Added a large portion of I-MIC-FPS's opengl rendering and model loading systems

lib/cyberarm_engine/opengl/light.rb

@@ -0,0 +1,49 @@
+module CyberarmEngine
+  class Light
+    DIRECTIONAL = 0
+    POINT = 1
+    SPOT = 2
+
+    attr_reader :light_id
+    attr_accessor :type, :ambient, :diffuse, :specular, :position, :direction, :intensity
+    def initialize(
+                    id:,
+                    type: Light::POINT,
+                    ambient: Vector.new(0.5, 0.5, 0.5),
+                    diffuse: Vector.new(1, 1, 1),
+                    specular: Vector.new(0.2, 0.2, 0.2),
+                    position: Vector.new(0, 0, 0),
+                    direction: Vector.new(0, 0, 0),
+                    intensity: 1
+                  )
+      @light_id = id
+      @type = type
+
+      @ambient  = ambient
+      @diffuse  = diffuse
+      @specular = specular
+      @position = position
+      @direction = direction
+
+      @intensity = intensity
+    end
+
+    def draw
+      glLightfv(@light_id, GL_AMBIENT, convert(@ambient).pack("f*"))
+      glLightfv(@light_id, GL_DIFFUSE, convert(@diffuse, true).pack("f*"))
+      glLightfv(@light_id, GL_SPECULAR, convert(@specular, true).pack("f*"))
+      glLightfv(@light_id, GL_POSITION, convert(@position).pack("f*"))
+      glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1)
+      glEnable(GL_LIGHTING)
+      glEnable(@light_id)
+    end
+
+    def convert(struct, apply_intensity = false)
+      if apply_intensity
+        return struct.to_a.compact.map{ |i| i * @intensity }
+      else
+        return struct.to_a.compact
+      end
+    end
+  end
+end

lib/cyberarm_engine/opengl/orthographic_camera.rb

@@ -0,0 +1,42 @@
+module CyberarmEngine
+  class OrthographicCamera
+    attr_accessor :position, :orientation, :zoom, :left, :right, :bottom, :top,
+                  :min_view_distance, :max_view_distance
+    def initialize(
+                    position:, orientation: Vector.new(0, 0, 0),
+                    zoom: 1, left: 0, right:, bottom: 0, top:,
+                    min_view_distance: 0.1, max_view_distance: 200.0
+                  )
+      @position = position
+      @orientation = orientation
+
+      @zoom = zoom
+
+      @left, @right, @bottom, @top = left, right, bottom, top
+
+      @min_view_distance = min_view_distance
+      @max_view_distance = max_view_distance
+    end
+
+    # Immediate mode renderering fallback
+    def draw
+      glMatrixMode(GL_PROJECTION)
+      glLoadIdentity
+      glOrtho(@left, @right, @bottom, @top, @min_view_distance, @max_view_distance)
+      glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)
+      glRotatef(@orientation.x, 1, 0, 0)
+      glRotatef(@orientation.y, 0, 1, 0)
+      glTranslatef(-@position.x, -@position.y, -@position.z)
+      glMatrixMode(GL_MODELVIEW)
+      glLoadIdentity
+    end
+
+    def projection_matrix
+      Transform.orthographic(@left, @right, @bottom, @top, @min_view_distance, @max_view_distance)
+    end
+
+    def view_matrix
+      Transform.translate_3d(@position * -1) * Transform.rotate_3d(@orientation)
+    end
+  end
+end

lib/cyberarm_engine/opengl/perspective_camera.rb

@@ -0,0 +1,35 @@
+module CyberarmEngine
+  class PerspectiveCamera
+    attr_accessor :position, :orientation, :aspect_ratio, :field_of_view
+    def initialize(position:, orientation: Vector.new(0, 0, 0), aspect_ratio:, field_of_view: 70.0, min_view_distance: 0.1, max_view_distance: 155.0)
+      @position = position
+      @orientation = orientation
+
+      @aspect_ratio = aspect_ratio
+      @field_of_view = field_of_view
+
+      @min_view_distance = min_view_distance
+      @max_view_distance = max_view_distance
+    end
+
+    def draw
+      glMatrixMode(GL_PROJECTION)
+      glLoadIdentity
+      gluPerspective(@field_of_view, @aspect_ratio, @min_view_distance, @max_view_distance)
+      glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST)
+      glRotatef(@orientation.x, 1, 0, 0)
+      glRotatef(@orientation.y, 0, 1, 0)
+      glTranslatef(-@position.x, -@position.y, -@position.z)
+      glMatrixMode(GL_MODELVIEW)
+      glLoadIdentity
+    end
+
+    def projection_matrix
+      Transform.perspective(@field_of_view, @aspect_ratio, @min_view_distance, @max_view_distance)
+    end
+
+    def view_matrix
+      Transform.translate_3d(@position * -1) * Transform.rotate_3d(@orientation)
+    end
+  end
+end

