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Cleans up DDSFileClass, adds references, fixes crash when indexing to…
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… memory buffer.
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@tomsons26
tomsons26 committed Jul 28, 2024
1 parent d2cb09d commit 028e653
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Showing 2 changed files with 52 additions and 41 deletions.
82 changes: 41 additions & 41 deletions src/w3d/renderer/ddsfile.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,12 @@
#include <algorithm>
#include <cstring>

// losely based on
// http://www.nvidia.com/view.asp?IO=dxtc_decompression_code
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dx8_c/hh/dx8_c/graphics_using_0j03.asp
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dx8_c/directx_cpp/Graphics/ProgrammersGuide/Appendix/DDSFileFormat/ovwDDSFileFormat.asp
// As the links are now dead use archive.org to access them

using rts::FourCC;
using std::memcpy;
using std::strlen;
Expand Down Expand Up @@ -382,7 +388,7 @@ bool DDSFileClass::Get_4x4_Block(uint8_t *dst_ptr,
// Gen and ZH only handle DXT1 and DXT5
switch (m_format) {
case WW3D_FORMAT_DXT1: {
int offset = (src_x / 4) + (src_y / 4) * (Get_Width(level) / 4);
int offset = (src_x / 4) * 8 + ((src_y / 4) * (Get_Width(level) / 4));
unsigned dst_pixel = 0;
uint8_t *block_mem = &Get_Memory_Pointer(level)[8 * offset];
uint32_t color_a = Decode_Packed_565(block_mem);
Expand All @@ -405,29 +411,26 @@ bool DDSFileClass::Get_4x4_Block(uint8_t *dst_ptr,
dst_ptr += dst_pitch;

for (int i = 0; i < 4; ++i) {
uint32_t final_color = 0;

switch (block_mem[j + 4] & 3) {
case 0:
final_color = color_a;
dst_pixel = color_a;
break;
case 1:
final_color = color_b;
dst_pixel = color_b;
break;
case 2:
final_color = ((85 * (color_b & 0xFF00) + 170 * (color_a & 0xFF00)) >> 8) & 0xFF00
| ((85 * (color_b & 0xFF00FF) + 170 * (color_a & 0xFF00FF)) >> 8) & 0xFF00FF;
dst_pixel = Merge_Color(color_b, color_a, 85);
break;
case 3:
final_color = ((85 * (color_a & 0xFF00) + 170 * (color_b & 0xFF00)) >> 8) & 0xFF00
| ((85 * (color_a & 0xFF00FF) + 170 * (color_b & 0xFF00FF)) >> 8) & 0xFF00FF;
dst_pixel = Merge_Color(color_a, color_b, 85);
break;
default:
break;
}

final_color |= 0xFF000000;
Color_To_Format(putp, final_color, dst_format);
dst_pixel |= 0xFF000000;
Color_To_Format(putp, dst_pixel, dst_format);
putp += dst_bpp;
}
}
Expand All @@ -447,29 +450,26 @@ bool DDSFileClass::Get_4x4_Block(uint8_t *dst_ptr,
dst_ptr += dst_pitch;

for (int i = 0; i < 4; ++i) {
uint32_t final_color = 0;

switch (block_mem[j + 4] & 3) {
case 0:
final_color = color_a;
dst_pixel = color_a;
break;
case 1:
final_color = color_b;
dst_pixel = color_b;
break;
case 2:
final_color =
((127 * (color_a & 0xFF00) + ((uint16_t)(color_b & 0xFF00) << 7)) >> 8) & 0xFF00
| ((((color_b & 0xFF00FF) << 7) + 0x7F * (color_a & 0xFF00FF)) >> 8) & 0xFF00FF;
dst_pixel = Merge_Color(color_b, color_a, 128);
break;
case 3:
final_color = 0;
dst_pixel = 0;
break;
default:
break;
}

final_color |= 0xFF000000;
Color_To_Format(putp, final_color, dst_format);
dst_pixel |= 0xFF000000;
Color_To_Format(putp, dst_pixel, dst_format);
putp += dst_bpp;
}
}
Expand All @@ -479,7 +479,7 @@ bool DDSFileClass::Get_4x4_Block(uint8_t *dst_ptr,
}
return has_alpha;
case WW3D_FORMAT_DXT5: {
int offset = (src_x / 4) + (src_y / 4) * (Get_Width(level) / 4);
int offset = (src_x / 4) * 16 + ((src_y / 4) * (Get_Width(level) / 4));
unsigned dst_pixel = 0;
uint8_t *block_mem = &Get_Memory_Pointer(level)[16 * offset];

Expand All @@ -490,20 +490,23 @@ bool DDSFileClass::Get_4x4_Block(uint8_t *dst_ptr,
alphas[0] = alpha0;
alphas[1] = alpha1;

