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fix: voxel cache rendering corruption #77

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Merged
ZivDero merged 5 commits into from
Aug 30, 2026
Merged

fix: voxel cache rendering corruption #77

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a37053b
Harden voxel cache RLE compression
Belonit Aug 30, 2026
6352ee6
Fix adjacent pixel indexing in voxel drawers
Belonit Aug 30, 2026
8f163a6
Avoid undefined voxel fixed-point conversions
Belonit Aug 30, 2026
2ccf4ea
Simplify voxel work buffer resets
Belonit Aug 30, 2026
cd5f29c
Use std::fill for voxel work buffers
Belonit Aug 30, 2026
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2 changes: 1 addition & 1 deletion code/rle.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,7 @@ int RLEEngine::Compress(void const * source, void * dest, int length) const
** Count the number of transparent pixels in this run.
*/
int runcount = 0;
while (sptr[runcount] == '\0' && runcount <= length) {
while (runcount < length && sptr[runcount] == '\0') {
runcount++;
}

Expand Down
9 changes: 7 additions & 2 deletions code/stbuffer.cpp
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Expand Up @@ -13,6 +13,7 @@

#include "rle.h"
#include "surface.h"
#include "voxdrsys.h"

#include <cstring>

Expand Down Expand Up @@ -44,8 +45,12 @@ StaticBufferClass::~StaticBufferClass(void)
}
}

static char CompressionBuffer[256];

/*
* A 256-pixel voxel row can expand when RLE encodes isolated transparent pixels:
* each such pixel takes two bytes, plus the row's length prefix. Reserve twice
* the voxel-buffer width so every cached voxel row fits.
*/
static char CompressionBuffer[2 * VOXEL_BITMAP_WIDTH];

/// <summary>
/// Adds a compressed copy of a surface region to the buffer.
Expand Down
98 changes: 8 additions & 90 deletions code/voxdrsys.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,9 @@
#include "voxlib.h"
#include "wwfile.h"

#include <algorithm>
#include <iterator>

BOOL VoxelDrawSystem::EnableLighting;
BOOL VoxelDrawSystem::EnableZBuffer;

Expand All @@ -29,8 +32,6 @@ BSurface VoxelZSurface(VOXEL_BITMAP_WIDTH, VOXEL_BITMAP_HEIGHT, VOXEL_BITMAP_BPP
Vector3 MinVoxelBounds;
Vector3 MaxVoxelBounds;

Rect LastRenderRect(0,0,VOXEL_BITMAP_WIDTH-1, VOXEL_BITMAP_HEIGHT-1);

VoxelRenderStruct VoxelRenderData[64];
VoxelShadowRenderStruct VoxelShadowRenderData[64];

Expand Down Expand Up @@ -176,31 +177,13 @@ void VoxelDrawSystem::Precalculate_Light(VoxelLibrary * voxlib, int layer, int i
/// <remarks>Forget this routine and the previous object is still sitting in the buffer.</remarks>
void VoxelDrawSystem::Reset(void)
{
static int _need_buffer_init = true;

VoxelRenderDataCount = 0;
VoxelShadowRenderDataCount = 0;

if (_need_buffer_init) {
Clear_Buffer();
/* Cached images must never retain a pixel outside a previous render's bounds. */
Clear_Buffer();
if (VoxelDrawSystem::EnableZBuffer) {
Clear_Z_Buffer();
_need_buffer_init = false;
} else {
//Clear_Buffer(VoxelRect.X, VoxelRect.Y, VoxelRect.Width, VoxelRect.Height);
if (LastRenderRect.X >= 0 && LastRenderRect.Y >= 0 && LastRenderRect.X + LastRenderRect.Width <= VOXEL_BITMAP_WIDTH-1 && LastRenderRect.Y + LastRenderRect.Height <= VOXEL_BITMAP_HEIGHT-1) {
for (int i = LastRenderRect.Y; i <= LastRenderRect.Y + LastRenderRect.Height; i++) {
memset(&VoxelDrawBuffer[VOXEL_BITMAP_HEIGHT * i + LastRenderRect.X], 0, LastRenderRect.Width + 1);
}
} else {
memset(VoxelDrawBuffer, 0, sizeof(VoxelDrawBuffer));
}
if (VoxelDrawSystem::EnableZBuffer) {
if (LastRenderRect.Y <= LastRenderRect.Height + LastRenderRect.Y) {
for (int i = LastRenderRect.Y; i <= LastRenderRect.Y + LastRenderRect.Height; i++) {
memset(&VoxelDrawZBuffer[VOXEL_BITMAP_HEIGHT * i + LastRenderRect.X], 0, LastRenderRect.Width + 1);
}
}
}
}