lib/cyberarm_engine/opengl/renderer/bounding_box_renderer.rb

@@ -0,0 +1,248 @@
+module CyberarmEngine
+  class BoundingBoxRenderer
+    attr_reader :bounding_boxes, :vertex_count
+    def initialize
+      @bounding_boxes = {}
+      @vertex_count = 0
+    end
+
+    def render(entities)
+      entities.each do |entity|
+        create_bounding_box(entity,color = nil)
+        draw_bounding_boxes
+      end
+
+      (@bounding_boxes.keys - entities.map { |e| e.object_id }).each do |key|
+        @bounding_boxes.delete(key)
+      end
+    end
+
+    def create_bounding_box(entity, color = nil)
+      color ||= entity.debug_color
+      entity_id = entity.object_id
+
+      if @bounding_boxes[entity_id]
+        if @bounding_boxes[entity_id][:color] != color
+          @bounding_boxes[entity_id][:colors] = mesh_colors(color).pack("f*")
+          @bounding_boxes[entity_id][:color]  = color
+          return
+        else
+          return
+        end
+      end
+
+      @bounding_boxes[entity_id] = {
+        entity: entity,
+        color: color,
+        objects: []
+      }
+
+      box = entity.normalize_bounding_box
+
+      normals  = mesh_normals
+      colors   = mesh_colors(color)
+      vertices = mesh_vertices(box)
+
+      @vertex_count+=vertices.size
+
+      @bounding_boxes[entity_id][:vertices_size] = vertices.size
+      @bounding_boxes[entity_id][:vertices]      = vertices.pack("f*")
+      @bounding_boxes[entity_id][:normals]       = normals.pack("f*")
+      @bounding_boxes[entity_id][:colors]        = colors.pack("f*")
+
+      entity.model.objects.each do |mesh|
+        data = {}
+        box = mesh.bounding_box.normalize(entity)
+
+        normals  = mesh_normals
+        colors   = mesh_colors(mesh.debug_color)
+        vertices = mesh_vertices(box)
+
+        @vertex_count+=vertices.size
+
+        data[:vertices_size] = vertices.size
+        data[:vertices]      = vertices.pack("f*")
+        data[:normals]       = normals.pack("f*")
+        data[:colors]        = colors.pack("f*")
+
+        @bounding_boxes[entity_id][:objects] << data
+      end
+    end
+
+    def mesh_normals
+      [
+        0,1,0,
+        0,1,0,
+        0,1,0,
+        0,1,0,
+        0,1,0,
+        0,1,0,
+
+        0,-1,0,
+        0,-1,0,
+        0,-1,0,
+        0,-1,0,
+        0,-1,0,
+        0,-1,0,
+
+        0,0,1,
+        0,0,1,
+        0,0,1,
+        0,0,1,
+        0,0,1,
+        0,0,1,
+
+        1,0,0,
+        1,0,0,
+        1,0,0,
+        1,0,0,
+        1,0,0,
+        1,0,0,
+
+        -1,0,0,
+        -1,0,0,
+        -1,0,0,
+        -1,0,0,
+        -1,0,0,
+        -1,0,0,
+
+        -1,0,0,
+        -1,0,0,
+        -1,0,0,
+
+        -1,0,0,
+        -1,0,0,
+        -1,0,0
+      ]
+    end
+
+    def mesh_colors(color)
+      [
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue,
+        color.red, color.green, color.blue
+      ]
+    end
+
+    def mesh_vertices(box)
+      [
+        box.min.x, box.max.y, box.max.z,
+        box.min.x, box.max.y, box.min.z,
+        box.max.x, box.max.y, box.min.z,
+
+        box.min.x, box.max.y, box.max.z,
+        box.max.x, box.max.y, box.max.z,
+        box.max.x, box.max.y, box.min.z,
+
+        box.max.x, box.min.y, box.min.z,
+        box.max.x, box.min.y, box.max.z,
+        box.min.x, box.min.y, box.max.z,
+
+        box.max.x, box.min.y, box.min.z,
+        box.min.x, box.min.y, box.min.z,
+        box.min.x, box.min.y, box.max.z,
+
+        box.min.x, box.max.y, box.max.z,
+        box.min.x, box.max.y, box.min.z,
+        box.min.x, box.min.y, box.min.z,
+
+        box.min.x, box.min.y, box.max.z,
+        box.min.x, box.min.y, box.min.z,
+        box.min.x, box.max.y, box.max.z,
+
+        box.max.x, box.max.y, box.max.z,
+        box.max.x, box.max.y, box.min.z,
+        box.max.x, box.min.y, box.min.z,
+
+        box.max.x, box.min.y, box.max.z,
+        box.max.x, box.min.y, box.min.z,
+        box.max.x, box.max.y, box.max.z,
+
+        box.min.x, box.max.y, box.max.z,
+        box.max.x, box.max.y, box.max.z,
+        box.max.x, box.min.y, box.max.z,
+
+        box.min.x, box.max.y, box.max.z,
+        box.max.x, box.min.y, box.max.z,
+        box.min.x, box.min.y, box.max.z,
+
+        box.max.x, box.min.y, box.min.z,
+        box.min.x, box.min.y, box.min.z,
+        box.min.x, box.max.y, box.min.z,
+
+        box.max.x, box.min.y, box.min.z,
+        box.min.x, box.max.y, box.min.z,
+        box.max.x, box.max.y, box.min.z
+      ]
+    end
+
+    def draw_bounding_boxes
+      @bounding_boxes.each do |key, bounding_box|
+        glPushMatrix
+
+        glTranslatef(
+          bounding_box[:entity].position.x,
+          bounding_box[:entity].position.y,
+          bounding_box[:entity].position.z
+        )
+        draw_bounding_box(bounding_box)
+        @bounding_boxes[key][:objects].each {|o| draw_bounding_box(o)}
+
+        glPopMatrix
+      end
+    end
+
+    def draw_bounding_box(bounding_box)
+      glEnableClientState(GL_VERTEX_ARRAY)
+      glEnableClientState(GL_COLOR_ARRAY)
+      glEnableClientState(GL_NORMAL_ARRAY)
+
+      glVertexPointer(3, GL_FLOAT, 0, bounding_box[:vertices])
+      glColorPointer(3, GL_FLOAT, 0, bounding_box[:colors])
+      glNormalPointer(GL_FLOAT, 0, bounding_box[:normals])
+
+      glPolygonMode(GL_FRONT_AND_BACK, GL_LINE)
+      glDisable(GL_LIGHTING)
+      glDrawArrays(GL_TRIANGLES, 0, bounding_box[:vertices_size] / 3)
+      glEnable(GL_LIGHTING)
+      glPolygonMode(GL_FRONT_AND_BACK, GL_FILL)
+
+      glDisableClientState(GL_VERTEX_ARRAY)
+      glDisableClientState(GL_COLOR_ARRAY)
+      glDisableClientState(GL_NORMAL_ARRAY)
+    end
+  end
+end

