[vlc-devel] [PATCH] opengl: insert shader headers at compile time
Romain Vimont
rom1v at videolabs.io
Thu Jun 18 11:08:15 CEST 2020
On Thu, Jun 18, 2020 at 10:58:30AM +0200, Alexandre Janniaux wrote:
> Hi,
>
> We can reintroduce the field later when we add a correct
> support for this.
This is just the renderer, the renderer itself does not (currently)
require GLSL > 120. If in the future it needs another version, maybe we
will use a field, maybe not… or maybe the content requiring GLSL > 120
will be in a separate filter… I don't know.
For now, these fields are just an annoying useless indirection.
> But that's not what the commit message is conveying.
The commit message says that the fiels are not used anymore, and that
the version and precision header are inserted into the shader code
directly, which is what the commit does. :)
> Regards,
> --
> Alexandre Janniaux
> Videolabs
>
> On Thu, Jun 18, 2020 at 10:52:51AM +0200, Romain Vimont wrote:
> > On Thu, Jun 18, 2020 at 10:23:21AM +0200, Alexandre Janniaux wrote:
> > > Hi,
> > >
> > > It doesn't feel like a good idea, and goes against Haasn
> > > patches a few week ago.
> >
> > I think this change is independant of his patches.
> >
> > (We already discussed about this for commit
> > 2fdbd23f2806cdad15ca03e0b83de46e543f6b6c.)
> >
> > > Are there reasons to do so?
> >
> > Currently, the renderer initializes two fields (glsl_version and
> > glsl_precision_header) from constants, and inject their value into the
> > shader code (via asprintf).
> >
> > Using these struct fields is useless: it's simpler to just put the
> > constants in the string.
> >
> > Btw, the sub_renderer already does that. This change had also been
> > independently proposed by Marvin:
> > https://mailman.videolan.org/pipermail/vlc-devel/2020-March/132784.html
> >
> > >
> > > Regards,
> > > --
> > > Alexandre Janniaux
> > > Videolabs
> > >
> > > On Wed, Jun 17, 2020 at 09:33:11PM +0200, Romain Vimont wrote:
> > > > The version and precision header strings are different for OpenGL and
> > > > OpenGL ES.
> > > >
> > > > Insert them directly into the shader string literal, instead of
> > > > initializing renderer fields and inserting them at runtime.
> > > > ---
> > > > modules/video_output/opengl/renderer.c | 31 ++++++++++++++------------
> > > > modules/video_output/opengl/renderer.h | 6 -----
> > > > 2 files changed, 17 insertions(+), 20 deletions(-)
> > > >
> > > > diff --git a/modules/video_output/opengl/renderer.c b/modules/video_output/opengl/renderer.c
> > > > index 335ca27e4841..6f7d42ee7ab9 100644
> > > > --- a/modules/video_output/opengl/renderer.c
> > > > +++ b/modules/video_output/opengl/renderer.c
> > > > @@ -169,12 +169,23 @@ InitStereoMatrix(GLfloat matrix_out[static 3*3],
> > > > #undef ROW
> > > > }
> > > >
> > > > +/* https://en.wikipedia.org/wiki/OpenGL_Shading_Language#Versions */
> > > > +#ifdef USE_OPENGL_ES2
> > > > +# define SHADER_VERSION "#version 100\n"
> > > > + /* In OpenGL ES, the fragment language has no default precision qualifier for
> > > > + * floating point types. */
> > > > +# define FRAGMENT_SHADER_PRECISION "precision highp float;\n"
> > > > +#else
> > > > +# define SHADER_VERSION "#version 120\n"
> > > > +# define FRAGMENT_SHADER_PRECISION
> > > > +#endif
> > > > +
> > > > static char *
> > > > BuildVertexShader(const struct vlc_gl_renderer *renderer)
> > > > {
> > > > /* Basic vertex shader */
> > > > static const char *template =
> > > > - "#version %u\n"
> > > > + SHADER_VERSION
> > > > "attribute vec2 PicCoordsIn;\n"