MinVoxelBounds = Vector3(10000, 10000, 10000);
Expand Down Expand Up @@ -378,7 +361,6 @@ void VoxelDrawSystem::Render(Rect & rect, int & x, int & y)

rect.X -= 4;
rect.Y -= 4;
LastRenderRect = rect;

x = (int)center.X - rect.Width / 2;
y = (int)center.Y - rect.Height / 2;
Expand Down Expand Up @@ -434,8 +416,6 @@ SurfaceRegion VoxelDrawSystem::Render(void)
int width = MaxVoxelBounds.X - MinVoxelBounds.X;
int height = MaxVoxelBounds.Y - MinVoxelBounds.Y;

LastRenderRect = Rect(VOXEL_BITMAP_WIDTH / 2 - width / 2 - 4, VOXEL_BITMAP_HEIGHT / 2 - height / 2 - 4, width + 8, height + 8);

SurfaceRegion region;
region.Point.X = (int)center.X - (width + 8) / 2;
region.Point.Y = (int)center.Y - (height + 8) / 2;
Expand All @@ -453,43 +433,7 @@ SurfaceRegion VoxelDrawSystem::Render(void)
/// </summary>
void VoxelDrawSystem::Clear_Buffer(void)
{
memset(VoxelDrawBuffer, 0, sizeof(VoxelDrawBuffer));
}


/// <summary>
/// Clears a rectangle of the voxel drawing buffer.
/// This routine is used to wipe only the part of the buffer that a drawn object occupied.
/// A rectangle that would stray outside the voxel bitmap is treated as a request to clear
/// the whole buffer.
/// </summary>
void VoxelDrawSystem::Clear_Buffer(int x, int y, int width, int height)
{
if (x >= 0 && y >= 0 && x + width <= VOXEL_BITMAP_WIDTH-1 && y + height <= VOXEL_BITMAP_HEIGHT-1) {
for (int i = y; i <= y + height; i++) {
memset(&VoxelDrawBuffer[VOXEL_BITMAP_HEIGHT * i + x], 0, width);
}
} else {
memset(VoxelDrawBuffer, 0, sizeof(VoxelDrawBuffer));
}
}


/// <summary>
/// Clears a region of the voxel drawing buffer.
/// This routine is used to wipe only the part of the buffer that a drawn object occupied.
/// A region that would stray outside the voxel bitmap is treated as a request to clear
/// the whole buffer.
/// </summary>
void VoxelDrawSystem::Clear_Buffer(SurfaceRegion & region)
{
if (region.Point.X >= 0 && region.Point.Y >= 0 && region.Point.X + region.Bounds.X <= VOXEL_BITMAP_WIDTH-1 && region.Point.Y + region.Bounds.Y <= VOXEL_BITMAP_HEIGHT-1) {
for (int i = region.Point.Y; i <= region.Point.Y + region.Bounds.Y; i++) {
memset(&VoxelDrawBuffer[VOXEL_BITMAP_HEIGHT * i + region.Point.X], 0, region.Bounds.X+1);
}
} else {
memset(VoxelDrawBuffer, 0, sizeof(VoxelDrawBuffer));
}
std::fill(std::begin(VoxelDrawBuffer), std::end(VoxelDrawBuffer), 0);
}


Expand All @@ -498,31 +442,5 @@ void VoxelDrawSystem::Clear_Buffer(SurfaceRegion & region)
/// </summary>
void VoxelDrawSystem::Clear_Z_Buffer(void)
{
memset(VoxelDrawZBuffer, 0, sizeof(VoxelDrawZBuffer));
}


/// <summary>
/// Clears a rectangle of the voxel depth buffer.
/// This routine is used to wipe only the part of the depth buffer that a drawn object
/// occupied, which is cheaper than erasing the whole thing between objects.
/// </summary>
void VoxelDrawSystem::Clear_Z_Buffer(int x, int y, int width, int height)
{
for (int i = y; i <= y + height; i++) {
memset(&VoxelDrawZBuffer[VOXEL_BITMAP_HEIGHT * i + x], 0, width);
}
}


