From f6cfbcc406875986c3f39314800f6c98200a07d9 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 14 Jan 2024 20:24:47 -0500
Subject: [PATCH] Add gltk

---
 Rsconscript              |   1 +
 libs/gltk/gltk/array.d   |  33 +++++++
 libs/gltk/gltk/buffer.d  |  48 +++++++++++
 libs/gltk/gltk/package.d |   7 ++
 libs/gltk/gltk/program.d | 182 +++++++++++++++++++++++++++++++++++++++
 libs/gltk/gltk/shader.d  |  81 +++++++++++++++++
 libs/gltk/gltk/texture.d |  45 ++++++++++
 src/app.d                |   3 +-
 src/gl.d                 |   3 +
 9 files changed, 402 insertions(+), 1 deletion(-)
 create mode 100644 libs/gltk/gltk/array.d
 create mode 100644 libs/gltk/gltk/buffer.d
 create mode 100644 libs/gltk/gltk/package.d
 create mode 100644 libs/gltk/gltk/program.d
 create mode 100644 libs/gltk/gltk/shader.d
 create mode 100644 libs/gltk/gltk/texture.d
 create mode 100644 src/gl.d

diff --git a/Rsconscript b/Rsconscript
index 04185ba..576eba1 100644
--- a/Rsconscript
+++ b/Rsconscript
@@ -8,6 +8,7 @@ env "app" do |env|
     "libs/bindbc-common/source",
     "libs/bindbc-sdl/source",
     "libs/glad",
+    "libs/gltk",
   ]
   sources = dirs.reduce([]) do |result, dir|
     result + glob("#{dir}/**/*.{d,c}")
diff --git a/libs/gltk/gltk/array.d b/libs/gltk/gltk/array.d
new file mode 100644
index 0000000..be36f1d
--- /dev/null
+++ b/libs/gltk/gltk/array.d
@@ -0,0 +1,33 @@
+module gltk.array;
+
+import gl;
+
+class Array
+{
+    private GLuint m_id;
+
+    this()
+    {
+        m_id = 0u;
+        glGenVertexArrays(1, &m_id);
+        if (m_id == 0u)
+        {
+            throw new Exception("Failed to allocate an OpenGL array");
+        }
+    }
+
+    ~this()
+    {
+        glDeleteVertexArrays(1, &m_id);
+    }
+
+    void bind()
+    {
+        glBindVertexArray(m_id);
+    }
+
+    @property GLuint id()
+    {
+        return m_id;
+    }
+}
diff --git a/libs/gltk/gltk/buffer.d b/libs/gltk/gltk/buffer.d
new file mode 100644
index 0000000..83d4cfb
--- /dev/null
+++ b/libs/gltk/gltk/buffer.d
@@ -0,0 +1,48 @@
+module gltk.buffer;
+
+import gl;
+
+class Buffer
+{
+    private GLuint m_id;
+
+    private GLenum m_target;
+
+    this(GLenum target)
+    {
+        m_id = 0u;
+        glGenBuffers(1, &m_id);
+        if (m_id == 0u)
+        {
+            throw new Exception("Failed to allocate an OpenGL buffer");
+        }
+        m_target = target;
+    }
+
+    ~this()
+    {
+        glDeleteBuffers(1, &m_id);
+    }
+
+    void bind()
+    {
+        glBindBuffer(m_target, m_id);
+    }
+
+    @property GLuint id()
+    {
+        return m_id;
+    }
+
+    void set_buffer_data(GLenum usage, const void * ptr, size_t size)
+    {
+        bind();
+        glBufferData(m_target, size, ptr, usage);
+    }
+
+    void set_buffer_data(T)(GLenum usage, T[] arr)
+    {
+        bind();
+        glBufferData(m_target, arr.length * arr[0].sizeof, arr.ptr, usage);
+    }
+}
diff --git a/libs/gltk/gltk/package.d b/libs/gltk/gltk/package.d
new file mode 100644
index 0000000..13ba04f
--- /dev/null
+++ b/libs/gltk/gltk/package.d
@@ -0,0 +1,7 @@
+module gltk;
+
+public import gltk.array;
+public import gltk.buffer;
+public import gltk.program;
+public import gltk.shader;
+public import gltk.texture;
diff --git a/libs/gltk/gltk/program.d b/libs/gltk/gltk/program.d
new file mode 100644
index 0000000..670bacd
--- /dev/null
+++ b/libs/gltk/gltk/program.d
@@ -0,0 +1,182 @@
+module gltk.program;
+
+import gltk.shader;
+import std.string;
+import gl;
+
+class Program(uniforms...)
