joeylib2/examples/spacetaxi/stRender.c
2026-09-17 17:46:47 -05:00

851 lines
33 KiB
C

// Space Taxi -- renderer: the simulation's screen RAM, colour RAM,
// charset and sprite frame onto the JoeyLib stage.
//
// The screen is 40x25 character cells painted from the live charset
// (the game edits glyphs at runtime: the transporter hatch, the title
// logo flip-book, the laser beams). A cell goes to the stage in one
// call: jlTilePasteGlyph takes the character's eight 1bpp charset rows
// as they stand and colours them from the cell's colour RAM, so an
// edited glyph needs no rebuild and a colour change costs nothing.
// Only the cells the simulation listed as dirty are
// repainted; a changed glyph dirties the cells showing it, found
// inside the cell range each character was last painted in. The eight
// VIC sprites are drawn from their bitmaps through a small cache of
// JoeyLib sprites keyed on (pointer, colour, multicolour mode), with
// save-under and LIFO restore. Sprite 0 has VIC priority, so the draw
// order is sprite 7 first, sprite 0 last, and a sprite that has not
// moved (and has nothing repainted under it) simply stays on the
// stage: only it and everything drawn after it are undrawn and redrawn
// when it changes.
//
// The title screen gets a special path (stRenderTitleLogo): its logo is
// 103 cells of one character that the flip-book animates by copying one
// of four frame glyphs over it, and a colour cycle that used to rewrite
// the colour of 407 cells. Both were pure repaint cost. Instead the four
// frames collapse into ONE tile whose pixels are drawn in reserved
// palette slots -- one slot per set of frames a pixel belongs to -- so a
// flip and a recolour are both a single palette write and no cell is
// ever repainted. The title's decoration sprites, which cycle colour
// with the logo, share one more reserved slot for the same reason.
#include <string.h>
#include "spacetaxi.h"
#include "stCels.h"
#define ST_SPRITE_TILES 3u
// The IIgs reaches its globals DBR-relative, so all of BSS must fit the
// entry bank below the I/O window; the caches are sized down there. The
// sprite cache must still hold every cel stRenderPrewarm builds (the
// cab, exhaust and passenger sets plus the intro star) or a cel change
// mid-play rebuilds and recompiles a sprite. Glyphs are direct-mapped
// by character, so the count is a power of two.
#if defined(__W65816__)
#define ST_SPRITE_CACHE 48u
#else
#define ST_SPRITE_CACHE 72u
#endif
#define ST_SPRITE_BACKUP_BYTES JOEY_SPRITE_BACKUP_BYTES(ST_SPRITE_TILES, ST_SPRITE_TILES)
#define ST_SPRITE_PX (8 * ST_SPRITE_TILES)
// Palette slots the title logo animation owns. The title screen draws
// in C64 colours 0, 1, 2, 6, 7, 11 and 12 only (plus colour 5 for the
// "GET READY" banner that appears over it), so these are free while it
// is up and the whole trick needs no per-scanline SCB band.
#define ST_PAL_LOGO_SPR 3u // the decoration sprites' cycling colour
#define ST_LOGO_PAL_SLOTS 7u
// The first hardware sprite that cycles colour with the logo.
#define ST_LOGO_SPR_FIRST 3u
// Where the startup message sits, and its C64 colour (1 = white).
#define ST_LOADING_ROW 12u
#define ST_LOADING_COLOR 1u
typedef struct {
jlSpriteT *sprite;
uint8_t ptr;
uint8_t color;
uint8_t multi;
uint8_t mc0;
uint8_t mc1;
uint8_t level; // level index the bitmap came from (level sprites)
bool used;
bool pinned; // prewarmed moving cel: never evicted (its
// compiled code is costly to re-emit on the 65816)
uint32_t lastUse; // for least-recently-used eviction
} StSpriteCacheT;
// What is drawn in a draw slot (slot 0 = sprite 7 ... slot 7 = sprite 0).
typedef struct {
bool drawn;
uint16_t x;
uint8_t y;
uint8_t ptr;
uint8_t color;
uint8_t multi;
} StDrawnT;
typedef struct {
jlSurfaceT *stage;
jlSurfaceT *scratch;
// Title logo (stRenderTitleLogo): all four flip-book frames in one
// tile, animated by rewriting logoSlotMask[]'s palette slots.
