mutter/cogl/cogl-pipeline-vertend-fixed.c
Neil Roberts d38ae0284b cogl-pipeline: Add two hook points for adding shader snippets
This adds two new public experimental functions for attaching
CoglSnippets to two hook points on a CoglPipeline:

void cogl_pipeline_add_vertex_hook (CoglPipeline *, CoglSnippet *)
void cogl_pipeline_add_fragment_hook (CoglPipeline *, CoglSnippet *)

The hooks are intended to be around the entire vertex or fragment
processing. That means the pre string in the snippet will be inserted
at the very top of the main function and the post function will be
inserted at the very end. The declarations get inserted in the global
scope.

The snippets are stored in two separate linked lists with a structure
containing an enum representing the hook point and a pointer to the
snippet. The lists are meant to be for hooks that affect the vertex
shader and fragment shader respectively. Although there are currently
only two hooks and the names match these two lists, the intention is
*not* that each new hook will be in a separate list. The separation of
the lists is just to make it easier to determine which shader needs to
be regenerated when a new snippet is added.

When a pipeline becomes the authority for either the vertex or
fragment snipper state, it simply copies the entire list from the
previous authority (although of course the shader snippet objects are
referenced instead of copied so it doesn't duplicate the source
strings).

Each string is inserted into its own block in the shader. This means
that each string has its own scope so it doesn't need to worry about
name collisions with variables in other snippets. However it does mean
that the pre and post strings can't share variables. It could be
possible to wrap both parts in one block and then wrap the actual
inner hook code in another block, however this would mean that any
further snippets within the outer snippet would be able to see those
variables. Perhaps something to consider would be to put each snippet
into its own function which calls another function between the pre and
post strings to do further processing.

The pipeline cache for generated programs was previously shared with
the fragment shader cache because the state that affects vertex
shaders was a subset of the state that affects fragment shaders. This
is no longer the case because there is a separate state mask for
vertex snippets so the program cache now has its own hash table.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-12-06 19:02:05 +00:00

141 lines
4.1 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2008,2009,2010 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:
* Neil Roberts <neil@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "cogl-context-private.h"
#include "cogl-pipeline-private.h"
#include "cogl-pipeline-state-private.h"
#include "cogl-pipeline-opengl-private.h"
#ifdef COGL_PIPELINE_VERTEND_FIXED
#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-context-private.h"
#include "cogl-handle.h"
#include "cogl-program-private.h"
const CoglPipelineVertend _cogl_pipeline_fixed_vertend;
static gboolean
_cogl_pipeline_vertend_fixed_start (CoglPipeline *pipeline,
int n_layers,
unsigned long pipelines_difference,
int n_tex_coord_attribs)
{
CoglProgram *user_program;
_COGL_GET_CONTEXT (ctx, FALSE);
if (G_UNLIKELY (COGL_DEBUG_ENABLED (COGL_DEBUG_DISABLE_FIXED)))
return FALSE;
if (ctx->driver == COGL_DRIVER_GLES2)
return FALSE;
/* Vertex snippets are only supported in the GLSL fragend */
if (_cogl_pipeline_has_vertex_snippets (pipeline))
return FALSE;
/* If there is a user program with a vertex shader then the
appropriate backend for that language should handle it. We can
still use the fixed vertex backend if the program only contains
a fragment shader */
user_program = cogl_pipeline_get_user_program (pipeline);
if (user_program != COGL_INVALID_HANDLE &&
_cogl_program_has_vertex_shader (user_program))
return FALSE;
_cogl_use_vertex_program (0, COGL_PIPELINE_PROGRAM_TYPE_FIXED);
return TRUE;
}
static gboolean
_cogl_pipeline_vertend_fixed_add_layer (CoglPipeline *pipeline,
CoglPipelineLayer *layer,
unsigned long layers_difference)
{
int unit_index = _cogl_pipeline_layer_get_unit_index (layer);
CoglTextureUnit *unit = _cogl_get_texture_unit (unit_index);
_COGL_GET_CONTEXT (ctx, FALSE);
if (layers_difference & COGL_PIPELINE_LAYER_STATE_USER_MATRIX)
{
CoglPipelineLayerState state = COGL_PIPELINE_LAYER_STATE_USER_MATRIX;
CoglPipelineLayer *authority =
_cogl_pipeline_layer_get_authority (layer, state);
_cogl_matrix_stack_set (unit->matrix_stack,
&authority->big_state->matrix);
_cogl_set_active_texture_unit (unit_index);
_cogl_matrix_stack_flush_to_gl (ctx, unit->matrix_stack,
COGL_MATRIX_TEXTURE);
}
return TRUE;
}
static gboolean
_cogl_pipeline_vertend_fixed_end (CoglPipeline *pipeline,
unsigned long pipelines_difference)
{
_COGL_GET_CONTEXT (ctx, FALSE);
if (pipelines_difference & COGL_PIPELINE_STATE_POINT_SIZE)
{
CoglPipeline *authority =
_cogl_pipeline_get_authority (pipeline, COGL_PIPELINE_STATE_POINT_SIZE);
if (ctx->point_size_cache != authority->big_state->point_size)
{
GE( ctx, glPointSize (authority->big_state->point_size) );
ctx->point_size_cache = authority->big_state->point_size;
}
}
return TRUE;
}
const CoglPipelineVertend _cogl_pipeline_fixed_vertend =
{
_cogl_pipeline_vertend_fixed_start,
_cogl_pipeline_vertend_fixed_add_layer,
_cogl_pipeline_vertend_fixed_end,
NULL, /* pipeline_change_notify */
NULL /* layer_change_notify */
};
#endif /* COGL_PIPELINE_VERTEND_FIXED */