Fix for Code

game/graphics/texture/TextureConverter.cpp

@@ -6,6 +6,8 @@
 
 #include "fmt/core.h"
 
+//TODO: IS THIS CLASS ANYWHERE USED?
+
 TextureConverter::TextureConverter() {
   m_vram.resize(4 * 1024 * 1024);
 }
@@ -41,63 +43,67 @@ void TextureConverter::download_rgba8888(u8* result,
                                          u32 clut_vram_addr,
                                          u32 expected_size_bytes) {
   u32 out_offset = 0;
-  int read_width = 64 * goal_tex_width;
-
-  // Helper for CLUT addressing
-  auto calculate_clut_address = [&](u8 value, int clut_psm) -> u32 {
-    u32 clut_chunk = value / 16;
-    u32 off_in_chunk = value % 16;
-    u8 clx = (clut_chunk & 1) ? 8 : 0;
-    u8 cly = (clut_chunk >> 1) * 2;
-    if (off_in_chunk >= 8) {
-      off_in_chunk -= 8;
-      cly++;
-    }
-    clx += off_in_chunk;
-    if (clut_psm == int(CPSM::PSMCT32)) {
-      return psmct32_addr(clx, cly, 64) + clut_vram_addr * 256;
-    } else if (clut_psm == int(CPSM::PSMCT16)) {
-      return psmct16_addr(clx, cly, 64) + clut_vram_addr * 256;
-    }
-    ASSERT(false);  // Invalid CLUT format
-    return 0;
-  };
+  // width is like the TEX0 register, in 64 texel units.
+  // not sure what the other widths are yet.
+  u32 read_width = 64 * goal_tex_width;
 
-  // Pixel processing function
-  auto process_pixel = [&](u32 x, u32 y, u32 addr, int clut_psm) -> u32 {
-    u8 value = *(u8*)(m_vram.data() + addr);
-    u32 clut_addr = calculate_clut_address(value, clut_psm);
+  // Looks for CLUT Value for given PSMCT Mode
+  auto lookup_CLUT = [&](u8 clx, u8 cly, u32 clut_psm) -> u32 {
     if (clut_psm == int(CPSM::PSMCT32)) {
+      u32 clut_addr = psmct32_addr(clx, cly, 64) + clut_vram_addr * 256;
       return *(u32*)(m_vram.data() + clut_addr);
     } else if (clut_psm == int(CPSM::PSMCT16)) {
+      u32 clut_addr = psmct16_addr(clx, cly, 64) + clut_vram_addr * 256;
       return rgba16_to_rgba32(*(u16*)(m_vram.data() + clut_addr));
     }
-    ASSERT(false);
+    ASSERT(false, "Wrong Clut_PSM given!");
     return 0;
   };
 
-  // Main loop
+  // Main Code: loop over pixels in output texture image
   for (u32 y = 0; y < h; y++) {
     for (u32 x = 0; x < w; x++) {
-      u32 addr = 0;
+      u32 rgba_value = 0;
+
       if (psm == int(PSM::PSMT8)) {
-        addr = psmt8_addr(x, y, read_width) + vram_addr * 256;
+        u32 addr = psmt8_addr(x, y, read_width) + vram_addr * 256;
+        u8 value = *(u8*)(m_vram.data() + addr);
+
+        // there's yet another scramble from the CLUT. The palette index turns into an X, Y value
+        // See GS manual 2.7.3 CLUT Storage Mode, IDTEX8 in CSM1 mode.
+        u32 clut_chunk = value / 16;
+        u32 off_in_chunk = value % 16;
+        u8 clx = (clut_chunk & 1) ? 8 : 0;
+        u8 cly = (clut_chunk >> 1) * 2;
+        if (off_in_chunk >= 8) {
+          off_in_chunk -= 8;
+          cly++;
+        }
+        clx += off_in_chunk;
+
+        rgba_value = lookup_CLUT(clx, cly, clut_psm);
       } else if (psm == int(PSM::PSMT4)) {
-        auto addr4 = psmt4_addr_half_byte(x, y, read_width) + vram_addr * 512;
-        u8 value = *(u8*)(m_vram.data() + addr4 / 2);
-        value = (addr4 & 1) ? (value >> 4) : (value & 0x0F);
-        addr = value;
+        u32 addr = psmt4_addr_half_byte(x, y, read_width) + vram_addr * 512;
+        u8 value = *(u8*)(m_vram.data() + addr / 2);
+        value = (addr & 1) ? (value >> 4) : (value & 0x0F);
+
+        // there's yet another scramble from the CLUT. The palette index turns into an X, Y value
+        // See GS manual 2.7.3 CLUT Storage Mode, IDTEX4 in CSM1 mode.
+        u8 clx = value & 0x7;
+        u8 cly = value >> 3;
+
+        rgba_value = lookup_CLUT(clx, cly, clut_psm);
       } else if (psm == int(PSM::PSMCT16) && clut_psm == 0) {
-        addr = psmct16_addr(x, y, read_width) + vram_addr * 256;
+        // plain 16-bit texture
+        // not a clut.
+        // will store output pixels, rgba (8888)
+        u32 addr = psmct16_addr(x, y, read_width) + vram_addr * 256;
         u16 value = *(u16*)(m_vram.data() + addr);
-        u32 rgba32 = rgba16_to_rgba32(value);
-        memcpy(result + out_offset, &rgba32, 4);
-        out_offset += 4;
-        continue;
+        rgba_value = rgba16_to_rgba32(value);
+      } else {
+        ASSERT(false);
       }
 
-      // Process pixel through CLUT
-      u32 rgba_value = process_pixel(x, y, addr, clut_psm);
       memcpy(result + out_offset, &rgba_value, 4);
       out_offset += 4;
     }