bool logoMode;
bool logoTileOk; // the live glyph is one of the frames
uint8_t logoSlotCount;
uint8_t logoSlotMask[ST_LOGO_PAL_SLOTS]; // frames each slot is lit in
uint8_t logoFrame; // frame the palette currently shows
uint8_t logoColor; // logo colour the palette currently shows
uint8_t logoSprColor; // decoration-sprite colour it shows
jlTileT logoTile;
// Cell range (inclusive) each character has been painted in since
// the last full repaint: where a changed glyph's cells can be.
uint16_t glyphFirst[ST_CHARSET_CHARS];
uint16_t glyphLast[ST_CHARSET_CHARS];
// Column band of the cells about to be repainted, per character row
// (min > max = the row is clean), the same shape as the library's
// own per-row dirty bands.
uint8_t dirtyColMin[ST_SCREEN_ROWS];
uint8_t dirtyColMax[ST_SCREEN_ROWS];
uint32_t cacheStamp;
StSpriteCacheT cache[ST_SPRITE_CACHE];
StSpriteCacheT *lastHit[ST_HW_SPRITES]; // the entry each hardware sprite used last
jlSpriteBackupT backup[ST_HW_SPRITES];
uint8_t backupMem[ST_HW_SPRITES][ST_SPRITE_BACKUP_BYTES] __attribute__((aligned(2)));
StDrawnT slot[ST_HW_SPRITES];
uint8_t lastPresentFrame;
} StRenderStateT;
static StRenderStateT gRender;
// Set across stRenderPrewarm so a cel built there is pinned in the cache.
static bool gPrewarming;
// The VIC-II palette in register order, $0RGB.
static const uint16_t kC64Palette[16] = {
0x0000, 0x0FFF, 0x0833, 0x06BB, 0x0839, 0x05A4, 0x0438, 0x0BC7,
0x0852, 0x0540, 0x0B66, 0x0555, 0x0777, 0x09E8, 0x076C, 0x09AA
};
// Palette slots the logo tile's pixels are drawn in, one per distinct
// set of flip-book frames a pixel belongs to. The four frames nest, so
// four of these are used; the rest are headroom if the frames change.
static const uint8_t kLogoPalSlot[ST_LOGO_PAL_SLOTS] = { 4u, 8u, 9u, 10u, 13u, 14u, 15u };
static void buildSpriteCel(const uint8_t *bm, uint8_t multi, uint8_t color, uint8_t mc0, uint8_t mc1);
static jlSpriteT *cachedSprite(StSimT *sim, uint8_t idx);
static uint8_t cellRow(uint16_t cell);
static void collectGlyphs(StSimT *sim);
static void dirtyBands(const StSimT *sim);
static bool dirtyUnderSprite(int16_t px, int16_t py);
static uint8_t drawColor(const StSimT *sim, uint8_t idx);
static void dropCache(void);
static bool loadPrecompiledCels(void);
static bool logoBuildTile(const StSimT *sim);
static uint8_t logoFrameIndex(const StSimT *sim);
static void logoPaletteApply(const StSimT *sim, uint8_t frame);
static void paintCells(jlSurfaceT *stage, StSimT *sim);
static void pasteCell(jlSurfaceT *stage, const StSimT *sim, uint16_t cell, uint8_t bx, uint8_t by);
static bool spriteOnScreen(int16_t px, int16_t py);
static void tileFromChunky(jlTileT *out, const uint8_t *chunky);
// Paint a VIC sprite bitmap onto the scratch surface's top-left 3x3
// tiles from the shared cel expansion (stCels.c, the same one the
// offline baker uses), so a cel built here for the interpreter fallback
// matches the precompiled .spc byte for byte.
static void buildSpriteCel(const uint8_t *bm, uint8_t multi, uint8_t color, uint8_t mc0, uint8_t mc1) {
uint8_t blob[ST_CEL_BYTES];
jlTileT tile;
uint8_t tx;
uint8_t ty;
stCelBlob(bm, multi, color, mc0, mc1, blob);
for (ty = 0u; ty < ST_SPRITE_TILES; ty++) {
for (tx = 0u; tx < ST_SPRITE_TILES; tx++) {
tileFromChunky(&tile, &blob[(ty * ST_SPRITE_TILES + tx) * TILE_BYTES]);
jlTilePaste(gRender.scratch, tx, ty, &tile);
}
}
}
// The JoeyLib sprite for hardware sprite `idx` of the current frame,
// built on first use from its VIC bitmap and colours.
