mutter/clutter/cogl/common/cogl-blend-string.h
Robert Bragg 33994caa71 [cogl-material] Support string based blending and layer combine descriptions
Setting up layer combine functions and blend modes is very awkward to do
programatically.  This adds a parser for string based descriptions which are
more consise and readable.

E.g. a material layer combine function could now be given as:
  "RGBA = ADD (TEXTURE[A], PREVIOUS[RGB])"
or
  "RGB = REPLACE (PREVIOUS)"
  "A = MODULATE (PREVIOUS, TEXTURE)"

The simple syntax and grammar are only designed to expose standard fixed
function hardware, more advanced combining must be done with shaders.

This includes standalone documentation of blend strings covering the aspects
that are common to blending and texture combining, and adds documentation
with examples specific to the new cogl_material_set_blend() and
cogl_material_layer_set_combine() functions.

Note: The hope is to remove the now redundant bits of the material API
before 1.0
2009-05-28 02:43:28 +01:00

152 lines
4.2 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 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.
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
*/
#ifndef COGL_BLEND_STRING_H
#define COGL_BLEND_STRING_H
#include <stdlib.h>
#include <glib.h>
typedef enum _CoglBlendStringContext
{
COGL_BLEND_STRING_CONTEXT_BLENDING,
COGL_BLEND_STRING_CONTEXT_TEXTURE_COMBINE
} CoglBlendStringContext;
#define COGL_BLEND_STRING_ERROR _cogl_blend_string_error_quark ()
typedef enum _CoglBlendStringError
{
COGL_BLEND_STRING_ERROR_PARSE_ERROR,
COGL_BLEND_STRING_ERROR_ARGUMENT_PARSE_ERROR,
COGL_BLEND_STRING_ERROR_INVALID_ERROR,
COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR
} CoglBlendStringError;
/* NB: debug stringify code will get upset if these
* are re-ordered */
typedef enum _CoglBlendStringChannelMask
{
COGL_BLEND_STRING_CHANNEL_MASK_RGB,
COGL_BLEND_STRING_CHANNEL_MASK_ALPHA,
COGL_BLEND_STRING_CHANNEL_MASK_RGBA
} CoglBlendStringChannelMask;
typedef enum _CoglBlendStringColorSourceType
{
/* blending */
COGL_BLEND_STRING_COLOR_SOURCE_SRC_COLOR,
COGL_BLEND_STRING_COLOR_SOURCE_DST_COLOR,
/* shared */
COGL_BLEND_STRING_COLOR_SOURCE_CONSTANT,
/* texture combining */
COGL_BLEND_STRING_COLOR_SOURCE_TEXTURE,
COGL_BLEND_STRING_COLOR_SOURCE_TEXTURE_N,
COGL_BLEND_STRING_COLOR_SOURCE_PRIMARY,
COGL_BLEND_STRING_COLOR_SOURCE_PREVIOUS
} CoglBlendStringColorSourceType;
typedef struct _CoglBlendStringColorSourceInfo
{
CoglBlendStringColorSourceType type;
const char *name;
size_t name_len;
} CoglBlendStringColorSourceInfo;
typedef struct _CoglBlendStringColorSource
{
gboolean is_zero;
const CoglBlendStringColorSourceInfo *info;
int texture; /* for the TEXTURE_N color source */
gboolean one_minus;
CoglBlendStringChannelMask mask;
} CoglBlendStringColorSource;
typedef struct _CoglBlendStringFactor
{
gboolean is_one;
gboolean is_src_alpha_saturate;
gboolean is_color;
CoglBlendStringColorSource source;
} CoglBlendStringFactor;
typedef struct _CoglBlendStringArgument
{
CoglBlendStringColorSource source;
CoglBlendStringFactor factor;
} CoglBlendStringArgument;
typedef enum _CoglBlendStringFunctionType
{
/* shared */
COGL_BLEND_STRING_FUNCTION_AUTO_COMPOSITE,
COGL_BLEND_STRING_FUNCTION_ADD,
/* texture combine only */
COGL_BLEND_STRING_FUNCTION_REPLACE,
COGL_BLEND_STRING_FUNCTION_MODULATE,
COGL_BLEND_STRING_FUNCTION_ADD_SIGNED,
COGL_BLEND_STRING_FUNCTION_INTERPOLATE,
COGL_BLEND_STRING_FUNCTION_SUBTRACT,
COGL_BLEND_STRING_FUNCTION_DOT3_RGB,
COGL_BLEND_STRING_FUNCTION_DOT3_RGBA
} CoglBlendStringFunctionType;
typedef struct _CoglBlendStringFunctionInfo
{
enum _CoglBlendStringFunctionType type;
const char *name;
size_t name_len;
int argc;
} CoglBlendStringFunctionInfo;
typedef struct _CoglBlendStringStatement
{
CoglBlendStringChannelMask mask;
const CoglBlendStringFunctionInfo *function;
CoglBlendStringArgument args[3];
} CoglBlendStringStatement;
gboolean
_cogl_blend_string_compile (const char *string,
CoglBlendStringContext context,
CoglBlendStringStatement *statements,
GError **error);
void
_cogl_blend_string_split_rgba_statement (CoglBlendStringStatement *statement,
CoglBlendStringStatement *rgb,
CoglBlendStringStatement *a);
GQuark
_cogl_blend_string_error_quark (void);
#endif /* COGL_BLEND_STRING_H */