Rendering pipeline¶

This page summarizes the primary render paths in crimsonland.exe.

Render dispatcher (FUN_00406af0)¶

If render_pass_mode (DAT_00487240) == 0 and game_state_id (DAT_00487270) != 5, it draws terrain only via terrain_render (FUN_004188a0).
Otherwise it runs the full gameplay render pass gameplay_render_world (FUN_00405960).
After either branch it applies a fullscreen fade (DAT_00487264), runs ui_elements_update_and_render, calls perk_prompt_update_and_render (FUN_00403550) (perk prompt), and renders the UI cursor.

Gameplay render pass (gameplay_render_world / FUN_00405960)¶

Order of major passes:

1) fx_queue_render (FUN_00427920) 2) terrain_render (FUN_004188a0) (terrain/backbuffer blit) 3) player_render_overlays (FUN_00428390) for players with player_health (DAT_004908d4) <= 0

4) creature_render_all (FUN_00419680) 5) player_render_overlays for players with player_health (DAT_004908d4) > 0 6) projectile_render (FUN_00422c70) 7) bonus_render (FUN_004295f0) 8) grim_draw_fullscreen_color fade when DAT_00487264 > 0

Notes:

DAT_004aaf0c is used as the player index during the two overlay passes.
ui_transition_alpha (DAT_00487278) is the frame alpha used by multiple render paths.
projectile_render binds both projectile_texture (0x0048f7d4) and projectile_bullet_texture (0x0049bb30, bullet_i) for distinct projectile sprite passes.
gameplay_transition_latch (0x00487241) is set on gameplay/Typ-o gameplay state entry and cleared when the HUD transition timeline reaches 1.0; while set, gameplay_render_world avoids forcing ui_transition_alpha to 1.0 in branch paths that normally suppress transition fades.
player_overlay_suppressed_latch (0x0048727c) is an additional hard gate for player_render_overlays during highscore-return/result-flow transitions.

HUD render (ui_render_hud / FUN_0041aed0)¶

The in-game HUD render is gated by demo_mode_active (DAT_0048700d) and is called from the main UI pass (hud_update_and_render). It binds ui_wicons and uses grim_set_sub_rect for weapon icons, along with health/score overlays.

hud_update_and_render sets explicit per-mode HUD gates before rendering:

hud_show_health_panel
hud_show_weapon_panel
hud_show_xp_panel
hud_show_quest_panel
hud_show_timer_panel

Shared tint vectors¶

Several UI/HUD paths use a shared global RGBA vector passed to grim_set_color_ptr:

render_tint_color_r/g/b/a (0x004965f8..0x00496604)
Alpha (render_tint_color_a) is animated in loading, HUD, game-over, and quest-results paths while RGB stays white.

High-score card divider rendering uses a second RGBA block:

highscore_card_divider_color_r/g/b/a (0x004ccca8..0x004cccb4)
Seeded from the shared tint vector with a dimmed alpha in ui_text_input_render, then consumed by highscore_card_draw_horizontal_divider and highscore_card_draw_vertical_divider.

Terrain generation (terrain_generate / FUN_00417b80)¶

terrain_generate renders the terrain texture into a render target and selects its base texture index from a per-level descriptor.

For the full pipeline (init, procedural stamping, FX decal baking, and final screen draw), see Terrain pipeline.

Runtime evidence (2026-01-20)¶

terrain_trace.jsonl confirms the render path uses config-sized UVs over a 1024×1024 terrain texture:

u0 = -camera_offset_x / terrain_texture_width
v0 = -camera_offset_y / terrain_texture_height
u1 = u0 + (config_screen_width / terrain_texture_width)
v1 = v0 + (config_screen_height / terrain_texture_height)

Example capture (800×600 config, 1024×1024 terrain): u0=0.21875, u1=1.0, v0≈0.2228192, v1≈0.8087567 (deltas match 800/1024 and 600/1024). This matches the decompile and shows camera clamping to the terrain edges.

The same trace confirms quest terrain indices: base/overlay/detail = (0,1,0), (2,3,2), (4,5,4), (6,7,6) for tiers 1–4, matching the quest metadata and terrain_ids_for logic.

UI overlays¶

player_render_overlays draws per-player indicators (aim reticles, shields, weapon indicators). It is gated by game_state_id (DAT_00487270) values (not drawn in modal states like 0x14/0x16), ui_transition_alpha (DAT_00487278) (transition alpha), and player_overlay_suppressed_latch (0x0048727c).

The same function also checks player_overlay_auto_target_line_perk_id (0x004c2bcc) via perk_count_get before drawing the segmented auto-target line overlay toward the current player_state.auto_target. In perk_metadata_init, this selector defaults to 0.

Runtime evidence (2026-01-26)¶

artifacts/frida/share/player_sprite_trace.jsonl (scripts/frida/player_sprite_trace.js, summarized in analysis/frida/player_sprite_trace_summary.json) matches the decompile:

Alive (player_state_table.health > 0): draws two sprite layers (UV frames 0..14 and +0x10) with a shadow/outline pass (scaled ~1.02/1.03 and offset) before the main pass; rotations come from heading vs aim_heading.
Dead: draws a single sprite layer indexed by ftol(death_timer) (observed monotonic 32..52 then hold at 52 / 0x34 fallback), also with shadow+main passes.

Player sprite UV tables (2026-01-26)¶

player_render_overlays uses two UV tables for the trooper sprite:

Legs: effect_uv8 (8×8 atlas grid, frames 0–14, empty 15)
Torso: player_overlay_torso_uv8, which is effect_uv8 + 16 (frames 16–30, empty 31)

This table is not filled separately; it aliases into effect_uv8, which is populated by effect_uv_tables_init (FUN_0041fed0), called during game_startup_init_prelude (FUN_0042b090).

Runtime trace (artifacts/frida/share/player_sprite_trace.jsonl) shows paired draw calls with indices (0,16) … (14,30), and the trooper atlas (game/trooper.png) has fully empty frames at 15 and 31, matching the decompile and the observed render order.

Recoil / muzzle-flash kick (2026-01-26)¶

Recoil is driven by player_state.muzzle_flash_alpha:

Decay: muzzle_flash_alpha = max(0, muzzle_flash_alpha - 2 * frame_dt) (applied in both player_update and player_fire_weapon).
On fire: muzzle_flash_alpha += weapon_table[weapon_id].spread_heat, then clamped (<= 1.0 immediately, and <= 0.8 at the end of player_fire_weapon).

TODO (runtime): confirm the effective decay rate and update order. The decompile shows the same decay expression in both player_update and player_fire_weapon; depending on call order and early returns, the value may decay once or twice per frame.

During player_render_overlays, the torso quad is offset by a recoil vector computed from aim heading:

dir = (cos(aim_heading + π/2), sin(aim_heading + π/2))
offset = dir * (muzzle_flash_alpha * 12.0)
the torso quad is drawn at (camera + pos - size/2) + offset

The recoil pass uses player_overlay_torso_uv8 and rotates by aim_heading. The shadow/highlight pass draws a slightly larger quad (size * 1.03) and shifts it by (+1, +1).