mutter/cogl/cogl-glsl-shader-boilerplate.h
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

79 lines
2.6 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 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:
* Robert Bragg <robert@linux.intel.com>
*/
#ifndef __COGL_SHADER_BOILERPLATE_H
#define __COGL_SHADER_BOILERPLATE_H
#define _COGL_COMMON_SHADER_BOILERPLATE \
"#define COGL_VERSION 100\n" \
"\n" \
"uniform mat4 cogl_modelview_matrix;\n" \
"uniform mat4 cogl_modelview_projection_matrix;\n" \
"uniform mat4 cogl_projection_matrix;\n"
/* This declares all of the variables that we might need. This is
* working on the assumption that the compiler will optimise them out
* if they are not actually used. The GLSL spec at least implies that
* this will happen for varyings but it doesn't explicitly so for
* attributes */
#define _COGL_VERTEX_SHADER_BOILERPLATE \
_COGL_COMMON_SHADER_BOILERPLATE \
"#define cogl_color_out _cogl_color\n" \
"varying vec4 _cogl_color;\n" \
"#define cogl_tex_coord_out _cogl_tex_coord\n" \
"#define cogl_position_out gl_Position\n" \
"#define cogl_point_size_out gl_PointSize\n" \
"\n" \
"attribute vec4 cogl_color_in;\n" \
"attribute vec4 cogl_position_in;\n" \
"#define cogl_tex_coord_in cogl_tex_coord0_in;\n" \
"attribute vec3 cogl_normal_in;\n"
#define _COGL_FRAGMENT_SHADER_BOILERPLATE \
"#if __VERSION__ == 100\n" \
"precision highp float;\n" \
"#endif\n" \
_COGL_COMMON_SHADER_BOILERPLATE \
"\n" \
"varying vec4 _cogl_color;\n" \
"\n" \
"#define cogl_color_in _cogl_color\n" \
"#define cogl_tex_coord_in _cogl_tex_coord\n" \
"\n" \
"#define cogl_color_out gl_FragColor\n" \
"#define cogl_depth_out gl_FragDepth\n" \
"\n" \
"#define cogl_front_facing gl_FrontFacing\n"
#if 0
/* GLSL 1.2 has a bottom left origin, though later versions
* allow use of an origin_upper_left keyword which would be
* more appropriate for Cogl. */
"#define coglFragCoord gl_FragCoord\n"
#endif
#endif /* __COGL_SHADER_BOILERPLATE_H */