func drawTexture(c *opengl.Context, texture opengl.Texture, projectionMatrix *[4][4]float64, quads TextureQuads, geo Matrix, color Matrix) error {
// NOTE: WebGL doesn't seem to have Check gl.MAX_ELEMENTS_VERTICES or gl.MAX_ELEMENTS_INDICES so far.
// Let's use them to compare to len(quads) in the future.
if !shadersInitialized {
if err := initialize(c); err != nil {
return err
}
shadersInitialized = true
}
if quads.Len() == 0 {
return nil
}
if quadsMaxNum < quads.Len() {
return errors.New(fmt.Sprintf("len(quads) must be equal to or less than %d", quadsMaxNum))
}
f := useProgramForTexture(c, glMatrix(projectionMatrix), texture, geo, color)
defer f.FinishProgram()
vertices := vertices[0:0]
num := 0
for i := 0; i < quads.Len(); i++ {
x0, y0, x1, y1 := quads.Vertex(i)
u0, v0, u1, v1 := quads.Texture(i)
if x0 == x1 || y0 == y1 || u0 == u1 || v0 == v1 {
continue
}
vertices = append(vertices,
int16(x0), int16(y0), int16(u0), int16(v0),
int16(x1), int16(y0), int16(u1), int16(v0),
int16(x0), int16(y1), int16(u0), int16(v1),
int16(x1), int16(y1), int16(u1), int16(v1),
)
num++
}
if len(vertices) == 0 {
return nil
}
c.BufferSubData(c.ArrayBuffer, vertices)
c.DrawElements(c.Triangles, 6*num)
return nil
}
func drawFilledRects(c *opengl.Context, projectionMatrix *[4][4]float64, rects Rects) error {
if !shadersInitialized {
if err := initialize(c); err != nil {
return err
}
shadersInitialized = true
}
if rects.Len() == 0 {
return nil
}
f := useProgramForRects(c, glMatrix(projectionMatrix))
defer f.FinishProgram()
vertices := vertices[0:0]
num := 0
for i := 0; i < rects.Len(); i++ {
x, y, w, h := rects.Rect(i)
if w == 0 || h == 0 {
continue
}
x0, y0, x1, y1 := x, y, x+w, y+h
r, g, b, a := rects.Color(i).RGBA()
vertices = append(vertices,
int16(x0), int16(y0), int16(r), int16(g), int16(b), int16(a),
int16(x1), int16(y0), int16(r), int16(g), int16(b), int16(a),
int16(x0), int16(y1), int16(r), int16(g), int16(b), int16(a),
int16(x1), int16(y1), int16(r), int16(g), int16(b), int16(a),
)
num++
}
if len(vertices) == 0 {
return nil
}
c.BufferSubData(c.ArrayBuffer, vertices)
c.DrawElements(c.Triangles, 6*num)
return nil
}
func drawLines(c *opengl.Context, projectionMatrix *[4][4]float64, lines Lines) error {
if !shadersInitialized {
if err := initialize(c); err != nil {
return err
}
shadersInitialized = true
}
if lines.Len() == 0 {
return nil
}
f := useProgramForLines(c, glMatrix(projectionMatrix))
defer f.FinishProgram()
vertices := vertices[0:0]
num := 0
for i := 0; i < lines.Len(); i++ {
x0, y0, x1, y1 := lines.Points(i)
if x0 == x1 && y0 == y1 {
continue
}
r, g, b, a := lines.Color(i).RGBA()
vertices = append(vertices,
int16(x0), int16(y0), int16(r), int16(g), int16(b), int16(a),
int16(x1), int16(y1), int16(r), int16(g), int16(b), int16(a),
)
num++
}
if len(vertices) == 0 {
return nil
}
c.BufferSubData(c.ArrayBuffer, vertices)
c.DrawElements(c.Lines, 2*num)
return nil
}