mutter/cogl/cogl-shader-boilerplate.h
Neil Roberts 6607306a2d cogl: Remove the generated array size for cogl_tex_coord_in
Under GLES2 we were defining the cogl_tex_coord_in varying as an array
with a size determined by the number of texture coordinate arrays
enabled whenever the program is used. This meant that we may have to
regenerate the shader with a different size if the shader is used with
more texture coord arrays later. However in OpenGL the equivalent
builtin varying gl_TexCoord is simply defined as:

varying vec4 gl_TexCoord[]; /* <-- no size */

GLSL is documented that if you declare an array with no size then you
can only access it with a constant index and the size of the array
will be determined by the highest index used. If you want to access it
with a non-constant expression you need to redeclare the array
yourself with a size.

We can replicate the same behaviour in our Cogl shaders by instead
declaring the cogl_tex_coord_in with no size. That way we don't have
to pass around the number of tex coord attributes enabled when we
flush a material. It also means that CoglShader can go back to
directly uploading the source string to GL when cogl_shader_source is
called so that we don't have to keep a copy of it around.

If the user wants to access cogl_tex_coord_in with a non-constant
index then they can simply redeclare the array themself. Hopefully
developers will expect to have to do this if they are accustomed to
the gl_TexCoord array.
2010-12-02 12:27:29 +00:00

109 lines
3.5 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
#include "cogl.h"
#define _COGL_COMMON_SHADER_BOILERPLATE \
"#define COGL_VERSION 100\n" \
"\n"
#ifndef HAVE_COGL_GLES2
#define _COGL_VERTEX_SHADER_BOILERPLATE \
_COGL_COMMON_SHADER_BOILERPLATE \
"#define cogl_position_in gl_Vertex\n" \
"#define cogl_color_in gl_Color\n" \
"#define cogl_tex_coord_in gl_MultiTexCoord0\n" \
"#define cogl_tex_coord0_in gl_MultiTexCoord0\n" \
"#define cogl_tex_coord1_in gl_MultiTexCoord1\n" \
"#define cogl_tex_coord2_in gl_MultiTexCoord2\n" \
"#define cogl_tex_coord3_in gl_MultiTexCoord3\n" \
"#define cogl_tex_coord4_in gl_MultiTexCoord4\n" \
"#define cogl_tex_coord5_in gl_MultiTexCoord5\n" \
"#define cogl_tex_coord6_in gl_MultiTexCoord6\n" \
"#define cogl_tex_coord7_in gl_MultiTexCoord7\n" \
"#define cogl_normal_in gl_Normal\n" \
"\n" \
"#define cogl_position_out gl_Position\n" \
"#define cogl_point_size_out gl_PointSize\n" \
"#define cogl_color_out gl_FrontColor\n" \
"#define cogl_tex_coord_out gl_TexCoord\n" \
"\n" \
"#define cogl_modelview_matrix gl_ModelViewMatrix\n" \
"#define cogl_modelview_projection_matrix gl_ModelViewProjectionMatrix\n" \
"#define cogl_projection_matrix gl_ProjectionMatrix\n" \
"#define cogl_texture_matrix gl_TextureMatrix\n" \
#define _COGL_FRAGMENT_SHADER_BOILERPLATE \
_COGL_COMMON_SHADER_BOILERPLATE \
"#define cogl_color_in gl_Color\n" \
"#define cogl_tex_coord_in gl_TexCoord\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
#else /* HAVE_COGL_GLES2 */
#define _COGL_VERTEX_SHADER_BOILERPLATE \
_COGL_COMMON_SHADER_BOILERPLATE \
"#define cogl_color_out _cogl_color\n" \
"#define cogl_point_coord_out _cogl_point_coord\n" \
"#define cogl_tex_coord_out _cogl_tex_coord\n"
#define _COGL_FRAGMENT_SHADER_BOILERPLATE \
_COGL_COMMON_SHADER_BOILERPLATE \
"#if __VERSION__ == 100\n" \
"precision highp float;\n" \
"#endif\n" \
"\n" \
"varying vec4 _cogl_color;\n" \
"varying vec4 _cogl_tex_coord[];\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"
#endif /* HAVE_COGL_GLES2 */
#endif /* __COGL_SHADER_BOILERPLATE_H */