lib/cyberarm_engine/opengl/renderer/g_buffer.rb

@@ -0,0 +1,162 @@
+module CyberarmEngine
+  class GBuffer
+    attr_reader :screen_vbo, :vertices, :uvs
+    def initialize(width:, height:)
+    @width, @height = width, height
+
+      @framebuffer = nil
+      @buffers = [:position, :diffuse, :normal, :texcoord]
+      @textures = {}
+      @screen_vbo = nil
+      @ready = false
+
+      @vertices = [
+        -1.0, -1.0, 0,
+        1.0,  -1.0, 0,
+        -1.0,  1.0, 0,
+
+        -1.0,  1.0, 0,
+        1.0,  -1.0, 0,
+        1.0,   1.0, 0,
+    ].freeze
+
+      @uvs = [
+        0, 0,
+        1, 0,
+        0, 1,
+
+        0, 1,
+        1, 0,
+        1, 1
+      ].freeze
+
+      create_framebuffer
+      create_screen_vbo
+    end
+
+    def create_framebuffer
+      buffer = ' ' * 4
+      glGenFramebuffers(1, buffer)
+      @framebuffer = buffer.unpack('L2').first
+
+      glBindFramebuffer(GL_DRAW_FRAMEBUFFER, @framebuffer)
+
+      create_textures
+
+      status = glCheckFramebufferStatus(GL_FRAMEBUFFER)
+
+      if status != GL_FRAMEBUFFER_COMPLETE
+        message = ""
+
+        case status
+        when GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT
+          message = "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT"
+        when GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT
+          message = "GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT"
+        when GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER
+          message = "GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER"
+        when GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER
+          message = "GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER"
+        when GL_FRAMEBUFFER_UNSUPPORTED
+          message = "GL_FRAMEBUFFER_UNSUPPORTED"
+        else
+          message = "Unknown error!"
+        end
+        puts "Incomplete framebuffer: #{status}\nError: #{message}"
+      else
+        @ready = true
+      end
+
+      glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0)
+    end
+
+    def create_textures
+      @buffers.size.times do |i|
+        buffer = ' ' * 4
+        glGenTextures(1, buffer)
+        texture_id = buffer.unpack('L2').first
+        @textures[@buffers[i]] = texture_id
+
+        glBindTexture(GL_TEXTURE_2D, texture_id)
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, @width, @height, 0, GL_RGBA, GL_FLOAT, nil)
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, texture_id, 0)
+      end
+
+      buffer = ' ' * 4
+      glGenTextures(1, buffer)
+      texture_id = buffer.unpack('L2').first
+      @textures[:depth] = texture_id
+
+      glBindTexture(GL_TEXTURE_2D, texture_id)
+      glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, @width, @height, 0, GL_DEPTH_COMPONENT, GL_FLOAT, nil)
+      glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, texture_id, 0)
+
+      draw_buffers = [ GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3 ]
+      glDrawBuffers(draw_buffers.size, draw_buffers.pack("I*"))
+    end
+
+    def create_screen_vbo
+      buffer = ' ' * 4
+      glGenVertexArrays(1, buffer)
+      @screen_vbo = buffer.unpack('L2').first
+
+      buffer = " " * 4
+      glGenBuffers(1, buffer)
+      @positions_buffer_id = buffer.unpack('L2').first
+
+      buffer = " " * 4
+      glGenBuffers(1, buffer)
+      @uvs_buffer_id = buffer.unpack('L2').first
+
+      glBindVertexArray(@screen_vbo)
+      glBindBuffer(GL_ARRAY_BUFFER, @positions_buffer_id)
+      glBufferData(GL_ARRAY_BUFFER, @vertices.size * Fiddle::SIZEOF_FLOAT, @vertices.pack("f*"), GL_STATIC_DRAW);
+      glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, nil)
+
+      glBindBuffer(GL_ARRAY_BUFFER, @uvs_buffer_id)
+      glBufferData(GL_ARRAY_BUFFER, @uvs.size * Fiddle::SIZEOF_FLOAT, @uvs.pack("f*"), GL_STATIC_DRAW);
+      glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, nil)
+
+      glEnableVertexAttribArray(0)
+      glEnableVertexAttribArray(1)
+
+      glBindVertexArray(0)
+    end
+
+    def bind_for_writing
+      glBindFramebuffer(GL_DRAW_FRAMEBUFFER, @framebuffer)
+    end
+
+    def bind_for_reading
+      glBindFramebuffer(GL_READ_FRAMEBUFFER, @framebuffer)
+    end
+
+    def set_read_buffer(buffer)
+      glReadBuffer(GL_COLOR_ATTACHMENT0 + @textures.keys.index(buffer))
+    end
+
+    def set_read_buffer_depth
+      glReadBuffer(GL_DEPTH_ATTACHMENT)
+    end
+
+    def unbind_framebuffer
+      glBindFramebuffer(GL_FRAMEBUFFER, 0)
+    end
+
+    def texture(type)
+      @textures[type]
+    end
+
+    def clean_up
+      glDeleteFramebuffers(1, [@framebuffer].pack("L"))
+
+      glDeleteTextures(@textures.values.size, @textures.values.pack("L*"))
+
+      glDeleteBuffers(2, [@positions_buffer_id, @uvs_buffer_id].pack("L*"))
+      glDeleteVertexArrays(1, [@screen_vbo].pack("L"))
+      gl_error?
+    end
+  end
+end