static jlSpriteT *cachedSprite(StSimT *sim, uint8_t idx) {
uint8_t ptr = sim->frame.ptr[idx];
uint8_t color = drawColor(sim, idx);
uint8_t multi = (uint8_t)((sim->frame.multiMask >> idx) & 1u);
uint8_t mc0 = multi ? sim->spriteMc0 : 0u;
uint8_t mc1 = multi ? sim->spriteMc1 : 0u;
uint8_t level = (ptr < ST_SPRITE_PTR_FIRST && sim->level != 0) ? sim->level->levelIndex : 0xFFu;
StSpriteCacheT *slot = 0;
StSpriteCacheT *e = gRender.lastHit[idx];
uint8_t k;
gRender.cacheStamp++;
// Most frames a hardware sprite shows the cel it showed last time.
if (e != 0 && e->used && e->ptr == ptr && e->color == color && e->multi == multi && e->mc0 == mc0 && e->mc1 == mc1 && e->level == level) {
e->lastUse = gRender.cacheStamp;
return e->sprite;
}
for (k = 0u; k < ST_SPRITE_CACHE; k++) {
e = &gRender.cache[k];
if (e->used && e->ptr == ptr && e->color == color && e->multi == multi && e->mc0 == mc0 && e->mc1 == mc1 && e->level == level) {
e->lastUse = gRender.cacheStamp;
gRender.lastHit[idx] = e;
return e->sprite;
}
// Pinned entries (prewarmed cab/exhaust/passenger cels) are the
// costly-to-recompile ones and are never evicted; the least-
// recently-used unpinned slot is the victim, a free slot first.
if (e->pinned) {
continue;
}
if (slot == 0 || !e->used || (slot->used && e->lastUse < slot->lastUse)) {
slot = e;
}
}
if (slot == 0) {
// Every slot is pinned (never happens with the prewarm set sized
// below the cache): reuse the queried entry's own slot is unsafe,
// so fail into the interpreter path.
return 0;
}
if (slot->used) {
jlSpriteDestroy(slot->sprite);
slot->sprite = 0;
slot->used = false;
}
buildSpriteCel(stSimSpriteBitmap(sim, ptr), multi, color, mc0, mc1);
slot->sprite = jlSpriteCreateFromSurface(gRender.scratch, 0, 0, ST_SPRITE_TILES, ST_SPRITE_TILES);
if (slot->sprite == 0) {
return 0;
}
// Only the cab, exhaust and passenger move every tick; the codegen
// arena is theirs. Everything else stays interpreted (drawn seldom).
if (idx <= 2u) {
(void)jlSpriteCompile(slot->sprite);
}
slot->lastUse = gRender.cacheStamp;
slot->ptr = ptr;
slot->color = color;
slot->multi = multi;
slot->mc0 = mc0;
slot->mc1 = mc1;
slot->level = level;
slot->used = true;
slot->pinned = gPrewarming;
gRender.lastHit[idx] = slot;
return slot->sprite;
}
// Block row of a screen cell: cell / 40, read from the 125 distinct
// results of (cell >> 3) / 5. The old (x * 205) >> 10 identity avoided a
// division but still called the 65816's software multiply, and this runs
// twice for every repainted cell.
static const uint8_t kCellRow[125] = {
0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4,
4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 9,
9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12,
12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 16,
16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 19, 19, 19,
19, 19, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22,
23, 23, 23, 23, 23, 24, 24, 24, 24, 24
};
static uint8_t cellRow(uint16_t cell) {
return kCellRow[cell >> 3];
}
// A changed glyph (the hatch, the logo flip, the laser beams) makes
// every cell that shows it dirty. The simulation hands over a short list
// of the characters it edited, so nothing scans the charset; the cell
// search covers only the range the character was last painted in. The
// glyph itself needs no invalidation -- the paste reads the live charset
// every time.
static void collectGlyphs(StSimT *sim) {
uint8_t k;
uint16_t cell;
uint16_t last;
if (sim->charDirtyAll) {
sim->charDirtyAll = false;
sim->charDirtyCount = 0u;
return;
}
for (k = 0u; k < sim->charDirtyCount; k++) {
uint8_t ch = sim->charDirtyList[k];
if (sim->dirtyAll) {
continue;
}
last = gRender.glyphLast[ch];
for (cell = gRender.glyphFirst[ch]; cell <= last; cell++) {
if (sim->screen[cell] != ch || sim->cellDirty[cell] != 0u) {
continue;
}
sim->cellDirty[cell] = 1u;
if (sim->dirtyCount < (uint16_t)(sizeof(sim->dirtyList) / sizeof(sim->dirtyList[0]))) {
sim->dirtyList[sim->dirtyCount++] = cell;
} else {
sim->dirtyAll = true;
break;
}
}
}
sim->charDirtyCount = 0u;
}
// Note where the cells about to be repainted are, as one column band
// per character row. This used to be a single bounding box over every
// dirty cell, and that box was wildly too coarse: the status row's
// score and fare meters sit at opposite ends of the screen and one of
// them moves on nearly every tick, so the box spanned the picture and
// every sprite counted as sitting over repainted ground -- all eight
// were undrawn and redrawn on about a third of all frames while only
// the cab and its exhaust had actually moved. Per row the bands are
// tight, and the rows a sprite covers are the only ones it tests.