// 8-alpha or 6-alpha block?
if (alpha0 > alpha1) {
alphas[2] = (alpha1 + 6 * alpha0 + 3) / 7;
alphas[3] = (5 * alpha0 + 2 * alpha1 + 3) / 7;
alphas[4] = (3 * alpha1 + 3 + 4 * alpha0) / 7;
alphas[5] = (3 * alpha0 + 3 + 4 * alpha1) / 7;
alphas[6] = (5 * alpha1 + 2 * alpha0 + 3) / 7;
alphas[7] = (alpha0 + 6 * alpha1 + 3) / 7;
alphas[2] = (6 * alpha1 + alpha0 + 3) / 7; // Bit code 010
alphas[3] = (5 * alpha0 + 2 * alpha1 + 3) / 7; // Bit code 011
alphas[4] = (3 * alpha1 + 4 * alpha0 + 3) / 7; // Bit code 100
alphas[5] = (3 * alpha0 + 4 * alpha1 + 3) / 7; // Bit code 101
alphas[6] = (5 * alpha1 + 2 * alpha0 + 3) / 7; // Bit code 110
alphas[7] = (alpha0 + 6 * alpha1 + 3) / 7; // Bit code 111
} else {
alphas[2] = (alpha1 + 4 * alpha0 + 2) / 5;
alphas[6] = 0;
alphas[7] = 255;
alphas[3] = (3 * alpha0 + 2 * alpha1 + 2) / 5;
alphas[4] = (3 * alpha1 + 2 * alpha0 + 2) / 5;
alphas[5] = (alpha0 + 4 * alpha1 + 2) / 5;
// 6-alpha block: derive the other alphas.
// 000 = alpha_0, 001 = alpha_1, others are interpolated
alphas[2] = (4 * alpha0 + alpha1 + 2) / 5; // Bit code 010
alphas[3] = (3 * alpha0 + 2 * alpha1 + 2) / 5; // Bit code 011
alphas[4] = (3 * alpha1 + 2 * alpha0 + 2) / 5; // Bit code 100
alphas[5] = (alpha0 + 4 * alpha1 + 2) / 5; // Bit code 101
alphas[6] = 0; // Bit code 110
alphas[7] = 255; // Bit code 111
}

uint32_t color_a = Decode_Packed_565(block_mem + 8);
Expand Down Expand Up @@ -533,27 +536,24 @@ bool DDSFileClass::Get_4x4_Block(uint8_t *dst_ptr,
for (int i = 0; i < 4; i++) {
unsigned alpha = alphas[alpha_indices[j * 4 + i]];
has_alpha = alpha < 255;
uint32_t final_color = 0;

switch (((block_mem[j + 12]) >> (2 * i)) & 3) {
case 0:
final_color = color_a | (alpha << 24);
dst_pixel = color_a | (alpha << 24);
break;
case 1:
final_color = color_b | (alpha << 24);
dst_pixel = color_b | (alpha << 24);
break;
case 2:
final_color = ((85 * (color_b & 0xFF00) + 170 * (color_a & 0xFF00)) >> 8) & 0xFF00
| ((85 * (color_b & 0xFF00FF) + 170 * (color_a & 0xFF00FF)) >> 8) & 0xFF00FF;
dst_pixel = Merge_Color(color_b, color_a, 85);
break;
case 3:
final_color = ((85 * (color_a & 0xFF00) + 170 * (color_b & 0xFF00)) >> 8) & 0xFF00
| ((85 * (color_a & 0xFF00FF) + 170 * (color_b & 0xFF00FF)) >> 8) & 0xFF00FF;
dst_pixel = Merge_Color(color_b, color_a, 85);
break;
}

final_color |= alpha;
Color_To_Format(putp, final_color, dst_format);
dst_pixel |= alpha;
Color_To_Format(putp, dst_pixel, dst_format);
putp += dst_bpp;
}
}
Expand Down
11 changes: 11 additions & 0 deletions src/w3d/renderer/ddsfile.h
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Original file line number Diff line number Diff line change
Expand Up @@ -151,6 +151,7 @@ class DDSFileClass
static unsigned Calculate_S3TC_Surface_Size(unsigned width, unsigned height, WW3DFormat format);
static uint32_t Decode_Packed_565(uint8_t *packed);
static uint32_t Decode_Line_Code(uint8_t *packed);
static uint32_t Merge_Color(uint32_t color_a, uint32_t color_b, uint32_t s1);

private:
unsigned m_width;
Expand Down Expand Up @@ -178,6 +179,16 @@ inline uint32_t DDSFileClass::Decode_Packed_565(uint8_t *packed)
return ((value & 0x1F) | ((value & 0x7E0) | ((value & 0xF800) << 3) << 2)) << 3;
}

inline uint32_t DDSFileClass::Merge_Color(uint32_t color_a, uint32_t color_b, uint32_t color_b_amount)
{
uint32_t color_a_amount = 0xFF - color_b_amount;
const uint32_t G_MASK = 0x0000FF00;
const uint32_t R_B_MASK = 0x00FF00FF;

return ((color_a_amount * (color_a & G_MASK)) + (color_b_amount * (color_b & G_MASK)) >> 8) & G_MASK
| ((color_a_amount * (color_a & R_B_MASK)) + (color_b_amount * (color_b & R_B_MASK)) >> 8) & R_B_MASK;
}

inline uint32_t DDSFileClass::Decode_Line_Code(uint8_t *packed)
{
return uint32_t(packed[0]) | (uint32_t(packed[1]) << 8) | (uint32_t(packed[2]) << 16) | (uint32_t(packed[3]) << 24);
Expand Down

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