From cbfa82f5be08ed05927fb5d4d73a178c18c879e7 Mon Sep 17 00:00:00 2001
From: CJSatnarine <satnarinecj101@gmail.com>
Date: Wed, 26 Feb 2025 16:07:08 -0500
Subject: [PATCH] added code

---
 CMakeLists.txt   |   4 +-
 src/main.cpp     |  13 ++
 src/tgaimage.cpp | 352 +++++++++++++++++++++++++++++++++++++++++++++++
 src/tgaimage.h   |  96 +++++++++++++
 4 files changed, 464 insertions(+), 1 deletion(-)
 create mode 100644 src/main.cpp
 create mode 100644 src/tgaimage.cpp
 create mode 100644 src/tgaimage.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f4387ea..cbfdb47 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,5 +2,7 @@ cmake_minimum_required(VERSION 3.5.0)
 project(tiny_renderer VERSION 0.1.0 LANGUAGES C CXX)
 
 add_executable(tiny_renderer
-
+    src/main.cpp
+    src/tgaimage.cpp
+    src/tgaimage.h
 )
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..2fba26a
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,13 @@
+#include "tgaimage.h"
+
+const TGAColor white = TGAColor(255, 255, 255, 255);
+const TGAColor red   = TGAColor(255, 0,   0,   255);
+
+int main(int argc, char** argv) {
+	TGAImage image(100, 100, TGAImage::RGB);
+	image.set(52, 41, red);
+	image.flip_vertically(); // i want to have the origin at the left bottom corner of the image
+	image.write_tga_file("output.tga");
+	return 0;
+}
+
diff --git a/src/tgaimage.cpp b/src/tgaimage.cpp
new file mode 100644
index 0000000..12eef1c
--- /dev/null
+++ b/src/tgaimage.cpp
@@ -0,0 +1,352 @@
+#include <iostream>
+#include <fstream>
+#include <string.h>
+#include <time.h>
+#include <math.h>
+#include "tgaimage.h"
+
+TGAImage::TGAImage() : data(NULL), width(0), height(0), bytespp(0) {
+}
+
+TGAImage::TGAImage(int w, int h, int bpp) : data(NULL), width(w), height(h), bytespp(bpp) {
+	unsigned long nbytes = width*height*bytespp;
+	data = new unsigned char[nbytes];
+	memset(data, 0, nbytes);
+}
+
+TGAImage::TGAImage(const TGAImage &img) {
+	width = img.width;
+	height = img.height;
+	bytespp = img.bytespp;
+	unsigned long nbytes = width*height*bytespp;
+	data = new unsigned char[nbytes];
+	memcpy(data, img.data, nbytes);
+}
+
+TGAImage::~TGAImage() {
+	if (data) delete [] data;
+}
+
+TGAImage & TGAImage::operator =(const TGAImage &img) {
+	if (this != &img) {
+		if (data) delete [] data;
+		width  = img.width;
+		height = img.height;
+		bytespp = img.bytespp;
+		unsigned long nbytes = width*height*bytespp;
+		data = new unsigned char[nbytes];
+		memcpy(data, img.data, nbytes);
+	}
+	return *this;
+}
+
+bool TGAImage::read_tga_file(const char *filename) {
+	if (data) delete [] data;
+	data = NULL;
+	std::ifstream in;
+	in.open (filename, std::ios::binary);
+	if (!in.is_open()) {
+		std::cerr << "can't open file " << filename << "\n";
+		in.close();
+		return false;
+	}
+	TGA_Header header;
+	in.read((char *)&header, sizeof(header));
+	if (!in.good()) {
+		in.close();
+		std::cerr << "an error occured while reading the header\n";
+		return false;
+	}
+	width   = header.width;
+	height  = header.height;
+	bytespp = header.bitsperpixel>>3;
+	if (width<=0 || height<=0 || (bytespp!=GRAYSCALE && bytespp!=RGB && bytespp!=RGBA)) {
+		in.close();
+		std::cerr << "bad bpp (or width/height) value\n";