static void dirtyBands(const StSimT *sim) {
uint16_t k;
uint8_t row;
if (sim->dirtyAll) {
for (row = 0u; row < ST_SCREEN_ROWS; row++) {
gRender.dirtyColMin[row] = 0u;
gRender.dirtyColMax[row] = ST_SCREEN_COLS - 1u;
}
return;
}
// A plain loop, not memset: 25 entries do not pay for the 65816
// libc's far-called byte loop.
for (row = 0u; row < ST_SCREEN_ROWS; row++) {
gRender.dirtyColMin[row] = 0xFFu;
gRender.dirtyColMax[row] = 0u;
}
for (k = 0u; k < sim->dirtyCount; k++) {
uint16_t cell = sim->dirtyList[k];
uint8_t r = cellRow(cell);
uint8_t col = (uint8_t)(cell - ((uint16_t)r << 5) - ((uint16_t)r << 3));
if (col < gRender.dirtyColMin[r]) {
gRender.dirtyColMin[r] = col;
}
if (col > gRender.dirtyColMax[r]) {
gRender.dirtyColMax[r] = col;
}
}
}
// True when a cell about to be repainted lies under the sprite drawn at
// (px, py): its save-under backup would hold stale background, so it
// has to be undrawn before the repaint and drawn again after.
static bool dirtyUnderSprite(int16_t px, int16_t py) {
int16_t x1 = (int16_t)(px + ST_SPRITE_W);
int16_t y1 = (int16_t)(py + ST_SPRITE_PX);
uint8_t row;
uint8_t rowEnd;
uint8_t colFirst;
uint8_t colLast;
if (x1 > SURFACE_WIDTH) {
x1 = SURFACE_WIDTH;
}
if (y1 > SURFACE_HEIGHT) {
y1 = SURFACE_HEIGHT;
}
// spriteOnScreen has already rejected anything fully off the stage,
// so only the top/left overhang needs clamping to row/column 0.
row = (uint8_t)(py < 0 ? 0 : (py >> 3));
rowEnd = (uint8_t)((y1 - 1) >> 3);
colFirst = (uint8_t)(px < 0 ? 0 : (px >> 3));
colLast = (uint8_t)((x1 - 1) >> 3);
for (; row <= rowEnd; row++) {
if (gRender.dirtyColMin[row] <= colLast && gRender.dirtyColMax[row] >= colFirst) {
return true;
}
}
return false;
}
// The palette index a hardware sprite is drawn in. On the title screen
// sprites 3..7 all follow the logo's colour cycle, so they share one
// reserved slot: the cycle then recolours them with a palette write
// instead of rebuilding five cels, and -- because their drawn state
// stops changing -- without redrawing the sprites stacked above them.
static uint8_t drawColor(const StSimT *sim, uint8_t idx) {
if (gRender.logoMode && idx >= ST_LOGO_SPR_FIRST) {
return ST_PAL_LOGO_SPR;
}
return sim->frame.color[idx];
}
static void dropCache(void) {
uint8_t k;
for (k = 0u; k < ST_SPRITE_CACHE; k++) {
if (gRender.cache[k].used) {
jlSpriteDestroy(gRender.cache[k].sprite);
gRender.cache[k].sprite = 0;
gRender.cache[k].used = false;
}
}
}
// Collapse the four flip-book frame glyphs into one tile: every pixel
// is drawn in the reserved palette slot that stands for the set of
// frames it is set in (no frame = colour 0, the background). Animating
// the logo is then a palette write per flip instead of a repaint of
// every cell showing it. Returns false if the frames need more distinct
// sets than there are reserved slots, leaving the ordinary per-cell
// repaint to draw the flip book.