lib/cyberarm_engine/opengl/renderer/opengl_renderer.rb

@@ -0,0 +1,285 @@
+module CyberarmEngine
+  class OpenGLRenderer
+    @@immediate_mode_warning = false
+
+    attr_accessor :show_wireframe
+    def initialize(width:, height:, show_wireframe: false)
+      @width, @height = width, height
+      @show_wireframe = show_wireframe
+
+      @g_buffer = GBuffer.new(width: @width, height: @height)
+    end
+
+    def canvas_size_changed
+      @g_buffer.unbind_framebuffer
+      @g_buffer.clean_up
+
+      @g_buffer = GBuffer.new(width: @width, height: @height)
+    end
+
+    def render(camera, lights, entities)
+      glViewport(0, 0, @width, @height)
+      glEnable(GL_DEPTH_TEST)
+
+      if Shader.available?("g_buffer") && Shader.available?("lighting")
+        @g_buffer.bind_for_writing
+        gl_error?
+
+        glClearColor(0.0, 0.0, 0.0, 0.0)
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
+
+        Shader.use("g_buffer") do |shader|
+          gl_error?
+
+          entities.each do |entity|
+            next unless entity.visible && entity.renderable
+
+            shader.uniform_transform("projection", camera.projection_matrix)
+            shader.uniform_transform("view", camera.view_matrix)
+            shader.uniform_transform("model", entity.model_matrix)
+            shader.uniform_vec3("cameraPosition", camera.position)
+
+            gl_error?
+            draw_model(entity.model, shader)
+            entity.draw
+          end
+        end
+
+        @g_buffer.unbind_framebuffer
+        gl_error?
+
+        @g_buffer.bind_for_reading
+        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0)
+
+        lighting(lights)
+        gl_error?
+
+        post_processing
+        gl_error?
+
+        # render_framebuffer
+        gl_error?
+
+        @g_buffer.unbind_framebuffer
+        gl_error?
+      else
+        puts "Shaders are disabled or failed to compile, using immediate mode for rendering..." unless @@immediate_mode_warning
+        @@immediate_mode_warning = true
+
+        gl_error?
+        lights.each(&:draw)
+        camera.draw
+
+        glEnable(GL_NORMALIZE)
+        entities.each do |entity|
+          next unless entity.visible && entity.renderable
+
+          glPushMatrix
+
+          glTranslatef(entity.position.x, entity.position.y, entity.position.z)
+          glScalef(entity.scale.x, entity.scale.y, entity.scale.z)
+          glRotatef(entity.orientation.x, 1.0, 0, 0)
+          glRotatef(entity.orientation.y, 0, 1.0, 0)
+          glRotatef(entity.orientation.z, 0, 0, 1.0)
+
+          gl_error?
+          draw_mesh(entity.model)
+          entity.draw
+          glPopMatrix
+        end
+      end
+
+      gl_error?
+    end
+
+    def copy_g_buffer_to_screen
+      @g_buffer.set_read_buffer(:position)
+      glBlitFramebuffer(0, 0, @g_buffer.width, @g_buffer.height,
+                        0, 0, @g_buffer.width / 2, @g_buffer.height / 2,
+                        GL_COLOR_BUFFER_BIT, GL_LINEAR)
+
+      @g_buffer.set_read_buffer(:diffuse)
+      glBlitFramebuffer(0, 0, @g_buffer.width, @g_buffer.height,
+                        0, @g_buffer.height / 2, @g_buffer.width / 2, @g_buffer.height,
+                        GL_COLOR_BUFFER_BIT, GL_LINEAR)
+
+      @g_buffer.set_read_buffer(:normal)
+      glBlitFramebuffer(0, 0, @g_buffer.width, @g_buffer.height,
+                        @g_buffer.width / 2, @g_buffer.height / 2, @g_buffer.width, @g_buffer.height,
+                        GL_COLOR_BUFFER_BIT, GL_LINEAR)
+
+      @g_buffer.set_read_buffer(:texcoord)
+      glBlitFramebuffer(0, 0, @g_buffer.width, @g_buffer.height,
+                        @g_buffer.width / 2, 0, @g_buffer.width, @g_buffer.height / 2,
+                        GL_COLOR_BUFFER_BIT, GL_LINEAR)
+    end
+
+    def lighting(lights)
+      Shader.use("lighting") do |shader|
+        glBindVertexArray(@g_buffer.screen_vbo)
+
+        glDisable(GL_DEPTH_TEST)
+        glEnable(GL_BLEND)
+
+        glActiveTexture(GL_TEXTURE0)
+        glBindTexture(GL_TEXTURE_2D, @g_buffer.texture(:diffuse))
+        shader.uniform_integer("diffuse", 0)
+
+        glActiveTexture(GL_TEXTURE1)
+        glBindTexture(GL_TEXTURE_2D, @g_buffer.texture(:position))
+        shader.uniform_integer("position", 1)
+
+        glActiveTexture(GL_TEXTURE2)
+        glBindTexture(GL_TEXTURE_2D, @g_buffer.texture(:texcoord))
+        shader.uniform_integer("texcoord", 2)
+
+        glActiveTexture(GL_TEXTURE3)
+        glBindTexture(GL_TEXTURE_2D, @g_buffer.texture(:normal))
+        shader.uniform_integer("normal", 3)
+
+        glActiveTexture(GL_TEXTURE4)
