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/**
@file GImage_tga.cpp
@author Morgan McGuire, http://graphics.cs.williams.edu
@created 2002-05-27
@edited 2009-05-10
*/
#include "G3D/platform.h"
#include "G3D/GImage.h"
#include "G3D/BinaryInput.h"
#include "G3D/BinaryOutput.h"
#include "G3D/Log.h"
namespace G3D {
void GImage::encodeTGA(
BinaryOutput& out) const {
out.setEndian(G3D_LITTLE_ENDIAN);
// ID length
out.writeUInt8(0);
// Color map Type
out.writeUInt8(0);
// Type
out.writeUInt8(2);
// Color map
out.skip(5);
// x, y offsets
out.writeUInt16(0);
out.writeUInt16(0);
// Width & height
out.writeUInt16(m_width);
out.writeUInt16(m_height);
// Color depth
if (m_channels == 1) {
// Force RGB mode
out.writeUInt8(8 * 3);
} else {
out.writeUInt8(8 * m_channels);
}
// Image descriptor
if (m_channels < 4) {
// 0 alpha bits
out.writeUInt8(0);
} else {
// 8 alpha bits
out.writeUInt8(8);
}
// Image ID (zero length)
if (m_channels == 1) {
// Pixels are upside down in BGR format.
for (int y = m_height - 1; y >= 0; --y) {
for (int x = 0; x < m_width; ++x) {
uint8 p = (m_byte[(y * m_width + x)]);
out.writeUInt8(p);
out.writeUInt8(p);
out.writeUInt8(p);
}
}
} else if (m_channels == 3) {
// Pixels are upside down in BGR format.
for (int y = m_height - 1; y >= 0; --y) {
for (int x = 0; x < m_width; ++x) {
uint8* p = &(m_byte[3 * (y * m_width + x)]);
out.writeUInt8(p[2]);
out.writeUInt8(p[1]);
out.writeUInt8(p[0]);
}
}
} else {
// Pixels are upside down in BGRA format.
for (int y = m_height - 1; y >= 0; --y) {
for (int x = 0; x < m_width; ++x) {
uint8* p = &(m_byte[4 * (y * m_width + x)]);
out.writeUInt8(p[2]);
out.writeUInt8(p[1]);
out.writeUInt8(p[0]);
out.writeUInt8(p[3]);
}
}
}
// Write "TRUEVISION-XFILE " 18 bytes from the end
// (with null termination)
out.writeString("TRUEVISION-XFILE ");
}
inline static void readBGR(uint8* byte, BinaryInput& bi) {
int b = bi.readUInt8();
int g = bi.readUInt8();
int r = bi.readUInt8();
byte[0] = r;
byte[1] = g;
byte[2] = b;
}
inline static void readBGRA(uint8* byte, BinaryInput& bi) {
readBGR(byte, bi);
byte[3] = bi.readUInt8();
}
void GImage::decodeTGA(
BinaryInput& input) {
// This is a simple TGA loader that can handle uncompressed
// truecolor TGA files (TGA type 2).
// Verify this is a TGA file by looking for the TRUEVISION tag.
int pos = input.getPosition();
input.setPosition(input.size() - 18);
std::string tag = input.readString(16);
if (tag != "TRUEVISION-XFILE") {
throw Error("Not a TGA file", input.getFilename());
}
input.setPosition(pos);
int IDLength = input.readUInt8();
int colorMapType = input.readUInt8();
int imageType = input.readUInt8();
(void)colorMapType;
// 2 is the type supported by this routine.
if (imageType != 2 && imageType != 10) {
throw Error("TGA images must be type 2 (Uncompressed truecolor) or 10 (Run-length truecolor)", input.getFilename());
}
// Color map specification
input.skip(5);
// Image specification
// Skip x and y offsets
input.skip(4);
m_width = input.readInt16();
m_height = input.readInt16();
int colorDepth = input.readUInt8();
if ((colorDepth != 24) && (colorDepth != 32)) {
throw Error("TGA files must be 24 or 32 bit.", input.getFilename());
}
if (colorDepth == 32) {
m_channels = 4;
} else {
m_channels = 3;
}
// Image descriptor contains overlay data as well
// as data indicating where the origin is
int imageDescriptor = input.readUInt8();
(void)imageDescriptor;
// Image ID
input.skip(IDLength);
m_byte = (uint8*)m_memMan->alloc(m_width * m_height * m_channels);
debugAssert(m_byte);
// Pixel data
int x;
int y;
if (imageType == 2) {
// Uncompressed
if (m_channels == 3) {
for (y = m_height - 1; y >= 0; --y) {
for (x = 0; x < m_width; ++x) {
int i = (x + y * m_width) * 3;
readBGR(m_byte + i, input);
}
}
} else {
for (y = m_height - 1; y >= 0; --y) {
for (x = 0; x < m_width; ++x) {
int i = (x + y * m_width) * 4;
readBGRA(m_byte + i, input);
}
}
}
} else if (imageType == 10) {
// Run-length encoded
for (y = m_height - 1; y >= 0; --y) {
for (int x = 0; x < m_width; /* intentionally no x increment */) {
// The specification guarantees that no packet will wrap past the end of a row
const uint8 repetitionCount = input.readUInt8();
const uint8 numValues = (repetitionCount & (~128)) + 1;
int byteOffset = (x + y * m_width) * 3;
if (repetitionCount & 128) {
// When the high bit is 1, this is a run-length packet
if (m_channels == 3) {
Color3uint8 value;
readBGR((uint8*)(&value), input);
for (int i = 0; i < numValues; ++i, ++x) {
for (int b = 0; b < 3; ++b, ++byteOffset) {
m_byte[byteOffset] = value[b];
}
}
} else {
Color4uint8 value;
readBGRA((uint8*)(&value), input);
for (int i = 0; i < numValues; ++i, ++x) {
for (int b = 0; b < 3; ++b, ++byteOffset) {
m_byte[byteOffset] = value[b];
}
}
}
} else {
// When the high bit is 0, this is a raw packet
for (int i = 0; i < numValues; ++i, ++x, byteOffset += m_channels) {
readBGR(m_byte + byteOffset, input);
}
}
}
}
} else {
alwaysAssertM(false, "Unsupported type");
}
}
}
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