cocos2dx版本为3.10
1.具体原理和代码可以参考博文《利用shader改变图片色相Hue》，下面的代码根据该博文进行整理优化。
基本原理就是将RGB值转换为HSL值后加上输入的HSL值，再转换为RGB值。
2.spine变色的思路有三种：
①spine::SkeletonAnimation调用shader
②读取spine对应的atlas文件，分析该文件得到所需的png图片，将该图片读入内存，修改内存中像素颜色，然后生成texture赋值给spine中的spAtlas->pages->rendererObject
③读取spine对应的atlas文件，分析该文件得到所需的png图片，将该图片读入内存，修改内存中像素颜色，保存为新的png图片；读取atlas文件，修改里面png名字为新png图片名字，保存为新的atlas文件；spine创建时使用新的png图片和新的atlas文件；
以上三种方法都可行，但在实现过程中我选择使用了第③种方法；
第①种方法简单易用，但是打包到一些低端的android手机时发现掉帧很厉害，所以才会有第②和第③种方法。
第②种方法经过测试也是可行的，但是破坏了spine的正常创建流程，导致对源码的修改过于复杂容易导致各种问题。
第③种方法独立在正常创建spine流程之前，更稳当可控。
3.根据资料色相H值的范围在[0,360],饱和度S值的范围在[0,1],明度L值的范围在[0,1]；在PhotoShop中(快捷键ctrl+u)可调值范围为色相H[-180,180],饱和度A[-100,100],明度I[-100,100]；
所以在代码中,H值不进行转换，S值和L值都除以100；在实际测试过程中发现，PS调试出来的效果和程序得到的效果在S/L不为0的情况下还是有区别的，具体原因不懂，估计可能是算法不一致吧。
4.第①种方法shader
①shader代码
1 #ifdef GL_ES
2 precision mediump float;
3 #endif
4 varying vec2 v_texCoord;
5 uniform float u_dH;
6 uniform float u_dS;
7 uniform float u_dL;
8 void main() {
9 vec4 texColor = texture2D(CC_Texture0, v_texCoord);
10 float r = texColor.r;
11 float g = texColor.g;
12 float b = texColor.b;
13 float a = texColor.a;
14 //convert rgb to hsl
15 float h;
16 float s;
17 float l;
18 {
19 float max = max(max(r, g), b);
20 float min = min(min(r, g), b);
21 //----h
22 if (max == min){
23 h = 0.0;
24 }
25 else if (max == r&&g >= b){
26 h = 60.0*(g - b) / (max - min) + 0.0;
27 }
28 else if (max == r&&g < b){
29 h = 60.0*(g - b) / (max - min) + 360.0;
30 }
31 else if (max == g){
32 h = 60.0*(b - r) / (max - min) + 120.0;
33 }
34 else if (max == b){
35 h = 60.0*(r - g) / (max - min) + 240.0;
36 }
37 //----l
38 l = 0.5*(max + min);
39 //----s
40 if (l == 0.0 || max == min){
41 s = 0.0;
42 }
43 else if (0.0 <= l&&l <= 0.5){
44 s = (max - min) / (2.0*l);
45 }
46 else if (l > 0.5){
47 s = (max - min) / (2.0 - 2.0*l);
48 }
49 }
50 //(h,s,l)+(dH,dS,dL) -> (h,s,l)
51 h = h + u_dH;
52 s = min(1.0, max(0.0, s + u_dS));
53 l = l + u_dL;
54 //convert (h,s,l) to rgb and got final color
55 vec4 finalColor;
56 {
57 float q;
58 if (l < 0.5){
59 q = l*(1.0 + s);
60 }
61 else if (l >= 0.5){
62 q = l + s - l*s;
63 }
64 float p = 2.0*l - q;
65 float hk = h / 360.0;
66
67 float t[3];
68 t[0] = hk + 1.0 / 3.0;
69 t[1] = hk;
70 t[2] = hk - 1.0 / 3.0;
71
72 float c[3];
73 for (int i = 0; i < 3; i++){
74 if (t[i] < 0.0)t[i] += 1.0;
75 if (t[i] > 1.0)t[i] -= 1.0;
76
77 if (t[i] < 1.0 / 6.0){
78 c[i] = p + ((q - p)*6.0*t[i]);
79 }
80 else if (1.0 / 6.0 <= t[i] && t[i] < 0.5){
81 c[i] = q;
82 }
83 else if (0.5 <= t[i] && t[i] < 2.0 / 3.0){
84 c[i] = p + ((q - p)*6.0*(2.0 / 3.0 - t[i]));
85 }
86 else{
87 c[i] = p;
88 }
89 }
90 finalColor = vec4(c[0], c[1], c[2], a);
91 }
92 finalColor += vec4(u_dL, u_dL, u_dL, 0.0);
93 gl_FragColor = finalColor;
94 }
②调用代码
1 auto glprogram = GLProgram::createWithByteArrays(ccPositionTextureColor_vert, shader_content);//如果是Sprite使用这个Shader，则需要换为ccPositionTextureColor_noMVP_vert
