[vlc-devel] [PATCH 04/13] opengl: use main shader for direct samplers

[Romain Vimont]

A sampler may receive their input picture either:
 - from an interop, uploading a picture_t
 - from a previous filter, giving an OpenGL texture directly (a "direct"
   sampler)

The fragment shader for a "direct" sampler was straightforward: the
input was always an RGBA texture. On the contrary, samplers from interop
always applied chroma conversion to expose individual pixels in RGBA.

However, deinterlace filters operate on individual input planes, so
the chroma conversion must be applied afterwards.

To prepare support for this feature, use the same fragment shader code
generation for both types of samplers.
---
 modules/video_output/opengl/sampler.c | 49 +++++----------------------
 1 file changed, 8 insertions(+), 41 deletions(-)

diff --git a/modules/video_output/opengl/sampler.c b/modules/video_output/opengl/sampler.c
index 1ba8440174..af3b2bddf3 100644
--- a/modules/video_output/opengl/sampler.c
+++ b/modules/video_output/opengl/sampler.c
@@ -1052,31 +1052,6 @@ vlc_gl_sampler_NewFromInterop(struct vlc_gl_interop *interop)
     return sampler;
 }
 
-
-static void
-sampler_direct_fetch_locations(struct vlc_gl_sampler *sampler, GLuint program)
-{
-    struct vlc_gl_sampler_priv *priv = PRIV(sampler);
-    const opengl_vtable_t *vt = priv->vt;
-
-    priv->uloc.Textures[0] =
-        vt->GetUniformLocation(program, "vlc_input_texture");
-    assert(priv->uloc.Textures[0] != -1);
-}
-
-static void
-sampler_direct_load(const struct vlc_gl_sampler *sampler)
-{
-    struct vlc_gl_sampler_priv *priv = PRIV(sampler);
-    const opengl_vtable_t *vt = priv->vt;
-
-    GLuint texture = priv->textures[0];
-
-    vt->ActiveTexture(GL_TEXTURE0);
-    vt->BindTexture(GL_TEXTURE_2D, texture);
-    vt->Uniform1i(priv->uloc.Textures[0], 0);
-}
-
 struct vlc_gl_sampler *
 vlc_gl_sampler_NewFromTexture2D(struct vlc_gl_t *gl,
                                 const struct vlc_gl_api *api,
@@ -1097,27 +1072,19 @@ vlc_gl_sampler_NewFromTexture2D(struct vlc_gl_t *gl,
     /* this is the only allocated field, and we don't need it */
     sampler->fmt.p_palette = NULL;
 
-    static const char *const SHADER_BODY =
-        "uniform sampler2D vlc_input_texture;\n"
-        "vec4 vlc_texture(vec2 pic_coords) {\n"
-        "  return texture2D(vlc_input_texture, pic_coords);\n"
-        "}\n";
+    sampler->shader.extensions = NULL;
+    sampler->shader.body = NULL;
 
-    sampler->shader.body = strdup(SHADER_BODY);
-    if (!sampler->shader.body)
+    int ret =
+        opengl_fragment_shader_init(sampler, GL_TEXTURE_2D, &priv->direct_fmt);
+    if (ret != VLC_SUCCESS)
     {
-        free(priv);
+        free(sampler);
         return NULL;
     }
 
-    /* No extension required */
-    sampler->shader.extensions = NULL;
-
-    static const struct vlc_gl_sampler_ops ops = {
-        .fetch_locations = sampler_direct_fetch_locations,
-        .load = sampler_direct_load,
-    };
-    sampler->ops = &ops;
+    memcpy(&priv->var.TexCoordsMaps[0], MATRIX3_IDENTITY,
+           sizeof(MATRIX3_IDENTITY));
 
     return sampler;
 }
-- 
2.30.1