static bool logoBuildTile(const StSimT *sim) {
uint8_t slotOfMask[1u << ST_LOGO_FRAMES];
uint8_t chunky[TILE_BYTES];
uint8_t row;
uint8_t col;
memset(slotOfMask, 0, sizeof(slotOfMask));
gRender.logoSlotCount = 0u;
for (row = 0u; row < TILE_PIXELS_PER_SIDE; row++) {
uint8_t *out = &chunky[row * TILE_BYTES_PER_ROW];
for (col = 0u; col < TILE_PIXELS_PER_SIDE; col++) {
uint8_t mask = 0u;
uint8_t f;
uint8_t slot;
for (f = 0u; f < ST_LOGO_FRAMES; f++) {
if (((sim->charset[ST_LOGO_FRAME_FIRST + f][row] >> (7u - col)) & 1u) != 0u) {
mask |= (uint8_t)(1u << f);
}
}
if (mask != 0u && slotOfMask[mask] == 0u) {
if (gRender.logoSlotCount == ST_LOGO_PAL_SLOTS) {
return false;
}
slotOfMask[mask] = kLogoPalSlot[gRender.logoSlotCount];
gRender.logoSlotMask[gRender.logoSlotCount] = mask;
gRender.logoSlotCount++;
}
slot = slotOfMask[mask];
if ((col & 1u) == 0u) {
out[col >> 1] = (uint8_t)(slot << 4);
} else {
out[col >> 1] |= slot;
}
}
}
tileFromChunky(&gRender.logoTile, chunky);
return true;
}
// Which flip-book frame the live logo glyph holds, or ST_LOGO_FRAMES if
// it matches none of them (then the logo tile does not stand for what
// the simulation is showing and the cells must be repainted normally).
static uint8_t logoFrameIndex(const StSimT *sim) {
uint8_t f;
for (f = 0u; f < ST_LOGO_FRAMES; f++) {
if (memcmp(sim->charset[ST_LOGO_CHAR], sim->charset[ST_LOGO_FRAME_FIRST + f], 8u) == 0) {
return f;
}
}
return ST_LOGO_FRAMES;
}
// Show flip-book frame `frame` in the logo's current colour: every
// reserved slot lights up in the colour if that frame is in its set and
// goes to the background colour if it is not. The decoration sprites'
// slot follows their own colour, which the cycle sets one step behind
// the logo's (the title's sprite table overwrites it on entry).
static void logoPaletteApply(const StSimT *sim, uint8_t frame) {
uint16_t pal[SURFACE_COLORS_PER_PALETTE];
uint16_t on = kC64Palette[sim->logoColor & 15u];
uint16_t off = kC64Palette[sim->bgColor & 15u];
uint8_t k;
jlPaletteGet(gRender.stage, 0u, pal);
for (k = 0u; k < gRender.logoSlotCount; k++) {
pal[kLogoPalSlot[k]] = (((gRender.logoSlotMask[k] >> frame) & 1u) != 0u) ? on : off;
}
pal[ST_PAL_LOGO_SPR] = kC64Palette[sim->frame.color[ST_LOGO_SPR_FIRST] & 15u];
jlPaletteSet(gRender.stage, 0u, pal);
gRender.logoFrame = frame;
gRender.logoColor = sim->logoColor;
gRender.logoSprColor = sim->frame.color[ST_LOGO_SPR_FIRST];
}
// Repaint the dirty cells: the list, or everything after an overflow
// or a scene change (which also restarts the per-character cell ranges).
static void paintCells(jlSurfaceT *stage, StSimT *sim) {
uint16_t cell;
uint16_t k;
uint8_t bx;
uint8_t by;
if (sim->dirtyAll) {
memset(gRender.glyphFirst, 0xFF, sizeof(gRender.glyphFirst));
memset(gRender.glyphLast, 0, sizeof(gRender.glyphLast));
cell = 0u;
for (by = 0u; by < ST_SCREEN_ROWS; by++) {
for (bx = 0u; bx < ST_SCREEN_COLS; bx++) {
pasteCell(stage, sim, cell, bx, by);
cell++;
}
}
memset(sim->cellDirty, 0, ST_SCREEN_CELLS);
sim->dirtyCount = 0u;
sim->dirtyAll = false;
return;
}
for (k = 0u; k < sim->dirtyCount; k++) {
cell = sim->dirtyList[k];
by = cellRow(cell);
bx = (uint8_t)(cell - ((uint16_t)by << 5) - ((uint16_t)by << 3));
pasteCell(stage, sim, cell, bx, by);
sim->cellDirty[cell] = 0u;
}
sim->dirtyCount = 0u;
}
// Paint one cell: the character's charset rows coloured from colour RAM
// over the background. Also notes the cell in the character's range,
// which is where a changed glyph's cells are looked for.