+		return false;
+	}
+	unsigned long nbytes = bytespp*width*height;
+	data = new unsigned char[nbytes];
+	if (3==header.datatypecode || 2==header.datatypecode) {
+		in.read((char *)data, nbytes);
+		if (!in.good()) {
+			in.close();
+			std::cerr << "an error occured while reading the data\n";
+			return false;
+		}
+	} else if (10==header.datatypecode||11==header.datatypecode) {
+		if (!load_rle_data(in)) {
+			in.close();
+			std::cerr << "an error occured while reading the data\n";
+			return false;
+		}
+	} else {
+		in.close();
+		std::cerr << "unknown file format " << (int)header.datatypecode << "\n";
+		return false;
+	}
+	if (!(header.imagedescriptor & 0x20)) {
+		flip_vertically();
+	}
+	if (header.imagedescriptor & 0x10) {
+		flip_horizontally();
+	}
+	std::cerr << width << "x" << height << "/" << bytespp*8 << "\n";
+	in.close();
+	return true;
+}
+
+bool TGAImage::load_rle_data(std::ifstream &in) {
+	unsigned long pixelcount = width*height;
+	unsigned long currentpixel = 0;
+	unsigned long currentbyte  = 0;
+	TGAColor colorbuffer;
+	do {
+		unsigned char chunkheader = 0;
+		chunkheader = in.get();
+		if (!in.good()) {
+			std::cerr << "an error occured while reading the data\n";
+			return false;
+		}
+		if (chunkheader<128) {
+			chunkheader++;
+			for (int i=0; i<chunkheader; i++) {
+				in.read((char *)colorbuffer.raw, bytespp);
+				if (!in.good()) {
+					std::cerr << "an error occured while reading the header\n";
+					return false;
+				}
+				for (int t=0; t<bytespp; t++)
+					data[currentbyte++] = colorbuffer.raw[t];
+				currentpixel++;
+				if (currentpixel>pixelcount) {
+					std::cerr << "Too many pixels read\n";
+					return false;
+				}
+			}
+		} else {
+			chunkheader -= 127;
+			in.read((char *)colorbuffer.raw, bytespp);
+			if (!in.good()) {
+				std::cerr << "an error occured while reading the header\n";
+				return false;
+			}
+			for (int i=0; i<chunkheader; i++) {
+				for (int t=0; t<bytespp; t++)
+					data[currentbyte++] = colorbuffer.raw[t];
+				currentpixel++;
+				if (currentpixel>pixelcount) {
+					std::cerr << "Too many pixels read\n";
+					return false;
+				}
+			}
+		}
+	} while (currentpixel < pixelcount);
+	return true;
+}
+
+bool TGAImage::write_tga_file(const char *filename, bool rle) {
+	unsigned char developer_area_ref[4] = {0, 0, 0, 0};
+	unsigned char extension_area_ref[4] = {0, 0, 0, 0};
+	unsigned char footer[18] = {'T','R','U','E','V','I','S','I','O','N','-','X','F','I','L','E','.','\0'};
+	std::ofstream out;
+	out.open (filename, std::ios::binary);
+	if (!out.is_open()) {
+		std::cerr << "can't open file " << filename << "\n";
+		out.close();
+		return false;
+	}
+	TGA_Header header;
+	memset((void *)&header, 0, sizeof(header));
+	header.bitsperpixel = bytespp<<3;
+	header.width  = width;
+	header.height = height;
+	header.datatypecode = (bytespp==GRAYSCALE?(rle?11:3):(rle?10:2));
+	header.imagedescriptor = 0x20; // top-left origin
+	out.write((char *)&header, sizeof(header));
+	if (!out.good()) {
+		out.close();
+		std::cerr << "can't dump the tga file\n";
+		return false;
+	}
+	if (!rle) {
+		out.write((char *)data, width*height*bytespp);
+		if (!out.good()) {
