- FMV: 24-bit frames AND streamed 15-bit MDEC video (Tomba plays its
movies 15-bit; depth24 alone missed them — user-reported) present
pinned to native 4:3. Detector = colour MDEC decode within the last
30 vblanks (mdec_recently_active); texture-decompression luma
decodes do not stamp. Both GL present paths take force_4_3; SW path
centers a 4:3 dst rect. User-verified on the intro movies.
- Menu garble: full-2D screens (no tagged prims in flight for 2
frames) now squash lines, polylines, flat rects and mono sprites
too — dialog borders are drawn with these and stuck out past the
squashed SPRT boxes. Full-width TILEs (fades) stay exempt; in-game
non-textured prims stay untouched (may be world-anchored).
- HUD positioning: in-game untagged SPRTs pivot by thirds — outer-
third elements anchor to their screen edge (16:9 corner position,
native proportions), middle third to centre. Full-2D screens keep
the single centre pivot so composites stay coherent.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Adds the DuckStation-style widescreen hack as a config option,
implemented in the runtime (no regen needed):
- gte.cpp: gte_set_display_aspect(num, den). RTPS/RTPT scale the
IR1*h/sz screen-X term by (4*den)/(3*num) around the game's own
OFX projection centre (identity at 4:3). Games cull against the
SXY values they read back from us, so post-projection screen-
bounds culls stay aligned with the visible frame.
- present: GL letterbox_rect generalised to the configured aspect
(gl_renderer_set_display_aspect); SDL_Renderer path gets an
aspect-derived logical size + dst rect. Window opens at the
configured aspect (clamp_window_4x3 -> clamp_window_aspect).
- config: [video] aspect_ratio = W:H (4:3 default, 16:9, up
to 32:9) in game.toml, settings.toml (load+save), launcher seed.
World geometry keeps correct proportions on the stretched present;
screen-space 2D (HUD, FMV, sprite quad widths) stretches — the
known limitation of the squash tier. EXPERIMENTAL.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Full rewrite of the GL backend around a single authoritative hr VRAM FBO
(RGBA8 + stencil mask-bit mirror, internal scale from [video]
supersampling): GPU fills/copies/draws rasterize into it, CPU uploads
batch through a pending-rect quad blit, a PACK pass re-encodes dirty
regions into the native R16UI raw mirror for texture sampling and
readback, and gpu.c routes GPUREAD/mask-check/peek reads through the
facade so the CPU array syncs before any CPU-side read.
Texture sampling adopts the Beetle-PSX model (structure only, studied
from beetle-psx-libretro):
- Per-primitive uv sampling bounds, clamped in the fragment shader when
no texture window is active. Filtered neighbours and S>1 interpolation
overshoot can never read outside the prim's own texture rect. Bounds
back off the exclusive max edge for axis-aligned (2D) uv mappings and
widen to the full page when the uv range crosses a 256 wrap boundary.
- Bilinear takes the NEAREST texel as base (cutout + STP authority),
neighbours toward the sub-texel offset, with per-texel opacity weights
and renormalised colour. The old "-0.5 then floor" base sampled one
texel OUTSIDE the prim on top/left edges; where that neighbour was
empty VRAM (e.g. tiled menu backgrounds with u0=0) the whole edge
column/row discarded — the vertical line on Tomba's title and the
cross seams on the memory-card screens.
The software renderer's bilinear gets the same reformulation so GL and
SW render filtered output identically; the SW nearest path (shipping
default) is untouched.
Also: always-on coherency event ring (flushes, fills, copies, draw
bboxes, packs, readbacks, presents, probe perturbations, with rects +
frame numbers) queryable via the debug server, and gl_vram_diff now
forces a full pack so it reads FBO truth even where the raw-mirror
invariant is broken.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Move the remaining 2D primitives (flat/textured rects, fill, lines) onto
the GPU, and present directly from the FBO color texture cropped to the
display region instead of reading the whole 1 MB FBO back to CPU VRAM
every frame.
Why both at once: the native present read the `vram` array directly and
relied on an incidental software op each frame (the HUD/sprites, drawn
last) to trigger the FBO->CPU sync. Moving every primitive to the GPU
removed that trigger, so a fully-GPU frame left `vram` stale -> black
present (the earlier FMV->black regression). The fix is to present from
the FBO when the GPU holds the freshest frame (gl_renderer_have_gpu_frame)
and to sync explicitly (gl_renderer_sync_cpu) on the software/24-bit path.
Result: the per-frame readback is gone for GPU scenes (the forest-lag
source), software/FMV frames keep the CPU present path (verified: the
MDEC intro renders correctly), and loads are faster.
KNOWN-FOLLOWUP cosmetic artifacts to clean up: the GPU textured shader
doesn't yet implement the texture window (wrap/mask), so tiled/wrapped
sprites show seams; bilinear texture_filtering isn't honored on the GPU
path; and the debug screenshot still reads CPU VRAM (stale under the
FBO-present path) so captures can lag the on-screen image.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The opengl backend now creates a genuine OpenGL context and presents through
it. Verified: Tomba boots and renders gameplay correctly via GL (context
"4.6.0 NVIDIA"), pixel-identical to software.
- gpu_gl_renderer.c: gl_renderer_init_context (SDL_GL context on a
SDL_WINDOW_OPENGL window), gl_renderer_present (upload ARGB image -> GL
texture -> full-screen quad -> SDL_GL_SwapWindow), present_blank, shutdown.
Legacy GL 1.x (immediate mode) so no GL loader needed yet (-lopengl32).
Backend vtable still delegates rasterization to sw_* this phase, so the GL
path is pixel-identical — this isolates/validates the context+present.
- main.cpp: window gains SDL_WINDOW_OPENGL when renderer=opengl; GL context
created with graceful fallback to the SDL_Renderer path on failure; present
+ disabled-frame + cleanup branch on g_gl_active. SW path untouched.
- runtime.cmake: link opengl32 (Win) / OpenGL::GL (other).
Phase 2b (next): move rasterization onto the GPU — VRAM as a GL texture/FBO,
modern-GL loader + shaders, primitives at internal resolution (the actual
scaling-without-perf-loss win).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Matthew Stanley