+        glBindTexture(GL_TEXTURE_2D, @g_buffer.texture(:depth))
+        shader.uniform_integer("depth", 4)
+
+        lights.each_with_index do |light, i|
+          shader.uniform_integer("light[0].type", light.type);
+          shader.uniform_vec3("light[0].direction", light.direction)
+          shader.uniform_vec3("light[0].position", light.position)
+          shader.uniform_vec3("light[0].diffuse", light.diffuse)
+          shader.uniform_vec3("light[0].ambient", light.ambient)
+          shader.uniform_vec3("light[0].specular", light.specular)
+
+          glDrawArrays(GL_TRIANGLES, 0, @g_buffer.vertices.size)
+        end
+
+        glBindVertexArray(0)
+      end
+    end
+
+    def post_processing
+    end
+
+    def render_framebuffer
+      if Shader.available?("lighting")
+        Shader.use("lighting") do |shader|
+          glBindVertexArray(@g_buffer.screen_vbo)
+
+          glDisable(GL_DEPTH_TEST)
+          glEnable(GL_BLEND)
+
+          glActiveTexture(GL_TEXTURE0)
+          glBindTexture(GL_TEXTURE_2D, @g_buffer.texture(:diffuse))
+          shader.uniform_integer("diffuse_texture", 0)
+
+          glDrawArrays(GL_TRIANGLES, 0, @g_buffer.vertices.size)
+
+          glBindVertexArray(0)
+        end
+      end
+    end
+
+    def draw_model(model, shader)
+      glBindVertexArray(model.vertex_array_id)
+      glEnableVertexAttribArray(0)
+      glEnableVertexAttribArray(1)
+      glEnableVertexAttribArray(2)
+      if model.has_texture?
+        glEnableVertexAttribArray(3)
+        glEnableVertexAttribArray(4)
+      end
+
+      if @show_wireframe
+        glLineWidth(2)
+        glPolygonMode(GL_FRONT_AND_BACK, GL_LINE)
+        Shader.active_shader.uniform_boolean("disableLighting", true)
+
+        glDrawArrays(GL_TRIANGLES, 0, model.faces.count * 3)
+
+        Shader.active_shader.uniform_boolean("disableLighting", false)
+        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL)
+        glLineWidth(1)
+      end
+
+      offset = 0
+      model.objects.each do |object|
+        shader.uniform_boolean("hasTexture", object.has_texture?)
+
+        if object.has_texture?
+          glBindTexture(GL_TEXTURE_2D, object.materials.find { |mat| mat.texture_id }.texture_id)
+        else
+          glBindTexture(GL_TEXTURE_2D, 0)
+        end
+
+        glDrawArrays(GL_TRIANGLES, offset, object.faces.count * 3)
+        offset += object.faces.count * 3
+      end
+
+      if model.has_texture?
+        glDisableVertexAttribArray(4)
+        glDisableVertexAttribArray(3)
+
+        glBindTexture(GL_TEXTURE_2D, 0)
+      end
+      glDisableVertexAttribArray(2)
+      glDisableVertexAttribArray(1)
+      glDisableVertexAttribArray(0)
+
+      glBindBuffer(GL_ARRAY_BUFFER, 0)
+      glBindVertexArray(0)
+    end
+
+    def draw_mesh(model)
+      model.objects.each_with_index do |o, i|
+        glEnable(GL_COLOR_MATERIAL)
+        glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE)
+        glShadeModel(GL_FLAT) unless o.faces.first[4]
+        glShadeModel(GL_SMOOTH) if o.faces.first[4]
+        glEnableClientState(GL_VERTEX_ARRAY)
+        glEnableClientState(GL_COLOR_ARRAY)
+        glEnableClientState(GL_NORMAL_ARRAY)
+
+        if o.has_texture?
+          glEnable(GL_TEXTURE_2D)
+          glBindTexture(GL_TEXTURE_2D, o.materials.find { |mat| mat.texture_id }.texture_id)
+          glEnableClientState(GL_TEXTURE_COORD_ARRAY)
+          glTexCoordPointer(3, GL_FLOAT, 0, o.flattened_uvs)
+        end
+
+        glVertexPointer(4, GL_FLOAT, 0, o.flattened_vertices)
+        glColorPointer(3, GL_FLOAT, 0, o.flattened_materials)
+        glNormalPointer(GL_FLOAT, 0, o.flattened_normals)
+
+        if @show_wireframe # This is kinda expensive
+          glDisable(GL_LIGHTING)
+          glPolygonMode(GL_FRONT_AND_BACK, GL_LINE)
+          glPolygonOffset(2, 0.5)
+          glLineWidth(3)
+
+          glDrawArrays(GL_TRIANGLES, 0, o.flattened_vertices_size/4)
+
+          glLineWidth(1)
+          glPolygonOffset(0, 0)
+          glPolygonMode(GL_FRONT_AND_BACK, GL_FILL)
+          glEnable(GL_LIGHTING)
+
+          glDrawArrays(GL_TRIANGLES, 0, o.flattened_vertices_size/4)
+        else
+          glDrawArrays(GL_TRIANGLES, 0, o.flattened_vertices_size/4)
+        end
+
+        # glBindBuffer(GL_ARRAY_BUFFER, 0)
+
+        glDisableClientState(GL_VERTEX_ARRAY)
+        glDisableClientState(GL_COLOR_ARRAY)
+        glDisableClientState(GL_NORMAL_ARRAY)
+
+        if o.has_texture?
+          glDisableClientState(GL_TEXTURE_COORD_ARRAY)
+          glDisable(GL_TEXTURE_2D)
+        end
+
+        glDisable(GL_COLOR_MATERIAL)
+      end
+    end
+  end
+end

