REminiscence/screenshot.cpp

71 lines
2.0 KiB
C++

#include "screenshot.h"
#include "file.h"
static void TO_LE16(uint8_t *dst, uint16_t value) {
for (int i = 0; i < 2; ++i) {
dst[i] = value & 255;
value >>= 8;
}
}
#define kTgaImageTypeUncompressedTrueColor 2
#define kTgaImageTypeRunLengthEncodedTrueColor 10
#define kTgaDirectionTop (1 << 5)
static const int TGA_HEADER_SIZE = 18;
void saveTGA(const char *filename, const uint8_t *rgba, int w, int h) {
static const uint8_t kImageType = kTgaImageTypeRunLengthEncodedTrueColor;
uint8_t buffer[TGA_HEADER_SIZE];
buffer[0] = 0; // ID Length
buffer[1] = 0; // ColorMap Type
buffer[2] = kImageType;
TO_LE16(buffer + 3, 0); // ColorMap Start
TO_LE16(buffer + 5, 0); // ColorMap Length
buffer[7] = 0; // ColorMap Bits
TO_LE16(buffer + 8, 0); // X-origin
TO_LE16(buffer + 10, 0); // Y-origin
TO_LE16(buffer + 12, w); // Image Width
TO_LE16(buffer + 14, h); // Image Height
buffer[16] = 24; // Pixel Depth
buffer[17] = kTgaDirectionTop; // Descriptor
File f;
if (f.open(filename, "wb", ".")) {
f.write(buffer, sizeof(buffer));
if (kImageType == kTgaImageTypeUncompressedTrueColor) {
for (int i = 0; i < w * h; ++i) {
f.writeByte(rgba[0]);
f.writeByte(rgba[1]);
f.writeByte(rgba[2]);
rgba += 4;
}
} else {
assert(kImageType == kTgaImageTypeRunLengthEncodedTrueColor);
int prevColor = rgba[2] + (rgba[1] << 8) + (rgba[0] << 16); rgba += 4;
int count = 0;
for (int i = 1; i < w * h; ++i) {
int color = rgba[2] + (rgba[1] << 8) + (rgba[0] << 16); rgba += 4;
if (prevColor == color && count < 127) {
++count;
continue;
}
f.writeByte(count | 0x80);
f.writeByte((prevColor >> 16) & 255);
f.writeByte((prevColor >> 8) & 255);
f.writeByte( prevColor & 255);
count = 0;
prevColor = color;
}
if (count != 0) {
f.writeByte(count | 0x80);
f.writeByte((prevColor >> 16) & 255);
f.writeByte((prevColor >> 8) & 255);
f.writeByte( prevColor & 255);
}
}
}
}