/// <summary>
/// Clears a region of the voxel depth buffer.
/// This routine is used to wipe only the part of the depth buffer that a drawn object
/// occupied, which is cheaper than erasing the whole thing between objects.
/// </summary>
void VoxelDrawSystem::Clear_Z_Buffer(SurfaceRegion & region)
{
for (int i = region.Point.Y; i <= region.Point.Y + region.Bounds.Y; i++) {
memset(&VoxelDrawZBuffer[VOXEL_BITMAP_HEIGHT * i + region.Point.X], 0, region.Bounds.X+1);
}
std::fill(std::begin(VoxelDrawZBuffer), std::end(VoxelDrawZBuffer), 0);
}
4 changes: 0 additions & 4 deletions code/voxdrsys.h
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Original file line number Diff line number Diff line change
Expand Up @@ -63,12 +63,8 @@ namespace VoxelDrawSystem
SurfaceRegion Render(void);

void Clear_Buffer(void);
void Clear_Buffer(int x, int y, int width, int height);
void Clear_Buffer(SurfaceRegion & region);

void Clear_Z_Buffer(void);
void Clear_Z_Buffer(int x, int y, int width, int height);
void Clear_Z_Buffer(SurfaceRegion & region);
};


Expand Down
48 changes: 24 additions & 24 deletions code/voxlib.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -15,8 +15,6 @@
#include "wwfile.h"

#include <algorithm>
#include <climits>


short VoxelPixelDeltaTable[VOXEL_BITMAP_WIDTH][2];
unsigned char VoxelNormalTranslateTable[VOXEL_PALETTE_SIZE];
Expand Down Expand Up @@ -820,22 +818,22 @@ void VoxelLibrary::Render_Object(VoxelRenderStruct & voxel, Vector3 & center)

/// The drawer sums these deltas down the length of the model, so an error of
/// one unit here becomes one unit per voxel by the far end.
arg.TransformMatrix[0].I = short(float((double)corner_0.X + 128 - (double)center.X) * 256);
arg.TransformMatrix[0].J = short(float((double)corner_0.Y + 128 - (double)center.Y) * 256);
arg.TransformMatrix[0].K = short(float((double)corner_0.Z + 128 - (double)center.Z) * 256);
arg.TransformMatrix[0].I = static_cast<unsigned short>(static_cast<int>(((double)corner_0.X + 128 - (double)center.X) * 256.0));
arg.TransformMatrix[0].J = static_cast<unsigned short>(static_cast<int>(((double)corner_0.Y + 128 - (double)center.Y) * 256.0));
arg.TransformMatrix[0].K = static_cast<unsigned short>(static_cast<int>(((double)corner_0.Z + 128 - (double)center.Z) * 256.0));

arg.TransformMatrix[1].I = short(float(corner_x.X - corner_0.X) / (double)x_size * 256);
arg.TransformMatrix[2].I = short(float(corner_y.X - corner_0.X) / (double)y_size * 256);
arg.TransformMatrix[3].I = short(float(corner_z.X - corner_0.X) / (double)z_size * 256);
arg.TransformMatrix[1].I = static_cast<unsigned short>(static_cast<int>((corner_x.X - corner_0.X) / (double)x_size * 256.0));
arg.TransformMatrix[2].I = static_cast<unsigned short>(static_cast<int>((corner_y.X - corner_0.X) / (double)y_size * 256.0));
arg.TransformMatrix[3].I = static_cast<unsigned short>(static_cast<int>((corner_z.X - corner_0.X) / (double)z_size * 256.0));

arg.TransformMatrix[1].J = short(float(corner_x.Y - corner_0.Y) / (double)x_size * 256);
arg.TransformMatrix[2].J = short(float(corner_y.Y - corner_0.Y) / (double)y_size * 256);
arg.TransformMatrix[3].J = short(float(corner_z.Y - corner_0.Y) / (double)z_size * 256);
arg.TransformMatrix[1].J = static_cast<unsigned short>(static_cast<int>((corner_x.Y - corner_0.Y) / (double)x_size * 256.0));
arg.TransformMatrix[2].J = static_cast<unsigned short>(static_cast<int>((corner_y.Y - corner_0.Y) / (double)y_size * 256.0));
arg.TransformMatrix[3].J = static_cast<unsigned short>(static_cast<int>((corner_z.Y - corner_0.Y) / (double)z_size * 256.0));

