1 //
2 // Copyright 2014 The ANGLE Project Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 //
6
7 #include "tga_utils.h"
8
9 #include <fstream>
10 #include <iostream>
11 #include <limits.h>
12 #include <stdint.h>
13 #include <string>
14
TGAImage()15 TGAImage::TGAImage()
16 : width(0), height(0), data(0)
17 {
18 }
19
20 struct TGAHeader
21 {
22 uint8_t idSize;
23 uint8_t mapType;
24 uint8_t imageType;
25 uint16_t paletteStart;
26 uint16_t paletteSize;
27 uint8_t paletteEntryDepth;
28 uint16_t x;
29 uint16_t y;
30 uint16_t width;
31 uint16_t height;
32 uint8_t colorDepth;
33 uint8_t descriptor;
34 };
35
36 #define INVERTED_BIT (1 << 5)
37
38 template <typename dataType>
readBinary(std::ifstream & stream,dataType & item)39 void readBinary(std::ifstream &stream, dataType &item)
40 {
41 stream.read(reinterpret_cast<char *>(&item), sizeof(dataType));
42 }
43
44 template <typename dataType>
readBinary(std::ifstream & stream,std::vector<dataType> & items)45 void readBinary(std::ifstream &stream, std::vector<dataType> &items)
46 {
47 stream.read(reinterpret_cast<char *>(items.data()), sizeof(dataType) * items.size());
48 }
49
LoadTGAImageFromFile(const std::string & path,TGAImage * image)50 bool LoadTGAImageFromFile(const std::string &path, TGAImage *image)
51 {
52 std::ifstream stream(path, std::ios::binary);
53 if (!stream)
54 {
55 std::cerr << "error opening tga file " << path << " for reading.\n";
56 return false;
57 }
58
59 TGAHeader header;
60 readBinary(stream, header.idSize);
61 readBinary(stream, header.mapType);
62 readBinary(stream, header.imageType);
63 readBinary(stream, header.paletteStart);
64 readBinary(stream, header.paletteSize);
65 readBinary(stream, header.paletteEntryDepth);
66 readBinary(stream, header.x);
67 readBinary(stream, header.y);
68 readBinary(stream, header.width);
69 readBinary(stream, header.height);
70 readBinary(stream, header.colorDepth);
71 readBinary(stream, header.descriptor);
72
73 image->width = header.width;
74 image->height = header.height;
75
76 size_t pixelComponentCount = header.colorDepth / CHAR_BIT;
77 std::vector<unsigned char> buffer(header.width * header.height * pixelComponentCount);
78 readBinary(stream, buffer);
79
80 image->data.reserve(header.width * header.height);
81
82 for (size_t y = 0; y < header.height; y++)
83 {
84 size_t rowIdx = ((header.descriptor & INVERTED_BIT) ? (header.height - 1 - y) : y) * header.width * pixelComponentCount;
85 for (size_t x = 0; x < header.width; x++)
86 {
87 size_t pixelIdx = rowIdx + x * pixelComponentCount;
88
89 Byte4 pixel;
90 pixel[0] = (pixelComponentCount > 2) ? buffer[pixelIdx + 2] : 0;
91 pixel[2] = (pixelComponentCount > 0) ? buffer[pixelIdx + 0] : 0;
92 pixel[1] = (pixelComponentCount > 1) ? buffer[pixelIdx + 1] : 0;
93 pixel[3] = (pixelComponentCount > 3) ? buffer[pixelIdx + 3] : 255;
94
95 image->data.push_back(pixel);
96 }
97 }
98
99 std::cout << "loaded image " << path << ".\n";
100
101 return true;
102 }
103
LoadTextureFromTGAImage(const TGAImage & image)104 GLuint LoadTextureFromTGAImage(const TGAImage &image)
105 {
106 if (image.width > 0 && image.height > 0)
107 {
108 GLuint texture;
109 glGenTextures(1, &texture);
110 glBindTexture(GL_TEXTURE_2D, texture);
111 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
112 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
113 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
114 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, static_cast<GLsizei>(image.width), static_cast<GLsizei>(image.height), 0,
115 GL_RGBA, GL_UNSIGNED_BYTE, image.data.data());
116 glGenerateMipmap(GL_TEXTURE_2D);
117 return texture;
118 }
119 else
120 {
121 return 0;
122 }
123 }
124