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//
// Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
#include "shader_utils.h"
#include <vector>
#include <iostream>
#include <fstream>
static std::string ReadFileToString(const std::string &source)
{
std::ifstream stream(source);
if (!stream)
{
std::cerr << "Failed to load shader file: " << source;
return "";
}
std::string result;
stream.seekg(0, std::ios::end);
result.reserve(static_cast<unsigned int>(stream.tellg()));
stream.seekg(0, std::ios::beg);
result.assign((std::istreambuf_iterator<char>(stream)), std::istreambuf_iterator<char>());
return result;
}
GLuint CompileShader(GLenum type, const std::string &source)
{
GLuint shader = glCreateShader(type);
const char *sourceArray[1] = { source.c_str() };
glShaderSource(shader, 1, sourceArray, NULL);
glCompileShader(shader);
GLint compileResult;
glGetShaderiv(shader, GL_COMPILE_STATUS, &compileResult);
if (compileResult == 0)
{
GLint infoLogLength;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLogLength);
std::vector<GLchar> infoLog(infoLogLength);
glGetShaderInfoLog(shader, infoLog.size(), NULL, &infoLog[0]);
std::cerr << "shader compilation failed: " << &infoLog[0];
glDeleteShader(shader);
shader = 0;
}
return shader;
}
GLuint CompileShaderFromFile(GLenum type, const std::string &sourcePath)
{
std::string source = ReadFileToString(sourcePath);
if (source.empty())
{
return 0;
}
return CompileShader(type, source);
}
GLuint CompileProgram(const std::string &vsSource, const std::string &fsSource)
{
GLuint program = glCreateProgram();
GLuint vs = CompileShader(GL_VERTEX_SHADER, vsSource);
GLuint fs = CompileShader(GL_FRAGMENT_SHADER, fsSource);
if (vs == 0 || fs == 0)
{
glDeleteShader(fs);
glDeleteShader(vs);
glDeleteProgram(program);
return 0;
}
glAttachShader(program, vs);
glDeleteShader(vs);
glAttachShader(program, fs);
glDeleteShader(fs);
glLinkProgram(program);
GLint linkStatus;
glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
if (linkStatus == 0)
{
GLint infoLogLength;
glGetProgramiv(program, GL_INFO_LOG_LENGTH, &infoLogLength);
std::vector<GLchar> infoLog(infoLogLength);
glGetProgramInfoLog(program, infoLog.size(), NULL, &infoLog[0]);
std::cerr << "program link failed: " << &infoLog[0];
glDeleteProgram(program);
return 0;
}
return program;
}
GLuint CompileProgramFromFiles(const std::string &vsPath, const std::string &fsPath)
{
std::string vsSource = ReadFileToString(vsPath);
std::string fsSource = ReadFileToString(fsPath);
if (vsSource.empty() || fsSource.empty())
{
return 0;
}
return CompileProgram(vsSource, fsSource);
}
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