Merge pull request #246 from dusk125/tri_shader

#244 GLTriangle's fragment shader is used when rendered by the Canvas.

pixelgl/canvas.go

@@ -19,7 +19,7 @@ import (
 // It supports TrianglesPosition, TrianglesColor, TrianglesPicture and PictureColor.
 type Canvas struct {
 	gf     *GLFrame
-	shader *glShader
+	shader *GLShader
 
 	cmp    pixel.ComposeMethod
 	mat    mgl32.Mat3
@@ -39,9 +39,8 @@ func NewCanvas(bounds pixel.Rect) *Canvas {
 		col: mgl32.Vec4{1, 1, 1, 1},
 	}
 
-	baseShader(c)
+	c.shader = NewGLShader(baseCanvasFragmentShader)
 	c.SetBounds(bounds)
-	c.shader.update()
 	return c
 }
 
@@ -49,22 +48,28 @@ func NewCanvas(bounds pixel.Rect) *Canvas {
 // attribute variable. If the uniform already exists, including defaults, they will be reassigned
 // to the new value. The value can be a pointer.
 func (c *Canvas) SetUniform(name string, value interface{}) {
-	c.shader.setUniform(name, value)
+	c.shader.SetUniform(name, value)
 }
 
 // SetFragmentShader allows you to set a new fragment shader on the underlying
 // framebuffer. Argument "src" is the GLSL source, not a filename.
 func (c *Canvas) SetFragmentShader(src string) {
 	c.shader.fs = src
-	c.shader.update()
+	c.shader.Update()
 }
 
 // MakeTriangles creates a specialized copy of the supplied Triangles that draws onto this Canvas.
 //
 // TrianglesPosition, TrianglesColor and TrianglesPicture are supported.
 func (c *Canvas) MakeTriangles(t pixel.Triangles) pixel.TargetTriangles {
+	if gt, ok := t.(*GLTriangles); ok {
 		return &canvasTriangles{
-		GLTriangles: NewGLTriangles(c.shader.s, t),
+			GLTriangles: gt,
+			dst:         c,
+		}
+	}
+	return &canvasTriangles{
+		GLTriangles: NewGLTriangles(c.shader, t),
 		dst:         c,
 	}
 }
@@ -290,15 +295,15 @@ func (ct *canvasTriangles) draw(tex *glhf.Texture, bounds pixel.Rect) {
 		setBlendFunc(cmp)
 
 		frame := ct.dst.gf.Frame()
-		shader := ct.dst.shader.s
+		shader := ct.shader.s
 
 		frame.Begin()
 		shader.Begin()
 
-		ct.dst.shader.uniformDefaults.transform = mat
-		ct.dst.shader.uniformDefaults.colormask = col
+		ct.shader.uniformDefaults.transform = mat
+		ct.shader.uniformDefaults.colormask = col
 		dstBounds := ct.dst.Bounds()
-		ct.dst.shader.uniformDefaults.bounds = mgl32.Vec4{
+		ct.shader.uniformDefaults.bounds = mgl32.Vec4{
 			float32(dstBounds.Min.X),
 			float32(dstBounds.Min.Y),
 			float32(dstBounds.W()),
@@ -306,15 +311,15 @@ func (ct *canvasTriangles) draw(tex *glhf.Texture, bounds pixel.Rect) {
 		}
 
 		bx, by, bw, bh := intBounds(bounds)
-		ct.dst.shader.uniformDefaults.texbounds = mgl32.Vec4{
+		ct.shader.uniformDefaults.texbounds = mgl32.Vec4{
 			float32(bx),
 			float32(by),
 			float32(bw),
 			float32(bh),
 		}
 
-		for loc, u := range ct.dst.shader.uniforms {
-			ct.dst.shader.s.SetUniformAttr(loc, u.Value())
+		for loc, u := range ct.shader.uniforms {
+			ct.shader.s.SetUniformAttr(loc, u.Value())
 		}
 
 		if clip, has := ct.ClipRect(); has {
@@ -360,17 +365,3 @@ func (cp *canvasPicture) Draw(t pixel.TargetTriangles) {
 	}
 	ct.draw(cp.GLPicture.Texture(), cp.GLPicture.Bounds())
 }
-
-const (
-	canvasPosition int = iota
-	canvasColor
-	canvasTexCoords
-	canvasIntensity
-)
-
-var defaultCanvasVertexFormat = glhf.AttrFormat{
-	canvasPosition:  {Name: "aPosition", Type: glhf.Vec2},
-	canvasColor:     {Name: "aColor", Type: glhf.Vec4},
-	canvasTexCoords: {Name: "aTexCoords", Type: glhf.Vec2},
-	canvasIntensity: {Name: "aIntensity", Type: glhf.Float},
-}

pixelgl/glshader.go

@@ -7,10 +7,10 @@ import (
 	"github.com/pkg/errors"
 )
 
