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mutter/clutter/cogl/common/cogl-blend-string.c
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

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/*
* 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>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-context.h"
#include "cogl-debug.h"
#include "cogl-blend-string.h"
typedef enum _ParserState
{
PARSER_STATE_EXPECT_DEST_CHANNELS,
PARSER_STATE_SCRAPING_DEST_CHANNELS,
PARSER_STATE_EXPECT_FUNCTION_NAME,
PARSER_STATE_SCRAPING_FUNCTION_NAME,
PARSER_STATE_EXPECT_ARG_START,
PARSER_STATE_EXPECT_STATEMENT_END
} ParserState;
typedef enum _ParserArgState
{
PARSER_ARG_STATE_START,
PARSER_ARG_STATE_EXPECT_MINUS,
PARSER_ARG_STATE_EXPECT_COLOR_SRC_NAME,
PARSER_ARG_STATE_SCRAPING_COLOR_SRC_NAME,
PARSER_ARG_STATE_MAYBE_COLOR_MASK,
PARSER_ARG_STATE_SCRAPING_MASK,
PARSER_ARG_STATE_MAYBE_MULT,
PARSER_ARG_STATE_EXPECT_OPEN_PAREN,
PARSER_ARG_STATE_EXPECT_FACTOR,
PARSER_ARG_STATE_MAYBE_SRC_ALPHA_SATURATE,
PARSER_ARG_STATE_MAYBE_MINUS,
PARSER_ARG_STATE_EXPECT_CLOSE_PAREN,
PARSER_ARG_STATE_EXPECT_END
} ParserArgState;
#define DEFINE_COLOR_SOURCE(NAME, NAME_LEN) \
{.type = COGL_BLEND_STRING_COLOR_SOURCE_ ## NAME, \
.name = #NAME, \
.name_len = NAME_LEN}
static CoglBlendStringColorSourceInfo blending_color_sources[] = {
DEFINE_COLOR_SOURCE (SRC_COLOR, 9),
DEFINE_COLOR_SOURCE (DST_COLOR, 9),
DEFINE_COLOR_SOURCE (CONSTANT, 8)
};
static CoglBlendStringColorSourceInfo tex_combine_color_sources[] = {
DEFINE_COLOR_SOURCE (TEXTURE, 7),
/* DEFINE_COLOR_SOURCE (TEXTURE_N, *) - handled manually */
DEFINE_COLOR_SOURCE (PRIMARY, 7),
DEFINE_COLOR_SOURCE (CONSTANT, 8),
DEFINE_COLOR_SOURCE (PREVIOUS, 8)
};
static CoglBlendStringColorSourceInfo tex_combine_texture_n_color_source = {
.type = COGL_BLEND_STRING_COLOR_SOURCE_TEXTURE_N,
.name = "TEXTURE_N",
.name_len = 0
};
#undef DEFINE_COLOR_SOURCE
#define DEFINE_FUNCTION(NAME, NAME_LEN, ARGC) \
{ .type = COGL_BLEND_STRING_FUNCTION_ ## NAME, \
.name = #NAME, \
.name_len = NAME_LEN, \
.argc = ARGC }
/* NB: These must be sorted so any name that's a subset of another
* comes later than the longer name. */
static CoglBlendStringFunctionInfo tex_combine_functions[] = {
DEFINE_FUNCTION (AUTO_COMPOSITE, 14, 0),
DEFINE_FUNCTION (REPLACE, 7, 1),
DEFINE_FUNCTION (MODULATE, 8, 2),
DEFINE_FUNCTION (ADD_SIGNED, 10, 2),
DEFINE_FUNCTION (ADD, 3, 2),
DEFINE_FUNCTION (INTERPOLATE, 11, 3),
DEFINE_FUNCTION (SUBTRACT, 8, 2),
DEFINE_FUNCTION (DOT3_RGBA, 9, 2),
DEFINE_FUNCTION (DOT3_RGB, 8, 2)
};
static CoglBlendStringFunctionInfo blend_functions[] = {
DEFINE_FUNCTION (AUTO_COMPOSITE, 14, 0),
DEFINE_FUNCTION (ADD, 3, 2)
};
#undef DEFINE_FUNCTION
GQuark
_cogl_blend_string_error_quark (void)
{
return g_quark_from_static_string ("cogl-blend-string-error-quark");
}
void
_cogl_blend_string_split_rgba_statement (CoglBlendStringStatement *statement,
CoglBlendStringStatement *rgb,
CoglBlendStringStatement *a)
{
int i;
memcpy (rgb, statement, sizeof (CoglBlendStringStatement));
memcpy (a, statement, sizeof (CoglBlendStringStatement));
rgb->mask = COGL_BLEND_STRING_CHANNEL_MASK_RGB;
a->mask = COGL_BLEND_STRING_CHANNEL_MASK_ALPHA;
