From 48659cd7fef1824dc20a04f88ae575c0370e49f2 Mon Sep 17 00:00:00 2001
From: Ross Andrews <ross.andrews@gmail.com>
Date: Sun, 20 Feb 2022 14:25:43 -0600
Subject: [PATCH] Basic high res gfx

---
 src/bus.rs                  |  2 +-
 src/cpu.rs                  | 11 ++++++++---
 src/main.rs                 | 37 ++++++++++++++++++++++++++-----------
 src/memory.rs               |  4 ++--
 src/{address.rs => word.rs} |  0
 5 files changed, 37 insertions(+), 17 deletions(-)
 rename src/{address.rs => word.rs} (100%)

diff --git a/src/bus.rs b/src/bus.rs
index 30fb061..a4b14dd 100644
--- a/src/bus.rs
+++ b/src/bus.rs
@@ -1,5 +1,5 @@
 use crate::memory::PeekPoke;
-use crate::address::Word;
+use crate::word::Word;
 
 pub trait Device {
     fn tick(&mut self);
diff --git a/src/cpu.rs b/src/cpu.rs
index bd30eac..c5a2d26 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -1,12 +1,12 @@
 use crate::opcodes::Opcode;
 use crate::opcodes::InvalidOpcode;
 use crate::memory::Memory;
-use crate::address::Word;
+use crate::word::Word;
 use crate::memory::PeekPoke;
 use std::convert::TryFrom;
 
 #[allow(clippy::upper_case_acronyms)]
-struct CPU {
+pub struct CPU {
     memory: Memory, // Main memory, all of it
     pc: Word, // program counter, address of the low byte of the instruction
     dp: Word, // data pointer, address of the low byte of one cell above the data stack
@@ -23,8 +23,13 @@ struct Instruction {
     length: u8
 }
 
+impl PeekPoke for CPU {
+    fn peek(&self, addr: Word) -> u8 { self.memory.peek(addr) }
+    fn poke(&mut self, addr: Word, val: u8) { self.memory.poke(addr, val) }
+}
+
 impl CPU {
-    fn new(memory: Memory) -> Self {
+    pub fn new(memory: Memory) -> Self {
         Self {
             memory,
             pc: 1024.into(),
diff --git a/src/main.rs b/src/main.rs
index 4aa05a3..ea90002 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,5 @@
 mod memory;
-mod address;
+mod word;
 mod opcodes;
 mod cpu;
 mod bus;
@@ -14,6 +14,10 @@ use winit::{
 use pixels::{Pixels, SurfaceTexture};
 use rand::RngCore;
 use std::time::Instant;
+use winit::window::Window;
+use crate::cpu::CPU;
+use crate::memory::{ Memory, PeekPoke };
+use crate::word::Word;
 
 fn main() {
     let event_loop = EventLoop::new();
@@ -33,6 +37,14 @@ fn main() {
         Pixels::new(640, 480, surface_texture).unwrap()
     };
 
+    let mut rng = rand::thread_rng();
+
+    let memory = Memory::from(rng);
+    let cpu = CPU::new(memory);
+    window_loop(event_loop, window, pixels, cpu)
+}
+
+fn window_loop(event_loop: EventLoop<()>, window: Window, mut pixels: Pixels, mut cpu: CPU) -> ! {
     event_loop.run(move |event, _, control_flow| {
         *control_flow = ControlFlow::Poll;
 
@@ -45,27 +57,30 @@ fn main() {
             }
             Event::MainEventsCleared => {
                 let start = Instant::now();
-                draw(pixels.get_frame());
+                draw(pixels.get_frame(), &mut cpu);
                 let draw_time = Instant::now() - start;
                 pixels.render().expect("Problem displaying framebuffer");
                 let total_time = Instant::now() - start;
-                println!("Tick took {} total, {} to draw", total_time.as_micros(), draw_time.as_micros());
+                //println!("Tick took {} total, {} to draw", total_time.as_micros(), draw_time.as_micros());
             }
             _ => {}
         }
     })
 }
 
-fn draw(frame: &mut [u8]) {
+fn draw(frame: &mut [u8], cpu: &mut CPU) {
     assert_eq!(frame.len(), 640 * 480 * 4);
-    let mut rng = rand::thread_rng();
 
-    for (_, pixel) in frame.chunks_exact_mut(4).enumerate() {
-        let p = rng.next_u32();
-        let [low, mid, high, _] = p.to_le_bytes();
-        pixel[0] = low;
-        pixel[1] = mid;
-        pixel[2] = high;
+    // For now, assume 160x120 direct graphics mode
+    for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
+        let (display_row, display_col) = (i / 640, i % 640);
+        let (vulcan_row, vulcan_col) = (display_row >> 2, display_col >> 2);
+        let vb = cpu.peek(Word::from((0x10000 + vulcan_row * 160 + vulcan_col) as u32));
+        let (red, green, blue) = (vb >> 5, (vb >> 3) & 7, (vb & 3) << 1);
+
+        pixel[0] = red << 5;
+        pixel[1] = green << 5;
+        pixel[2] = blue << 5;
         pixel[3] = 0xff;
     }
 }
\ No newline at end of file
diff --git a/src/memory.rs b/src/memory.rs
index 7961292..be43e71 100644
--- a/src/memory.rs
+++ b/src/memory.rs
@@ -1,6 +1,6 @@
 use rand::Rng;
-use crate::address::Word;
-use crate::address::MEM_SIZE;
+use crate::word::Word;
+use crate::word::MEM_SIZE;
 
 pub struct Memory([u8; MEM_SIZE as usize]);
 
diff --git a/src/address.rs b/src/word.rs
similarity index 100%
rename from src/address.rs
rename to src/word.rs