1 /* 2 * Copyright 2004, Axel Dörfler, axeld@pinc-software.de. All rights reserved. 3 * Copyright 2015, Augustin Cavalier <waddlesplash>. All rights reserved. 4 * Distributed under the terms of the MIT License. 5 * 6 * Effect from corTeX / Optimum. 7 */ 8 9 #include <SupportDefs.h> 10 11 #include "Draw.h" 12 13 14 // Hand-translated from x86 assembly. 15 /* memshset (char *dst, int center_shade,int fixed_shade, int length_2) */ 16 /* dst is the *center* of the dst segment */ 17 /* center shade is the initial color (at center) (!! 8:8 also) */ 18 /* fixed_shade is the fixed point increment (8:8) */ 19 /* length_2 is the 1/2 length to set (to the left, and to the right) */ 20 21 /* a memaddshadedset function (or something like that ) */ 22 void memshset(char* dstParam, int center_shade, int fixed_shade, int half_length) 23 { 24 unsigned char* dst; 25 unsigned char* source; 26 int offset; 27 28 if (half_length == 0) 29 return; 30 31 dst = (unsigned char*)dstParam; 32 source = dst; 33 dst -= half_length; // Left segment 34 source += half_length; // Right segment 35 source++; // Don't overlap at middle 36 37 offset = half_length; 38 offset = -offset; 39 offset--; // For in-advance incl in loop 40 41 do { 42 int tmp; 43 center_shade += fixed_shade; // Increment color. 44 center_shade &= 0xFFFF; // Mask so we can do overflow tests. 45 offset++; 46 47 tmp = dst[half_length] + (center_shade >> 8); // Increment left pixel. 48 // Did it overflow? 49 if (tmp & 0xFF00) 50 dst[half_length] = 255; 51 else 52 dst[half_length] = tmp; 53 54 tmp = source[offset] + (center_shade >> 8); // Increment right pixel. 55 if (tmp & 0xFF00) 56 source[offset] = 255; 57 else 58 source[offset] = tmp; 59 } while (--half_length != 0); 60 } 61 62 63 /* do the "motion blur" (actually the pixel fading) */ 64 void mblur(char* srcParam, int nbpixels) 65 { 66 unsigned int clear1UpperBit = 0x7f7f7f7f; 67 unsigned int clear3UpperBits = 0x1f1f1f1f; 68 unsigned long* src = (unsigned long*)srcParam; 69 70 if ((nbpixels >>= 2) == 0) 71 return; 72 73 do { 74 long eax, ebx; 75 eax = *src; 76 src++; 77 78 ebx = eax; 79 eax >>= 1; 80 81 ebx >>= 3; 82 eax &= clear1UpperBit; 83 84 ebx &= clear3UpperBits; 85 86 eax += ebx; 87 src[-1] = eax; 88 } while (--nbpixels != 0); 89 } 90