Example: Working chip8 display

pvcraven · Jun 4, 2020 · 1a2e9bb · 1a2e9bb
1 parent 98934c4
commit 1a2e9bb
Showing 1 changed file with 56 additions and 10 deletions.
diff --git a/arcade/experimental/examples/chip8_display.py b/arcade/experimental/examples/chip8_display.py
@@ -18,8 +18,8 @@
 from arcade import get_projection
 
 # Do the math to figure out our screen dimensions
-SCREEN_WIDTH = 64 * 10
-SCREEN_HEIGHT = 32 * 10
+SCREEN_WIDTH = 64 * 20
+SCREEN_HEIGHT = 32 * 20
 SCREEN_TITLE = "CHIP-8 Screen"
 
 
@@ -31,38 +31,84 @@ def __init__(self, width, height, title):
         self.program = self.ctx.program(
             vertex_shader="""
             #version 330
+
             uniform mat4 projection;
+
             in vec2 in_vert;
             in vec2 in_uv;
             out vec2 v_uv;
+
             void main() {
                 gl_Position = projection * vec4(in_vert, 0.0, 1.0);
                 v_uv = in_uv;
             }
             """,
             fragment_shader="""
             #version 330
+
+            // Unsigned integer sampler for reading uint data from texture
             uniform usampler2D screen;
+
             in vec2 v_uv;
             out vec4 out_color;
+
             void main() {
-                out_color = vec4(vec3(texture(screen, v_uv * vec2(1.0, -1.0)).r), 1.0);
+                // Calculate the bit position on the x axis
+                uint bit_pos = uint(round((v_uv.x * 64) - 0.5)) % 8u;
+                // Create bit mask we can AND the fragment with to extract the pixel value
+                uint flag = uint(pow(2u, 7u - bit_pos));
+                // Read the fragment value (We reverse the y axis here as well)
+                uint frag = texture(screen, v_uv * vec2(1.0, -1.0)).r;
+                // Write the pixel value. Values above 1 will be clamped to 1.
+                out_color = vec4(vec3(frag & flag), 1.0);
             }
             """
         )
         # 8 x 4 
         self.program['projection'] = get_projection().flatten()
         self.program['screen'] = 0
-        self.quad = geometry.screen_rectangle(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)
-        self.texture = self.ctx.texture((8, 4), components=1, dtype='i1')
+        b = 0  # border to test scale
+        self.quad = geometry.screen_rectangle(b, b, SCREEN_WIDTH - b * 2, SCREEN_HEIGHT - b * 2)
+        self.texture = self.ctx.texture((8, 32), components=1, dtype='i1')
         self.texture.write(array(
             'B',
             [
-                # 62 x 32 screen
-                0xF0, 0x00, 0x00, 0x00, 0xFF, 0x00, 0x00, 0xF0,
-                0x00, 0x00, 0x00, 0x00, 0xFF, 0x00, 0x00, 0x00,
-                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-                0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF0,
+                # 64 x 32 screen
+                0xAA, 0xAA, 0xF0, 0xF0, 0xFF, 0x00, 0xFF, 0xFF,
+                0x55, 0x55, 0xF0, 0xF0, 0xFF, 0x00, 0xFF, 0xFF,
+                0xAA, 0xAA, 0xF0, 0xF0, 0xFF, 0x00, 0xFF, 0xFF,
+                0x55, 0x55, 0xF0, 0xF0, 0xFF, 0x00, 0xFF, 0xFF,
+                0xAA, 0xAA, 0x0F, 0x0F, 0xFF, 0x00, 0xFF, 0xFF,
+                0x55, 0x55, 0x0F, 0x0F, 0xFF, 0x00, 0xFF, 0xFF,
+                0xAA, 0xAA, 0x0F, 0x0F, 0xFF, 0x00, 0xFF, 0xFF,
+                0x55, 0x55, 0x0F, 0x0F, 0xFF, 0x00, 0xFF, 0xFF,
+
+                0xAA, 0xAA, 0xF0, 0xF0, 0x00, 0xFF, 0xFF, 0xFF,
+                0x55, 0x55, 0xF0, 0xF0, 0x00, 0xFF, 0xFF, 0xFF,
+                0xAA, 0xAA, 0xF0, 0xF0, 0x00, 0xFF, 0xFF, 0xFF,
+                0x55, 0x55, 0xF0, 0xF0, 0x00, 0xFF, 0xFF, 0xFF,
+                0xAA, 0xAA, 0x0F, 0x0F, 0x00, 0xFF, 0xFF, 0xFF,
+                0x55, 0x55, 0x0F, 0x0F, 0x00, 0xFF, 0xFF, 0xFF,
+                0xAA, 0xAA, 0x0F, 0x0F, 0x00, 0xFF, 0xFF, 0xFF,
+                0x55, 0x55, 0x0F, 0x0F, 0x00, 0xFF, 0xFF, 0xFF,
+
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x80, 0x00,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x40, 0x00,
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x20, 0x00,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x10, 0x00,
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x08, 0x00,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x04, 0x00,
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x02, 0x00,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x01, 0x00,
+
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x80,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x40,
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x20,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x10,
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x08,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x04,
+                0xAA, 0xAA, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x02,
+                0x55, 0x55, 0xCC, 0x99, 0xbd, 0x63, 0x00, 0x01,
             ]
         ).tobytes())