To modify a TGA file and append content to a specific channel in C++, you would need to:
Here's some example code to get you started:
#include <cstdio>
int main()
{
// Open the TGA file for reading
FILE* tgaFile = fopen("myfile.tga", "rb");
if (!tgaFile)
{
printf("Failed to open TGA file!\n");
return 1;
}
// Read in the TGA file data
fseek(tgaFile, 0, SEEK_END);
const long fileSize = ftell(tgaFile);
fseek(tgaFile, 0, SEEK_SET);
unsigned char* imageData = new unsigned char[fileSize];
const size_t bytesRead = fread(imageData, 1, fileSize, tgaFile);
fclose(tgaFile);
if (bytesRead != fileSize)
{
printf("Error reading TGA file data!\n");
delete[] imageData;
return 1;
}
// Extract the TGA header information
const int width = imageData[12] + (imageData[13] << 8);
const int height = imageData[14] + (imageData[15] << 8);
const int bpp = imageData[16] >> 3;
// Find the desired channel and modify its content
const int channelIndex = 2; // For example, modify the blue channel
for (int i = 0; i < width * height; ++i)
{
const int pixelIndex = i * bpp;
imageData[pixelIndex + channelIndex] = 255; // Modify the channel value as needed
}
// Write the modified data buffer back to the TGA file
tgaFile = fopen("myfile_modified.tga", "wb");
if (!tgaFile)
{
printf("Failed to open TGA file for writing!\n");
delete[] imageData;
return 1;
}
const size_t bytesWritten = fwrite(imageData, 1, fileSize, tgaFile);
fclose(tgaFile);
if (bytesWritten != fileSize)
{
printf("Error writing modified TGA file data!\n");
delete[] imageData;
return 1;
}
// Cleanup
delete[] imageData;
return 0;
}
Note that this is just a basic example and assumes a lot of things about the TGA file format. You'll need to add error checking, handle different TGA formats, and modify the channel values appropriately for your specific use case.
Asked: 2022-06-29 11:00:00 +0000
Seen: 9 times
Last updated: Jun 04 '21