From 60a7776b22c3d284e0d87061b6e3779fac7321e2 Mon Sep 17 00:00:00 2001
From: Zack Buhman <zack@buhman.org>
Date: Sat, 28 Jan 2023 14:11:14 -0800
Subject: [PATCH] vdp1: polygon example

---
 Makefile         |  2 ++
 vdp1/polygon.cpp | 82 ++++++++++++++++++++++++++++++++++++++++++++++++
 vdp2/nbg0.cpp    |  2 +-
 3 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 vdp1/polygon.cpp

diff --git a/Makefile b/Makefile
index 647ba01..65e5e93 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,8 @@ raytracing/raytracing.elf: raytracing/main-saturn.o raytracing/raytracing.o sh/l
 
 vdp2/nbg0.elf: vdp2/nbg0.o res/butterfly.data.o res/butterfly.data.pal.o
 
+vdp1/polygon.elf: vdp1/polygon.o
+
 # clean
 clean: clean-sh
 clean-sh:
diff --git a/vdp1/polygon.cpp b/vdp1/polygon.cpp
new file mode 100644
index 0000000..f701598
--- /dev/null
+++ b/vdp1/polygon.cpp
@@ -0,0 +1,82 @@
+#include <stdint.h>
+#include "vdp2.h"
+#include "vdp1.h"
+
+void main()
+{
+  // DISP: Please make sure to change this bit from 0 to 1 during V blank.
+  vdp2.reg.TVMD = ( TVMD__DISP | TVMD__LSMD__NON_INTERLACE
+                  | TVMD__VRESO__240 | TVMD__HRESO__NORMAL_320);
+
+  // VDP2 User's Manual:
+  // "When sprite data is in an RGB format, sprite register 0 is selected"
+  // "When the value of a priority number is 0h, it is read as transparent"
+  //
+  // The power-on value of PRISA is zero. Set the priority for sprite register 0
+  // to some number greater than zero, so that the color data is not interpreted
+  // as "transparent".
+  vdp2.reg.PRISA = PRISA__S0PRIN(1); // Sprite register 0 Priority Number
+
+  /* TVM settings must be performed from the second H-blank IN interrupt after the
+  V-blank IN interrupt to the H-blank IN interrupt immediately after the V-blank
+  OUT interrupt. */
+  // "normal" display resolution, 16 bits per pixel, 512x256 framebuffer
+  vdp1.reg.TVMR = TVMR__TVM__NORMAL;
+
+  // swap framebuffers every 1 cycle; non-interlace
+  vdp1.reg.FBCR = 0;
+
+  // during a framebuffer erase cycle, write the color "black" to each pixel
+  constexpr uint16_t black = 0x0000;
+  vdp1.reg.EWDR = black;
+
+  // the EWLR/EWRR macros use somewhat nontrivial math for the X1 coordinates
+  // erase upper-left coordinate
+  vdp1.reg.EWLR = EWLR__16BPP_X1(0) | EWLR__Y1(0);
+
+  // erase lower-right coordinate
+  vdp1.reg.EWRR = EWRR__16BPP_X3(319) | EWRR__Y3(239);
+
+  vdp1.vram.cmd[0].CTRL = CTRL__JP__JUMP_NEXT | CTRL__COMM__USER_CLIP_COORDINATES;
+  vdp1.vram.cmd[0].LINK = 0;
+  vdp1.vram.cmd[0].XA = 0;
+  vdp1.vram.cmd[0].YA = 0;
+  vdp1.vram.cmd[0].XC = 319;
+  vdp1.vram.cmd[0].YC = 239;
+
+  vdp1.vram.cmd[1].CTRL = CTRL__JP__JUMP_NEXT | CTRL__COMM__SYSTEM_CLIP_COORDINATES;
+  vdp1.vram.cmd[1].LINK = 0;
+  vdp1.vram.cmd[1].XC = 319;
+  vdp1.vram.cmd[1].YC = 239;
+
+  vdp1.vram.cmd[2].CTRL = CTRL__JP__JUMP_NEXT | CTRL__COMM__LOCAL_COORDINATE;
+  vdp1.vram.cmd[2].LINK = 0;
+  vdp1.vram.cmd[2].XA = 0;
+  vdp1.vram.cmd[2].YA = 0;
+
+  constexpr uint16_t magenta = (0x31 << 10) | (0x31 << 0);
+  vdp1.vram.cmd[3].CTRL = CTRL__JP__JUMP_NEXT | CTRL__COMM__POLYGON;
+  vdp1.vram.cmd[3].LINK = 0;
+  vdp1.vram.cmd[3].PMOD = CTRL__PMOD__ECD | CTRL__PMOD__SPD;
+  vdp1.vram.cmd[3].COLR = (1 << 15) | magenta; // non-palettized (rgb15) color data
+  vdp1.vram.cmd[3].XA = 100;
+  vdp1.vram.cmd[3].YA = 50;
+  vdp1.vram.cmd[3].XB = 150;
+  vdp1.vram.cmd[3].YB = 100;
+  vdp1.vram.cmd[3].XC = 100;
+  vdp1.vram.cmd[3].YC = 150;
+  vdp1.vram.cmd[3].XD =  50;
+  vdp1.vram.cmd[3].YD = 100;
+
+  vdp1.vram.cmd[4].CTRL = CTRL__END;
+
+  // start drawing (execute the command list) on every frame
+  vdp1.reg.PTMR = PTMR__PTM__FRAME_CHANGE;
+}
+
+extern "C"
+void start(void)
+{
+  main();
+  while (1) {}
+}
diff --git a/vdp2/nbg0.cpp b/vdp2/nbg0.cpp
index 88e3a65..308b8e8 100644
--- a/vdp2/nbg0.cpp
+++ b/vdp2/nbg0.cpp
@@ -56,7 +56,7 @@ void cell_data()
   }
 }
 
-template <class T>
+template <typename T>
 void fill(T * buf, T v, int32_t n) noexcept
 {
   while (n > 0) {