vo_gpu: add namespace query mechanism

Backported from @haasn's change to libplacebo. More flexible than the
previous "shared || non-shared" distinction. The extra flexibility is
needed for Direct3D 11, but it also doesn't hurt code-wise.

video/out/gpu/ra.h

@@ -50,8 +50,7 @@ enum {
     RA_CAP_BUF_RO         = 1 << 5, // supports RA_VARTYPE_BUF_RO
     RA_CAP_BUF_RW         = 1 << 6, // supports RA_VARTYPE_BUF_RW
     RA_CAP_NESTED_ARRAY   = 1 << 7, // supports nested arrays
-    RA_CAP_SHARED_BINDING = 1 << 8, // sampler/image/buffer namespaces are disjoint
-    RA_CAP_GLOBAL_UNIFORM = 1 << 9, // supports using "naked" uniforms (not UBO)
+    RA_CAP_GLOBAL_UNIFORM = 1 << 8, // supports using "naked" uniforms (not UBO)
 };
 
 enum ra_ctype {
@@ -206,8 +205,8 @@ struct ra_renderpass_input {
     // RA_VARTYPE_IMG_W: image unit
     // RA_VARTYPE_BUF_* buffer binding point
     // Other uniforms: unused
-    // If RA_CAP_SHARED_BINDING is set, these may only be unique per input type.
-    // Otherwise, these must be unique for all input values.
+    // Bindings must be unique within each namespace, as specified by
+    // desc_namespace()
     int binding;
 };
 
@@ -396,6 +395,11 @@ struct ra_fns {
     // but must be implemented if ra.max_pushc_size > 0.
     struct ra_layout (*push_constant_layout)(struct ra_renderpass_input *inp);
 
+    // Returns an abstract namespace index for a given renderpass input type.
+    // This will always be a value >= 0 and < RA_VARTYPE_COUNT. This is used to
+    // figure out which inputs may share the same value of `binding`.
+    int (*desc_namespace)(enum ra_vartype type);
+
     // Clear the dst with the given color (rgba) and within the given scissor.
     // dst must have dst->params.render_dst==true. Content outside of the
     // scissor is preserved.

video/out/gpu/shader_cache.c

@@ -254,11 +254,7 @@ static struct sc_uniform *find_uniform(struct gl_shader_cache *sc,
 
 static int gl_sc_next_binding(struct gl_shader_cache *sc, enum ra_vartype type)
 {
-    if (sc->ra->caps & RA_CAP_SHARED_BINDING) {
-        return sc->next_binding[type]++;
-    } else {
-        return sc->next_binding[0]++;
-    }
+    return sc->next_binding[sc->ra->fns->desc_namespace(type)]++;
 }
 
 void gl_sc_uniform_dynamic(struct gl_shader_cache *sc)

video/out/opengl/ra_gl.c

@@ -96,7 +96,6 @@ static int ra_init_gl(struct ra *ra, GL *gl)
 
     static const int caps_map[][2] = {
         {RA_CAP_DIRECT_UPLOAD,      0},
-        {RA_CAP_SHARED_BINDING,     0},
         {RA_CAP_GLOBAL_UNIFORM,     0},
         {RA_CAP_TEX_1D,             MPGL_CAP_1D_TEX},
         {RA_CAP_TEX_3D,             MPGL_CAP_3D_TEX},
@@ -653,6 +652,11 @@ static void gl_blit(struct ra *ra, struct ra_tex *dst, struct ra_tex *src,
     gl->BindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 }
 
+static int gl_desc_namespace(enum ra_vartype type)
+{
+    return type;
+}
+
 static void gl_renderpass_destroy(struct ra *ra, struct ra_renderpass *pass)
 {
     GL *gl = ra_gl_get(ra);
@@ -1122,6 +1126,7 @@ static struct ra_fns ra_fns_gl = {
     .clear                  = gl_clear,
     .blit                   = gl_blit,
     .uniform_layout         = std140_layout,
+    .desc_namespace         = gl_desc_namespace,
     .renderpass_create      = gl_renderpass_create,
     .renderpass_destroy     = gl_renderpass_destroy,
     .renderpass_run         = gl_renderpass_run,

video/out/vulkan/ra_vk.c

@@ -1585,6 +1585,11 @@ static void vk_clear(struct ra *ra, struct ra_tex *tex, float color[4],
     }
 }
 
+static int vk_desc_namespace(enum ra_vartype type)
+{
+    return 0;
+}
+
 #define VK_QUERY_POOL_SIZE (MPVK_MAX_STREAMING_DEPTH * 4)
 
 struct vk_timer {
@@ -1688,6 +1693,7 @@ static struct ra_fns ra_fns_vk = {
     .blit                   = vk_blit,
     .uniform_layout         = std140_layout,
     .push_constant_layout   = std430_layout,
+    .desc_namespace         = vk_desc_namespace,
     .renderpass_create      = vk_renderpass_create,
     .renderpass_destroy     = vk_renderpass_destroy_lazy,
     .renderpass_run         = vk_renderpass_run,