[nostalgia] Move glutils into separate library

src/nostalgia/glutils/glutils.hpp

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2016 - 2021 gary@drinkingtea.net
+ *
+ * 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 <ox/std/defines.hpp>
+
+#define GL_GLEXT_PROTOTYPES 1
+#ifdef OX_OS_Darwin
+#define GL_SILENCE_DEPRECATION
+#include <OpenGL/gl3.h>
+#else
+#include <GLES3/gl3.h>
+#endif
+
+namespace nostalgia::glutils {
+
+struct Empty {};
+
+struct TextureBase {
+
+	GLsizei width = 0;
+	GLsizei height = 0;
+
+	constexpr TextureBase() noexcept = default;
+
+	constexpr TextureBase(TextureBase &&tb) noexcept {
+		width = tb.width;
+		height = tb.height;
+		tb.width = 0;
+		tb.height = 0;
+	}
+
+	constexpr TextureBase &operator=(TextureBase &&tb) noexcept {
+		width = tb.width;
+		height = tb.height;
+		tb.width = 0;
+		tb.height = 0;
+		return *this;
+	}
+
+};
+
+
+template<auto del, typename Base = Empty>
+struct GLObject: public Base {
+
+	GLuint id = 0;
+
+	constexpr GLObject() noexcept = default;
+
+	explicit constexpr GLObject(GLuint id) noexcept {
+		this->id = id;
+	}
+
+	constexpr GLObject(GLObject &&o) noexcept: Base(ox::move(o)) {
+		id = o.id;
+		o.id = 0;
+	}
+
+	~GLObject() {
+		del(id);
+	}
+
+	GLObject &operator=(GLObject &&o) noexcept {
+		if (this != &o) {
+			del(id);
+			Base::operator=(ox::move(o));
+			id = o.id;
+			o.id = 0;
+		}
+		return *this;
+	}
+
+	constexpr GLuint release() noexcept {
+		auto out = id;
+		id = 0;
+		return out;
+	}
+
+	constexpr operator GLuint&() noexcept {
+		return id;
+	}
+
+	constexpr operator const GLuint&() const noexcept {
+		return id;
+	}
+
+};
+
+void deleteBuffer(GLuint b) noexcept;
+void deleteTexture(GLuint t) noexcept;
+void deleteVertexArray(GLuint v) noexcept;
+
+extern template struct GLObject<deleteBuffer>;
+extern template struct GLObject<deleteTexture, TextureBase>;
+extern template struct GLObject<deleteVertexArray>;
+extern template struct GLObject<glDeleteProgram>;
+extern template struct GLObject<glDeleteShader>;
+
+using GLBuffer = GLObject<deleteBuffer>;
+using GLShader = GLObject<glDeleteShader>;
+using GLProgram = GLObject<glDeleteProgram>;
+using GLTexture = GLObject<deleteTexture, TextureBase>;
+using GLVertexArray = GLObject<deleteVertexArray>;
+
+[[nodiscard]]
+ox::Result<GLProgram> buildShaderProgram(const GLchar *vert, const GLchar *frag) noexcept;
+
+}