vo_opengl: dynamically manage texture units

A minor cleanup that makes the code simpler, and guarantees that we
cleanup the GL state properly at any point.

We do this by reusing the uniform caching, and assigning each sampler
uniform its own texture unit by incrementing a counter. This has various
subtle consequences for the GL driver, which hopefully don't matter. For
example, it will bind fewer textures at a time, but also rebind them
more often.

For some reason we keep TEXUNIT_VIDEO_NUM, because it limits the number
of hook passes that can be bound at the same time.

OSD rendering is an exception: we do many passes with the same shader,
and rebinding the texture each pass. For now, this is handled in an
unclean way, and we make the shader cache reserve texture unit 0 for the
OSD texture. At a later point, we should allocate that one dynamically
too, and just pass the texture unit to the OSD rendering code. Right now
I feel like vo_rpi.c (may it rot in hell) is in the way.

1 files changed, 7 insertions, 16 deletions

diff --git a/video/out/opengl/video.c b/video/out/opengl/video.c
index b000b2e7ce..4121ff785c 100644
--- a/video/out/opengl/video.c
+++ b/video/out/opengl/video.c
@@ -673,7 +673,6 @@ static bool gl_video_get_lut3d(struct gl_video *p, enum mp_csp_prim prim,
     if (!p->lut_3d_texture)
         gl->GenTextures(1, &p->lut_3d_texture);
 
-    gl->ActiveTexture(GL_TEXTURE0 + TEXUNIT_3DLUT);
     gl->BindTexture(GL_TEXTURE_3D, p->lut_3d_texture);
     gl->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
     gl->TexImage3D(GL_TEXTURE_3D, 0, GL_RGB16, lut3d->size[0], lut3d->size[1],
@@ -684,7 +683,7 @@ static bool gl_video_get_lut3d(struct gl_video *p, enum mp_csp_prim prim,
     gl->TexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     gl->TexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
     gl->TexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
-    gl->ActiveTexture(GL_TEXTURE0);
+    gl->BindTexture(GL_TEXTURE_3D, 0);
 
     debug_check_gl(p, "after 3d lut creation");
 
@@ -946,7 +945,6 @@ static void uninit_video(struct gl_video *p)
 
 static void pass_prepare_src_tex(struct gl_video *p)
 {
-    GL *gl = p->gl;
     struct gl_shader_cache *sc = p->sc;
 
     for (int n = 0; n < p->pass_tex_num; n++) {
@@ -964,9 +962,9 @@ static void pass_prepare_src_tex(struct gl_video *p)
         snprintf(pixel_size, sizeof(pixel_size), "pixel_size%d", n);
 
         if (s->use_integer) {
-            gl_sc_uniform_sampler_ui(sc, texture_name, n);
+            gl_sc_uniform_tex_ui(sc, texture_name, s->gl_tex);
         } else {
-            gl_sc_uniform_sampler(sc, texture_name, s->gl_target, n);
+            gl_sc_uniform_tex(sc, texture_name, s->gl_target, s->gl_tex);
         }
         float f[2] = {1, 1};
         if (s->gl_target != GL_TEXTURE_RECTANGLE) {
@@ -977,11 +975,7 @@ static void pass_prepare_src_tex(struct gl_video *p)
         gl_sc_uniform_mat2(sc, texture_rot, true, (float *)s->transform.m);
         gl_sc_uniform_vec2(sc, pixel_size, (GLfloat[]){1.0f / f[0],
                                                        1.0f / f[1]});
-
-        gl->ActiveTexture(GL_TEXTURE0 + n);
-        gl->BindTexture(s->gl_target, s->gl_tex);
     }
-    gl->ActiveTexture(GL_TEXTURE0);
 }
 
 static void render_pass_quad(struct gl_video *p, int vp_w, int vp_h,
@@ -1401,8 +1395,6 @@ static void reinit_scaler(struct gl_video *p, struct scaler *scaler,
     const struct gl_format *fmt = gl_find_float16_format(gl, elems_per_pixel);
     GLenum target = scaler->gl_target;
 
-    gl->ActiveTexture(GL_TEXTURE0 + TEXUNIT_SCALERS + scaler->index);
-
     if (!scaler->gl_lut)
         gl->GenTextures(1, &scaler->gl_lut);
 
@@ -1429,7 +1421,7 @@ static void reinit_scaler(struct gl_video *p, struct scaler *scaler,
     if (target != GL_TEXTURE_1D)
         gl->TexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 
-    gl->ActiveTexture(GL_TEXTURE0);
+    gl->BindTexture(target, 0);
 
     debug_check_gl(p, "after initializing scaler");
 }
@@ -2184,7 +2176,7 @@ static void pass_colormanage(struct gl_video *p, struct mp_colorspace src, bool
                    p->opts.tone_mapping_param);
 
     if (p->use_lut_3d) {
-        gl_sc_uniform_sampler(p->sc, "lut_3d", GL_TEXTURE_3D, TEXUNIT_3DLUT);
+        gl_sc_uniform_tex(p->sc, "lut_3d", GL_TEXTURE_3D, p->lut_3d_texture);
         GLSL(vec3 cpos;)
         for (int i = 0; i < 3; i++)
             GLSLF("cpos[%d] = LUT_POS(color[%d], %d.0);\n", i, i, p->lut_3d_size[i]);
@@ -2250,7 +2242,6 @@ static void pass_dither(struct gl_video *p)
 
         p->dither_size = tex_size;
 
-        gl->ActiveTexture(GL_TEXTURE0 + TEXUNIT_DITHER);
         gl->GenTextures(1, &p->dither_texture);
         gl->BindTexture(GL_TEXTURE_2D, p->dither_texture);
         gl->PixelStorei(GL_UNPACK_ALIGNMENT, 1);
@@ -2261,7 +2252,7 @@ static void pass_dither(struct gl_video *p)
         gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
         gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
         gl->PixelStorei(GL_UNPACK_ALIGNMENT, 4);
-        gl->ActiveTexture(GL_TEXTURE0);
+        gl->BindTexture(GL_TEXTURE_2D, 0);
 
         debug_check_gl(p, "dither setup");
     }
@@ -2274,7 +2265,7 @@ static void pass_dither(struct gl_video *p)
     // dither patterns can be visible.
     int dither_quantization = (1 << dst_depth) - 1;
 
-    gl_sc_uniform_sampler(p->sc, "dither", GL_TEXTURE_2D, TEXUNIT_DITHER);
+    gl_sc_uniform_tex(p->sc, "dither", GL_TEXTURE_2D, p->dither_texture);
 
     GLSLF("vec2 dither_pos = gl_FragCoord.xy / %d.0;\n", p->dither_size);