for (i = 0; i < statement->function->argc; i++)
{
CoglBlendStringArgument *arg = &statement->args[i];
CoglBlendStringArgument *rgb_arg = &rgb->args[i];
CoglBlendStringArgument *a_arg = &a->args[i];
if (arg->source.mask == COGL_BLEND_STRING_CHANNEL_MASK_RGBA)
{
rgb_arg->source.mask = COGL_BLEND_STRING_CHANNEL_MASK_RGB;
a_arg->source.mask = COGL_BLEND_STRING_CHANNEL_MASK_ALPHA;
}
if (arg->factor.is_color &&
arg->factor.source.mask == COGL_BLEND_STRING_CHANNEL_MASK_RGBA)
{
rgb_arg->factor.source.mask = COGL_BLEND_STRING_CHANNEL_MASK_RGB;
a_arg->factor.source.mask = COGL_BLEND_STRING_CHANNEL_MASK_ALPHA;
}
}
}
static gboolean
validate_tex_combine_statements (CoglBlendStringStatement *statements,
int n_statements,
GError **error)
{
int i, j;
const char *error_string;
CoglBlendStringError detail = COGL_BLEND_STRING_ERROR_INVALID_ERROR;
for (i = 0; i < n_statements; i++)
{
#ifdef HAVE_COGL_GLES2
if (statements[i].function->type != COGL_BLEND_STRING_FUNCTION_MODULATE)
{
error_string = "Using anything but MODULATE() for texture combining"
" under GLES 2 is currently unsupported";
detail = COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR;
goto error;
}
#endif
for (j = 0; j < statements[i].function->argc; j++)
{
CoglBlendStringArgument *arg = &statements[i].args[j];
if (arg->source.is_zero)
{
error_string = "You can't use the constant '0' as a texture "
"combine argument";
goto error;
}
if (!arg->factor.is_one)
{
error_string = "Argument factors are only relevant to blending "
"not texture combining";
goto error;
}
#ifdef HAVE_COGL_GLES2
if (arg->source.info->type == COGL_BLEND_STRING_COLOR_SOURCE_CONSTANT)
{
error_string = "Using a constant for texture combining isn't "
"currently supported with GLES 2 "
"(TODO: glTexEnvf)";
detail = COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR;
goto error;
}
#endif
}
}
return TRUE;
error:
g_set_error (error,
COGL_BLEND_STRING_ERROR,
detail,
"Invalid texture combine string: %s",
error_string);
if (cogl_debug_flags & COGL_DEBUG_BLEND_STRINGS)
{
g_debug ("Invalid texture combine string: %s",
error_string);
}
return FALSE;
}
static gboolean
validate_blend_statements (CoglBlendStringStatement *statements,
int n_statements,
GError **error)
{
int i, j;
const char *error_string;
CoglBlendStringError detail = COGL_BLEND_STRING_ERROR_INVALID_ERROR;
#ifdef HAVE_COGL_GL
_COGL_GET_CONTEXT (ctx, 0);
#endif
#ifdef HAVE_COGL_GL
if (n_statements == 2)
{
/* glBlendEquationSeperate is GL 2.0 only */
if (!ctx->pf_glBlendEquationSeparate &&
statements[0].function->type != statements[1].function->type)
{
error_string = "Separate blend functions for the RGB an A "
"channels isn't supported by the driver";
detail = COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR;
goto error;
}
}
#elif defined(HAVE_COGL_GLES)
if (n_statements != 1)
{
error_string = "Separate blend functions for the RGB an A "
"channels isn't supported by the GLES 1";
detail = COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR;
goto error;
}
#endif
for (i = 0; i < n_statements; i++)
for (j = 0; j < statements[i].function->argc; j++)
{
CoglBlendStringArgument *arg = &statements[i].args[j];
