Merge pull request #599 from Subv/morton

GPU: Implemented bits 3 and 1 from the display transfer flags.

src/citra_qt/debugger/graphics_framebuffer.cpp

@@ -9,8 +9,10 @@
 #include <QPushButton>
 #include <QSpinBox>
 
+#include "core/hw/gpu.h"
 #include "video_core/color.h"
 #include "video_core/pica.h"
+#include "video_core/utils.h"
 
 #include "graphics_framebuffer.h"
 
@@ -195,16 +197,20 @@ void GraphicsFramebufferWidget::OnUpdate()
 
     // TODO: Implement a good way to visualize alpha components!
     // TODO: Unify this decoding code with the texture decoder
+    u32 bytes_per_pixel = GPU::Regs::BytesPerPixel(GPU::Regs::PixelFormat(framebuffer_format));
+
     switch (framebuffer_format) {
     case Format::RGBA8:
     {
         QImage decoded_image(framebuffer_width, framebuffer_height, QImage::Format_ARGB32);
-        u32* color_buffer = (u32*)Memory::GetPointer(Pica::PAddrToVAddr(framebuffer_address));
+        u8* color_buffer = Memory::GetPointer(Pica::PAddrToVAddr(framebuffer_address));
         for (unsigned int y = 0; y < framebuffer_height; ++y) {
             for (unsigned int x = 0; x < framebuffer_width; ++x) {
-                u32 value = *(color_buffer + x + y * framebuffer_width);
+                const u32 coarse_y = y & ~7;
+                u32 offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * framebuffer_width * bytes_per_pixel;
+                u8* value = color_buffer + offset;
 
-                decoded_image.setPixel(x, y, qRgba((value >> 16) & 0xFF, (value >> 8) & 0xFF, value & 0xFF, 255/*value >> 24*/));
+                decoded_image.setPixel(x, y, qRgba(value[3], value[2], value[1], 255/*value >> 24*/));
             }
         }
         pixmap = QPixmap::fromImage(decoded_image);
@@ -217,7 +223,9 @@ void GraphicsFramebufferWidget::OnUpdate()
         u8* color_buffer = Memory::GetPointer(Pica::PAddrToVAddr(framebuffer_address));
         for (unsigned int y = 0; y < framebuffer_height; ++y) {
             for (unsigned int x = 0; x < framebuffer_width; ++x) {
-                u8* pixel_pointer = color_buffer + x * 3 + y * 3 * framebuffer_width;
+                const u32 coarse_y = y & ~7;
+                u32 offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * framebuffer_width * bytes_per_pixel;
+                u8* pixel_pointer = color_buffer + offset;
 
                 decoded_image.setPixel(x, y, qRgba(pixel_pointer[0], pixel_pointer[1], pixel_pointer[2], 255/*value >> 24*/));
             }
@@ -229,10 +237,12 @@ void GraphicsFramebufferWidget::OnUpdate()
     case Format::RGBA5551:
     {
         QImage decoded_image(framebuffer_width, framebuffer_height, QImage::Format_ARGB32);
-        u32* color_buffer = (u32*)Memory::GetPointer(Pica::PAddrToVAddr(framebuffer_address));
+        u8* color_buffer = Memory::GetPointer(Pica::PAddrToVAddr(framebuffer_address));
         for (unsigned int y = 0; y < framebuffer_height; ++y) {
             for (unsigned int x = 0; x < framebuffer_width; ++x) {
-                u16 value = *(u16*)(((u8*)color_buffer) + x * 2 + y * framebuffer_width * 2);
+                const u32 coarse_y = y & ~7;
+                u32 offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * framebuffer_width * bytes_per_pixel;
+                u16 value = *(u16*)(color_buffer + offset);
                 u8 r = Color::Convert5To8((value >> 11) & 0x1F);
                 u8 g = Color::Convert5To8((value >> 6) & 0x1F);
                 u8 b = Color::Convert5To8((value >> 1) & 0x1F);

src/core/hw/gpu.cpp

@@ -18,10 +18,10 @@
 #include "core/hw/gpu.h"
 
