33 lines
874 B
C
33 lines
874 B
C
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#include "decode.h"
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void decode_ega_spr(const uint8_t *src, int src_pitch, int w, int h, uint8_t *dst, int dst_pitch, int dst_x, int dst_y, int xflip) {
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assert((src_pitch & 7) == 0);
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src_pitch /= 8;
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assert((w & 7) == 0);
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w /= 8;
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const int bitplane_size = w * h;
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for (int y = 0; y < h; ++y) {
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const int y_offset = dst_y + y;
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for (int x = 0; x < w; ++x) {
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for (int i = 0; i < 8; ++i) {
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int color = 0;
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const int mask = 1 << (7 - i);
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for (int bit = 0; bit < 4; ++bit) {
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if (src[bit * bitplane_size] & mask) {
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color |= 1 << (3 - bit);
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}
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}
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if (color != 0) {
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const int x_offset = dst_x + (xflip ? (w * 8 - x * 8 - i) : (x * 8 + i));
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if (x_offset >= 0 && x_offset < 320 && y_offset >= 0 && y_offset < 200) {
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dst[y_offset * dst_pitch + x_offset] = color;
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}
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}
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}
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++src;
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}
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src += src_pitch - w;
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}
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}
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