> > > > "varying vec2 PicCoords;\n"
> > > > "attribute vec3 VertexPosition;\n"
> > > > @@ -188,8 +199,8 @@ BuildVertexShader(const struct vlc_gl_renderer *renderer)
> > > > " * vec4(VertexPosition, 1.0);\n"
> > > > "}";
> > > >
> > > > - char *code;
> > > > - if (asprintf(&code, template, renderer->glsl_version) < 0)
> > > > + char *code = strdup(template);
> > > > + if (!code)
> > > > return NULL;
> > > >
> > > > if (renderer->dump_shaders)
> > > > @@ -204,9 +215,9 @@ BuildFragmentShader(struct vlc_gl_renderer *renderer)
> > > > struct vlc_gl_sampler *sampler = renderer->sampler;
> > > >
> > > > static const char *template =
> > > > - "#version %u\n"
> > > > + SHADER_VERSION
> > > > "%s" /* extensions */
> > > > - "%s" /* precision header */
> > > > + FRAGMENT_SHADER_PRECISION
> > > > "%s" /* vlc_texture definition */
> > > > "varying vec2 PicCoords;\n"
> > > > "void main() {\n"
> > > > @@ -217,8 +228,7 @@ BuildFragmentShader(struct vlc_gl_renderer *renderer)
> > > > ? sampler->shader.extensions : "";
> > > >
> > > > char *code;
> > > > - int ret = asprintf(&code, template, renderer->glsl_version, extensions,
> > > > - renderer->glsl_precision_header, sampler->shader.body);
> > > > + int ret = asprintf(&code, template, extensions, sampler->shader.body);
> > > > if (ret < 0)
> > > > return NULL;
> > > >
> > > > @@ -328,13 +338,6 @@ vlc_gl_renderer_New(vlc_gl_t *gl, const struct vlc_gl_api *api,
> > > > renderer->api = api;
> > > > renderer->vt = vt;
> > > > renderer->dump_shaders = var_InheritInteger(gl, "verbose") >= 4;
> > > > -#if defined(USE_OPENGL_ES2)
> > > > - renderer->glsl_version = 100;
> > > > - renderer->glsl_precision_header = "precision highp float;\n";
> > > > -#else
> > > > - renderer->glsl_version = 120;
> > > > - renderer->glsl_precision_header = "";
> > > > -#endif
> > > >
> > > > int ret = opengl_link_program(renderer);
> > > > if (ret != VLC_SUCCESS)
> > > > diff --git a/modules/video_output/opengl/renderer.h b/modules/video_output/opengl/renderer.h
> > > > index 6f4029504fb2..7130cfb26263 100644
> > > > --- a/modules/video_output/opengl/renderer.h
> > > > +++ b/modules/video_output/opengl/renderer.h
> > > > @@ -50,12 +50,6 @@ struct vlc_gl_renderer
> > > > /* True to dump shaders */
> > > > bool dump_shaders;
> > > >
> > > > - /* GLSL version, set by the caller. 100 for GLSL ES, 120 for desktop GLSL */
> > > > - unsigned glsl_version;
> > > > - /* Precision header, set by the caller. In OpenGLES, the fragment language
> > > > - * has no default precision qualifier for floating point types. */
> > > > - const char *glsl_precision_header;
> > > > -
> > > > GLuint program_id;
> > > >
> > > > struct {
> > > > --
> > > > 2.27.0
> > > >
> > > > _______________________________________________
> > > > vlc-devel mailing list
> > > > To unsubscribe or modify your subscription options:
> > > > https://mailman.videolan.org/listinfo/vlc-devel
> > > _______________________________________________
> > > vlc-devel mailing list
> > > To unsubscribe or modify your subscription options:
> > > https://mailman.videolan.org/listinfo/vlc-devel
> > _______________________________________________
> > vlc-devel mailing list
> > To unsubscribe or modify your subscription options:
> > https://mailman.videolan.org/listinfo/vlc-devel
> _______________________________________________
> vlc-devel mailing list
> To unsubscribe or modify your subscription options:
> https://mailman.videolan.org/listinfo/vlc-devel
More information about the vlc-devel
mailing list