-// glShader is a type to assist with managing a canvas's underlying
+// GLShader is a type to assist with managing a canvas's underlying
 // shader configuration. This allows for customization of shaders on
 // a per canvas basis.
-type glShader struct {
+type GLShader struct {
 	s      *glhf.Shader
 	vf, uf glhf.AttrFormat
 	vs, fs string
@@ -32,8 +32,42 @@ type gsUniformAttr struct {
 	ispointer bool
 }
 
-// reinitialize GLShader data and recompile the underlying gl shader object
-func (gs *glShader) update() {
+const (
+	canvasPosition int = iota
+	canvasColor
+	canvasTexCoords
+	canvasIntensity
+)
+
+var defaultCanvasVertexFormat = glhf.AttrFormat{
+	canvasPosition:  {Name: "aPosition", Type: glhf.Vec2},
+	canvasColor:     {Name: "aColor", Type: glhf.Vec4},
+	canvasTexCoords: {Name: "aTexCoords", Type: glhf.Vec2},
+	canvasIntensity: {Name: "aIntensity", Type: glhf.Float},
+}
+
+// Sets up a base shader with everything needed for a Pixel
+// canvas to render correctly. The defaults can be overridden
+// by simply using the SetUniform function.
+func NewGLShader(fragmentShader string) *GLShader {
+	gs := &GLShader{
+		vf: defaultCanvasVertexFormat,
+		vs: baseCanvasVertexShader,
+		fs: fragmentShader,
+	}
+
+	gs.SetUniform("uTransform", &gs.uniformDefaults.transform)
+	gs.SetUniform("uColorMask", &gs.uniformDefaults.colormask)
+	gs.SetUniform("uBounds", &gs.uniformDefaults.bounds)
+	gs.SetUniform("uTexBounds", &gs.uniformDefaults.texbounds)
+
+	gs.Update()
+
+	return gs
+}
+
+// Update reinitialize GLShader data and recompile the underlying gl shader object
+func (gs *GLShader) Update() {
 	gs.uf = nil
 	for _, u := range gs.uniforms {
 		gs.uf = append(gs.uf, glhf.Attr{
@@ -59,7 +93,7 @@ func (gs *glShader) update() {
 }
 
 // gets the uniform index from GLShader
-func (gs *glShader) getUniform(Name string) int {
+func (gs *GLShader) getUniform(Name string) int {
 	for i, u := range gs.uniforms {
 		if u.Name == Name {
 			return i
@@ -75,7 +109,7 @@ func (gs *glShader) getUniform(Name string) int {
 //
 //   utime := float32(time.Since(starttime)).Seconds())
 //   mycanvas.shader.AddUniform("u_time", &utime)
-func (gs *glShader) setUniform(name string, value interface{}) {
+func (gs *GLShader) SetUniform(name string, value interface{}) {
 	t, p := getAttrType(value)
 	if loc := gs.getUniform(name); loc > -1 {
 		gs.uniforms[loc].Name = name
@@ -92,24 +126,6 @@ func (gs *glShader) setUniform(name string, value interface{}) {
 	})
 }
 
-// Sets up a base shader with everything needed for a Pixel
-// canvas to render correctly. The defaults can be overridden
-// by simply using the SetUniform function.
-func baseShader(c *Canvas) {
-	gs := &glShader{
-		vf: defaultCanvasVertexFormat,
-		vs: baseCanvasVertexShader,
-		fs: baseCanvasFragmentShader,
-	}
-
-	gs.setUniform("uTransform", &gs.uniformDefaults.transform)
-	gs.setUniform("uColorMask", &gs.uniformDefaults.colormask)
-	gs.setUniform("uBounds", &gs.uniformDefaults.bounds)
-	gs.setUniform("uTexBounds", &gs.uniformDefaults.texbounds)
-
-	c.shader = gs
-}
-
 // Value returns the attribute's concrete value. If the stored value
 // is a pointer, we return the dereferenced value.
 func (gu *gsUniformAttr) Value() interface{} {

pixelgl/gltriangles.go

@@ -15,7 +15,7 @@ import (
 type GLTriangles struct {
 	vs     *glhf.VertexSlice
 	data   []float32
-	shader *glhf.Shader
+	shader *GLShader
 	clip   pixel.Rect
 }
 
@@ -28,11 +28,11 @@ var (
 // NewGLTriangles returns GLTriangles initialized with the data from the supplied Triangles.
 //
 // Only draw the Triangles using the provided Shader.
-func NewGLTriangles(shader *glhf.Shader, t pixel.Triangles) *GLTriangles {
+func NewGLTriangles(shader *GLShader, t pixel.Triangles) *GLTriangles {
 	var gt *GLTriangles
 	mainthread.Call(func() {
 		gt = &GLTriangles{
-			vs:     glhf.MakeVertexSlice(shader, 0, t.Len()),
+			vs:     glhf.MakeVertexSlice(shader.s, 0, t.Len()),
 			shader: shader,
 		}
 	})
@@ -49,7 +49,7 @@ func (gt *GLTriangles) VertexSlice() *glhf.VertexSlice {
 }
 
 // Shader returns the GLTriangles's associated shader.
-func (gt *GLTriangles) Shader() *glhf.Shader {
+func (gt *GLTriangles) Shader() *GLShader {
 	return gt.shader
 }