--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/opengl.h	Sun Nov 26 16:27:50 2023 +0100
@@ -0,0 +1,61 @@
+/**
+ * ShaderShark
+ * Copyright © 2023 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <string>
+#include <stdexcept>
+
+#include <epoxy/gl.h>
+#include <epoxy/glx.h>
+#include <GL/glu.h>
+
+#include <glm/glm.hpp>
+#include <glm/ext.hpp>
+
+inline
+void quads(GLfloat tx, GLfloat ty, GLfloat x, GLfloat y, GLfloat z) {
+	glTexCoord2f(tx, ty);
+	glVertex3f(x, y, z);
+}
+
+inline
+void checkError(std::ostream* out) {
+	GLenum code = glGetError();
+	if (code == GL_NO_ERROR) {
+		if (out) *out << "GL check: OK" << std::endl;
+	} else {
+		const char* string = (const char*) gluErrorString(code);
+		if (out) *out << "GL check: " << string << std::endl;
+		else throw std::logic_error(std::string("GL error: ") + string);
+	}
+}
+
+inline
+GLenum toShaderType(const std::string& fileName) {
+	if (fileName.ends_with(".vert")) return GL_VERTEX_SHADER;
+	else if (fileName.ends_with(".frag")) return GL_FRAGMENT_SHADER;
+	else throw std::invalid_argument("Expecting *.vert or *.frag file");
+}
+
+inline
+void dump(const char* name, const glm::vec3& value) {
+	std::cerr << "dump: " << name << " = ["
+			<< value.x << ", "
+			<< value.y << ", "
+			<< value.z << "]" << std::endl;
+}
\ No newline at end of file