lib/cyberarm_engine/opengl/renderer/renderer.rb

@@ -0,0 +1,22 @@
+module CyberarmEngine
+  class Renderer
+    attr_reader :opengl_renderer, :bounding_box_renderer
+
+    def initialize
+      @bounding_box_renderer = BoundingBoxRenderer.new
+      @opengl_renderer = OpenGLRenderer.new(width: $window.width, height: $window.height)
+    end
+
+    def draw(camera, lights, entities)
+      @opengl_renderer.render(camera, lights, entities)
+      @bounding_box_renderer.render(entities) if @show_bounding_boxes
+    end
+
+    def canvas_size_changed
+      @opengl_renderer.canvas_size_changed
+    end
+
+    def finalize # cleanup
+    end
+  end
+end

lib/cyberarm_engine/opengl/shader.rb

@@ -0,0 +1,398 @@
+module CyberarmEngine
+  # Ref: https://github.com/vaiorabbit/ruby-opengl/blob/master/sample/OrangeBook/brick.rb
+  class Shader
+    include OpenGL
+    @@shaders = {} # Cache for {Shader} instances
+    PREPROCESSOR_CHARACTER = "@".freeze # magic character for preprocessor phase of {Shader} compilation
+
+    # add instance of {Shader} to cache
+    #
+    # @param name [String]
+    # @param instance [Shader]
+    def self.add(name, instance)
+      @@shaders[name] = instance
+    end
+
+    # removes {Shader} from cache and cleans up
+    #
+    # @param name [String]
+    def self.delete(name)
+      shader = @@shaders.dig(name)
+
+      if shader
+        @@shaders.delete(name)
+
+        if shader.compiled?
+          glDeleteProgram(shader.program)
+        end
+      end
+    end
+
+    ##
+    # runs _block_ using {Shader} with _name_
+    #
+    # @example
+    #
+    #   CyberarmEngine::Shader.use("blur") do |shader|
+    #     shader.uniform_float("radius", 20.0)
+    #     # OpenGL Code that uses shader
+    #   end
+    #
+    # @param name [String] name of {Shader} to use
+    # @return [void]
+    def self.use(name, &block)
+      shader = @@shaders.dig(name)
+      if shader
+        shader.use(&block)
+      else
+        raise ArgumentError, "Shader '#{name}' not found!"
+      end
+    end
+
+    # returns whether {Shader} with _name_ is in cache
+    #
+    # @param name [String]
+    # @return [Boolean]
+    def self.available?(name)
+      @@shaders.dig(name).is_a?(Shader)
+    end
+
+    # returns instance of {Shader}, if it exists
+    #
+    # @param name [String]
+    # @return [Shader?]
+    def self.get(name)
+      @@shaders.dig(name)
+    end
+
+    # returns currently active {Shader}, if one is active
+    #
+    # @return [Shader?]
+    def self.active_shader
+      @active_shader
+    end
+
+    # sets currently active {Shader}
+    #
+    # @param instance [Shader] instance of {Shader} to set as active
+    def self.active_shader=(instance)
+      @active_shader = instance
+    end
+
+    # stops using currently active {Shader}
+    def self.stop
+      shader = Shader.active_shader
+
+      if shader
+        shader.stop
+      else
+        raise ArgumentError, "No active shader to stop!"
+      end
+    end
+
+    # returns location of OpenGL Shader uniform
+    #
+    # @param variable [String]
+    def self.attribute_location(variable)
+      raise RuntimeError, "No active shader!" unless Shader.active_shader
+      Shader.active_shader.attribute_location(variable)
+    end
+
+    # sets _variable_ to _value_
+    #
+    # @param variable [String]
+    # @param value
+    def self.set_uniform(variable, value)
+      raise RuntimeError, "No active shader!" unless Shader.active_shader
+      Shader.active_shader.set_uniform(variable, value)
+    end
+
+    attr_reader :name, :program
+    def initialize(name:, includes_dir: nil, vertex: "shaders/default.vert", fragment:)
+      raise "Shader name can not be blank" if name.length == 0
+
+      @name = name
+      @includes_dir = includes_dir
+      @compiled = false
+
+      @program = nil
+
+      @error_buffer_size = 1024 * 8
+      @variable_missing = {}
+
+      @data = {shaders: {}}
+
+      unless shader_files_exist?(vertex: vertex, fragment: fragment)
+        raise ArgumentError, "Shader files not found: #{vertex} or #{fragment}"
+      end
+
+      create_shader(type: :vertex, source: File.read(vertex))
+      create_shader(type: :fragment, source: File.read(fragment))
+
+      compile_shader(type: :vertex)
+      compile_shader(type: :fragment)
+      link_shaders
+
+      @data[:shaders].each { |key, id| glDeleteShader(id) }
+
+      # Only add shader if it successfully compiles
+      if @compiled
+        puts "compiled!"
+        puts "Compiled shader: #{@name}"
+        Shader.add(@name, self)
+      else
+        glDeleteProgram(@program)
+        warn "FAILED to compile shader: #{@name}", ""
+      end
+    end
+
+    # whether vertex and fragment files exist on disk
+    #
+    # @return [Boolean]
+    def shader_files_exist?(vertex:, fragment:)
+      File.exist?(vertex) && File.exist?(fragment)
+    end
+
+    # creates an OpenGL Shader of _type_ using _source_
+    #
+    # @param type [Symbol] valid values are: :vertex, :fragment
+    # @param source [String] source code for shader
+    def create_shader(type:, source:)
+      _shader = nil
+
+      case type
+      when :vertex
+        _shader = glCreateShader(GL_VERTEX_SHADER)
+      when :fragment
+        _shader = glCreateShader(GL_FRAGMENT_SHADER)
+      else
+        raise ArgumentError, "Unsupported shader type: #{type.inspect}"
+      end
+
+      processed_source = preprocess_source(source: source)
+
+      _source = [processed_source].pack("p")
+      _size = [processed_source.length].pack("I")
+      glShaderSource(_shader, 1, _source, _size)
+
+      @data[:shaders][type] =_shader
+    end
+
+    # evaluates shader preprocessors
+    #
+    # currently supported preprocessors:
+    #
+    #   @include "file/path" "another/file/path" # => Replace line with contents of file; Shader includes_dir must be specified in constructor
+    #
+    # @example
+    #   # Example Vertex Shader #
+    #   # #version 330 core
+    #   # @include "material_struct"
+    #   # void main() {
+    #   #   gl_Position = vec4(1, 1, 1, 1);
+    #   # }
+    #
+    #   Shader.new(name: "model_renderer", includes_dir: "path/to/includes", vertex: "path/to/vertex_shader.glsl")