if (arg->source.is_zero)
continue;
if ((j == 0 &&
arg->source.info->type !=
COGL_BLEND_STRING_COLOR_SOURCE_SRC_COLOR)
|| (j == 1 &&
arg->source.info->type !=
COGL_BLEND_STRING_COLOR_SOURCE_DST_COLOR))
{
error_string = "For blending you must always use SRC_COLOR "
"for arg0 and DST_COLOR for arg1";
goto error;
}
#ifdef HAVE_COGL_GLES
if (arg->factor.is_color &&
arg->factor.source.info->type == COGL_BLEND_STRING_COLOR_SOURCE_CONSTANT)
{
error_string = "GLES Doesn't support constant blend factors";
detail = COGL_BLEND_STRING_ERROR_GPU_UNSUPPORTED_ERROR;
goto error;
}
#endif
}
return TRUE;
error:
g_set_error (error,
COGL_BLEND_STRING_ERROR,
detail,
"Invalid blend string: %s",
error_string);
return FALSE;
}
static gboolean
validate_statements_for_context (CoglBlendStringStatement *statements,
int n_statements,
CoglBlendStringContext context,
GError **error)
{
const char *error_string;
if (n_statements == 1)
{
if (statements[0].mask == COGL_BLEND_STRING_CHANNEL_MASK_ALPHA)
{
error_string = "You need to also give a blend statement for the RGB"
"channels";
goto error;
}
else if (statements[0].mask == COGL_BLEND_STRING_CHANNEL_MASK_RGB)
{
error_string = "You need to also give a blend statement for the "
"Alpha channel";
goto error;
}
}
if (context == COGL_BLEND_STRING_CONTEXT_BLENDING)
return validate_blend_statements (statements, n_statements, error);
else
return validate_tex_combine_statements (statements, n_statements, error);
error:
g_set_error (error,
COGL_BLEND_STRING_ERROR,
COGL_BLEND_STRING_ERROR_INVALID_ERROR,
"Invalid %s string: %s",
context == COGL_BLEND_STRING_CONTEXT_BLENDING ?
"blend" : "texture combine",
error_string);
if (cogl_debug_flags & COGL_DEBUG_BLEND_STRINGS)
{
g_debug ("Invalid %s string: %s",
context == COGL_BLEND_STRING_CONTEXT_BLENDING ?
"blend" : "texture combine",
error_string);
}
return FALSE;
}
static void
print_argument (CoglBlendStringArgument *arg)
{
const char *mask_names[] = {
"RGB",
"A",
"RGBA"
};
g_print (" Arg:\n");
g_print (" is zero = %s\n", arg->source.is_zero ? "yes" : "no");
if (!arg->source.is_zero)
{
g_print (" color source = %s\n", arg->source.info->name);
g_print (" one minus = %s\n", arg->source.one_minus ? "yes" : "no");
g_print (" mask = %s\n", mask_names[arg->source.mask]);
g_print (" texture = %d\n", arg->source.texture);
g_print ("\n");
g_print (" factor is_one = %s\n", arg->factor.is_one ? "yes" : "no");
g_print (" factor is_src_alpha_saturate = %s\n",
arg->factor.is_src_alpha_saturate ? "yes" : "no");
g_print (" factor is_color = %s\n", arg->factor.is_color ? "yes" : "no");
if (arg->factor.is_color)
{
g_print (" factor color:is zero = %s\n",
arg->factor.source.is_zero ? "yes" : "no");
g_print (" factor color:color source = %s\n",
arg->factor.source.info->name);
g_print (" factor color:one minus = %s\n",
arg->factor.source.one_minus ? "yes" : "no");
g_print (" factor color:mask = %s\n",
mask_names[arg->factor.source.mask]);
g_print (" factor color:texture = %d\n",
arg->factor.source.texture);
}
}
}
static void
print_statement (int num, CoglBlendStringStatement *statement)
{
const char *mask_names[] = {
"RGB",
"A",
"RGBA"
};
int i;
g_print ("Statement %d:\n", num);
