fader.c

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/* CARDGAME's screen fader. */
 
#include "cardgame/card_battle.h"
 
/* Draws the fader over RECT, in layer 0x100 */
void CARDGAME_drawFader(CardFader *fader, RECT rect) {
    Layer *layer = GFX.funcs.getLayer(0x100);
    u_long *ot = layer->getOtEntry(layer, 0);
    POLY_F4 *poly = GFX.funcs.getPrim();
    DR_TPAGE *mode;
 
    poly->r0 = fader->color[0];
    poly->g0 = fader->color[1];
    poly->b0 = fader->color[2];
    setlen(poly, 5);
    poly->code = 0x2A;
    poly->x0 = rect.x;
    poly->x1 = rect.x + rect.w;
    poly->x2 = rect.x;
    poly->x3 = rect.x + rect.w;
    poly->y0 = rect.y;
    poly->y1 = rect.y;
    poly->y2 = rect.y + rect.h;
    poly->y3 = rect.y + rect.h;
    addPrim(ot, poly);
    mode = (DR_TPAGE *)(poly + 1);
    setlen(mode, 1);
    mode->code[0] = ((fader->blend & 3) << 5) | 0xE1000205;
    addPrim(ot, mode);
    GFX.funcs.setPrim(mode + 1);
}
 
/* Moves the colour towards the target as the time runs out */
void CARDGAME_stepFader(CardFader *fader) {
    s32 i;
 
    fader->time -= GFX.funcs.getFrameTime();
    if (fader->time > 0) {
        for (i = 0; i < 3; i++) {
            fader->color[i] = fader->target[i] - (fader->target[i] - fader->from[i]) * fader->time / fader->duration;
        }
        return;
    }
    if (fader->killWhenDone != 0) {
        fader->mode = 2;
        return;
    }
    fader->mode = 0;
    fader->color[0] = fader->target[0];
    fader->color[1] = fader->target[1];
    fader->color[2] = fader->target[2];
}
 
/* Sets the colour at once */
void CARDGAME_setFaderColor(CardFader *fader, u8 r, u8 g, u8 b) {
    fader->color[0] = r;
    fader->color[1] = g;
    fader->color[2] = b;
}
 
/* Fades from the current colour to r, g, b in FRAMES vsyncs; the task
   ends at the end when KILLWHENDONE is set */
void CARDGAME_startFade(CardFader *fader, u8 r, u8 g, u8 b, s32 frames, s32 killWhenDone) {
    s32 i;
 
    for (i = 0; i < 3; i++) {
        fader->from[i] = fader->color[i];
    }
    fader->target[0] = r;
    fader->target[1] = g;
    fader->target[2] = b;
    fader->time = frames;
    fader->duration = frames;
    fader->mode = 1;
    fader->killWhenDone = killWhenDone;
}
 
/* 1 once the fade has reached its colour */
s32 CARDGAME_isFadeDone(CardFader *fader) {
    return fader->mode == 0;
}
 
/* Ends the task */
void CARDGAME_killFader(CardFader *fader) {
    fader->mode = 2;
}
 
/* A fader's task: steps its fade while fading, draws it over
   CARDGAME_fadeRect every frame and ends once killed */
void CARDGAME_tickFader(CardFader *fader) {
    switch (fader->state) {
    case 0:
    default:
        fader->nextState(fader);
        break;
    case 1:
        if (fader->mode == 1) {
            CARDGAME_stepFader(fader);
        }
        CARDGAME_drawFader(fader, CARDGAME_fadeRect);
        if (fader->mode == 2) {
            fader->setState(fader, 3);
        }
        break;
    case 2:
    case 3:
        break;
    }
}
 
/* Creates a fader, with the semi-transparency rate BLEND */
CardFader *CARDGAME_createFader(u8 blend) {
    CardFader *fader = createTask(CARDGAME_tickFader, sizeof(CardFader), 4);
 
    fader->setColor = CARDGAME_setFaderColor;
    fader->start = CARDGAME_startFade;
    fader->isDone = CARDGAME_isFadeDone;
    fader->blend = blend;
    fader->kill = CARDGAME_killFader;
    return fader;
}