preparations for shaders

shader.cpp

@@ -0,0 +1,73 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "stdafx.h"
+#include "shader.h"
+
+inline bool strcend(std::string const &value, std::string const &ending)
+{
+	if (ending.size() > value.size())
+		return false;
+	return std::equal(ending.rbegin(), ending.rend(), value.rbegin());
+}
+
+gl_shader::gl_shader(std::string filename)
+{
+	std::stringstream stream;
+	std::ifstream f;
+	f.exceptions(std::ifstream::badbit);
+
+	f.open("shaders/" + filename);
+	stream << f.rdbuf();
+	f.close();
+
+	std::string str = stream.str();
+	const GLchar *cstr = str.c_str();
+
+	if (!cstr[0])
+		throw std::runtime_error("cannot read shader " + filename);
+
+	GLuint type;
+	if (strcend(filename, ".vert"))
+		type = GL_VERTEX_SHADER;
+	else if (strcend(filename, ".frag"))
+		type = GL_FRAGMENT_SHADER;
+	else
+		throw std::runtime_error("unknown shader " + filename);
+
+	id = glCreateShader(type);
+	glShaderSource(id, 1, &cstr, 0);
+	glCompileShader(id);
+
+	GLint status;
+	glGetShaderiv(id, GL_COMPILE_STATUS, &status);
+	if (!status)
+	{
+		GLchar info[512];
+		glGetShaderInfoLog(id, 512, 0, info);
+		throw std::runtime_error("failed to compile " + filename + ": " + std::string(info));
+	}
+}
+
+gl_program::gl_program(std::vector<gl_shader> shaders)
+{
+	id = glCreateProgram();
+	for (auto s : shaders)
+		glAttachShader(id, s.id);
+	glLinkProgram(id);
+
+	GLint status;
+	glGetProgramiv(id, GL_LINK_STATUS, &status);
+	if (!status)
+	{
+		GLchar info[512];
+		glGetProgramInfoLog(id, 512, 0, info);
+		throw std::runtime_error("failed to link program: " + std::string(info));
+	}
+}
+
+void gl_program::use()
+{
+	glUseProgram(id);
+}

shader.h

@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+class gl_shader
+{
+public:
+	GLuint id;
+
+	gl_shader();
+	gl_shader(std::string);
+};
+
+class gl_program
+{
+	GLuint id;
+public:
+	gl_program() = default;
+	gl_program(std::vector<gl_shader>);
+
+	void use();
+};