 #include "video_core/command_processor.h"
+#include "video_core/utils.h"
 #include "video_core/video_core.h"
 #include <video_core/color.h>
 
-
 namespace GPU {
 
 Regs g_regs;
@@ -116,24 +116,64 @@ inline void Write(u32 addr, const T data) {
             u8* source_pointer = Memory::GetPointer(Memory::PhysicalToVirtualAddress(config.GetPhysicalInputAddress()));
             u8* dest_pointer = Memory::GetPointer(Memory::PhysicalToVirtualAddress(config.GetPhysicalOutputAddress()));
 
-            // Cheap emulation of horizontal scaling: Just skip each second pixel of the
+            unsigned horizontal_scale = (config.scale_horizontally != 0) ? 2 : 1;
-            // input framebuffer. We keep track of this in the pixel_skip variable.
+            unsigned vertical_scale = (config.scale_vertically != 0) ? 2 : 1;
-            unsigned pixel_skip = (config.scale_horizontally != 0) ? 2 : 1;
 
-            u32 output_width = config.output_width / pixel_skip;
+            u32 output_width = config.output_width / horizontal_scale;
+            u32 output_height = config.output_height / vertical_scale;
 
-            for (u32 y = 0; y < config.output_height; ++y) {
+            if (config.raw_copy) {
-                // TODO: Why does the register seem to hold twice the framebuffer width?
+                // Raw copies do not perform color conversion nor tiled->linear / linear->tiled conversions
+                // TODO(Subv): Verify if raw copies perform scaling
+                memcpy(dest_pointer, source_pointer, config.output_width * config.output_height * 
+                        GPU::Regs::BytesPerPixel(config.output_format));
                 
+                LOG_TRACE(HW_GPU, "DisplayTriggerTransfer: 0x%08x bytes from 0x%08x(%ux%u)-> 0x%08x(%ux%u), flags 0x%08X, Raw copy",
+                    config.output_height * output_width * GPU::Regs::BytesPerPixel(config.output_format),
+                    config.GetPhysicalInputAddress(), config.input_width.Value(), config.input_height.Value(),
+                    config.GetPhysicalOutputAddress(), config.output_width.Value(), config.output_height.Value(),
+                    config.output_format.Value(), config.flags);
+
+                GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PPF);
+                break;
+            }
+
+            // TODO(Subv): Blend the pixels when horizontal / vertical scaling is enabled, 
+            // right now we're just skipping the extra pixels.
+            for (u32 y = 0; y < output_height; ++y) {
                 for (u32 x = 0; x < output_width; ++x) {
                     struct {
                         int r, g, b, a;
                     } source_color = { 0, 0, 0, 0 };
 
+                    u32 scaled_x = x * horizontal_scale;
+                    u32 scaled_y = y * vertical_scale;
+
+                    u32 dst_bytes_per_pixel = GPU::Regs::BytesPerPixel(config.output_format);
+                    u32 src_bytes_per_pixel = GPU::Regs::BytesPerPixel(config.input_format);
+                    u32 src_offset;
+                    u32 dst_offset;
+
+                    if (config.output_tiled) {
+                        // Interpret the input as linear and the output as tiled
+                        u32 coarse_y = y & ~7;
+                        u32 stride = output_width * dst_bytes_per_pixel;
+
+                        src_offset = (scaled_x + scaled_y * config.input_width) * src_bytes_per_pixel;
+                        dst_offset = VideoCore::GetMortonOffset(x, y, dst_bytes_per_pixel) + coarse_y * stride;
+                    } else {
+                        // Interpret the input as tiled and the output as linear
+                        u32 coarse_y = scaled_y & ~7;
+                        u32 stride = config.input_width * src_bytes_per_pixel;
+
+                        src_offset = VideoCore::GetMortonOffset(scaled_x, scaled_y, src_bytes_per_pixel) + coarse_y * stride;
+                        dst_offset = (x + y * output_width) * dst_bytes_per_pixel;
+                    }
+
                     switch (config.input_format) {
                     case Regs::PixelFormat::RGBA8:
                     {
-                        u8* srcptr = source_pointer + (x * pixel_skip + y * config.input_width) * 4;
+                        u8* srcptr = source_pointer + src_offset;
                         source_color.r = srcptr[3]; // red
                         source_color.g = srcptr[2]; // green
                         source_color.b = srcptr[1]; // blue
@@ -143,7 +183,7 @@ inline void Write(u32 addr, const T data) {
 
