Add some examples from learnopengl.com

.gitignore

@@ -4,6 +4,11 @@
 /.shards/
 *.dwarf
 
+/examples/**/docs/
+/examples/**/lib/
+/examples/**/bin/
+/examples/**/.shards/
+
 # Libraries don't need dependency lock
 # Dependencies will be locked in applications that use them
 /shard.lock

.gitlab-ci.yml

@@ -14,12 +14,12 @@ before_script:
 format:
   script:
     - shards
-    - crystal tool format --check
+    - crystal tool format --check src/ spec/
 
 style:
   script:
     - shards
-    - bin/ameba
+    - bin/ameba src/
 
 pages:
   stage: deploy

examples/learnopengl.com/01-getting-started/01-hello-window/main.cr

@@ -0,0 +1,71 @@
+# Original post available here:
+# https://learnopengl.com/Getting-started/Hello-Triangle
+# and source code available here:
+# https://learnopengl.com/code_viewer_gh.php?code=src/1.getting_started/2.2.hello_triangle_indexed/hello_triangle_indexed.cpp
+
+require "glfw"
+require "gloop"
+
+# settings
+SCR_WIDTH = 800
+SCR_HEIGHT = 600
+
+# process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
+# ---------------------------------------------------------------------------------------------------------
+def process_input(window)
+  if LibGLFW.get_key(window, LibGLFW::Key::Escape) == LibGLFW::Action::Press
+    LibGLFW.set_window_should_close(window, LibGLFW::Bool::True)
+  end
+end
+
+# glfw: whenever the window size changed (by OS or user resize) this callback function executes
+# ---------------------------------------------------------------------------------------------
+def framebuffer_size_callback(window, width, height)
+  # make sure the viewport matches the new window dimensions; note that width and
+  # height will be significantly larger than specified on retina displays.
+  LibGL.viewport(0, 0, width, height)
+end
+
+# glfw: initialize and configure
+# ------------------------------
+LibGLFW.init
+LibGLFW.window_hint(LibGLFW::WindowHint::ContextVersionMajor, 3)
+LibGLFW.window_hint(LibGLFW::WindowHint::ContextVersionMinor, 3)
+LibGLFW.window_hint(LibGLFW::WindowHint::OpenGLProfile, LibGLFW::OpenGLProfile::Core)
+
+{% if flag?(:darwin) %}
+LibGLFW.window_hint(LibGLFW::WindowHint::OpenGLForwardCompat, LibGLFW::Bool::True)
+{% end %}
+
+# glfw window creation
+# --------------------
+window = LibGLFW.create_window(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", nil, nil)
+if window.nil?
+  puts "Failed to create GLFW window"
+  LibGLFW.terminate
+  exit -1
+end
+LibGLFW.make_context_current(window)
+LibGLFW.set_framebuffer_size_callback(window, ->framebuffer_size_callback)
+
+# render loop
+# -----------
+while LibGLFW.window_should_close(window).false?
+  # input
+  # -----
+  process_input(window)
+
+  # render
+  # ------
+  LibGL.clear_color(0.2, 0.3, 0.3, 1.0)
+  LibGL.clear(LibGL::ClearBufferMask::ColorBuffer)
+
+  # glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
+  # -------------------------------------------------------------------------------
+  LibGLFW.swap_buffers(window)
+  LibGLFW.poll_events
+end
+
+# glfw: terminate, clearing all previously allocated GLFW resources.
+# ------------------------------------------------------------------
+LibGLFW.terminate

examples/learnopengl.com/01-getting-started/01-hello-window/shard.lock

@@ -0,0 +1,14 @@
+version: 2.0
+shards:
+  glfw:
+    git: https://gitlab.com/arctic-fox/glfw.cr.git
+    version: 3.3.1
+
+  gloop:
+    path: ../../../../
+    version: 0.2.0
+
+  opengl:
+    git: https://gitlab.com/arctic-fox/opengl.cr.git
+    version: 4.6.0+git.commit.5d9c884c7fc7a62edfa7883dc16365d6b2dfa487
+

examples/learnopengl.com/01-getting-started/01-hello-window/shard.yml

@@ -0,0 +1,27 @@
+name: hello-window
+version: 1.0.0
+
+authors:
+  - www.learnopengl.com
+  - Michael Miller <[email protected]>
+
+dependencies:
+  gloop:
+    path: ../../../../
+  opengl:
+    gitlab: arctic-fox/opengl.cr
+    branch: gl-4.6-core
+  glfw:
+    gitlab: arctic-fox/glfw.cr
+    version: ~> 3.3.1
+
+libraries:
+  libgl: ~> 3.3.0
+
+targets:
+  hello-window:
+    main: main.cr
+
+crystal: 1.0.0
+
+license: MIT