+			std::cerr << "can't unload raw data\n";
+			out.close();
+			return false;
+		}
+	} else {
+		if (!unload_rle_data(out)) {
+			out.close();
+			std::cerr << "can't unload rle data\n";
+			return false;
+		}
+	}
+	out.write((char *)developer_area_ref, sizeof(developer_area_ref));
+	if (!out.good()) {
+		std::cerr << "can't dump the tga file\n";
+		out.close();
+		return false;
+	}
+	out.write((char *)extension_area_ref, sizeof(extension_area_ref));
+	if (!out.good()) {
+		std::cerr << "can't dump the tga file\n";
+		out.close();
+		return false;
+	}
+	out.write((char *)footer, sizeof(footer));
+	if (!out.good()) {
+		std::cerr << "can't dump the tga file\n";
+		out.close();
+		return false;
+	}
+	out.close();
+	return true;
+}
+
+// TODO: it is not necessary to break a raw chunk for two equal pixels (for the matter of the resulting size)
+bool TGAImage::unload_rle_data(std::ofstream &out) {
+	const unsigned char max_chunk_length = 128;
+	unsigned long npixels = width*height;
+	unsigned long curpix = 0;
+	while (curpix<npixels) {
+		unsigned long chunkstart = curpix*bytespp;
+		unsigned long curbyte = curpix*bytespp;
+		unsigned char run_length = 1;
+		bool raw = true;
+		while (curpix+run_length<npixels && run_length<max_chunk_length) {
+			bool succ_eq = true;
+			for (int t=0; succ_eq && t<bytespp; t++) {
+				succ_eq = (data[curbyte+t]==data[curbyte+t+bytespp]);
+			}
+			curbyte += bytespp;
+			if (1==run_length) {
+				raw = !succ_eq;
+			}
+			if (raw && succ_eq) {
+				run_length--;
+				break;
+			}
+			if (!raw && !succ_eq) {
+				break;
+			}
+			run_length++;
+		}
+		curpix += run_length;
+		out.put(raw?run_length-1:run_length+127);
+		if (!out.good()) {
+			std::cerr << "can't dump the tga file\n";
+			return false;
+		}
+		out.write((char *)(data+chunkstart), (raw?run_length*bytespp:bytespp));
+		if (!out.good()) {
+			std::cerr << "can't dump the tga file\n";
+			return false;
+		}
+	}
+	return true;
+}
+
+TGAColor TGAImage::get(int x, int y) {
+	if (!data || x<0 || y<0 || x>=width || y>=height) {
+		return TGAColor();
+	}
+	return TGAColor(data+(x+y*width)*bytespp, bytespp);
+}
+
+bool TGAImage::set(int x, int y, TGAColor c) {
+	if (!data || x<0 || y<0 || x>=width || y>=height) {
+		return false;
+	}
+	memcpy(data+(x+y*width)*bytespp, c.raw, bytespp);
+	return true;
+}
+
+int TGAImage::get_bytespp() {
+	return bytespp;
+}
+
+int TGAImage::get_width() {
+	return width;
+}
+
+int TGAImage::get_height() {
+	return height;
+}
+
+bool TGAImage::flip_horizontally() {
+	if (!data) return false;
+	int half = width>>1;
+	for (int i=0; i<half; i++) {
+		for (int j=0; j<height; j++) {
+			TGAColor c1 = get(i, j);
+			TGAColor c2 = get(width-1-i, j);
+			set(i, j, c2);
+			set(width-1-i, j, c1);
+		}
+	}
+	return true;
+}
+
+bool TGAImage::flip_vertically() {
+	if (!data) return false;
+	unsigned long bytes_per_line = width*bytespp;
+	unsigned char *line = new unsigned char[bytes_per_line];
+	int half = height>>1;
+	for (int j=0; j<half; j++) {
+		unsigned long l1 = j*bytes_per_line;
+		unsigned long l2 = (height-1-j)*bytes_per_line;
+		memmove((void *)line,      (void *)(data+l1), bytes_per_line);
+		memmove((void *)(data+l1), (void *)(data+l2), bytes_per_line);