                     case Regs::PixelFormat::RGB5A1:
                     {
-                        u16 srcval = *(u16*)(source_pointer + x * 4 * pixel_skip + y * config.input_width * 4 * pixel_skip);
+                        u16 srcval = *(u16*)(source_pointer + src_offset);
                         source_color.r = Color::Convert5To8((srcval >> 11) & 0x1F); // red
                         source_color.g = Color::Convert5To8((srcval >>  6) & 0x1F); // green
                         source_color.b = Color::Convert5To8((srcval >>  1) & 0x1F); // blue
@@ -153,7 +193,7 @@ inline void Write(u32 addr, const T data) {
 
                     case Regs::PixelFormat::RGBA4:
                     {
-                        u16 srcval = *(u16*)(source_pointer + x * 4 * pixel_skip + y * config.input_width * 4 * pixel_skip);
+                        u16 srcval = *(u16*)(source_pointer + src_offset);
                         source_color.r = Color::Convert4To8((srcval >> 12) & 0xF); // red
                         source_color.g = Color::Convert4To8((srcval >>  8) & 0xF); // green
                         source_color.b = Color::Convert4To8((srcval >>  4) & 0xF); // blue
@@ -169,7 +209,7 @@ inline void Write(u32 addr, const T data) {
                     switch (config.output_format) {
                     case Regs::PixelFormat::RGBA8:
                     {
-                        u8* dstptr = dest_pointer + (x * pixel_skip + y * config.output_width) * 4;
+                        u8* dstptr = dest_pointer + dst_offset;
                         dstptr[3] = source_color.r;
                         dstptr[2] = source_color.g;
                         dstptr[1] = source_color.b;
@@ -179,7 +219,7 @@ inline void Write(u32 addr, const T data) {
 
                     case Regs::PixelFormat::RGB8:
                     {
-                        u8* dstptr = dest_pointer + (x + y * output_width) * 3;
+                        u8* dstptr = dest_pointer + dst_offset;
                         dstptr[2] = source_color.r; // red
                         dstptr[1] = source_color.g; // green
                         dstptr[0] = source_color.b; // blue
@@ -188,7 +228,7 @@ inline void Write(u32 addr, const T data) {
 
                     case Regs::PixelFormat::RGB5A1:
                     {
-                        u16* dstptr = (u16*)(dest_pointer + x * 2 + y * config.output_width * 2);
+                        u16* dstptr = (u16*)(dest_pointer + dst_offset);
                         *dstptr = ((source_color.r >> 3) << 11) | ((source_color.g >> 3) << 6)
                                 | ((source_color.b >> 3) <<  1) | ( source_color.a >> 7);
                         break;
@@ -196,7 +236,7 @@ inline void Write(u32 addr, const T data) {
 
                     case Regs::PixelFormat::RGBA4:
                     {
-                        u16* dstptr = (u16*)(dest_pointer + x * 2 + y * config.output_width * 2);
+                        u16* dstptr = (u16*)(dest_pointer + dst_offset);
                         *dstptr = ((source_color.r >> 4) << 12) | ((source_color.g >> 4) << 8)
                                 | ((source_color.b >> 4) <<  4) | ( source_color.a >> 4);
                         break;
@@ -209,11 +249,11 @@ inline void Write(u32 addr, const T data) {
                 }
             }
 
