fic: Support rendering cursors

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

libavcodec/fic.c

@@ -38,6 +38,7 @@ typedef struct FICThreadContext {
 typedef struct FICContext {
     AVCodecContext *avctx;
     AVFrame *frame;
+    AVFrame *final_frame;
 
     FICThreadContext *slice_data;
     int slice_data_size;
@@ -48,6 +49,8 @@ typedef struct FICContext {
 
     int aligned_width, aligned_height;
     int num_slices, slice_h;
+
+    uint8_t cursor_buf[4096];
 } FICContext;
 
 static const uint8_t fic_qmat_hq[64] = {
@@ -186,6 +189,69 @@ static int fic_decode_slice(AVCodecContext *avctx, void *tdata)
     return 0;
 }
 
+static av_always_inline void fic_alpha_blend(uint8_t *dst, uint8_t *src,
+                                             int size, uint8_t *alpha)
+{
+    int i;
+
+    for (i = 0; i < size; i++)
+        dst[i] = (dst[i] * (256 - alpha[i]) + src[i] * alpha[i]) >> 8;
+}
+
+static void fic_draw_cursor(AVCodecContext *avctx, int cur_x, int cur_y)
+{
+    FICContext *ctx = avctx->priv_data;
+    uint8_t *ptr    = ctx->cursor_buf;
+    uint8_t *dstptr[3];
+    uint8_t planes[4][1024];
+    uint8_t chroma[3][256];
+    int i, j, p;
+
+    /* Convert to YUVA444. */
+    for (i = 0; i < 1024; i++) {
+        planes[0][i] = av_clip_uint8((( 25 * ptr[0] + 129 * ptr[1] +  66 * ptr[2]) / 255) + 16);
+        planes[1][i] = av_clip_uint8(((-38 * ptr[0] + 112 * ptr[1] + -74 * ptr[2]) / 255) + 128);
+        planes[2][i] = av_clip_uint8(((-18 * ptr[0] + 112 * ptr[1] + -94 * ptr[2]) / 255) + 128);
+        planes[3][i] = ptr[3];
+
+        ptr += 4;
+    }
+
+    /* Subsample chroma. */
+    for (i = 0; i < 32; i += 2)
+        for (j = 0; j < 32; j += 2)
+            for (p = 0; p < 3; p++)
+                chroma[p][16 * (i / 2) + j / 2] = (planes[p + 1][32 *  i      + j    ] +
+                                                   planes[p + 1][32 *  i      + j + 1] +
+                                                   planes[p + 1][32 * (i + 1) + j    ] +
+                                                   planes[p + 1][32 * (i + 1) + j + 1]) / 4;
+
+    /* Seek to x/y pos of cursor. */
+    for (i = 0; i < 3; i++)
+        dstptr[i] = ctx->final_frame->data[i]                        +
+                    (ctx->final_frame->linesize[i] * (cur_y >> !!i)) +
+                    (cur_x >> !!i) + !!i;
+
+    /* Copy. */
+    for (i = 0; i < FFMIN(32, avctx->height - cur_y) - 1; i += 2) {
+        int lsize = FFMIN(32, avctx->width - cur_x);
+        int csize = lsize / 2;
+
+        fic_alpha_blend(dstptr[0],
+                        planes[0] + i * 32, lsize, planes[3] + i * 32);
+        fic_alpha_blend(dstptr[0] + ctx->final_frame->linesize[0],
+                        planes[0] + (i + 1) * 32, lsize, planes[3] + (i + 1) * 32);
+        fic_alpha_blend(dstptr[1],
+                        chroma[0] + (i / 2) * 16, csize, chroma[2] + (i / 2) * 16);
+        fic_alpha_blend(dstptr[2],
+                        chroma[1] + (i / 2) * 16, csize, chroma[2] + (i / 2) * 16);
+
+        dstptr[0] += ctx->final_frame->linesize[0] * 2;
+        dstptr[1] += ctx->final_frame->linesize[1];
+        dstptr[2] += ctx->final_frame->linesize[2];
+    }
+}
+
 static int fic_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame, AVPacket *avpkt)
 {
@@ -195,6 +261,8 @@ static int fic_decode_frame(AVCodecContext *avctx, void *data,
     int slice, nslices;
     int msize;
     int tsize;
+    int cur_x, cur_y;
+    int skip_cursor = 0;
     uint8_t *sdata;
 
     if ((ret = ff_reget_buffer(avctx, ctx->frame)) < 0) {
@@ -232,6 +300,28 @@ static int fic_decode_frame(AVCodecContext *avctx, void *data,
         return AVERROR_INVALIDDATA;
     }
 
+    if (tsize < 32) {
+        av_log(avctx, AV_LOG_WARNING,
+               "Cursor data too small. Skipping cursor.\n");
+        skip_cursor = 1;
+    }
+
+    /* Cursor position. */
+    cur_x = AV_RL16(src + 33);
+    cur_y = AV_RL16(src + 35);
+    if (cur_x > avctx->width || cur_y > avctx->height) {
+        av_log(avctx, AV_LOG_WARNING,
+               "Invalid cursor position: (%d,%d). Skipping cusor.\n",
+               cur_x, cur_y);
+        skip_cursor = 1;
+    }
+
+    if (AV_RL16(src + 37) != 32 || AV_RL16(src + 39) != 32) {
+        av_log(avctx, AV_LOG_WARNING,
+               "Invalid cursor size. Skipping cursor.\n");
+        skip_cursor = 1;
+    }
+
     /* Slice height for all but the last slice. */
     ctx->slice_h = 16 * (ctx->aligned_height >> 4) / nslices;
     if (ctx->slice_h % 16)
@@ -296,9 +386,28 @@ static int fic_decode_frame(AVCodecContext *avctx, void *data,
                               NULL, nslices, sizeof(ctx->slice_data[0]))) < 0)
         return ret;
 
+    av_frame_free(&ctx->final_frame);
+    ctx->final_frame = av_frame_clone(ctx->frame);
+    if (!ctx->final_frame) {
+        av_log(avctx, AV_LOG_ERROR, "Could not clone frame buffer.\n");
+        return AVERROR(ENOMEM);
+    }
+
+    /* Make sure we use a user-supplied buffer. */
+    if ((ret = ff_reget_buffer(avctx, ctx->final_frame)) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Could not make frame writable.\n");
+        return ret;
+    }
+
+    /* Draw cursor. */
+    if (!skip_cursor) {
+        memcpy(ctx->cursor_buf, src + 59, 32 * 32 * 4);
+        fic_draw_cursor(avctx, cur_x, cur_y);
+    }
+
 skip:
     *got_frame = 1;
-    if ((ret = av_frame_ref(data, ctx->frame)) < 0)
+    if ((ret = av_frame_ref(data, ctx->final_frame)) < 0)
         return ret;
 
     return avpkt->size;
@@ -309,6 +418,7 @@ static av_cold int fic_decode_close(AVCodecContext *avctx)
     FICContext *ctx = avctx->priv_data;
 
     av_freep(&ctx->slice_data);
+    av_frame_free(&ctx->final_frame);
     av_frame_free(&ctx->frame);
 
     return 0;