From eecc55bbd7990cab93eba4425b3563e1f996c8fd Mon Sep 17 00:00:00 2001
From: Guy Perfect <guytpk@gmail.com>
Date: Wed, 16 Oct 2024 16:53:33 -0500
Subject: [PATCH] Display tweaks, add vbGetPixels()

---
 core/vb.c  | 40 ++++++++++++++++++++++++++++++++++++++++
 core/vb.h  |  1 +
 core/vip.c | 43 +++++++++++++++++++++++++++++++++++--------
 3 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/core/vb.c b/core/vb.c
index 391b16e..165a1af 100644
--- a/core/vb.c
+++ b/core/vb.c
@@ -279,6 +279,46 @@ VBAPI vbOnFrame vbGetFrameCallback(VB *sim) {
     return sim->onFrame;
 }
 
+/* Retrieve the most recent frame image pixels */
+VBAPI void vbGetPixels(VB *sim, void *left, int leftStrideX, int leftStrideY,
+    void *right, int rightStrideX, int rightStrideY) {
+    uint8_t *dest;    /* Output data */
+    int      offset;  /* Horizontal offset of output pixel */
+    uint8_t *src;     /* Source data */
+    int      xStride; /* Bytes between output pixels */
+    int      yStride; /* Bytes between output lines */
+    int      i, x, y; /* Iterators */
+
+    /* Process both eyes */
+    for (i = 0; i < 2; i++) {
+
+        /* Working variables for left image */
+        if (i == 0) {
+            dest    = left;
+            xStride = leftStrideX;
+            yStride = leftStrideY;
+        }
+
+        /* Working variables for right image */
+        else {
+            dest    = right;
+            xStride = rightStrideX;
+            yStride = rightStrideY;
+        }
+
+        /* Nothing to do */
+        if (dest == NULL)
+            continue;
+
+        /* Transfer pixels to the destination */
+        src = sim->vip.frames[sim->vip.dp.buffer][i];
+        for (y = 0; y < 224; y++, dest += yStride)
+        for (x = offset = 0; x < 384; x++, offset += xStride)
+            dest[offset] = *src++;
+    }
+
+}
+
 /* Retrieve the value of the program counter */
 VBAPI uint32_t vbGetProgramCounter(VB *sim) {
     return sim->cpu.pc;
diff --git a/core/vb.h b/core/vb.h
index b07e266..d1ac6ea 100644
--- a/core/vb.h
+++ b/core/vb.h
@@ -107,6 +107,7 @@ VBAPI vbOnException vbGetExceptionCallback(VB *sim);
 VBAPI vbOnExecute   vbGetExecuteCallback  (VB *sim);
 VBAPI vbOnFetch     vbGetFetchCallback    (VB *sim);
 VBAPI vbOnFrame     vbGetFrameCallback    (VB *sim);
+VBAPI void          vbGetPixels           (VB *sim, void *left, int leftStrideX, int leftStrideY, void *right, int rightStrideX, int rightStrideY);
 VBAPI uint32_t      vbGetProgramCounter   (VB *sim);
 VBAPI int32_t       vbGetProgramRegister  (VB *sim, int index);
 VBAPI vbOnRead      vbGetReadCallback     (VB *sim);
diff --git a/core/vip.c b/core/vip.c
index 8e34b4b..2d3f319 100644
--- a/core/vip.c
+++ b/core/vip.c
@@ -44,13 +44,26 @@ static void vipThrow(VB *sim, uint16_t cause) {
 
 /* Transfer one column of frame buffer pixels to output */
 static void vipTransferColumn(VB *sim, int32_t eye) {
-    int32_t bits; /* Pixel bits from frame buffer */
-    int     y, z; /* Iterators */
+    int32_t  bits; /* Pixel bits from frame buffer */
+    uint8_t *dest; /* Host frame image output */
+    uint8_t *src;  /* Simulation frame buffer input */
+    int      y, z; /* Iterators */
 
-    /* Select source and destination addresses in host memory */
-    uint8_t *dest = &sim->vip.frames
+    /* Select destination address in host memory */
+    dest = &sim->vip.frames
         [sim->vip.dp.buffer][eye][sim->vip.dp.column];
-    uint8_t *src  = &sim->vip.ram[
+
+    /* Output is disabled */
+    if ((sim->vip.dp.disp & sim->vip.dp.synce) == 0) {
+        for (z = 0; z < 0x15000; z += 4) {
+            busWriteBuffer(dest, VB_S32, 0);
+            dest += 4;
+        }
+        return;
+    }
+
+    /* Select source address in host memory */
+    src = &sim->vip.ram[
         eye                << 16 |
         sim->vip.dp.buffer << 15 |
         sim->vip.dp.column <<  6
@@ -363,9 +376,9 @@ static int vipOnFrame(VB *sim) {
 
 
 
-/***************************** Library Functions *****************************/
+/***************************** Display Processor *****************************/
 
-/* Display processor */
+/* Process sub-component */
 static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
 
     /* Process all clocks */
@@ -474,10 +487,24 @@ static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
     return 0;
 }
 
+
+
+/****************************** Pixel Processor ******************************/
+
+/* Process sub-component */
+static void vipEmulateDrawing(VB *sim, uint32_t clocks) {
+    (void) sim;
+    (void) clocks;
+}
+
+
+
+/***************************** Library Functions *****************************/
+
 /* Process component */
 static int vipEmulate(VB *sim, uint32_t clocks) {
     int brk = vipEmulateDisplay(sim, clocks);
-    /*vipEmulateDrawing(sim, clocks);*/
+    vipEmulateDrawing(sim, clocks);
     return brk;
 }