-            LOG_TRACE(HW_GPU, "DisplayTriggerTransfer: 0x%08x bytes from 0x%08x(%ux%u)-> 0x%08x(%ux%u), dst format %x",
+            LOG_TRACE(HW_GPU, "DisplayTriggerTransfer: 0x%08x bytes from 0x%08x(%ux%u)-> 0x%08x(%ux%u), dst format %x, flags 0x%08X",
-                      config.output_height * output_width * 4,
+                      config.output_height * output_width * GPU::Regs::BytesPerPixel(config.output_format),
-                      config.GetPhysicalInputAddress(), (u32)config.input_width, (u32)config.input_height,
+                      config.GetPhysicalInputAddress(), config.input_width.Value(), config.input_height.Value(),
-                      config.GetPhysicalOutputAddress(), (u32)output_width, (u32)config.output_height,
+                      config.GetPhysicalOutputAddress(), output_width, output_height,
-                      config.output_format.Value());
+                      config.output_format.Value(), config.flags);
 
             GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PPF);
         }

src/core/hw/gpu.h

@@ -192,12 +192,13 @@ struct Regs {
             u32 flags;
 
             BitField< 0, 1, u32> flip_data;        // flips input data horizontally (TODO) if true
+            BitField< 1, 1, u32> output_tiled;     // Converts from linear to tiled format
+            BitField< 3, 1, u32> raw_copy;         // Copies the data without performing any processing
             BitField< 8, 3, PixelFormat> input_format;
             BitField<12, 3, PixelFormat> output_format;
-            BitField<16, 1, u32> output_tiled;     // stores output in a tiled format
 
-            // TODO: Not really sure if this actually scales, or even resizes at all.
             BitField<24, 1, u32> scale_horizontally;
+            BitField<25, 1, u32> scale_vertically;
         };
 
         INSERT_PADDING_WORDS(0x1);

src/video_core/debug_utils/debug_utils.cpp

@@ -23,6 +23,7 @@
 #include "video_core/color.h"
 #include "video_core/math.h"
 #include "video_core/pica.h"
+#include "video_core/utils.h"
 
 #include "debug_utils.h"
 
@@ -306,63 +307,33 @@ std::unique_ptr<PicaTrace> FinishPicaTracing()
 }
 
 const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const TextureInfo& info, bool disable_alpha) {
-    // Images are split into 8x8 tiles. Each tile is composed of four 4x4 subtiles each
-    // of which is composed of four 2x2 subtiles each of which is composed of four texels.
-    // Each structure is embedded into the next-bigger one in a diagonal pattern, e.g.
-    // texels are laid out in a 2x2 subtile like this:
-    // 2 3
-    // 0 1
-    //
-    // The full 8x8 tile has the texels arranged like this:
-    //
-    // 42 43 46 47 58 59 62 63
-    // 40 41 44 45 56 57 60 61
-    // 34 35 38 39 50 51 54 55
-    // 32 33 36 37 48 49 52 53
-    // 10 11 14 15 26 27 30 31
-    // 08 09 12 13 24 25 28 29
-    // 02 03 06 07 18 19 22 23
-    // 00 01 04 05 16 17 20 21
-
-    const unsigned int block_width = 8;
-    const unsigned int block_height = 8;
-
     const unsigned int coarse_x = x & ~7;
     const unsigned int coarse_y = y & ~7;
 
-    // Interleave the lower 3 bits of each coordinate to get the intra-block offsets, which are
-    // arranged in a Z-order curve. More details on the bit manipulation at:
-    // https://fgiesen.wordpress.com/2009/12/13/decoding-morton-codes/
-    unsigned int i = (x & 7) | ((y & 7) << 8); // ---- -210
-    i = (i ^ (i << 2)) & 0x1313;               // ---2 --10
-    i = (i ^ (i << 1)) & 0x1515;               // ---2 -1-0
-    i = (i | (i >> 7)) & 0x3F;
-
     if (info.format != Regs::TextureFormat::ETC1 &&
         info.format != Regs::TextureFormat::ETC1A4) {
         // TODO(neobrain): Fix code design to unify vertical block offsets!
         source += coarse_y * info.stride;
     }
-    const unsigned int offset = coarse_x * block_height;
     