+{
+    /* The number of template parameters must be a multiple of 2. */
+    static assert((uniforms.length % 2) == 0);
+
+    private GLuint m_id;
+
+    static foreach (i, v; uniforms)
+    {
+        static if ((i % 2) == 0)
+        {
+            mixin("private GLint m_uniform_" ~ v ~ ";");
+        }
+    }
+
+    this(Args...)(Args args)
+    {
+        m_id = glCreateProgram();
+        if (m_id == 0u)
+        {
+            throw new Exception("Failed to allocate an OpenGL program");
+        }
+        static if (args.length > 0u)
+        {
+            build(args);
+        }
+    }
+
+    ~this()
+    {
+        glDeleteProgram(m_id);
+    }
+
+    void attach_shader(Shader shader) const
+    {
+        glAttachShader(m_id, shader.id);
+    }
+
+    void bind_attrib_location(string name, uint index) const
+    {
+        glBindAttribLocation(m_id, index, name.toStringz());
+    }
+
+    void link()
+    {
+        glLinkProgram(m_id);
+
+        GLint link_status;
+        glGetProgramiv(m_id, GL_LINK_STATUS, &link_status);
+        if (link_status != GL_TRUE)
+        {
+            string message = "Failed to link program";
+            GLint log_length = 0;
+            glGetProgramiv(m_id, GL_INFO_LOG_LENGTH, &log_length);
+            if (log_length > 0)
+            {
+                char[] log = new char[log_length];
+                glGetProgramInfoLog(m_id, log_length, &log_length, log.ptr);
+                message ~= "\n";
+                message ~= log;
+                message ~= "\n";
+            }
+            throw new Exception(message);
+        }
+
+        static foreach(i, v; uniforms)
+        {
+            static if ((i % 2) == 0)
+            {
+                mixin("m_uniform_" ~ v ~ " = glGetUniformLocation(m_id, \"" ~ v ~ "\");");
+            }
+        }
+    }
+
+    GLint get_uniform_location(string uniform_name) const
+    {
+        return glGetUniformLocation(m_id, uniform_name.toStringz());
+    }
+
+    void get_uniform_locations(Args...)(string uniform_name, GLint * uniform_location, Args args) const
+    {
+        *uniform_location = get_uniform_location(uniform_name);
+        static if (args.length > 0u)
+        {
+            get_uniform_locations(args);
+        }
+    }
+
+    @property GLuint id() const
+    {
+        return m_id;
+    }
+
+    void use() const
+    {
+        glUseProgram(m_id);
+    }
+
+    private static string uniform_param_decl_list(string spec)
+    {
+        int count = spec[0] - '0';
+        string type;
+        if (spec[1] == 'i')
+        {
+            type = "GLint";
+        }
+        else if (spec[1..2] == "ui")
+        {
+            type = "GLuint";
+        }
+        else if (spec[1] == 'f')
+        {
+            type = "GLfloat";
+        }
+        assert(type != "");
+        if (spec[$ - 1] == 'v')
+        {
+            return "uint count, const " ~ type ~ " * v";
+        }
+        else
+        {
+            string[] decls;
+            for (int i = 0; i < count; i++)
+            {
+                decls ~= type ~ " v" ~ cast(char)('0' + i);
+            }
+            return decls.join(", ");
+        }
+    }
+
+    private static string uniform_param_list(string spec)
+    {
+        int count = spec[0] - '0';
+        if (spec[$ - 1] == 'v')
+        {
+            return "count, v";
+        }
+        else
+        {
+            string[] vees;
+            for (int i = 0; i < count; i++)
+            {
+                vees ~= "v" ~ cast(char)('0' + i);
+            }
+            return vees.join(", ");
+        }
+    }
+
+    static foreach (i, v; uniforms)
+    {
+        static if ((i % 2) == 0)
+        {
+            mixin("void set_" ~ v ~ "(" ~ uniform_param_decl_list(uniforms[i + 1]) ~ ")" ~
+                  "{" ~
