summaryrefslogtreecommitdiff
path: root/src/blitter/8bpp_optimized.cpp
blob: 4cc86673a0e10af9fb7c9d84129857540b785ec2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file 8bpp_optimized.cpp Implementation of the optimized 8 bpp blitter. */

#include "../stdafx.h"
#include "../zoom_func.h"
#include "../core/math_func.hpp"
#include "8bpp_optimized.hpp"

static FBlitter_8bppOptimized iFBlitter_8bppOptimized;

void Blitter_8bppOptimized::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
{
	/* Find the offset of this zoom-level */
	const SpriteData *sprite_src = (const SpriteData *)bp->sprite;
	uint offset = sprite_src->offset[zoom];

	/* Find where to start reading in the source sprite */
	const uint8 *src = sprite_src->data + offset;
	uint8 *dst_line = (uint8 *)bp->dst + bp->top * bp->pitch + bp->left;

	/* Skip over the top lines in the source image */
	for (int y = 0; y < bp->skip_top; y++) {
		for (;;) {
			uint trans = *src++;
			uint pixels = *src++;
			if (trans == 0 && pixels == 0) break;
			src += pixels;
		}
	}

	const uint8 *src_next = src;

	for (int y = 0; y < bp->height; y++) {
		uint8 *dst = dst_line;
		dst_line += bp->pitch;

		uint skip_left = bp->skip_left;
		int width = bp->width;

		for (;;) {
			src = src_next;
			uint trans = *src++;
			uint pixels = *src++;
			src_next = src + pixels;
			if (trans == 0 && pixels == 0) break;
			if (width <= 0) continue;

			if (skip_left != 0) {
				if (skip_left < trans) {
					trans -= skip_left;
					skip_left = 0;
				} else {
					skip_left -= trans;
					trans = 0;
				}
				if (skip_left < pixels) {
					src += skip_left;
					pixels -= skip_left;
					skip_left = 0;
				} else {
					src += pixels;
					skip_left -= pixels;
					pixels = 0;
				}
			}
			if (skip_left != 0) continue;

			/* Skip transparent pixels */
			dst += trans;
			width -= trans;
			if (width <= 0 || pixels == 0) continue;
			pixels = min<uint>(pixels, (uint)width);
			width -= pixels;

			switch (mode) {
				case BM_COLOUR_REMAP: {
					const uint8 *remap = bp->remap;
					do {
						uint m = remap[*src];
						if (m != 0) *dst = m;
						dst++; src++;
					} while (--pixels != 0);
				} break;

				case BM_TRANSPARENT: {
					const uint8 *remap = bp->remap;
					src += pixels;
					do {
						*dst = remap[*dst];
						dst++;
					} while (--pixels != 0);
				} break;

				default:
					memcpy(dst, src, pixels);
					dst += pixels; src += pixels;
					break;
			}
		}
	}
}

Sprite *Blitter_8bppOptimized::Encode(SpriteLoader::Sprite *sprite, Blitter::AllocatorProc *allocator)
{
	/* Make memory for all zoom-levels */
	uint memory = sizeof(SpriteData);

	for (ZoomLevel i = ZOOM_LVL_BEGIN; i < ZOOM_LVL_END; i++) {
		memory += UnScaleByZoom(sprite->height, i) * UnScaleByZoom(sprite->width, i);
	}

	/* We have no idea how much memory we really need, so just guess something */
	memory *= 5;

	/* Don't allocate memory each time, but just keep some
	 * memory around as this function is called quite often
	 * and the memory usage is quite low. */
	static ReusableBuffer<byte> temp_buffer;
	SpriteData *temp_dst = (SpriteData *)temp_buffer.Allocate(memory);
	byte *dst = temp_dst->data;

	/* Make the sprites per zoom-level */
	for (ZoomLevel i = ZOOM_LVL_BEGIN; i < ZOOM_LVL_END; i++) {
		/* Store the index table */
		uint offset = dst - temp_dst->data;
		temp_dst->offset[i] = offset;

		/* cache values, because compiler can't cache it */
		int scaled_height = UnScaleByZoom(sprite->height, i);
		int scaled_width  = UnScaleByZoom(sprite->width,  i);
		int scaled_1      =   ScaleByZoom(1,              i);

		for (int y = 0; y < scaled_height; y++) {
			uint trans = 0;
			uint pixels = 0;
			uint last_colour = 0;
			byte *count_dst = NULL;

			/* Store the scaled image */
			const SpriteLoader::CommonPixel *src = &sprite->data[ScaleByZoom(y, i) * sprite->width];
			const SpriteLoader::CommonPixel *src_end = &src[sprite->width];

			for (int x = 0; x < scaled_width; x++) {
				uint colour = 0;

				/* Get the colour keeping in mind the zoom-level */
				for (int j = 0; j < scaled_1; j++) {
					if (src->m != 0) colour = src->m;
					/* Because of the scaling it might happen we read outside the buffer. Avoid that. */
					if (++src == src_end) break;
				}

				if (last_colour == 0 || colour == 0 || pixels == 255) {
					if (count_dst != NULL) {
						/* Write how many non-transparent bytes we get */
						*count_dst = pixels;
						pixels = 0;
						count_dst = NULL;
					}
					/* As long as we find transparency bytes, keep counting */
					if (colour == 0) {
						last_colour = 0;
						trans++;
						continue;
					}
					/* No longer transparency, so write the amount of transparent bytes */
					*dst = trans;
					dst++;
					trans = 0;
					/* Reserve a byte for the pixel counter */
					count_dst = dst;
					dst++;
				}
				last_colour = colour;
				pixels++;
				*dst = colour;
				dst++;
			}

			if (count_dst != NULL) *count_dst = pixels;

			/* Write line-ending */
			*dst = 0; dst++;
			*dst = 0; dst++;
		}
	}

	uint size = dst - (byte *)temp_dst;

	/* Safety check, to make sure we guessed the size correctly */
	assert(size < memory);

	/* Allocate the exact amount of memory we need */
	Sprite *dest_sprite = (Sprite *)allocator(sizeof(*dest_sprite) + size);

	dest_sprite->height = sprite->height;
	dest_sprite->width  = sprite->width;
	dest_sprite->x_offs = sprite->x_offs;
	dest_sprite->y_offs = sprite->y_offs;
	memcpy(dest_sprite->data, temp_dst, size);

	return dest_sprite;
}