     // TODO: Assert that width/height are multiples of block dimensions
 
     switch (info.format) {
     case Regs::TextureFormat::RGBA8:
     {
-        const u8* source_ptr = source + offset * 4 + i * 4;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 4);
         return { source_ptr[3], source_ptr[2], source_ptr[1], disable_alpha ? (u8)255 : source_ptr[0] };
     }
 
     case Regs::TextureFormat::RGB8:
     {
-        const u8* source_ptr = source + offset * 3 + i * 3;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 3);
         return { source_ptr[2], source_ptr[1], source_ptr[0], 255 };
     }
 
     case Regs::TextureFormat::RGBA5551:
     {
-        const u16 source_ptr = *(const u16*)(source + offset * 2 + i * 2);
+        const u16 source_ptr = *(const u16*)(source + VideoCore::GetMortonOffset(x, y, 2));
         u8 r = (source_ptr >> 11) & 0x1F;
         u8 g = ((source_ptr) >> 6) & 0x1F;
         u8 b = (source_ptr >> 1) & 0x1F;
@@ -373,7 +344,7 @@ const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const Texture
 
     case Regs::TextureFormat::RGB565:
     {
-        const u16 source_ptr = *(const u16*)(source + offset * 2 + i * 2);
+        const u16 source_ptr = *(const u16*)(source + VideoCore::GetMortonOffset(x, y, 2));
         u8 r = Color::Convert5To8((source_ptr >> 11) & 0x1F);
         u8 g = Color::Convert6To8(((source_ptr) >> 5) & 0x3F);
         u8 b = Color::Convert5To8((source_ptr) & 0x1F);
@@ -382,7 +353,7 @@ const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const Texture
 
     case Regs::TextureFormat::RGBA4:
     {
-        const u8* source_ptr = source + offset * 2 + i * 2;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 2);
         u8 r = Color::Convert4To8(source_ptr[1] >> 4);
         u8 g = Color::Convert4To8(source_ptr[1] & 0xF);
         u8 b = Color::Convert4To8(source_ptr[0] >> 4);
@@ -392,7 +363,7 @@ const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const Texture
 
     case Regs::TextureFormat::IA8:
     {
-        const u8* source_ptr = source + offset * 2 + i * 2;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 2);
 
         if (disable_alpha) {
             // Show intensity as red, alpha as green
@@ -404,13 +375,13 @@ const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const Texture
 
     case Regs::TextureFormat::I8:
     {
-        const u8* source_ptr = source + offset + i;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 1);
         return { *source_ptr, *source_ptr, *source_ptr, 255 };
     }
 
     case Regs::TextureFormat::A8:
     {
-        const u8* source_ptr = source + offset + i;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 1);
 
         if (disable_alpha) {
             return { *source_ptr, *source_ptr, *source_ptr, 255 };
@@ -421,7 +392,7 @@ const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const Texture
 
     case Regs::TextureFormat::IA4:
     {
-        const u8* source_ptr = source + offset + i;
+        const u8* source_ptr = source + VideoCore::GetMortonOffset(x, y, 1);
 
         u8 i = Color::Convert4To8(((*source_ptr) & 0xF0) >> 4);
         u8 a = Color::Convert4To8((*source_ptr) & 0xF);
@@ -436,9 +407,10 @@ const Math::Vec4<u8> LookupTexture(const u8* source, int x, int y, const Texture
 
     case Regs::TextureFormat::A4:
     {
-        const u8* source_ptr = source + (offset + i) / 2;
+        u32 morton_offset = VideoCore::GetMortonOffset(x, y, 1);
+        const u8* source_ptr = source + morton_offset / 2;
 
-        u8 a = (i % 2) ? ((*source_ptr & 0xF0) >> 4) : (*source_ptr & 0xF);
+        u8 a = (morton_offset % 2) ? ((*source_ptr & 0xF0) >> 4) : (*source_ptr & 0xF);
         a = Color::Convert4To8(a);
 
         if (disable_alpha) {

src/video_core/rasterizer.cpp

@@ -7,13 +7,14 @@
 #include "common/common_types.h"
 #include "common/math_util.h"
 
