mutter/cogl/driver/gl/cogl-pipeline-progend-fixed.c
Neil Roberts 6d51a18e7c Add support for per-vertex point sizes
This adds a new function to enable per-vertex point size on a
pipeline. This can be set with
cogl_pipeline_set_per_vertex_point_size(). Once enabled the point size
can be set either by drawing with an attribute named
'cogl_point_size_in' or by writing to the 'cogl_point_size_out'
builtin from a snippet.

There is a feature flag which must be checked for before using
per-vertex point sizes. This will only be set on GL >= 2.0 or on GLES
2.0. GL will only let you set a per-vertex point size from GLSL by
writing to gl_PointSize. This is only available in GL2 and not in the
older GLSL extensions.

The per-vertex point size has its own pipeline state flag so that it
can be part of the state that affects vertex shader generation.

Having to enable the per vertex point size with a separate function is
a bit awkward. Ideally it would work like the color attribute where
you can just set it for every vertex in your primitive with
cogl_pipeline_set_color or set it per-vertex by just using the
attribute. This is harder to get working with the point size because
we need to generate a different vertex shader depending on what
attributes are bound. I think if we wanted to make this work
transparently we would still want to internally have a pipeline
property describing whether the shader was generated with per-vertex
support so that it would work with the shader cache correctly.
Potentially we could make the per-vertex property internal and
automatically make a weak pipeline whenever the attribute is bound.
However we would then also need to automatically detect when an
application is writing to cogl_point_size_out from a snippet.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 8495d9c1c15ce389885a9356d965eabd97758115)

Conflicts:
	cogl/cogl-context.c
	cogl/cogl-pipeline-private.h
	cogl/cogl-pipeline.c
	cogl/cogl-private.h
	cogl/driver/gl/cogl-pipeline-progend-fixed.c
	cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
2013-06-07 16:53:29 +01:00

107 lines
3.2 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2011 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 <string.h>
#include "cogl-pipeline-private.h"
#include "cogl-pipeline-state-private.h"
#ifdef COGL_PIPELINE_PROGEND_FIXED
#include "cogl-context.h"
#include "cogl-context-private.h"
#include "cogl-framebuffer-private.h"
static CoglBool
_cogl_pipeline_progend_fixed_start (CoglPipeline *pipeline)
{
_COGL_GET_CONTEXT (ctx, FALSE);
if (G_UNLIKELY (COGL_DEBUG_ENABLED (COGL_DEBUG_DISABLE_FIXED)))
return FALSE;
if (!(ctx->private_feature_flags & COGL_PRIVATE_FEATURE_FIXED_FUNCTION))
return FALSE;
/* Vertex snippets are only supported in the GLSL fragend */
if (_cogl_pipeline_has_vertex_snippets (pipeline))
return FALSE;
/* Fragment snippets are only supported in the GLSL fragend */
if (_cogl_pipeline_has_fragment_snippets (pipeline))
return FALSE;
/* If there is a user program then the appropriate backend for that
* language should handle it. */
if (cogl_pipeline_get_user_program (pipeline))
return FALSE;
/* The fixed progend can't handle the per-vertex point size
* attribute */
if (cogl_pipeline_get_per_vertex_point_size (pipeline))
return FALSE;
return TRUE;
}
static void
_cogl_pipeline_progend_fixed_pre_paint (CoglPipeline *pipeline,
CoglFramebuffer *framebuffer)
{
CoglContext *ctx = framebuffer->context;
if (ctx->current_projection_entry)
_cogl_matrix_entry_flush_to_gl_builtins (ctx,
ctx->current_projection_entry,
COGL_MATRIX_PROJECTION,
framebuffer,
FALSE /* enable flip */);
if (ctx->current_modelview_entry)
_cogl_matrix_entry_flush_to_gl_builtins (ctx,
ctx->current_modelview_entry,
COGL_MATRIX_MODELVIEW,
framebuffer,
FALSE /* enable flip */);
}
const CoglPipelineProgend _cogl_pipeline_fixed_progend =
{
COGL_PIPELINE_VERTEND_FIXED,
COGL_PIPELINE_FRAGEND_FIXED,
_cogl_pipeline_progend_fixed_start,
NULL, /* end */
NULL, /* pre_change_notify */
NULL, /* layer_pre_change_notify */
_cogl_pipeline_progend_fixed_pre_paint
};
#endif /* COGL_PIPELINE_PROGEND_FIXED */