static void pasteCell(jlSurfaceT *stage, const StSimT *sim, uint16_t cell, uint8_t bx, uint8_t by) {
uint8_t chr = sim->screen[cell];
if (cell < gRender.glyphFirst[chr]) {
gRender.glyphFirst[chr] = cell;
}
if (cell > gRender.glyphLast[chr]) {
gRender.glyphLast[chr] = cell;
}
// On the title the logo's cells carry all four flip-book frames at
// once; the palette decides which one shows, so they are pasted as
// they are and never touched again.
if (gRender.logoTileOk && chr == ST_LOGO_CHAR) {
jlTilePaste(stage, bx, by, &gRender.logoTile);
return;
}
jlTilePasteGlyph(stage, bx, by, sim->charset[chr], sim->color[cell], sim->bgColor);
}
static bool spriteOnScreen(int16_t px, int16_t py) {
return px < SURFACE_WIDTH && py < SURFACE_HEIGHT && px > -ST_SPRITE_W && py > -(int16_t)ST_SPRITE_PX;
}
// A chunky 8x8 tile (four bytes per row, high nibble = left pixel) as
// this port's jlTileT: a straight copy on the chunky ports, drawn and
// snapped through the scratch surface on the planar ones.
static void tileFromChunky(jlTileT *out, const uint8_t *chunky) {
#if defined(JOEYLIB_NATIVE_CHUNKY)
memcpy(out->pixels, chunky, TILE_BYTES);
#else
uint8_t row;
uint8_t k;
for (row = 0u; row < TILE_PIXELS_PER_SIDE; row++) {
for (k = 0u; k < TILE_BYTES_PER_ROW; k++) {
uint8_t b = chunky[row * TILE_BYTES_PER_ROW + k];
jlDrawPixel(gRender.scratch, (int16_t)(k * 2u), (int16_t)row, (uint8_t)(b >> 4));
jlDrawPixel(gRender.scratch, (int16_t)(k * 2u + 1u), (int16_t)row, (uint8_t)(b & 0x0Fu));
}
}
jlTileSnap(gRender.scratch, 0u, 0u, out);
#endif
}
// ---------------------------------------------------------------------------
// Public
// ---------------------------------------------------------------------------
void stRenderFrame(jlSurfaceT *stage, StSimT *sim) {
uint8_t first = ST_HW_SPRITES;
uint8_t k;
// Find the first draw slot whose sprite changed, vanished, or sits
// over cells about to be repainted; it and every later slot are
// undrawn (last first) and redrawn below, the rest stay put.
if (gRender.logoMode) {
// The flip book only ever swaps the logo glyph for one of the
// four frames the logo tile already carries: recolour the
// reserved slots and drop the glyph's repaint on the floor.
uint8_t frame = logoFrameIndex(sim);
gRender.logoTileOk = (frame < ST_LOGO_FRAMES);
if (gRender.logoTileOk) {
// The flip book only swapped in a frame the logo tile already
// carries, so drop the repaint it asked for.
if (sim->charDirtyCount == 1u && sim->charDirtyList[0] == ST_LOGO_CHAR) {
sim->charDirtyCount = 0u;
}
if (frame != gRender.logoFrame || sim->logoColor != gRender.logoColor
|| sim->frame.color[ST_LOGO_SPR_FIRST] != gRender.logoSprColor) {
logoPaletteApply(sim, frame);
}
}
}
collectGlyphs(sim);
dirtyBands(sim);
for (k = 0u; k < ST_HW_SPRITES; k++) {
uint8_t idx = (uint8_t)(ST_HW_SPRITES - 1u - k);
StDrawnT *d = &gRender.slot[k];
uint8_t multi = (uint8_t)((sim->frame.multiMask >> idx) & 1u);
int16_t px = (int16_t)((int16_t)sim->frame.x[idx] - ST_SPRITE_X_ORIGIN);
int16_t py = (int16_t)((int16_t)sim->frame.y[idx] - ST_SPRITE_Y_ORIGIN);
bool want = (sim->frame.enableMask & (uint8_t)(1u << idx)) != 0u && spriteOnScreen(px, py);
bool same = (want == d->drawn);
if (same && want) {
same = (d->x == sim->frame.x[idx] && d->y == sim->frame.y[idx] && d->ptr == sim->frame.ptr[idx] && d->color == drawColor(sim, idx) && d->multi == multi);
}
if (same && want && dirtyUnderSprite(px, py)) {
same = false;
}
if (!same) {
first = k;
break;
}
}
for (k = ST_HW_SPRITES; k > first; k--) {
StDrawnT *d = &gRender.slot[k - 1u];
if (d->drawn) {
jlSpriteRestoreUnder(stage, &gRender.backup[k - 1u]);
d->drawn = false;
}
}
paintCells(stage, sim);
for (k = first; k < ST_HW_SPRITES; k++) {
uint8_t idx = (uint8_t)(ST_HW_SPRITES - 1u - k);
StDrawnT *d = &gRender.slot[k];
jlSpriteT *sp;
int16_t px;
int16_t py;
if ((sim->frame.enableMask & (uint8_t)(1u << idx)) == 0u) {
continue;
}
px = (int16_t)((int16_t)sim->frame.x[idx] - ST_SPRITE_X_ORIGIN);
py = (int16_t)((int16_t)sim->frame.y[idx] - ST_SPRITE_Y_ORIGIN);
if (!spriteOnScreen(px, py)) {
continue;
}
sp = cachedSprite(sim, idx);
if (sp == 0) {
continue;
}
jlSpriteSaveAndDraw(stage, sp, px, py, &gRender.backup[k]);
d->drawn = true;
d->x = sim->frame.x[idx];
d->y = sim->frame.y[idx];
d->ptr = sim->frame.ptr[idx];
d->color = drawColor(sim, idx);
d->multi = (uint8_t)((sim->frame.multiMask >> idx) & 1u);
}
{
// Sync to the retrace unless the frame already spans more than
// one: a late frame goes out at once rather than waiting again.