2 GLProgramState* glState = GLProgramState::getOrCreateWithGLProgram(glprogram);
3
4 glState->setUniformFloat("u_dH", h);
5 glState->setUniformFloat("u_dS", s / 100);
6 glState->setUniformFloat("u_dL", l / 100);
7
8 skeleton_animation->setGLProgramState(glState);
5.第③种方法创建新的png文件和atlas文件
①创建新png文件函数(这里的函数实现和参考博文《利用shader改变图片色相Hue》的实现不一样，参考博文只传了一个H值，这里是直接根据shader进行的移植修改)
1 Image* create_new_image_hsl(Image* image, float u_dH, float u_dS, float u_dL){
2 u_dH = u_dH;
3 u_dS = u_dS / 100.0f;
4 u_dL = u_dL / 100.0f;
5
6 bool hasAlpha = image->hasAlpha();
7 Texture2D::PixelFormat pixelFormat = image->getRenderFormat();
8 int bit_per_pixel = image->getBitPerPixel(); //每像素多少位
9 unsigned int length = image->getWidth()*image->getHeight();
10
11 if (hasAlpha){
12 //只处理了RGBA8888的格式
13 if (pixelFormat == Texture2D::PixelFormat::RGBA8888){
14 unsigned int* inPixel32 = (unsigned int*)image->getData();
15 for (unsigned int i = 0; i < length; ++i, ++inPixel32)
16 {
17 unsigned char cr = (*inPixel32 >> 0) & 0xFF; // R
18 unsigned char cg = (*inPixel32 >> 8) & 0xFF; // G
19 unsigned char cb = (*inPixel32 >> 16) & 0xFF; // B
20 unsigned char ca = (*inPixel32 >> 24) & 0xFF; // A
21 //透明图层不做处理
22 if (ca){
23 float r = cr*1.0f / 0xFF;
24 float g = cg*1.0f / 0xFF;
25 float b = cb*1.0f / 0xFF;
26
27 float h = 0;
28 float s = 0;
29 float l = 0;
30 {
31 float max = r > g ? r : g;
32 max = max > b ? max : b;
33
34 float min = r < g ? r : g;
35 min = min < b ? min : b;
36
37 //----h
38 if (max == min){
39 h = 0;
40 }
41 else if (max == r && g >= b){
42 h = 60.0f*(g - b) / (max - min);
43 }
44 else if (max == r && g < b){
45 h = 60.0f*(g - b) / (max - min) + 360.0f;
46 }
47 else if (max == g){
48 h = 60.0f*(b - r) / (max - min) + 120.0f;
49 }
50 else if (max == b){
51 h = 60.0f*(r - g) / (max - min) + 240.0f;
52 }
53 //----l
54 l = 0.5f*(max + min);
55 //----s
56 if (l == 0 || max == min){
57 s = 0;
58 }
59 else if (0 <= l&&l <= 0.5f){
60 s = (max - min) / (2.0f*l);
61 }
62 else if (l > 0.5f){
63 s = (max - min) / (2.0f - 2.0f*l);
64 }
65 }
66 //(h,s,l)+(dH,dS,dL) -> (h,s,l)
67 h = h + u_dH;
68 s = 0 > s + u_dS ? 0 : s + u_dS;
69 s = s < 1.0f ? s : 1.0f;
70
71 l = l + u_dL;
72 //convert (h,s,l) to rgb and got final color
73
74 //vec4 finalColor;
75 {
76 float q;
77 if (l < 0.5f){
78 q = l*(1.0f + s);
79 }
80 else if (l >= 0.5f){
81 q = l + s - l*s;
82 }
83 float p = 2.0f*l - q;
84 float hk = h / 360.0f;
85
86 float t[3] = {};
87 t[0] = hk + 1.0f / 3.0f;
88 t[1] = hk;
89 t[2] = hk - 1.0f / 3.0f;
90
91 float c[3] = {};
92 for (int i = 0; i < 3; i++){
93 if (t[i] < 0){
94 t[i] += 1.0f;
95 }
96 if (t[i] > 1.0f){
97 t[i] -= 1.0f;
98 }
99
100 if (t[i] < 1.0f / 6.0f){
101 c[i] = p + ((q - p)*6.0f*t[i]);
102 }
103 else if (1.0f / 6.0f <= t[i] && t[i] < 0.5f){
104 c[i] = q;
105 }
106 else if (0.5f <= t[i] && t[i] < 2.0f / 3.0f){
