some screen primitives

desktop/src/main.rs

@@ -37,7 +37,6 @@ fn main() {
     let mut vrambuf: Vec<u8> = vec![0xFF; (256 * 513 * 3) as usize];
 
     let mut screen = Frame::new(0, 350, 320, 240, "");
-    let mut screenbuf: Vec<u8> = vec![0xFF; (320 * 240 * 3) as usize];
 
     wind.end();
     wind.show();
@@ -45,7 +44,7 @@ fn main() {
     unsafe {
         draw::draw_rgb_nocopy(&mut pal, &palbuf);
         draw::draw_rgb_nocopy(&mut vram, &vrambuf);
-        draw::draw_rgb_nocopy(&mut screen, &screenbuf);
+        draw::draw_rgb_nocopy(&mut screen, &emu.screen);
     }
 
     pal.set_size(160,40);
@@ -94,7 +93,6 @@ fn main() {
 
         if running {
             emu.frame();
-
         }
         let mut debug = String::new();
         debug.push_str(&format!("PC: {:X}\n\n", emu.core.pc));
@@ -164,18 +162,6 @@ fn main() {
             }
         }
 
-        // render screen
-
-        let bg_color = emu.core.mem.vdp.bg_color();
-
-        // clear screen
-        for pixel in screenbuf.chunks_mut(3) {
-            pixel[0] = bg_color.0;
-            pixel[1] = bg_color.1;
-            pixel[2] = bg_color.2;
-        };
-
-
         wind.redraw();
 
         app::sleep(0.016);

emu/src/lib.rs

@@ -9,6 +9,7 @@ mod z80;
 
 pub struct Megadrive {
     pub core: ConfiguredCore<AutoInterruptController, mem::Mem>,
+    pub screen: [u8; 320 * 240 * 3],
 }
 
 impl Megadrive {
@@ -22,6 +23,7 @@ impl Megadrive {
 
         Megadrive {
             core,
+            screen: [0; 320 * 240 * 3],
         }
     }
 
@@ -31,57 +33,6 @@ impl Megadrive {
         }
     }
 
-    pub fn frame(&mut self) {
-        // https://segaretro.org/Sega_Mega_Drive/Technical_specifications#Graphics
-
-        self.core.mem.vdp.unset_status(vdp::VBLANK_MASK);
-
-        self.core.mem.vdp.unset_status(128);
-
-        let screen_height = self.core.mem.vdp.screen_height();
-        let mut hint_counter = self.core.mem.vdp.hint_counter();
-        for _ in 0..screen_height {
-            self.core.execute(2680);
-
-            hint_counter -= 1;
-            if hint_counter < 0 {
-                hint_counter = self.core.mem.vdp.hint_counter();
-
-                if self.core.mem.vdp.registers[0] & 0x10 > 0 {
-                    self.core.int_ctrl.request_interrupt(4);
-                }
-
-            }
-
-            self.core.mem.vdp.set_status(vdp::HBLANK_MASK);
-            self.core.execute(636);
-            self.core.mem.vdp.unset_status(vdp::HBLANK_MASK);
-
-            self.core.execute(104);
-
-            // render
-        }
-
-        self.core.mem.vdp.set_status(vdp::VBLANK_MASK);
-
-        self.core.execute(588);
-
-        self.core.mem.vdp.status |= 0x80;
-
-        self.core.execute(200);
-
-        if self.core.mem.vdp.registers[1] & 0x20 > 0 {
-            self.core.int_ctrl.request_interrupt(6);
-            self.core.mem.vdp.set_status(128);
-        }
-
-        self.core.execute(3420-788);
-
-        for _ in screen_height..262 {
-            self.core.execute(3420);
-        }
-    }
-
     pub fn disasm(&self) -> Vec<(u32, String)> {
         use r68k_tools::PC;
         let mut buffer = Vec::new();
@@ -102,4 +53,68 @@ impl Megadrive {
 
         opcodes
     }
+
+    pub fn frame(&mut self) {
+        self.clear_screen();
+
+        self.core.mem.vdp.unset_status(vdp::VBLANK_MASK);
+
+        self.core.mem.vdp.unset_status(128);
+
+        let screen_height = self.core.mem.vdp.screen_height();
+        let mut hint_counter = self.core.mem.vdp.hint_counter();
+        for line in 0..screen_height {
+            self.core.execute(2680);
+
+            hint_counter -= 1;
+            if hint_counter < 0 {
+                hint_counter = self.core.mem.vdp.hint_counter();
+
+                if self.core.mem.vdp.registers[0] & 0x10 > 0 {
+                    self.core.int_ctrl.request_interrupt(4);
+                }
+
+            }
+
+            self.core.mem.vdp.set_status(vdp::HBLANK_MASK);
+            self.core.execute(636);
+            self.core.mem.vdp.unset_status(vdp::HBLANK_MASK);
+
+            self.core.execute(104);
+
+            self.render_line(line);
+        }
+
+        self.core.mem.vdp.set_status(vdp::VBLANK_MASK);
+
+        self.core.execute(588);
+
+        self.core.mem.vdp.status |= 0x80;
+
+        self.core.execute(200);
+
+        if self.core.mem.vdp.registers[1] & 0x20 > 0 {
+            self.core.int_ctrl.request_interrupt(6);
+            self.core.mem.vdp.set_status(128);
+        }
+
+        self.core.execute(3420-788);
+
+        for _ in screen_height..262 {
+            self.core.execute(3420);
+        }
+    }
+
+    fn clear_screen(&mut self) {
+        let bg_color = self.core.mem.vdp.bg_color();
+        for pixel in self.screen.chunks_mut(3) {
+            pixel[0] = bg_color.0;
+            pixel[1] = bg_color.1;
+            pixel[2] = bg_color.2;
+        };
+    }
+
+    fn render_line(&mut self, line: usize) {
+
+    }
 }

emu/src/vdp.rs

@@ -95,13 +95,16 @@ impl VDP {
 
     pub fn plane_size(&self) -> (u8, u8) {
         let to_cells = |size| 32 + (size * 32);
-
         (
             to_cells(self.registers[0x10] & 3),
             to_cells((self.registers[0x10] >> 4) & 3),
         )
     }
 
+    pub fn hscroll_addr(&self) -> usize {
+        (self.registers[0xD] as usize & 0b111111) << 10
+    }
+
     pub fn read(&self, mut address: u32) -> u32 {
         address &= 0x1F;