+                  "    glUniform" ~ uniforms[i + 1] ~ "(m_uniform_" ~ v ~ ", " ~ uniform_param_list(uniforms[i + 1]) ~ ");" ~
+                  "}");
+        }
+    }
+
+    private void build(Args...)(Shader s, Args args)
+    {
+        attach_shader(s);
+        build(args);
+    }
+
+    private void build(Args...)(string attrib_name, uint index, Args args)
+    {
+        bind_attrib_location(attrib_name, index);
+        build(args);
+    }
+
+    private void build()
+    {
+        link();
+    }
+}
diff --git a/libs/gltk/gltk/shader.d b/libs/gltk/gltk/shader.d
new file mode 100644
index 0000000..30fc62d
--- /dev/null
+++ b/libs/gltk/gltk/shader.d
@@ -0,0 +1,81 @@
+module gltk.shader;
+
+import gl;
+static import std.file;
+
+class Shader
+{
+    private GLuint m_id;
+
+    private GLenum m_shader_type;
+
+    this(GLenum shader_type)
+    {
+        m_shader_type = shader_type;
+        m_id = glCreateShader(shader_type);
+        if (m_id == 0u)
+        {
+            throw new Exception("Failed to allocate an OpenGL shader");
+        }
+    }
+
+    ~this()
+    {
+        glDeleteShader(m_id);
+    }
+
+    void set_source(const char * source, int length = -1)
+    {
+        GLint status;
+
+        GLint gllength = length;
+        glShaderSource(m_id, 1, &source, &gllength);
+
+        glCompileShader(m_id);
+
+        glGetShaderiv(m_id, GL_COMPILE_STATUS, &status);
+        if (status == GL_TRUE)
+        {
+            return;
+        }
+
+        string message = "Error compiling ";
+        switch (m_shader_type)
+        {
+            case GL_VERTEX_SHADER:
+                message ~= "vertex";
+                break;
+            case GL_FRAGMENT_SHADER:
+                message ~= "fragment";
+                break;
+            default:
+                message ~= "unknown";
+                break;
+        }
+        message ~= " shader";
+
+        GLint log_length;
+        glGetShaderiv(m_id, GL_INFO_LOG_LENGTH, &log_length);
+        if (log_length > 0)
+        {
+            char[] log = new char[log_length];
+            glGetShaderInfoLog(m_id, log_length, &log_length, log.ptr);
+            message ~= "\nShader Log:\n";
+            message ~= log;
+            message ~= "\n";
+        }
+        glDeleteShader(m_id);
+        throw new Exception(message);
+    }
+
+    void set_source_from_file(string filename)
+    {
+        const(char)[] file_data = cast(const(char)[])std.file.read(filename);
+        set_source(file_data.ptr, cast(int)file_data.length);
+    }
+
+    @property GLuint id()
+    {
+        return m_id;
+    }
+}
diff --git a/libs/gltk/gltk/texture.d b/libs/gltk/gltk/texture.d
new file mode 100644
index 0000000..73a9b4d
--- /dev/null
+++ b/libs/gltk/gltk/texture.d
@@ -0,0 +1,45 @@
+module gltk.texture;
+
+import gl;
+
+class Texture
+{
+    private GLuint m_id;
+
+    this()
+    {
+        m_id = 0u;
+        glGenTextures(1, &m_id);
+        if (m_id == 0u)
+        {
+            throw new Exception("Failed to allocate an OpenGL texture");
+        }
+    }
+
+    ~this()
+    {
+        glDeleteTextures(1, &m_id);
+    }
+
+    void bind(GLenum target) const
+    {
+        glBindTexture(target, m_id);
+    }
+
+    @property GLuint id()
+    {
+        return m_id;
+    }
+
+    static uint next_power_of_2(uint n)
+    {
+        n--;
+        n |= n >> 1u;
+        n |= n >> 2u;
+        n |= n >> 4u;
+        n |= n >> 8u;
+        n |= n >> 16u;
+        n++;
+        return n;
+    }
+};
diff --git a/src/app.d b/src/app.d
index 912a81a..87cb9d2 100644
--- a/src/app.d
+++ b/src/app.d
@@ -1,7 +1,8 @@
 import std.stdio;
 import sdl;
-import glad.gl.all;
+import gl;
 import glad.gl.loader;
+import gltk;
 
 enum int WIDTH = 800;
 enum int HEIGHT = 600;
diff --git a/src/gl.d b/src/gl.d
new file mode 100644
index 0000000..069c86b
--- /dev/null
+++ b/src/gl.d
@@ -0,0 +1,3 @@
+module gl;
+
+public import glad.gl.all;