examples/learnopengl.com/01-getting-started/02-hello-triangle/main.cr

@@ -0,0 +1,177 @@
+# Original post available here:
+# https://learnopengl.com/Getting-started/Hello-Window
+# and source code available here:
+# https://learnopengl.com/code_viewer_gh.php?code=src/1.getting_started/1.2.hello_window_clear/hello_window_clear.cpp
+
+require "glfw"
+require "gloop"
+
+# settings
+SCR_WIDTH = 800
+SCR_HEIGHT = 600
+
+VERTEX_SHADER_SOURCE = <<-SHADER
+  #version 330 core
+  layout (location = 0) in vec3 aPos;
+  void main()
+  {
+    gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+  }
+SHADER
+
+FRAGMENT_SHADER_SOURCE = <<-SHADER
+  #version 330 core
+  out vec4 FragColor;
+  void main()
+  {
+    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
+  }
+SHADER
+
+# process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
+# ---------------------------------------------------------------------------------------------------------
+def process_input(window)
+  if LibGLFW.get_key(window, LibGLFW::Key::Escape).press?
+    LibGLFW.set_window_should_close(window, LibGLFW::Bool::True)
+  end
+end
+
+# glfw: whenever the window size changed (by OS or user resize) this callback function executes
+# ---------------------------------------------------------------------------------------------
+def framebuffer_size_callback(window, width, height)
+  # make sure the viewport matches the new window dimensions; note that width and
+  # height will be significantly larger than specified on retina displays.
+  LibGL.viewport(0, 0, width, height)
+end
+
+# glfw: initialize and configure
+# ------------------------------
+LibGLFW.init
+LibGLFW.window_hint(LibGLFW::WindowHint::ContextVersionMajor, 3)
+LibGLFW.window_hint(LibGLFW::WindowHint::ContextVersionMinor, 3)
+LibGLFW.window_hint(LibGLFW::WindowHint::OpenGLProfile, LibGLFW::OpenGLProfile::Core)
+
+{% if flag?(:darwin) %}
+LibGLFW.window_hint(LibGLFW::WindowHint::OpenGLForwardCompat, LibGLFW::Bool::True)
+{% end %}
+
+# glfw window creation
+# --------------------
+window = LibGLFW.create_window(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", nil, nil)
+if window.nil?
+  puts "Failed to create GLFW window"
+  LibGLFW.terminate
+  exit -1
+end
+LibGLFW.make_context_current(window)
+LibGLFW.set_framebuffer_size_callback(window, ->framebuffer_size_callback)
+
+# build and compile our shader program
+# ------------------------------------
+# vertex shader
+vertex_shader = Gloop::VertexShader.create
+vertex_shader.source = VERTEX_SHADER_SOURCE
+vertex_shader.compile
+# check for shader compile errors
+unless vertex_shader.compiled?
+  puts "ERROR::SHADER::VERTEX::COMPILATION_FAILED"
+  puts vertex_shader.info_log
+end
+# fragment shader
+fragment_shader = Gloop::FragmentShader.create
+fragment_shader.source = FRAGMENT_SHADER_SOURCE
+fragment_shader.compile
+# check for shader compile errors
+unless fragment_shader.compiled?
+  puts "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED"
+  puts fragment_shader.info_log
+end
+# link shaders
+shader_program = Gloop::Program.create
+shader_program.attach(vertex_shader)
+shader_program.attach(fragment_shader)
+shader_program.link
+# check for linking errors
+unless shader_program.linked?
+  puts "ERROR::SHADER::PROGRAM::LINKING_FAILED"
+  puts shader_program.info_log
+end
+vertex_shader.delete
+fragment_shader.delete
+
+# set up vertex data (and buffer(s)) and configure vertex attributes
+# ------------------------------------------------------------------
+vertices = Float32.static_array(
+   0.5,  0.5, 0.0,  # top right
+   0.5, -0.5, 0.0,  # bottom right
+  -0.5, -0.5, 0.0,  # bottom left
+  -0.5,  0.5, 0.0   # top left
+)
+indices = UInt32.static_array( # note that we start from 0!
+  0, 1, 3,  # first Triangle
+  1, 2, 3   # second Triangle
+)
+LibGL.gen_vertex_arrays(1, out vao)
+LibGL.gen_buffers(1, out vbo)
+LibGL.gen_buffers(1, out ebo)
+# bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
+LibGL.bind_vertex_array(vao)
+
+LibGL.bind_buffer(LibGL::BufferTargetARB::ArrayBuffer, vbo)
+LibGL.buffer_data(LibGL::BufferTargetARB::ArrayBuffer, sizeof(typeof(vertices)), vertices, LibGL::BufferUsageARB::StaticDraw)
+
+LibGL.bind_buffer(LibGL::BufferTargetARB::ElementArrayBuffer, ebo)
+LibGL.buffer_data(LibGL::BufferTargetARB::ElementArrayBuffer, sizeof(typeof(indices)), indices, LibGL::BufferUsageARB::StaticDraw)
+
+LibGL.vertex_attrib_pointer(0, 3, LibGL::VertexAttribPointerType::Float, LibGL::Boolean::False, 3 * sizeof(Float32), nil)
+LibGL.enable_vertex_attrib_array(0)
+
+# note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
+LibGL.bind_buffer(LibGL::BufferTargetARB::ArrayBuffer, 0)
+
+# remember: do NOT unbind the EBO while a VAO is active as the bound element buffer object IS stored in the VAO; keep the EBO bound.
+#LibGL.bind_buffer(LibGL::BufferTargetARB::ElementArrayBuffer, 0)
+
+# You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
+# VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
+LibGL.bind_vertex_array(0)
+
+
+# uncomment this call to draw in wireframe polygons.
+#LibGL.polygon_mode(LibGL::MaterialFace::FrontAndBack, LibGL::PolygonMode::Line)
+
+# render loop
+# -----------
+while LibGLFW.window_should_close(window).false?
+  # input
+  # -----
+  process_input(window)
+
+  # render
+  # ------
+  LibGL.clear_color(0.2, 0.3, 0.3, 1.0)
+  LibGL.clear(LibGL::ClearBufferMask::ColorBuffer)
+
+  # draw our first triangle
+  shader_program.activate
+  LibGL.bind_vertex_array(vao) # seeing as we only have a single VAO there's no need to bind it every time, but we'll do so to keep things a bit more organized
+  #LibGL.draw_arrays(LibGL::PrimitiveType::Triangles, 0, 6)
+  LibGL.draw_elements(LibGL::PrimitiveType::Triangles, 6, LibGL::DrawElementsType::UnsignedInt, nil)
+  #LibGL.bind_vertex_array(0) # no need to unbind it every time
+
+  # glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
+  # -------------------------------------------------------------------------------
+  LibGLFW.swap_buffers(window)
+  LibGLFW.poll_events
+end
+
+# optional: de-allocate all resources once they've outlived their purpose:
+# ------------------------------------------------------------------------
+LibGL.delete_vertex_arrays(1, pointerof(vao))
+LibGL.delete_buffers(1, pointerof(vbo))
+LibGL.delete_buffers(1, pointerof(ebo))
+shader_program.delete
+
+# glfw: terminate, clearing all previously allocated GLFW resources.
+# ------------------------------------------------------------------
+LibGLFW.terminate