+    #
+    # @param source shader source code
+    def preprocess_source(source:)
+      lines = source.lines
+
+      lines.each_with_index do |line, i|
+        if line.start_with?(PREPROCESSOR_CHARACTER)
+          preprocessor = line.strip.split(" ")
+          lines.delete(line)
+
+          case preprocessor.first
+          when "@include"
+            raise ArgumentError, "Shader preprocessor include directory was not given for shader #{@name}" unless @includes_dir
+
+            preprocessor[1..preprocessor.length - 1].join.scan(/"([^"]*)"/).flatten.each do |file|
+              source = File.read("#{@includes_dir}/#{file}.glsl")
+
+              lines.insert(i, source)
+            end
+          else
+            warn "Unsupported preprocessor #{preprocessor.first} for #{@name}"
+          end
+        end
+      end
+
+      lines.join
+    end
+
+    # compile OpenGL Shader of _type_
+    #
+    # @return [Boolean] whether compilation succeeded
+    def compile_shader(type:)
+      _compiled = false
+      _shader = @data[:shaders][type]
+      raise ArgumentError, "No shader for #{type.inspect}" unless _shader
+
+      glCompileShader(_shader)
+      buffer = '    '
+      glGetShaderiv(_shader, GL_COMPILE_STATUS, buffer)
+      compiled = buffer.unpack('L')[0]
+
+      if compiled == 0
+        log = ' ' * @error_buffer_size
+        glGetShaderInfoLog(_shader, @error_buffer_size, nil, log)
+        puts "Shader Error: Program \"#{@name}\""
+        puts "  #{type.to_s.capitalize} Shader InfoLog:", "  #{log.strip.split("\n").join("\n  ")}\n\n"
+        puts "  Shader Compiled status: #{compiled}"
+        puts "    NOTE: assignment of uniforms in shaders is illegal!"
+        puts
+      else
+        _compiled = true
+      end
+
+      return _compiled
+    end
+
+    # link compiled OpenGL Shaders in to a OpenGL Program
+    #
+    # @note linking must succeed or shader cannot be used
+    #
+    # @return [Boolean] whether linking succeeded
+    def link_shaders
+      @program = glCreateProgram
+      @data[:shaders].values.each do |_shader|
+        glAttachShader(@program, _shader)
+      end
+      glLinkProgram(@program)
+
+      buffer = '    '
+      glGetProgramiv(@program, GL_LINK_STATUS, buffer)
+      linked = buffer.unpack('L')[0]
+
+      if linked == 0
+        log = ' ' * @error_buffer_size
+        glGetProgramInfoLog(@program, @error_buffer_size, nil, log)
+        puts "Shader Error: Program \"#{@name}\""
+        puts "  Program InfoLog:", "  #{log.strip.split("\n").join("\n  ")}\n\n"
+      end
+
+      @compiled = linked == 0 ? false : true
+    end
+
+    # Returns the location of a uniform _variable_
+    #
+    # @param variable [String]
+    # @return [Integer] location of uniform
+    def variable(variable)
+      loc = glGetUniformLocation(@program, variable)
+      if (loc == -1)
+        puts "Shader Error: Program \"#{@name}\" has no such uniform named \"#{variable}\"", "  Is it used in the shader? GLSL may have optimized it out.", "  Is it miss spelled?" unless @variable_missing[variable]
+        @variable_missing[variable] = true
+      end
+      return loc
+    end
+
+    # @see Shader.use Shader.use
+    def use(&block)
+      return unless compiled?
+      raise "Another shader is already in use! #{Shader.active_shader.name.inspect}" if Shader.active_shader
+      Shader.active_shader=self
+
+      glUseProgram(@program)
+
+      if block
+        block.call(self)
+        stop
+      end
+    end
+
+    # stop using shader, if shader is active
+    def stop
+      Shader.active_shader = nil if Shader.active_shader == self
+      glUseProgram(0)
+    end
+
+    # @return [Boolean] whether {Shader} successfully compiled
+    def compiled?
+      @compiled
+    end
+
+    # returns location of a uniform _variable_
+    #
+    # @note Use {#variable} for friendly error handling
+    # @see #variable Shader#variable
+    #
+    # @param variable [String]
+    # @return [Integer]
+    def attribute_location(variable)
+      glGetUniformLocation(@program, variable)
+    end
+
+    # send {Transform} to {Shader}
+    #
+    # @param variable [String]
+    # @param value [Transform]
+    # @param location [Integer]
+    # @return [void]
+    def uniform_transform(variable, value, location = nil)
+      attr_loc = location ? location : attribute_location(variable)
+
+      glUniformMatrix4fv(attr_loc, 1, GL_FALSE, value.to_gl.pack("F16"))
+    end
+
+    # send Boolean to {Shader}
+    #
+    # @param variable [String]
+    # @param value [Boolean]
+    # @param location [Integer]
+    # @return [void]
+    def uniform_boolean(variable, value, location = nil)
+      attr_loc = location ? location : attribute_location(variable)
+
+      glUniform1i(attr_loc, value ? 1 : 0)
+    end
+
+    # send Integer to {Shader}
+    # @param variable [String]
+    # @param value [Integer]
+    # @param location [Integer]
+    # @return [void]
+    def uniform_integer(variable, value, location = nil)
+      attr_loc = location ? location : attribute_location(variable)
+
+      glUniform1i(attr_loc, value)
+    end
+
+    # send Float to {Shader}
+    #
+    # @param variable [String]
+    # @param value [Float]
+    # @param location [Integer]
+    # @return [void]
+    def uniform_float(variable, value, location = nil)
+      attr_loc = location ? location : attribute_location(variable)
+
+      glUniform1f(attr_loc, value)
+    end
+
+    # send {Vector} (x, y, z) to {Shader}
+    #
+    # @param variable [String]
+    # @param value [Vector]
+    # @param location [Integer]
+    # @return [void]
+    def uniform_vec3(variable, value, location = nil)
+      attr_loc = location ? location : attribute_location(variable)
+
+      glUniform3f(attr_loc, *value.to_a[0..2])
+    end
+
+    # send {Vector} to {Shader}
+    #
+    # @param variable [String]
+    # @param value [Vector]
+    # @param location [Integer]
+    # @return [void]
+    def uniform_vec4(variable, value, location = nil)
+      attr_loc = location ? location : attribute_location(variable)
+
+      glUniform4f(attr_loc, *value.to_a)
+    end
+  end
+end