107 c[i] = p + ((q - p)*6.0f*(2.0f / 3.0f - t[i]));
108 }
109 else{
110 c[i] = p;
111 }
112 }
113 //finalColor = vec4(c[0], c[1], c[2], a);
114
115 r = c[0];
116 g = c[1];
117 b = c[2];
118 }
119
120 //finalColor += vec4(u_dL, u_dL, u_dL, 0.0);
121 r += u_dL;
122 g += u_dL;
123 b += u_dL;
124 //限制rgb值的有效范围
125 if (r > 1.0f) r = 1.0f;
126 if (g > 1.0f) g = 1.0f;
127 if (b > 1.0f) b = 1.0f;
128 if (r < 0) r = 0;
129 if (g < 0) g = 0;
130 if (b < 0) b = 0;
131
132 unsigned char final_r = r * 0xFF;
133 unsigned char final_g = g * 0xFF;
134 unsigned char final_b = b * 0xFF;
135 unsigned char final_a = ca;
136
137
138 unsigned int val = final_a;
139 val = val << 8;
140 val |= final_b;
141 val = val << 8;
142 val |= final_g;
143 val = val << 8;
144 val |= final_r;
145
146 *inPixel32 = val;
147 }
148 }
149 }
150 }
151
152 return image;
153 }
②分析atlas文件，得到对应的png文件，并生成新png文件和atlas文件
1 bool create_new_png_and_atlas(const char* atlas_name_no_extension, float u_dH, float u_dS, float u_dL)
2 {
3 bool ret = false;
4
5 std::string atlas_name = atlas_name_no_extension;
6 atlas_name += ".atlas";
7 std::string atlas_file_full_name = FileUtils::getInstance()->fullPathForFilename(atlas_name);
8 Data data = FileUtils::getInstance()->getDataFromFile(atlas_file_full_name);
9
10 if (!data.isNull()){
11 std::string writeable_path = FileUtils::getInstance()->getWritablePath();
12
13 char* orginal_atlas_content = new char[data.getSize()]();
14 memcpy(orginal_atlas_content, data.getBytes(), data.getSize());
15
16 char sz_new_atlas_path[256] = {};
17 sprintf(sz_new_atlas_path, "%s%s_%d_%d_%d.atlas", writeable_path.c_str(), atlas_name_no_extension, (int)u_dH, (int)u_dS, (int)u_dL);
18
19 //为了保证大小，创建一个两倍大小的内存大小(这里可以适当减少大小)
20 unsigned char* new_atlas_content = new unsigned char[2 * data.getSize()]();
21 memset(new_atlas_content, 0, 2 * data.getSize());
22
23 //分析得出png文件名字，可能有分为多个png的情况
24 std::vector<std::string> png_no_extension_list;
25 int line_start_idx = 0, line_end_idx = 0;
26 int orginal_content_start_idx = 0, new_content_idx = 0, new_content_total_len = 0;
27
28 for (int i = 0; i < data.getSize(); ++i){
29 line_end_idx = i;
30
31 //每一行判断是否为png
32 if (orginal_atlas_content[i] == '
'){
33 int line_len = line_end_idx - line_start_idx;
34
35 //处理是图片的情况
36 if (line_len > 4 && orginal_atlas_content[line_end_idx - 4] == '.' &&
37 (orginal_atlas_content[line_end_idx - 3] == 'p' || orginal_atlas_content[line_end_idx - 3] == 'P') &&
38 (orginal_atlas_content[line_end_idx - 2] == 'n' || orginal_atlas_content[line_end_idx - 2] == 'N') &&
39 (orginal_atlas_content[line_end_idx - 1] == 'g' || orginal_atlas_content[line_end_idx - 1] == 'G')){
40 //将png行前面的数据拷贝进来
41 int cpy_len = line_start_idx - orginal_content_start_idx;
42 if (cpy_len > 0){
43 memcpy(new_atlas_content + new_content_idx, orginal_atlas_content + orginal_content_start_idx, cpy_len);