g_print (" Destination channel mask = %s\n",
mask_names[statement->mask]);
g_print (" Function = %s\n", statement->function->name);
for (i = 0; i < statement->function->argc; i++)
print_argument (&statement->args[i]);
}
static const CoglBlendStringFunctionInfo *
get_function_info (const char *mark,
const char *p,
CoglBlendStringContext context)
{
size_t len = p - mark;
CoglBlendStringFunctionInfo *functions;
size_t array_len;
int i;
if (context == COGL_BLEND_STRING_CONTEXT_BLENDING)
{
functions = blend_functions;
array_len = G_N_ELEMENTS (blend_functions);
}
else
{
functions = tex_combine_functions;
array_len = G_N_ELEMENTS (tex_combine_functions);
}
for (i = 0; i < array_len; i++)
{
if (len >= functions[i].name_len
&& strncmp (mark, functions[i].name, functions[i].name_len) == 0)
return &functions[i];
}
return NULL;
}
static const CoglBlendStringColorSourceInfo *
get_color_src_info (const char *mark,
const char *p,
CoglBlendStringContext context)
{
size_t len = p - mark;
CoglBlendStringColorSourceInfo *sources;
size_t array_len;
int i;
if (context == COGL_BLEND_STRING_CONTEXT_BLENDING)
{
sources = blending_color_sources;
array_len = G_N_ELEMENTS (blending_color_sources);
}
else
{
sources = tex_combine_color_sources;
array_len = G_N_ELEMENTS (tex_combine_color_sources);
}
for (i = 0; i < array_len; i++)
{
if (len >= sources[i].name_len
&& strncmp (mark, sources[i].name, sources[i].name_len) == 0)
return &sources[i];
}
if (len >= 9 &&
strncmp (mark, "TEXTURE_", 8) == 0 &&
g_ascii_isdigit (mark[8]))
{
return &tex_combine_texture_n_color_source;
}
return NULL;
}
static gboolean
is_symbol_char (const char c)
{
return (g_ascii_isalpha (c) || c == '_') ? TRUE : FALSE;
}
static gboolean
parse_argument (const char *string, /* original user string */
const char **ret_p, /* start of argument IN:OUT */
const CoglBlendStringStatement *statement,
int current_arg,
CoglBlendStringArgument *arg, /* OUT */
CoglBlendStringContext context,
GError **error)
{
const char *p = *ret_p;
const char *mark;
const char *error_string;
ParserArgState state = PARSER_ARG_STATE_START;
gboolean parsing_factor = FALSE;
arg->source.is_zero = FALSE;
arg->source.info = NULL;
arg->source.texture = 0;
arg->source.one_minus = FALSE;
arg->source.mask = statement->mask;
arg->factor.is_one = FALSE;
arg->factor.is_color = FALSE;
arg->factor.is_src_alpha_saturate = FALSE;
arg->factor.source.is_zero = FALSE;
arg->factor.source.info = NULL;
arg->factor.source.texture = 0;
arg->factor.source.one_minus = FALSE;
arg->factor.source.mask = statement->mask;
do
{
if (g_ascii_isspace (*p))
continue;
if (*p == '\0')
{
error_string = "Unexpected end of string while parsing argument";
goto error;
}
switch (state)
{
case PARSER_ARG_STATE_START:
if (*p == '1')
state = PARSER_ARG_STATE_EXPECT_MINUS;
else if (*p == '0')
{
arg->source.is_zero = TRUE;
state = PARSER_ARG_STATE_EXPECT_END;
}
else
{
p--; /* backtrack */
state = PARSER_ARG_STATE_EXPECT_COLOR_SRC_NAME;
}
continue;
case PARSER_ARG_STATE_EXPECT_MINUS:
if (*p != '-')
{
error_string = "expected a '-' following the 1";
goto error;
}
arg->source.one_minus = TRUE;
state = PARSER_ARG_STATE_EXPECT_COLOR_SRC_NAME;
continue;
