从资产文件编译和链接 GLSL-ES 着色器
该资产文件夹来存储你的 GLSL-ES 着色器文件中的最常见的地方。要在 OpenGL ES 应用程序中使用它们,你需要首先将它们加载到字符串中。此函数从资产文件创建一个字符串:
private String loadStringFromAssetFile(Context myContext, String filePath){
StringBuilder shaderSource = new StringBuilder();
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(myContext.getAssets().open(filePath)));
String line;
while((line = reader.readLine()) != null){
shaderSource.append(line).append("\n");
}
reader.close();
return shaderSource.toString();
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "Could not load shader file");
return null;
}
}
现在你需要创建一个函数来编译存储在 sting 中的着色器:
private int compileShader(int shader_type, String shaderString){
// This compiles the shader from the string
int shader = glCreateShader(shader_type);
glShaderSource(shader, shaderString);
glCompileShader(shader);
// This checks for for compilation errors
int[] compiled = new int[1];
glGetShaderiv(shader, GL_COMPILE_STATUS, compiled, 0);
if (compiled[0] == 0) {
String log = glGetShaderInfoLog(shader);
Log.e(TAG, "Shader compilation error: ");
Log.e(TAG, log);
}
return shader;
}
现在你可以加载,编译和链接着色器:
// Load shaders from file
String vertexShaderString = loadStringFromAssetFile(context, "your_vertex_shader.glsl");
String fragmentShaderString = loadStringFromAssetFile(context, "your_fragment_shader.glsl");
// Compile shaders
int vertexShader = compileShader(GL_VERTEX_SHADER, vertexShaderString);
int fragmentShader = compileShader(GL_FRAGMENT_SHADER, fragmentShaderString);
// Link shaders and create shader program
int shaderProgram = glCreateProgram();
glAttachShader(shaderProgram , vertexShader);
glAttachShader(shaderProgram , fragmentShader);
glLinkProgram(shaderProgram);
// Check for linking errors:
int linkStatus[] = new int[1];
glGetProgramiv(shaderProgram, GL_LINK_STATUS, linkStatus, 0);
if (linkStatus[0] != GL_TRUE) {
String log = glGetProgramInfoLog(shaderProgram);
Log.e(TAG,"Could not link shader program: ");
Log.e(TAG, log);
}
如果没有错误,你的着色器程序就可以使用了:
glUseProgram(shaderProgram);