+#include "core/hw/gpu.h"
+#include "debug_utils/debug_utils.h"
 #include "math.h"
 #include "color.h"
 #include "pica.h"
 #include "rasterizer.h"
 #include "vertex_shader.h"
-
+#include "video_core/utils.h"
-#include "debug_utils/debug_utils.h"
 
 namespace Pica {
 
@@ -27,10 +28,14 @@ static void DrawPixel(int x, int y, const Math::Vec4<u8>& color) {
     // NOTE: The framebuffer height register contains the actual FB height minus one.
     y = (registers.framebuffer.height - y);
 
+    const u32 coarse_y = y & ~7;
+    u32 bytes_per_pixel = GPU::Regs::BytesPerPixel(GPU::Regs::PixelFormat(registers.framebuffer.color_format.Value()));
+    u32 dst_offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * registers.framebuffer.width * bytes_per_pixel;
+
     switch (registers.framebuffer.color_format) {
     case registers.framebuffer.RGBA8:
     {
-        u8* pixel = color_buffer + (x + y * registers.framebuffer.GetWidth()) * 4;
+        u8* pixel = color_buffer + dst_offset;
         pixel[3] = color.r();
         pixel[2] = color.g();
         pixel[1] = color.b();
@@ -40,14 +45,14 @@ static void DrawPixel(int x, int y, const Math::Vec4<u8>& color) {
 
     case registers.framebuffer.RGBA4:
     {
-        u8* pixel = color_buffer + (x + y * registers.framebuffer.GetWidth()) * 2;
+        u8* pixel = color_buffer + dst_offset;
         pixel[1] = (color.r() & 0xF0) | (color.g() >> 4);
         pixel[0] = (color.b() & 0xF0) | (color.a() >> 4);
         break;
     }
 
     default:
-        LOG_CRITICAL(Render_Software, "Unknown framebuffer color format %x", registers.framebuffer.color_format);
+        LOG_CRITICAL(Render_Software, "Unknown framebuffer color format %x", registers.framebuffer.color_format.Value());
         UNIMPLEMENTED();
     }
 }
@@ -58,11 +63,15 @@ static const Math::Vec4<u8> GetPixel(int x, int y) {
 
     y = (registers.framebuffer.height - y);
 
+    const u32 coarse_y = y & ~7;
+    u32 bytes_per_pixel = GPU::Regs::BytesPerPixel(GPU::Regs::PixelFormat(registers.framebuffer.color_format.Value()));
+    u32 src_offset = VideoCore::GetMortonOffset(x, y, bytes_per_pixel) + coarse_y * registers.framebuffer.width * bytes_per_pixel;
+
     switch (registers.framebuffer.color_format) {
     case registers.framebuffer.RGBA8:
     {
         Math::Vec4<u8> ret;
-        u8* pixel = color_buffer + (x + y * registers.framebuffer.GetWidth()) * 4;
+        u8* pixel = color_buffer + src_offset;
         ret.r() = pixel[3];
         ret.g() = pixel[2];
         ret.b() = pixel[1];
@@ -73,7 +82,7 @@ static const Math::Vec4<u8> GetPixel(int x, int y) {
     case registers.framebuffer.RGBA4:
     {
         Math::Vec4<u8> ret;
-        u8* pixel = color_buffer + (x + y * registers.framebuffer.GetWidth()) * 2;
+        u8* pixel = color_buffer + src_offset;
         ret.r() = Color::Convert4To8(pixel[1] >> 4);
         ret.g() = Color::Convert4To8(pixel[1] & 0x0F);
         ret.b() = Color::Convert4To8(pixel[0] >> 4);
@@ -82,7 +91,7 @@ static const Math::Vec4<u8> GetPixel(int x, int y) {
     }
 
     default:
-        LOG_CRITICAL(Render_Software, "Unknown framebuffer color format %x", registers.framebuffer.color_format);
+        LOG_CRITICAL(Render_Software, "Unknown framebuffer color format %x", registers.framebuffer.color_format.Value());
         UNIMPLEMENTED();
     }
 