if (VoxelDrawSystem::EnableZBuffer) {
arg.TransformMatrix[1].K = short(float(corner_x.Z - corner_0.Z) / (double)x_size * 256);
arg.TransformMatrix[2].K = short(float(corner_y.Z - corner_0.Z) / (double)y_size * 256);
arg.TransformMatrix[3].K = short(float(corner_z.Z - corner_0.Z) / (double)z_size * 256);
arg.TransformMatrix[1].K = static_cast<unsigned short>(static_cast<int>((corner_x.Z - corner_0.Z) / (double)x_size * 256.0));
arg.TransformMatrix[2].K = static_cast<unsigned short>(static_cast<int>((corner_y.Z - corner_0.Z) / (double)y_size * 256.0));
arg.TransformMatrix[3].K = static_cast<unsigned short>(static_cast<int>((corner_z.Z - corner_0.Z) / (double)z_size * 256.0));
}

int funcnum = VoxelRenderOrientations[orientation].Reversed;
Expand Down Expand Up @@ -936,14 +934,14 @@ void VoxelLibrary::Render_Shadow(VoxelShadowRenderStruct & voxel, Vector3 & cent
arg.StrideY = x_size;
arg.StartIndex = 0;

arg.TransformMatrix[0].I = short(float(corner_0.X + 128 - center.X) * 256);
arg.TransformMatrix[0].J = short(float(corner_0.Y + 128 - center.Y) * 256);
arg.TransformMatrix[0].I = static_cast<unsigned short>(static_cast<int>((corner_0.X + 128 - center.X) * 256.0));
arg.TransformMatrix[0].J = static_cast<unsigned short>(static_cast<int>((corner_0.Y + 128 - center.Y) * 256.0));

arg.TransformMatrix[1].I = short(float(corner_x.X - corner_0.X) / x_size * 256);
arg.TransformMatrix[2].I = short(float(corner_y.X - corner_0.X) / y_size * 256);
arg.TransformMatrix[1].I = static_cast<unsigned short>(static_cast<int>((corner_x.X - corner_0.X) / x_size * 256.0));
arg.TransformMatrix[2].I = static_cast<unsigned short>(static_cast<int>((corner_y.X - corner_0.X) / y_size * 256.0));

arg.TransformMatrix[1].J = short(float(corner_x.Y - corner_0.Y) / x_size * 256);
arg.TransformMatrix[2].J = short(float(corner_y.Y - corner_0.Y) / y_size * 256);
arg.TransformMatrix[1].J = static_cast<unsigned short>(static_cast<int>((corner_x.Y - corner_0.Y) / x_size * 256.0));
arg.TransformMatrix[2].J = static_cast<unsigned short>(static_cast<int>((corner_y.Y - corner_0.Y) / y_size * 256.0));

_voxel_draw_shadow(&arg);
}
Expand Down Expand Up @@ -1989,8 +1987,9 @@ void __cdecl Draw_Voxel_Regular(VoxelFuncArgumentStruct * state)
ptr++;

/// Compute buffer index and write color
VoxelDrawBuffer[(pixel_x >> 8) | (pixel_y & 0xFF00)] = color_index;
VoxelDrawBuffer[(pixel_x >> 8) | (pixel_y & 0xFF00) + 1] = color_index;
unsigned int buffer_index = (pixel_x >> 8) | (pixel_y & 0xFF00);
VoxelDrawBuffer[buffer_index] = color_index;
VoxelDrawBuffer[buffer_index + 1] = color_index;

pixel_x += state->TransformMatrix[3].I;
pixel_y += state->TransformMatrix[3].J;
Expand Down Expand Up @@ -2069,8 +2068,9 @@ void __cdecl Draw_Voxel_Reverse(VoxelFuncArgumentStruct * state)
ptr--;

/// Compute buffer index and write color
VoxelDrawBuffer[(pixel_x >> 8) | (pixel_y & 0xFF00)] = color_index;
VoxelDrawBuffer[(pixel_x >> 8) | (pixel_y & 0xFF00) + 1] = color_index;
unsigned int buffer_index = (pixel_x >> 8) | (pixel_y & 0xFF00);
VoxelDrawBuffer[buffer_index] = color_index;
VoxelDrawBuffer[buffer_index + 1] = color_index;

pixel_x += state->TransformMatrix[3].I;
pixel_y += state->TransformMatrix[3].J;
Expand Down
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