case PARSER_ARG_STATE_EXPECT_COLOR_SRC_NAME:
if (!is_symbol_char (*p))
{
error_string = "expected a color source name";
goto error;
}
state = PARSER_ARG_STATE_SCRAPING_COLOR_SRC_NAME;
mark = p;
if (parsing_factor)
arg->factor.is_color = TRUE;
/* fall through */
case PARSER_ARG_STATE_SCRAPING_COLOR_SRC_NAME:
if (!is_symbol_char (*p))
{
CoglBlendStringColorSource *source =
parsing_factor ? &arg->factor.source : &arg->source;
source->info = get_color_src_info (mark, p, context);
if (!source->info)
{
error_string = "Unknown color source name";
goto error;
}
if (source->info->type ==
COGL_BLEND_STRING_COLOR_SOURCE_TEXTURE_N)
{
char *endp;
source->texture =
strtoul (&mark[strlen ("TEXTURE_")], &endp, 10);
if (mark == endp)
{
error_string = "invalid texture number given with "
"TEXTURE_N color source";
goto error;
}
p = endp;
}
state = PARSER_ARG_STATE_MAYBE_COLOR_MASK;
}
else
continue;
/* fall through */
case PARSER_ARG_STATE_MAYBE_COLOR_MASK:
if (*p != '[')
{
p--; /* backtrack */
if (!parsing_factor)
state = PARSER_ARG_STATE_MAYBE_MULT;
else
state = PARSER_ARG_STATE_EXPECT_END;
continue;
}
state = PARSER_ARG_STATE_SCRAPING_MASK;
mark = p;
/* fall through */
case PARSER_ARG_STATE_SCRAPING_MASK:
if (*p == ']')
{
size_t len = p - mark;
CoglBlendStringColorSource *source =
parsing_factor ? &arg->factor.source : &arg->source;
if (len == 5 && strncmp (mark, "[RGBA", len) == 0)
{
if (statement->mask != COGL_BLEND_STRING_CHANNEL_MASK_RGBA)
{
error_string = "You can't use an RGBA color mask if the "
"statement hasn't also got an RGBA= mask";
goto error;
}
source->mask = COGL_BLEND_STRING_CHANNEL_MASK_RGBA;
}
else if (len == 4 && strncmp (mark, "[RGB", len) == 0)
source->mask = COGL_BLEND_STRING_CHANNEL_MASK_RGB;
else if (len == 2 && strncmp (mark, "[A", len) == 0)
source->mask = COGL_BLEND_STRING_CHANNEL_MASK_ALPHA;
else
{
error_string = "Expected a channel mask of [RGBA]"
"[RGB] or [A]";
goto error;
}
if (parsing_factor)
state = PARSER_ARG_STATE_EXPECT_CLOSE_PAREN;
else
state = PARSER_ARG_STATE_MAYBE_MULT;
}
continue;
case PARSER_ARG_STATE_EXPECT_OPEN_PAREN:
if (*p != '(')
{
error_string = "Expected '(' before blend factor - the parser "
"currently requires that all blend factors "
"following a '*' be surrounded in brackets";
goto error;
}
parsing_factor = TRUE;
state = PARSER_ARG_STATE_EXPECT_FACTOR;
continue;
case PARSER_ARG_STATE_EXPECT_FACTOR:
if (*p == '1')
state = PARSER_ARG_STATE_MAYBE_MINUS;
else if (*p == '0')
{
arg->source.is_zero = TRUE;
state = PARSER_ARG_STATE_EXPECT_CLOSE_PAREN;
}
else
{
state = PARSER_ARG_STATE_MAYBE_SRC_ALPHA_SATURATE;
mark = p;
}
continue;
case PARSER_ARG_STATE_MAYBE_SRC_ALPHA_SATURATE:
if (!is_symbol_char (*p))
{
size_t len = p - mark;
if (len >= strlen ("SRC_ALPHA_SATURATE") &&
strncmp (mark, "SRC_ALPHA_SATURATE", len) == 0)
{
arg->factor.is_src_alpha_saturate = TRUE;
state = PARSER_ARG_STATE_EXPECT_CLOSE_PAREN;
}
else
{
state = PARSER_ARG_STATE_EXPECT_COLOR_SRC_NAME;
p = mark - 1; /* backtrack */
}
}
continue;
case PARSER_ARG_STATE_MAYBE_MINUS:
if (*p == '-')
{
arg->factor.source.one_minus = TRUE;
state = PARSER_ARG_STATE_EXPECT_COLOR_SRC_NAME;
}
else
{
arg->factor.is_one = TRUE;
