem>GL_POINTS</listitem>
|
|
* <listitem>GL_LINE_STRIP</listitem>
|
|
* <listitem>GL_LINE_LOOP</listitem>
|
|
* <listitem>GL_LINES</listitem>
|
|
* <listitem>GL_TRIANGLE_STRIP</listitem>
|
|
* <listitem>GL_TRIANGLE_FAN</listitem>
|
|
* <listitem>GL_TRIANGLES</listitem>
|
|
* </itemizedlist>
|
|
* (Note: only types available in GLES are listed)
|
|
* @min_index: Specifies the minimum vertex index contained in indices
|
|
* @max_index: Specifies the maximum vertex index contained in indices
|
|
* @count: Specifies the number of vertices you want to draw.
|
|
* @indices_type: Specifies the data type used for the indices, and must be
|
|
* one of:
|
|
* <itemizedlist>
|
|
* <listitem>GL_UNSIGNED_BYTE</listitem>
|
|
* <listitem>GL_UNSIGNED_SHORT</listitem>
|
|
* <listitem>GL_UNSIGNED_INT</listitem>
|
|
* </itemizedlist>
|
|
* @indices: Specifies the address of your array of indices
|
|
*
|
|
* This function lets you use an array of indices to specify the vertices
|
|
* within your vertex buffer that you want to draw.
|
|
*/
|
|
void
|
|
cogl_vertex_buffer_draw_range_elements (CoglHandle handle,
|
|
GLenum mode,
|
|
GLuint min_index,
|
|
GLuint max_index,
|
|
GLsizei count,
|
|
GLenum indices_type,
|
|
const GLvoid *indices);
|
|
|
|
/**
|
|
* cogl_vertex_buffer_ref:
|
|
* @handle: a @CoglHandle.
|
|
*
|
|
* Increment the reference count for a vertex buffer
|
|
*
|
|
* Returns: the @handle.
|
|
*/
|
|
CoglHandle
|
|
cogl_vertex_buffer_ref (CoglHandle handle);
|
|
|
|
/**
|
|
* cogl_vertex_buffer_unref:
|
|
* @handle: a @CoglHandle.
|
|
*
|
|
* Decrement the reference count for a vertex buffer
|
|
*/
|
|
void
|
|
cogl_vertex_buffer_unref (CoglHandle handle);
|
|
|
|
|
|
G_END_DECLS
|
|
|
|
#endif /* __COGL_VERTEX_BUFFER_H__ */
|