uint8_t now = (uint8_t)jlFrameCount();
if ((uint8_t)(now - gRender.lastPresentFrame) < 2u) {
jlWaitVBL();
}
jlStagePresent();
gRender.lastPresentFrame = (uint8_t)jlFrameCount();
}
}
void stRenderInit(jlSurfaceT *stage) {
uint8_t k;
memset(&gRender, 0, sizeof(gRender));
memset(gRender.glyphFirst, 0xFF, sizeof(gRender.glyphFirst));
gRender.stage = stage;
for (k = 0u; k < ST_HW_SPRITES; k++) {
gRender.backup[k].bytes = gRender.backupMem[k];
}
jlPaletteSet(stage, 0u, kC64Palette);
jlScbSetRange(stage, 0u, (uint16_t)(SURFACE_HEIGHT - 1u), 0u);
jlSurfaceClear(stage, 0u);
gRender.scratch = jlSurfaceCreate();
if (gRender.scratch != 0) {
jlPaletteSet(gRender.scratch, 0u, kC64Palette);
jlScbSetRange(gRender.scratch, 0u, (uint16_t)(SURFACE_HEIGHT - 1u), 0u);
jlSurfaceClear(gRender.scratch, 0u);
}
}
// Build (and compile) the cels the game draws every screen -- cab,
// exhaust, passenger, wreck, warp, intro cab and star -- up front, so
// no frame pays for a sprite build mid-play. A bar on the stage shows
// progress on the slower ports.
// Load the offline-baked, already-compiled cel bank into the pinned
// cache so no cel is JIT-compiled at boot (each 65816 compile costs
// ~0.4 s). Every kStCels entry becomes a pinned cache slot keyed exactly
// as the play lookups: system ptr (level 0xFF), the level-wide colours.
// Returns false if the .spc is missing or built for another target/shift
// count (other ports, or a stale bake), so the caller falls back to the
// runtime JIT prewarm below. Its cross-platform contract makes this a
// no-op everywhere but the IIgs, where the bake is wired.
static bool loadPrecompiledCels(void) {
jlSpriteT *cels[64];
uint16_t n;
uint16_t i;
if (kStCelCount > (uint16_t)(sizeof(cels) / sizeof(cels[0])) || kStCelCount > ST_SPRITE_CACHE) {
return false;
}
n = jlSpriteBankLoadPrecompiled("sprites/staxicels.spc", cels, kStCelCount, 0);
if (n < kStCelCount) {
for (i = 0u; i < n; i++) {
jlSpriteDestroy(cels[i]);
}
return false;
}
for (i = 0u; i < n; i++) {
StSpriteCacheT *e = &gRender.cache[i];
e->sprite = cels[i];
e->ptr = kStCels[i].ptr;
e->color = kStCels[i].color;
e->multi = kStCels[i].multi;
e->mc0 = kStCels[i].mc0;
e->mc1 = kStCels[i].mc1;
e->level = 0xFFu;
e->used = true;
e->pinned = true;
e->lastUse = 0u;
}
return true;
}
// "LOADING..." centred on an otherwise black stage. The charset is the
// game's own, indexed by ASCII (the C64 font's letters sit at their
// ASCII codes), so this needs no font surface and no simulation state.
