func (v *Viewport) ScreenCoordinatesToTile(sx, sy int, config DisplayConfig) (float64, float64) {
// I have never been more ashamed of code I have written
w, h := float64(config.TileW), float64(config.TileH)
fx, fy := float32(sx), float32(sy)
var trans allegro.Transform
trans.Identity()
// Builds the viewport alignment matrix
trans.Build(float32(-v.x), float32(-v.y), float32(v.xZoom), float32(v.yZoom),
0)
// Invert it to get back to pixel coordinates
trans.Invert()
// We need to translate back half a width to get to the pivot of the tiles
trans.Translate(-float32(w/2), 0)
x, y := trans.Apply(fx, fy)
// Then we manually rotate it (because I'm bad at maths I guess)
tx := float64(float64(y)*w-float64(x)*h) / (w * h)
ty := float64(float64(y)*w+float64(x)*h) / (w * h)
return tx, ty
}
func (d *DisplayEngine) drawFrame() {
toDraw := make([][]*resources.Bitmap, d.config.MapW*d.config.MapH)
drawPasses := 0
for x := 0; x < d.config.MapW; x++ {
for y := 0; y < d.config.MapH; y++ {
toDraw[x*d.config.MapW+y] = (*d.gameEngine).GetTile(x, y)
length := len(toDraw[x*d.config.MapW+y])
if length > drawPasses {
drawPasses = length
}
}
}
viewport := d.viewport
font := allegro.CreateBuiltinFont()
// Don't want anyone changing the viewport mid frame or any such highjinks
d.Display.SetTargetBackbuffer()
allegro.RunInThread(func() {
r, g, b, a := d.config.BGColor.GetRGBA()
gl.ClearColor(
gl.GLclampf(r)/255.0,
gl.GLclampf(g)/255.0,
gl.GLclampf(b)/255.0,
gl.GLclampf(a)/255.0)
gl.Clear(gl.COLOR_BUFFER_BIT)
viewport.SetupTransform()
for p := 0; p < drawPasses; p++ {
m := d.config.MapW
n := d.config.MapH
for s := 0; s < m+n; s++ {
for x := 0; x < s; x++ {
y := s - x - 1
if x >= m || y < 0 || y >= n {
continue
}
if len(toDraw[x*d.config.MapW+y]) < p {
continue
}
// Coordinates in terms of pixels
px := (y - x) * d.config.TileW / 2
py := (x + y) * d.config.TileH / 2
bmp := toDraw[x*d.config.MapW+y][p]
/* ox := bmp.OffX
oy := bmp.OffY*/
bw, bh := bmp.W, bmp.H
if viewport.OnScreen(px, py, bw, bh) {
gl.Begin(gl.QUADS)
bmp.Tex.Bind(gl.TEXTURE_2D)
gl.TexCoord2f(0, 0)
gl.Vertex3i(px, py, 0)
gl.TexCoord2f(0, 1)
gl.Vertex3i(px, py+bw, 0)
gl.TexCoord2f(1, 1)
gl.Vertex3i(px+bh, py+bw, 0)
gl.TexCoord2f(1, 0)
gl.Vertex3i(px+bh, py, 0)
gl.End()
}
}
}
}
gl.Flush()
})
var trans allegro.Transform
trans.Identity()
trans.Use()
font.Draw(allegro.CreateColor(0, 255, 0, 255), 0, 0, 0, fmt.Sprint(int(d.fps)))
allegro.Flip()
d.frameDrawing.Unlock()
}