// Continuously update the screen with something interesting
func render() {
counter := 0
for {
w, h := leggo.Dimensions()
for y := 0; y < h; y += 1 {
for x := 0; x < w; x += 1 {
var r, g, b byte
// Some random things to look at
switch mode % 8 {
case 0:
r = byte(rand.Uint32())
g = r
b = r
case 1:
r = byte(rand.Uint32())
g = byte(rand.Uint32())
b = byte(rand.Uint32())
case 2:
r = byte(x * y)
case 3:
r = byte(x*y - int(rand.Uint32())%50)
case 4:
if x == counter%w {
r = 255
g = 255
b = 255
}
case 5:
if counter%2 == 1 {
g = 255
} else {
r = 255
}
time.Sleep(10000)
case 6:
if x == w/2 {
g = 255
}
if y == h/2 {
r = 255
}
case 7:
if x == y {
b = 255
}
}
leggo.WritePixel(x, y, r, g, b, 0)
}
}
counter += 1
}
}
// Draw pattern to screen for debugging purposes
func (ppu *PPU) DrawPattern(pattern [8][8]uint8, offX int, offY int, tileAttr uint8) {
for row := 0; row < 8; row += 1 {
for column := 0; column < 8; column += 1 {
// Lower 3 bits of color index
index := pattern[7-column][7-row]
/*
if index == 0 {
// TODO: 0 is transparent, don't draw it
continue
}*/
// Combine with attribute table
index |= tileAttr << 2
// Lookup from internal "palette" table (really a lookup table)
// TODO: background/sprite select. This one assumes background.
color := ppu.Memory[IMAGE_PALETTE_1+uint16(index)]
// Convert from color into RGB
rgb := PPU_PALETTE_RGB[color]
r, g, b := float(rgb[0])/255, float(rgb[1])/255, float(rgb[2])/255
// Emphasize colors
// Note: generating NTSC waveform and rendering it manually would be more accurate
intensity := INTENSIFY_COEFFICIENTS[ppu.intensifyMask]
ir, ig, ib := intensity[0], intensity[1], intensity[2]
r *= ir
g *= ig
b *= ib
// Clipping
if row+offX > PIXELS_VISIBLE || column+offY > SCANLINES_VISIBLE {
continue
}
drawX := row + offX
drawY := (7 - column) + offY
leggo.WritePixel(drawX, drawY, uint8(r*255), uint8(g*255), uint8(b*255), 0)
}
}
}
