Added keyframe animation and demo.

keyframe.go

@@ -0,0 +1,250 @@
+package goga
+
+import (
+	"github.com/go-gl/gl/v4.5-core/gl"
+)
+
+const (
+	keyframe_sprite_renderer_name = "keyframeRenderer"
+)
+
+// A single keyframe within a keyframe set.
+type Keyframe struct {
+	texCoord *VBO
+	Min, Max Vec2
+}
+
+// Creates a new single keyframe with texture VBO.
+func NewKeyframe(min, max Vec2) *Keyframe {
+	keyframe := &Keyframe{Min: min, Max: max}
+
+	texData := make([]float32, 8)
+	texData = []float32{float32(min.X),
+		float32(max.Y),
+		float32(max.X),
+		float32(max.Y),
+		float32(min.X),
+		float32(min.Y),
+		float32(max.X),
+		float32(min.Y)}
+
+	keyframe.texCoord = NewVBO(gl.ARRAY_BUFFER)
+	keyframe.texCoord.Fill(gl.Ptr(texData), 4, 8, gl.STATIC_DRAW)
+
+	CheckGLError()
+
+	return keyframe
+}
+
+// A set of keyframes making up an animation.
+type KeyframeSet struct {
+	Keyframes []Keyframe
+}
+
+// Creates a new empty keyframe set with given size.
+func NewKeyframeSet() *KeyframeSet {
+	set := &KeyframeSet{}
+	set.Keyframes = make([]Keyframe, 0)
+
+	return set
+}
+
+// Adds a new keyframe to set and returns new length.
+func (s *KeyframeSet) Add(frame *Keyframe) int {
+	s.Keyframes = append(s.Keyframes, *frame)
+	return len(s.Keyframes)
+}
+
+// Keyframe animation component.
+// It has a start and an end frame, a play speed and option to loop.
+type KeyframeAnimation struct {
+	Start, End    int
+	Loop          bool
+	Speed         float64
+	Current       int
+	Interpolation float64
+}
+
+// Creates a new keyframe animation with given start, end and loop.
+func NewKeyframeAnimation(start, end int, loop bool, speed float64) *KeyframeAnimation {
+	return &KeyframeAnimation{start, end, loop, speed, 0, 0}
+}
+
+// An animated sprite is a sprite with keyframe animation information.
+// It will be updated and rendered by the KeyframeRenderer.
+type AnimatedSprite struct {
+	*Actor
+	*Pos2D
+	*Tex
+	*KeyframeSet
+	*KeyframeAnimation
+}
+
+// Creates a new animated sprite.
+func NewAnimatedSprite(tex *Tex, set *KeyframeSet, width, height int) *AnimatedSprite {
+	sprite := &AnimatedSprite{}
+	sprite.Actor = NewActor()
+	sprite.Pos2D = NewPos2D()
+	sprite.Tex = tex
+	sprite.KeyframeSet = set
+	sprite.Scale = Vec2{1, 1}
+	sprite.Visible = true
+
+	if width > 0 && height > 0 {
+		sprite.Size = Vec2{float64(width), float64(height)}
+	} else {
+		sprite.Size = Vec2{tex.GetSize().X, tex.GetSize().Y}
+	}
+
+	CheckGLError()
+
+	return sprite
+}
+
+// The keyframe renderer renders animated sprites.
+// It has a 2D position component, to move all sprites at once.
+type KeyframeRenderer struct {
+	Pos2D
+
+	Shader *Shader
+	Camera *Camera
+
+	sprites       []AnimatedSprite
+	index, vertex *VBO
+	vao           *VAO
+}
+
+// Creates a new keyframe renderer using given shader and camera.
+// If shader and/or camera are nil, the default one will be used.