+		memmove((void *)(data+l2), (void *)line,      bytes_per_line);
+	}
+	delete [] line;
+	return true;
+}
+
+unsigned char *TGAImage::buffer() {
+	return data;
+}
+
+void TGAImage::clear() {
+	memset((void *)data, 0, width*height*bytespp);
+}
+
+bool TGAImage::scale(int w, int h) {
+	if (w<=0 || h<=0 || !data) return false;
+	unsigned char *tdata = new unsigned char[w*h*bytespp];
+	int nscanline = 0;
+	int oscanline = 0;
+	int erry = 0;
+	unsigned long nlinebytes = w*bytespp;
+	unsigned long olinebytes = width*bytespp;
+	for (int j=0; j<height; j++) {
+		int errx = width-w;
+		int nx   = -bytespp;
+		int ox   = -bytespp;
+		for (int i=0; i<width; i++) {
+			ox += bytespp;
+			errx += w;
+			while (errx>=(int)width) {
+				errx -= width;
+				nx += bytespp;
+				memcpy(tdata+nscanline+nx, data+oscanline+ox, bytespp);
+			}
+		}
+		erry += h;
+		oscanline += olinebytes;
+		while (erry>=(int)height) {
+			if (erry>=(int)height<<1) // it means we jump over a scanline
+				memcpy(tdata+nscanline+nlinebytes, tdata+nscanline, nlinebytes);
+			erry -= height;
+			nscanline += nlinebytes;
+		}
+	}
+	delete [] data;
+	data = tdata;
+	width = w;
+	height = h;
+	return true;
+}
+
diff --git a/src/tgaimage.h b/src/tgaimage.h
new file mode 100644
index 0000000..7d5d9fb
--- /dev/null
+++ b/src/tgaimage.h
@@ -0,0 +1,96 @@
+#ifndef __IMAGE_H__
+#define __IMAGE_H__
+
+#include <fstream>
+
+#pragma pack(push,1)
+struct TGA_Header {
+	char idlength;
+	char colormaptype;
+	char datatypecode;
+	short colormaporigin;
+	short colormaplength;
+	char colormapdepth;
+	short x_origin;
+	short y_origin;
+	short width;
+	short height;
+	char  bitsperpixel;
+	char  imagedescriptor;
+};
+#pragma pack(pop)
+
+
+
+struct TGAColor {
+	union {
+		struct {
+			unsigned char b, g, r, a;
+		};
+		unsigned char raw[4];
+		unsigned int val;
+	};
+	int bytespp;
+
+	TGAColor() : val(0), bytespp(1) {
+	}
+
+	TGAColor(unsigned char R, unsigned char G, unsigned char B, unsigned char A) : b(B), g(G), r(R), a(A), bytespp(4) {
+	}
+
+	TGAColor(int v, int bpp) : val(v), bytespp(bpp) {
+	}
+
+	TGAColor(const TGAColor &c) : val(c.val), bytespp(c.bytespp) {
+	}
+
+	TGAColor(const unsigned char *p, int bpp) : val(0), bytespp(bpp) {
+		for (int i=0; i<bpp; i++) {
+			raw[i] = p[i];
+		}
+	}
+
+	TGAColor & operator =(const TGAColor &c) {
+		if (this != &c) {
+			bytespp = c.bytespp;
+			val = c.val;
+		}
+		return *this;
+	}
+};
+
+
+class TGAImage {
+protected:
+	unsigned char* data;
+	int width;
+	int height;
+	int bytespp;
+
+	bool   load_rle_data(std::ifstream &in);
+	bool unload_rle_data(std::ofstream &out);
+public:
+	enum Format {
+		GRAYSCALE=1, RGB=3, RGBA=4
+	};
+
+	TGAImage();
+	TGAImage(int w, int h, int bpp);
+	TGAImage(const TGAImage &img);
+	bool read_tga_file(const char *filename);
+	bool write_tga_file(const char *filename, bool rle=true);
+	bool flip_horizontally();
+	bool flip_vertically();
+	bool scale(int w, int h);
+	TGAColor get(int x, int y);
+	bool set(int x, int y, TGAColor c);
+	~TGAImage();
+	TGAImage & operator =(const TGAImage &img);
+	int get_width();
+	int get_height();
+	int get_bytespp();
+	unsigned char *buffer();
+	void clear();
+};
+
+#endif //__IMAGE_H__