re: the splashes have NO post-process -- one pass, source-over, alpha in the vertex stream

Play-test finding 4 asked, in order: is there a pass, what is it, where do
its parameters come from, only then what curve. All four, from GPU state.

1. NO post-process pass. Over all 1 048 draws of frames 4..226 (both boot
   splashes): rt0=[tile=0 fmt=0 exp=0] on 1048/1048, pitch=1280 msaa=0 on
   1048/1048, edram_mode only ever kColorDepth or kCopy, resolve dests only
   the two alternating front buffers, and NO texture base anywhere in the
   capture equals a resolve destination. The only texture bound in the whole
   splash region is the sprite page 0x11A50000. No blur, no bloom, no fade
   quad over a resolved image, no tone curve, no resolve-and-resample.

2. What it is: per frame, a full-screen replace triangle (the clear), a
   full-screen black quad through the ordinary blend, ONE batched sprite
   draw carrying every visible element (indices 4/8/12/24), and the two
   presentation resolves.

3. Where the parameters come from: NOT the constant banks -- the splash
   pixel shaders read zero float constants, ps_c[n=0] on 1048/1048, taken
   off each shader's own float_bitmap. NOT immediates. The fade is the
   per-vertex k_8_8_8_8 colour in a vertex buffer the guest rewrites every
   frame.

4. The curve falls out of 3 and is the corpus's existing 34/frame law,
   reproduced on an independent capture. Not claimed as new.

And the composite is ORDINARY SOURCE-OVER, confirmed from the shader ucode
rather than inferred from the blend register: the register reads
ONE/ONE_MINUS_SRC_ALPHA, which looks premultiplied, and is -- because the
shader premultiplies. The two together are src*A + dst*(1-A). So the 'more
pronounced' fade is neither a blend difference nor a pass.

The likely mechanism instead: the developer splash submits SIX quads, three
logos plus three slightly-larger companions that lead them by 8 frames and
are gone 79 frames early. Two over-blended copies of the same art at
different scale is a halo, on screen only during the entry.

Refutation attempt, recorded: REFUTED.md's re-opened rest() pair states its
settling condition as 'a draw capture of the developer splash naming which
of the three glows is submitted at rest'. This is that capture. All three
companions ARE submitted in all 21 frames -- so no rule that hides one
describes this stream -- but they are NOT interchangeable: Q6 leaves the
plateau on its own -5.6/frame decay while Q4 and Q5 hold 255. The one-byte
sibling difference is drawn.

Trap recorded with the evidence: censusing the whole 600-frame log finds six
640x360 textures sampled ~330 times each, which reads exactly like a
half-resolution blur chain. They are the attract movie's chroma planes and
first appear at frame 234, after both splashes. Restricting the window is
what separates them.

Evidence: docs/re/data/splash-draw-pass-census.txt,
docs/re/data/splash-quad-timeline.txt, docs/re/data/shaders/*.ucode.frag.
Logger: canary sylpheed-re d90d14e02.

docs/re/data/shaders/shader_2E372EA28CC404B7.ucode.frag

@@ -0,0 +1,3 @@
+/*    0.0 */       alloc colors
+/*    0.1 */       exece
+/*    1   */          max oC0, r0, r0

docs/re/data/shaders/shader_5773DC18083C4C20.ucode.frag

@@ -0,0 +1,4 @@
+/*    0.0 */       alloc colors
+/*    0.1 */       exece
+/*    1   */          mul oC0.xyz_, r0.xyzz, r0.wwww
+              +       maxs oC0.___w, r0.ww

docs/re/data/shaders/shader_E59B2B3DA4AA9008.ucode.frag

@@ -0,0 +1,9 @@
+/*    0.0 */       exec
+/*    2   */          tfetch2D r2, r1.xy, tf0
+/*    0.1 */       alloc colors
+/*    1.0 */       exece
+/*    3   */          mul r1.___w, r2.wwww, r0.wwww
+/*    4   */          mul r0.xyz_, r2.xyzz, r0.xyzz
+/*    5   */          mul r1.xyz_, r0.xyzz, r1.wwww
+/*    6   */          max oC0, r1, r1
+/*    1.1 */       cnop