From e94dc4055b5e46f95ef0276d304f7a7d1aab325b Mon Sep 17 00:00:00 2001
From: David Chavez <david@dcvz.io>
Date: Tue, 18 Jun 2024 23:00:26 +0200
Subject: [PATCH] Implement osViRepeatLine (#30)

* Implement osViRepeatLine

* Address feedback

* Include helpers header

* Address feedback
---
 librecomp/src/vi.cpp                      |  5 ++++
 ultramodern/include/ultramodern/ultra64.h |  1 +
 ultramodern/src/events.cpp                | 30 +++++++++++++++++++----
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/librecomp/src/vi.cpp b/librecomp/src/vi.cpp
index e38152f..1f3a4cf 100644
--- a/librecomp/src/vi.cpp
+++ b/librecomp/src/vi.cpp
@@ -1,5 +1,6 @@
 #include <ultramodern/ultramodern.hpp>
 #include "recomp.h"
+#include "helpers.hpp"
 
 extern "C" void osViSetYScale_recomp(uint8_t* rdram, recomp_context * ctx) {
     osViSetYScale(ctx->f12.fl);
@@ -17,6 +18,10 @@ extern "C" void osViBlack_recomp(uint8_t* rdram, recomp_context* ctx) {
     osViBlack((uint32_t)ctx->r4);
 }
 
+extern "C" void osViRepeatLine_recomp(uint8_t* rdram, recomp_context* ctx) {
+    osViRepeatLine(_arg<0, u8>(rdram, ctx));
+}
+
 extern "C" void osViSetSpecialFeatures_recomp(uint8_t* rdram, recomp_context* ctx) {
     osViSetSpecialFeatures((uint32_t)ctx->r4);
 }
diff --git a/ultramodern/include/ultramodern/ultra64.h b/ultramodern/include/ultramodern/ultra64.h
index ef9a86a..bce6090 100644
--- a/ultramodern/include/ultramodern/ultra64.h
+++ b/ultramodern/include/ultramodern/ultra64.h
@@ -284,6 +284,7 @@ void osViSwapBuffer(RDRAM_ARG PTR(void) frameBufPtr);
 void osViSetMode(RDRAM_ARG PTR(OSViMode));
 void osViSetSpecialFeatures(uint32_t func);
 void osViBlack(uint8_t active);
+void osViRepeatLine(uint8_t active);
 void osViSetXScale(float scale);
 void osViSetYScale(float scale);
 PTR(void) osViGetNextFramebuffer();
diff --git a/ultramodern/src/events.cpp b/ultramodern/src/events.cpp
index 3131610..0b4db7b 100644
--- a/ultramodern/src/events.cpp
+++ b/ultramodern/src/events.cpp
@@ -345,9 +345,12 @@ extern unsigned int VI_V_BURST_REG;
 extern unsigned int VI_X_SCALE_REG;
 extern unsigned int VI_Y_SCALE_REG;
 
+#define VI_STATE_BLACK 0x20
+#define VI_STATE_REPEATLINE 0x40
+
 uint32_t hstart = 0;
 uint32_t vi_origin_offset = 320 * sizeof(uint16_t);
-bool vi_black = false;
+static uint16_t vi_state = 0;
 
 void set_dummy_vi() {
     VI_STATUS_REG = 0x311E;
@@ -366,11 +369,16 @@ void set_dummy_vi() {
 }
 
 extern "C" void osViSwapBuffer(RDRAM_ARG PTR(void) frameBufPtr) {
-    if (vi_black) {
+    VI_H_START_REG = hstart;
+    if (vi_state & VI_STATE_BLACK) {
         VI_H_START_REG = 0;
-    } else {
-        VI_H_START_REG = hstart;
     }
+
+    if (vi_state & VI_STATE_REPEATLINE) {
+        VI_Y_SCALE_REG = 0;
+        VI_ORIGIN_REG = osVirtualToPhysical(frameBufPtr);
+    }
+    
     events_context.vi.next_buffer = frameBufPtr;
     events_context.action_queue.enqueue(SwapBuffersAction{ osVirtualToPhysical(frameBufPtr) + vi_origin_offset });
 }
@@ -457,7 +465,19 @@ extern "C" void osViSetSpecialFeatures(uint32_t func) {
 }
 
 extern "C" void osViBlack(uint8_t active) {
-    vi_black = active;
+    if (active) {
+        vi_state |= VI_STATE_BLACK;
+    } else {
+        vi_state &= ~VI_STATE_BLACK;
+    }
+}
+
+extern "C" void osViRepeatLine(uint8_t active) {
+    if (active) {
+        vi_state |= VI_STATE_REPEATLINE;
+    } else {
+        vi_state &= ~VI_STATE_REPEATLINE;
+    }
 }
 
 extern "C" void osViSetXScale(float scale) {