44 new_content_idx += cpy_len;
45 new_content_total_len += cpy_len;
46 }
47
48 //没有后缀的png的名字
49 char png_name_no_extension[256] = {};
50 memcpy(png_name_no_extension, orginal_atlas_content + line_start_idx, line_len - 4);
51 png_no_extension_list.push_back(png_name_no_extension);
52
53 //记录列表
54 char sz_new_png_name[256] = {};
55 sprintf(sz_new_png_name, "%s_%d_%d_%d.png
", png_name_no_extension, (int)u_dH, (int)u_dS, (int)u_dL);
56
57 //将图片名字写入新内容
58 cpy_len = strlen(sz_new_png_name);
59 memcpy(new_atlas_content + new_content_idx, sz_new_png_name, cpy_len);
60 new_content_idx += cpy_len;
61 new_content_total_len += cpy_len;
62
63 orginal_content_start_idx = line_end_idx + 1;
64 }
65
66 line_start_idx = line_end_idx + 1;
67 }
68 }
69
70 //将最后一个png行到最后那部分数据也拷贝进来
71 if (data.getSize() > orginal_content_start_idx){
72 int cpy_len = data.getSize() - orginal_content_start_idx;
73 memcpy(new_atlas_content + new_content_idx, orginal_atlas_content + orginal_content_start_idx, cpy_len);
74 new_content_total_len += cpy_len;
75 }
76
77
78 Data data;
79 data.copy(new_atlas_content, new_content_total_len);
80
81 if (!FileUtils::getInstance()->writeDataToFile(data, sz_new_atlas_path)){
82 cocos2d::log("========!!! save file %s error !!!========.", sz_new_atlas_path);
83 }
84 else{
85 ret = true;
86 }
87
88 data.clear();
89
90 delete[]orginal_atlas_content;
91 delete[]new_atlas_content;
92
93 if (png_no_extension_list.size() <= 0){
94 cocos2d::log("========!!! png_name_list is empty error !!!========.");
95 return false;
96 }
97
98 if (!ret){
99 return false;
100 }
101
102 //写入新图片
103 for (std::vector<std::string>::iterator it = png_no_extension_list.begin(); it != png_no_extension_list.end(); ++it){
104 if (!ret){
105 break;
106 }
107
108 char sz_new_png_path[256] = {};
109 sprintf(sz_new_png_path, "%s%s_%d_%d_%d.png", writeable_path.c_str(), it->c_str(), (int)u_dH, (int)u_dS, (int)u_dL);
110
111 char sz_png_name[256] = {};
112 sprintf(sz_png_name, "%s.png", it->c_str());
113 std::string png_file_full_name = FileUtils::getInstance()->fullPathForFilename(sz_png_name);
114
115 Image* image = new Image();
116 if (image->initWithImageFile(png_file_full_name)){
117 if (Image* new_image = create_new_image_hsl(image, u_dH, u_dS, u_dL)){
118 if (!new_image->saveToFile(sz_new_png_path, false)){
119 cocos2d::log("========!!! save file %s error !!!========.", sz_new_png_path);
120 ret = false;
121 }
122 }
123 else{
124 cocos2d::log("========!!! create_new_image_hsl %s error !!!========.", sz_new_png_path);
125 ret = false;
126 }
127 }
128 else{
129 cocos2d::log("========!!! initWithImageFile %s error !!!========.", png_file_full_name.c_str());
130 ret = false;
131 }
132
133 delete image;
134 }
135 }
136
137 return ret;
138 }
6.实现效果
①原图
②PhotoShop中调到115,0,0的效果
③传入参数115,0,0后创建新Image的效果
可以看到，使用ps修改的效果和程序输出的效果基本一样。
以上，完。