void stRenderLoading(jlSurfaceT *stage) {
static const char kLoading[] = "LOADING...";
const uint8_t *charset = stC64Charset();
uint8_t col = (uint8_t)((ST_SCREEN_COLS - (sizeof(kLoading) - 1u)) / 2u);
uint8_t k;
jlSurfaceClear(stage, 0u);
for (k = 0u; k < (uint8_t)(sizeof(kLoading) - 1u); k++) {
jlTilePasteGlyph(stage, (uint8_t)(col + k), ST_LOADING_ROW,
&charset[(uint8_t)kLoading[k] * 8u], ST_LOADING_COLOR, 0u);
}
jlStagePresent();
}
void stRenderPrewarm(jlSurfaceT *stage, StSimT *sim) {
static const uint8_t kCabPtrs[] = { 0xC0, 0xC1, 0xDC, 0xDD, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8 };
static const uint8_t kPassPtrs[] = { 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xD9 };
static const uint8_t kFlamePtrs[] = { 0xD8, 0xD4, 0xD5, 0xD2, 0xD1, 0xD7, 0xD3, 0xD6 };
uint8_t total = (uint8_t)(sizeof(kCabPtrs) + sizeof(kPassPtrs) + sizeof(kFlamePtrs) + 1u);
uint8_t done = 0u;
uint8_t k;
StFrameT saved;
// Precompiled bank: instant, no per-cel JIT. Falls through to the
// runtime build below on any port without a matching .spc.
if (loadPrecompiledCels()) {
return;
}
saved = sim->frame;
gPrewarming = true;
sim->frame.multiMask = 0x07u;
sim->spriteMc0 = 0x02u;
sim->spriteMc1 = 0x07u;
for (k = 0u; k < sizeof(kCabPtrs); k++) {
sim->frame.ptr[0] = kCabPtrs[k];
sim->frame.color[0] = 0x06u;
(void)cachedSprite(sim, 0u);
done++;
jlFillRect(stage, 60, 110, (uint16_t)((uint16_t)done * 200u / total), 6u, 1u);
jlStagePresent();
}
for (k = 0u; k < sizeof(kPassPtrs); k++) {
sim->frame.ptr[1] = kPassPtrs[k];
sim->frame.color[1] = 0x06u;
(void)cachedSprite(sim, 1u);
done++;
jlFillRect(stage, 60, 110, (uint16_t)((uint16_t)done * 200u / total), 6u, 1u);
jlStagePresent();
}
for (k = 0u; k < sizeof(kFlamePtrs); k++) {
sim->frame.ptr[2] = kFlamePtrs[k];
sim->frame.color[2] = 0x07u;
(void)cachedSprite(sim, 2u);
done++;
jlFillRect(stage, 60, 110, (uint16_t)((uint16_t)done * 200u / total), 6u, 1u);
jlStagePresent();
}
// The intro star is a hires sprite in colour 7. Build it as a moving
// (idx <= 2) cel so it compiles: the level-name intro draws seven of
// them every frame, and the interpreter cannot keep up.
sim->frame.multiMask = 0u;
sim->frame.ptr[2] = 0xDAu;
sim->frame.color[2] = 0x07u;
(void)cachedSprite(sim, 2u);
sim->frame = saved;
gPrewarming = false;
jlFillRect(stage, 60, 110, 200u, 6u, 0u);
}
// A new scene: nothing drawn is valid any more.
void stRenderSceneChanged(StSimT *sim) {
uint8_t k;
if (gRender.logoMode) {
// The logo's reserved slots go back to being C64 colours.
gRender.logoMode = false;
gRender.logoTileOk = false;
jlPaletteSet(gRender.stage, 0u, kC64Palette);
}
for (k = 0u; k < ST_HW_SPRITES; k++) {
gRender.slot[k].drawn = false;
}
stSimDirtyAll(sim);
sim->charDirtyAll = true;
sim->charDirtyCount = 0u;
}
// Turn on the title's palette-animated logo. Call it after
// stRenderSceneChanged (which turns it back off) on entry to the title
// screen; from then on a flip-book step and a colour cycle both cost
// one palette write and no cell repaint at all.
void stRenderTitleLogo(StSimT *sim) {
uint8_t frame;
if (!logoBuildTile(sim)) {
return;
}
frame = logoFrameIndex(sim);
gRender.logoMode = true;
gRender.logoTileOk = (frame < ST_LOGO_FRAMES);
logoPaletteApply(sim, gRender.logoTileOk ? frame : 0u);
stSimDirtyAll(sim);
}
void stRenderShutdown(void) {
dropCache();
if (gRender.scratch != 0) {
jlSurfaceDestroy(gRender.scratch);
gRender.scratch = 0;
}
}