+func NewKeyframeRenderer(shader *Shader, camera *Camera) *KeyframeRenderer {
+	if shader == nil {
+		shader = Default2DShader
+	}
+
+	if camera == nil {
+		camera = DefaultCamera
+	}
+
+	var tc *VBO
+
+	renderer := &KeyframeRenderer{}
+	renderer.Shader = shader
+	renderer.Camera = camera
+	renderer.sprites = make([]AnimatedSprite, 0)
+	renderer.index, renderer.vertex, tc = CreateRectMesh(false)
+	tc.Drop() // we don't need that VBO
+	renderer.Size = Vec2{1, 1}
+	renderer.Scale = Vec2{1, 1}
+
+	renderer.vao = NewVAO()
+	renderer.vao.Bind()
+	renderer.Shader.EnableVertexAttribArrays()
+	renderer.index.Bind()
+	renderer.vertex.Bind()
+	renderer.vertex.AttribPointer(shader.GetAttribLocation(Default_shader_2D_vertex_attrib), 2, gl.FLOAT, false, 0)
+	renderer.vao.Unbind()
+
+	CheckGLError()
+
+	return renderer
+}
+
+// Frees recources created by keyframe renderer.
+// This is called automatically when system gets removed.
+func (s *KeyframeRenderer) Cleanup() {
+	s.index.Drop()
+	s.vertex.Drop()
+	s.vao.Drop()
+}
+
+// Adds animated sprite to the renderer.
+func (s *KeyframeRenderer) Add(actor *Actor, pos *Pos2D, tex *Tex, set *KeyframeSet, animation *KeyframeAnimation) bool {
+	id := actor.GetId()
+
+	for _, sprite := range s.sprites {
+		if id == sprite.Actor.GetId() {
+			return false
+		}
+	}
+
+	s.sprites = append(s.sprites, AnimatedSprite{actor, pos, tex, set, animation})
+
+	return true
+}
+
+// Removes animated sprite from renderer.
+func (s *KeyframeRenderer) Remove(actor *Actor) bool {
+	return s.RemoveById(actor.GetId())
+}
+
+// Removes sprite from renderer by ID.
+func (s *KeyframeRenderer) RemoveById(id ActorId) bool {
+	for i, sprite := range s.sprites {
+		if sprite.Actor.GetId() == id {
+			s.sprites = append(s.sprites[:i], s.sprites[i+1:]...)
+			return true
+		}
+	}
+
+	return false
+}
+
+// Removes all animated sprites.
+func (s *KeyframeRenderer) RemoveAll() {
+	s.sprites = make([]AnimatedSprite, 0)
+}
+
+// Returns number of sprites.
+func (s *KeyframeRenderer) Len() int {
+	return len(s.sprites)
+}
+
+func (s *KeyframeRenderer) GetName() string {
+	return keyframe_sprite_renderer_name
+}
+
+// Updates animation state and renders sprites.
+func (s *KeyframeRenderer) Update(delta float64) {
+	// update animation state
+	for i := range s.sprites {
+		if s.sprites[i].KeyframeAnimation == nil {
+			continue
+		}
+
+		s.sprites[i].Interpolation += delta * s.sprites[i].KeyframeAnimation.Speed
+
+		if s.sprites[i].Interpolation > 1 {
+			s.sprites[i].Interpolation = 0
+			s.sprites[i].Current++
+
+			if s.sprites[i].Current > s.sprites[i].KeyframeAnimation.End {
+				if s.sprites[i].KeyframeAnimation.Loop {
+					s.sprites[i].Current = s.sprites[i].KeyframeAnimation.Start
+				} else {
+					s.sprites[i].Current = s.sprites[i].KeyframeAnimation.End
+				}
+			}
+		}
+	}
+
+	// render
+	s.Shader.Bind()
+	s.Shader.SendMat3(Default_shader_2D_ortho, *MultMat3(s.Camera.CalcOrtho(), s.CalcModel()))
+	s.Shader.SendUniform1i(Default_shader_2D_tex, 0)
+	s.vao.Bind()
+
+	for i := range s.sprites {
+		if !s.sprites[i].Visible {
+			continue
+		}
+
+		texCoord := s.sprites[i].KeyframeSet.Keyframes[s.sprites[i].Current].texCoord
+		texCoord.Bind()
+		texCoord.AttribPointer(s.Shader.GetAttribLocation(Default_shader_2D_texcoord_attrib), 2, gl.FLOAT, false, 0)
+
+		s.Shader.SendMat3(Default_shader_2D_model, *s.sprites[i].CalcModel())
+		s.sprites[i].Tex.Bind()
+
+		gl.DrawElements(gl.TRIANGLES, 6, gl.UNSIGNED_INT, nil)
+	}
+}