examples/learnopengl.com/01-getting-started/02-hello-triangle/shard.lock

@@ -0,0 +1,14 @@
+version: 2.0
+shards:
+  glfw:
+    git: https://gitlab.com/arctic-fox/glfw.cr.git
+    version: 3.3.1
+
+  gloop:
+    path: ../../../../
+    version: 0.2.0
+
+  opengl:
+    git: https://gitlab.com/arctic-fox/opengl.cr.git
+    version: 4.6.0+git.commit.5d9c884c7fc7a62edfa7883dc16365d6b2dfa487
+

examples/learnopengl.com/01-getting-started/02-hello-triangle/shard.yml

@@ -0,0 +1,27 @@
+name: hello-triangle
+version: 1.0.0
+
+authors:
+  - www.learnopengl.com
+  - Michael Miller <[email protected]>
+
+dependencies:
+  gloop:
+    path: ../../../../
+  opengl:
+    gitlab: arctic-fox/opengl.cr
+    branch: gl-4.6-core
+  glfw:
+    gitlab: arctic-fox/glfw.cr
+    version: ~> 3.3.1
+
+libraries:
+  libgl: ~> 3.3.0
+
+targets:
+  hello-triangle:
+    main: main.cr
+
+crystal: 1.0.0
+
+license: MIT