lib/cyberarm_engine/opengl/texture.rb

@@ -0,0 +1,67 @@
+module CyberarmEngine
+  class Texture
+    DEFAULT_TEXTURE = "#{CYBERARM_ENGINE_ROOT_PATH}/assets/textures/default.png"
+
+    CACHE = {}
+
+    def self.release_textures
+      CACHE.values.each do |id|
+        glDeleteTextures(id)
+      end
+    end
+
+    def self.from_cache(path, retro)
+      return CACHE.dig("#{path}?retro=#{retro}")
+    end
+
+    attr_reader :id
+    def initialize(path: nil, image: nil, retro: false)
+      raise "keyword :path or :image must be provided!" if path.nil? && image.nil?
+      @retro = retro
+      @path = path
+
+      if @path
+        unless File.exist?(@path)
+          warn "Missing texture at: #{@path}"
+          @retro = true # override retro setting
+          @path = DEFAULT_TEXTURE
+        end
+
+        if texture = Texture.from_cache(@path, @retro)
+          @id = texture.id
+          return
+        end
+
+        image = load_image(@path)
+        @id = create_from_image(image)
+      else
+        @id = create_from_image(image)
+      end
+    end
+
+    def load_image(path)
+      CACHE["#{path}?retro=#{@retro}"] = self
+      Gosu::Image.new(path, retro: @retro)
+    end
+
+    def create_from_image(image)
+      array_of_pixels = image.to_blob
+
+      tex_names_buf = ' ' * 4
+      glGenTextures(1, tex_names_buf)
+      texture_id = tex_names_buf.unpack('L2').first
+
+      glBindTexture(GL_TEXTURE_2D, texture_id)
+      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, array_of_pixels)
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST) if @retro
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR) unless @retro
+      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR)
+      glGenerateMipmap(GL_TEXTURE_2D)
+      gl_error?
+
+      return texture_id
+    end
+  end
+end