state = PARSER_ARG_STATE_EXPECT_CLOSE_PAREN;
}
continue;
case PARSER_ARG_STATE_EXPECT_CLOSE_PAREN:
if (*p != ')')
{
error_string = "Expected closing parenthesis after blend factor";
goto error;
}
state = PARSER_ARG_STATE_EXPECT_END;
continue;
case PARSER_ARG_STATE_MAYBE_MULT:
if (*p == '*')
{
state = PARSER_ARG_STATE_EXPECT_OPEN_PAREN;
continue;
}
arg->factor.is_one = TRUE;
state = PARSER_ARG_STATE_EXPECT_END;
/* fall through */
case PARSER_ARG_STATE_EXPECT_END:
if (*p != ',' && *p != ')')
{
error_string = "expected , or )";
goto error;
}
*ret_p = p - 1;
return TRUE;
}
}
while (p++);
error:
{
int offset = p - string;
g_set_error (error,
COGL_BLEND_STRING_ERROR,
COGL_BLEND_STRING_ERROR_ARGUMENT_PARSE_ERROR,
"Syntax error for argument %d at offset %d: %s",
current_arg,
offset,
error_string);
if (cogl_debug_flags & COGL_DEBUG_BLEND_STRINGS)
{
g_debug ("Syntax error for argument %d at offset %d: %s",
current_arg, offset, error_string);
}
return FALSE;
}
}
int
_cogl_blend_string_compile (const char *string,
CoglBlendStringContext context,
CoglBlendStringStatement *statements,
GError **error)
{
const char *p = string;
const char *mark;
const char *error_string;
ParserState state = PARSER_STATE_EXPECT_DEST_CHANNELS;
CoglBlendStringStatement *statement = statements;
int current_statement = 0;
int current_arg = 0;
int remaining_argc;
#if 0
cogl_debug_flags |= COGL_DEBUG_BLEND_STRINGS;
#endif
if (cogl_debug_flags & COGL_DEBUG_BLEND_STRINGS)
{
COGL_NOTE (BLEND_STRINGS, "Compiling %s string:\n%s\n",
context == COGL_BLEND_STRING_CONTEXT_BLENDING ?
"blend" : "texture combine",
string);
}
do
{
if (g_ascii_isspace (*p))
continue;
if (*p == '\0')
{
switch (state)
{
case PARSER_STATE_EXPECT_DEST_CHANNELS:
if (current_statement != 0)
goto finished;
error_string = "Empty statement";
goto error;
case PARSER_STATE_SCRAPING_DEST_CHANNELS:
error_string = "Expected an '=' following the destination "
"channel mask";
goto error;
case PARSER_STATE_EXPECT_FUNCTION_NAME:
error_string = "Expected a function name";
goto error;
case PARSER_STATE_SCRAPING_FUNCTION_NAME:
error_string = "Expected parenthesis after the function name";
goto error;
case PARSER_STATE_EXPECT_ARG_START:
error_string = "Expected to find the start of an argument";
goto error;
case PARSER_STATE_EXPECT_STATEMENT_END:
error_string = "Expected closing parenthesis for statement";
goto error;
}
}
switch (state)
{
case PARSER_STATE_EXPECT_DEST_CHANNELS:
mark = p;
state = PARSER_STATE_SCRAPING_DEST_CHANNELS;
/* fall through */
case PARSER_STATE_SCRAPING_DEST_CHANNELS:
if (*p != '=')
continue;
if (strncmp (mark, "RGBA", 4) == 0)
statement->mask = COGL_BLEND_STRING_CHANNEL_MASK_RGBA;
else if (strncmp (mark, "RGB", 3) == 0)
statement->mask = COGL_BLEND_STRING_CHANNEL_MASK_RGB;
else if (strncmp (mark, "A", 1) == 0)
statement->mask = COGL_BLEND_STRING_CHANNEL_MASK_ALPHA;
else
{
error_string = "Unknown destination channel mask; "
"expected RGBA=, RGB= or A=";
goto error;
}
state = PARSER_STATE_EXPECT_FUNCTION_NAME;
continue;
case PARSER_STATE_EXPECT_FUNCTION_NAME:
mark = p;
state = PARSER_STATE_SCRAPING_FUNCTION_NAME;
/* fall through */
case PARSER_STATE_SCRAPING_FUNCTION_NAME:
if (*p != '(')
{