@@ -91,22 +100,28 @@ static const Math::Vec4<u8> GetPixel(int x, int y) {
 
 static u32 GetDepth(int x, int y) {
     const PAddr addr = registers.framebuffer.GetDepthBufferPhysicalAddress();
-    u16* depth_buffer = reinterpret_cast<u16*>(Memory::GetPointer(PAddrToVAddr(addr)));
+    u8* depth_buffer = Memory::GetPointer(PAddrToVAddr(addr));
 
     y = (registers.framebuffer.height - y);
     
+    const u32 coarse_y = y & ~7;
+    u32 stride = registers.framebuffer.width * 2;
+
     // Assuming 16-bit depth buffer format until actual format handling is implemented
-    return *(depth_buffer + x + y * registers.framebuffer.GetWidth());
+    return *(u16*)(depth_buffer + VideoCore::GetMortonOffset(x, y, 2) + coarse_y * stride);
 }
 
 static void SetDepth(int x, int y, u16 value) {
     const PAddr addr = registers.framebuffer.GetDepthBufferPhysicalAddress();
-    u16* depth_buffer = reinterpret_cast<u16*>(Memory::GetPointer(PAddrToVAddr(addr)));
+    u8* depth_buffer = Memory::GetPointer(PAddrToVAddr(addr));
 
     y = (registers.framebuffer.height - y);
 
+    const u32 coarse_y = y & ~7;
+    u32 stride = registers.framebuffer.width * 2;
+
     // Assuming 16-bit depth buffer format until actual format handling is implemented
-    *(depth_buffer + x + y * registers.framebuffer.GetWidth()) = value;
+    *(u16*)(depth_buffer + VideoCore::GetMortonOffset(x, y, 2) + coarse_y * stride) = value;
 }
 
 // NOTE: Assuming that rasterizer coordinates are 12.4 fixed-point values

src/video_core/utils.h

@@ -35,4 +35,54 @@ struct TGAHeader {
  */
 void DumpTGA(std::string filename, short width, short height, u8* raw_data);
 
+/**
+ * Interleave the lower 3 bits of each coordinate to get the intra-block offsets, which are
+ * arranged in a Z-order curve. More details on the bit manipulation at:
+ * https://fgiesen.wordpress.com/2009/12/13/decoding-morton-codes/
+ */
+static inline u32 MortonInterleave(u32 x, u32 y) {
+    u32 i = (x & 7) | ((y & 7) << 8); // ---- -210
+    i = (i ^ (i << 2)) & 0x1313;      // ---2 --10
+    i = (i ^ (i << 1)) & 0x1515;      // ---2 -1-0
+    i = (i | (i >> 7)) & 0x3F;
+    return i;
+}
+
+/**
+ * Calculates the offset of the position of the pixel in Morton order
+ */
+static inline u32 GetMortonOffset(u32 x, u32 y, u32 bytes_per_pixel) {
+    // Images are split into 8x8 tiles. Each tile is composed of four 4x4 subtiles each
+    // of which is composed of four 2x2 subtiles each of which is composed of four texels.
+    // Each structure is embedded into the next-bigger one in a diagonal pattern, e.g.
+    // texels are laid out in a 2x2 subtile like this:
+    // 2 3
+    // 0 1
+    //
+    // The full 8x8 tile has the texels arranged like this:
+    //
+    // 42 43 46 47 58 59 62 63
+    // 40 41 44 45 56 57 60 61
+    // 34 35 38 39 50 51 54 55
+    // 32 33 36 37 48 49 52 53
+    // 10 11 14 15 26 27 30 31
+    // 08 09 12 13 24 25 28 29
+    // 02 03 06 07 18 19 22 23
+    // 00 01 04 05 16 17 20 21
+    //
+    // This pattern is what's called Z-order curve, or Morton order.
+
+    const unsigned int block_width = 8;
+    const unsigned int block_height = 8;
+
+    const unsigned int coarse_x = x & ~7;
+    const unsigned int coarse_y = y & ~7;
+
+    u32 i = VideoCore::MortonInterleave(x, y);
+
+    const unsigned int offset = coarse_x * block_height;
+
+    return (i + offset) * bytes_per_pixel;
+}
+
 } // namespace