wasp: simulator: Add ST7789 simulation

1 files changed, 73 insertions, 0 deletions

diff --git a/wasp/boards/simulator/display.py b/wasp/boards/simulator/display.py
new file mode 100644
index 0000000..dc303d9
--- /dev/null
+++ b/wasp/boards/simulator/display.py
@@ -0,0 +1,73 @@
+""" Simulated ST7789 display. """
+
+import sys
+import sdl2
+import sdl2.ext
+
+CASET = 0x2a
+RASET = 0x2b
+RAMWR = 0x2c
+
+class ST7789Sim(object):
+    def __init__(self, width=240, height=240):
+        sdl2.ext.init()
+
+        self.width = width
+        self.height = height
+
+        self.x = 0
+        self.y = 0
+        self.colclip = [0, width-1]
+        self.rowclip = [0, height-1]
+        self.cmd = 0
+
+        self.window = sdl2.ext.Window("ST7789", size=(width, height))
+        self.window.show()
+        self.windowsurface = self.window.get_surface()
+        sdl2.ext.fill(self.windowsurface, (0, 0, 0))
+
+    def write(self, data):
+        if len(data) == 1:
+            # Assume if we get a byte at a time then it is command.
+            # This is a simplification do we don't have to track
+            # the D/C pin from within the simulator.
+            self.cmd = data[0]
+
+        elif self.cmd == CASET:
+            self.colclip[0] = (data[0] << 8) + data[1]
+            self.colclip[1] = (data[2] << 8) + data[3]
+            self.x = self.colclip[0]
+
+        elif self.cmd == RASET:
+            self.rowclip[0] = (data[0] << 8) + data[1]
+            self.rowclip[1] = (data[2] << 8) + data[3]
+            self.y = self.rowclip[0]
+
+        elif self.cmd == RAMWR:
+            pixelview = sdl2.ext.PixelView(self.windowsurface)
+
+            half = False
+            for d in data:
+                if not half:
+                    rgb = d << 8
+                    half = True
+                    continue
+                rgb |= d
+                half = False
+
+                pixel = ((rgb & 0xf800) >> 8,
+                         (rgb & 0x07e0) >> 3,
+                         (rgb & 0x001f) << 3)
+            
+                pixelview[self.y][self.x] = pixel
+
+                self.x += 1
+                if self.x > self.rowclip[1]:
+                    self.x = self.rowclip[0]
+                    self.y += 1
+                if self.y > self.colclip[1]:
+                    self.y = self.colclip[0]
+            
+            # Forcibly release the surface to ensure it is unlocked
+            del pixelview
+            self.window.refresh()