if (!is_symbol_char (*p))
{
error_string = "non alpha numeric character in function"
"name";
goto error;
}
continue;
}
statement->function = get_function_info (mark, p, context);
if (!statement->function)
{
error_string = "Unknown function name";
goto error;
}
remaining_argc = statement->function->argc;
current_arg = 0;
state = PARSER_STATE_EXPECT_ARG_START;
/* fall through */
case PARSER_STATE_EXPECT_ARG_START:
if (*p != '(' && *p != ',')
continue;
if (remaining_argc)
{
p++; /* parse_argument expects to see the first char of the arg */
if (!parse_argument (string, &p, statement,
current_arg, &statement->args[current_arg],
context, error))
return 0;
current_arg++;
remaining_argc--;
}
if (!remaining_argc)
state = PARSER_STATE_EXPECT_STATEMENT_END;
continue;
case PARSER_STATE_EXPECT_STATEMENT_END:
if (*p != ')')
{
error_string = "Expected end of statement";
goto error;
}
state = PARSER_STATE_EXPECT_DEST_CHANNELS;
if (current_statement++ == 1)
goto finished;
statement = &statements[current_statement];
}
}
while (p++);
finished:
if (cogl_debug_flags & COGL_DEBUG_BLEND_STRINGS)
{
if (current_statement > 0)
print_statement (0, &statements[0]);
if (current_statement > 1)
print_statement (1, &statements[1]);
}
if (!validate_statements_for_context (statements,
current_statement,
context,
error))
return 0;
return current_statement;
error:
{
int offset = p - string;
g_set_error (error,
COGL_BLEND_STRING_ERROR,
COGL_BLEND_STRING_ERROR_PARSE_ERROR,
"Syntax error at offset %d: %s",
offset,
error_string);
if (cogl_debug_flags & COGL_DEBUG_BLEND_STRINGS)
{
g_debug ("Syntax error at offset %d: %s",
offset, error_string);
}
return 0;
}
}
/*
* INTERNAL TESTING CODE ...
*/
struct _TestString
{
const char *string;
CoglBlendStringContext context;
};
int
_cogl_blend_string_test (void)
{
struct _TestString strings[] = {
{" A = MODULATE ( TEXTURE[RGB], PREVIOUS[A], PREVIOUS[A] ) ",
COGL_BLEND_STRING_CONTEXT_TEXTURE_COMBINE },
{" RGB = MODULATE ( TEXTURE[RGB], PREVIOUS[A] ) ",
COGL_BLEND_STRING_CONTEXT_TEXTURE_COMBINE },
{"A=ADD(TEXTURE[A],PREVIOUS[RGB])",
COGL_BLEND_STRING_CONTEXT_TEXTURE_COMBINE },
{"A=ADD(TEXTURE[A],PREVIOUS[RGB])",
COGL_BLEND_STRING_CONTEXT_TEXTURE_COMBINE },
{"RGBA = ADD(SRC_COLOR*(SRC_COLOR[A]), DST_COLOR*(1-SRC_COLOR[A]))",
COGL_BLEND_STRING_CONTEXT_BLENDING },
{"RGB = ADD(SRC_COLOR, DST_COLOR*(0))",
COGL_BLEND_STRING_CONTEXT_BLENDING },
{"RGB = ADD(SRC_COLOR, 0)",
COGL_BLEND_STRING_CONTEXT_BLENDING },
{"RGB = ADD()",
COGL_BLEND_STRING_CONTEXT_BLENDING },
{"RGB = ADD(SRC_COLOR, 0, DST_COLOR)",
COGL_BLEND_STRING_CONTEXT_BLENDING },
{NULL}
};
int i;
GError *error = NULL;
for (i = 0; strings[i].string; i++)
{
CoglBlendStringStatement statements[2];
int count = _cogl_blend_string_compile (strings[i].string,
strings[i].context,
statements,
&error);
if (!count)
{
g_print ("Failed to parse string:\n%s\n%s\n",
strings[i].string,
error->message);
g_error_free (error);
error = NULL;
continue;
}
g_print ("Original:\n");
g_print ("%s\n", strings[i].string);
if (count > 0)
print_statement (0, &statements[0]);
if (count > 1)
print_statement (1, &statements[1]);
}
return 0;
}
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