WIP Custom Skin Support

CMakeLists.txt

@@ -65,6 +65,9 @@ else()
     string(APPEND MCPI_VARIANT_NAME "-client")
 endif()
 
+# Skin Server
+set(MCPI_SKIN_SERVER "http://localhost:8000" CACHE STRING "Skin Server")
+
 # Specify Installation Paths
 set(MCPI_INSTALL_DIR "lib/${MCPI_VARIANT_NAME}")
 set(MCPI_BIN_DIR "${MCPI_INSTALL_DIR}/bin")

libreborn/include/libreborn/config.h.in

@@ -11,3 +11,4 @@
 #cmakedefine MCPI_VERSION "@MCPI_VERSION@"
 #cmakedefine MCPI_VARIANT_NAME "@MCPI_VARIANT_NAME@"
 #cmakedefine MCPI_SDK_DIR "@MCPI_SDK_DIR@"
+#cmakedefine MCPI_SKIN_SERVER "@MCPI_SKIN_SERVER@"

libreborn/src/util/exec.c

@@ -107,16 +107,50 @@ char *run_command(const char *const command[], int *exit_status) {
 
         // Read stdout
         close(output_pipe[1]);
-        char *output = NULL;
 #define BUFFER_SIZE 1024
+        size_t size = BUFFER_SIZE;
+        char *output = malloc(size);
         char buf[BUFFER_SIZE];
+        size_t position = 0;
         ssize_t bytes_read = 0;
-        while ((bytes_read = read(output_pipe[0], (void *) buf, BUFFER_SIZE - 1 /* Account For NULL-Terminator */)) > 0) {
-            buf[bytes_read] = '\0';
-            string_append(&output, "%s", buf);
+        while ((bytes_read = read(output_pipe[0], (void *) buf, BUFFER_SIZE)) > 0) {
+            // Grow Output If Needed
+            size_t needed_size = position + bytes_read;
+            if (needed_size > size) {
+                // More Memeory Needed
+                size_t new_size = size;
+                while (new_size < needed_size) {
+                    new_size += BUFFER_SIZE;
+                }
+                char *new_output = realloc(output, new_size);
+                if (new_output == NULL) {
+                    ERR("Unable To Grow Output Buffer");
+                } else {
+                    output = new_output;
+                    size = new_size;
+                }
+            }
+
+            // Copy Data To Output
+            memcpy(output + position, buf, bytes_read);
+            position += bytes_read;
         }
         close(output_pipe[0]);
 
+        // Add NULL-Terminator To Output
+        size_t needed_size = position + 1;
+        if (needed_size > size) {
+            // More Memeory Needed
+            size_t new_size = size + 1;
+            char *new_output = realloc(output, new_size);
+            if (new_output == NULL) {
+                ERR("Unable To Grow Output Buffer (For NULL-Terminator)");
+            } else {
+                output = new_output;
+            }
+        }
+        output[position] = '\0';
+
         // Get Return Code
         int status;
         waitpid(ret, &status, 0);

mods/CMakeLists.txt

@@ -80,6 +80,9 @@ else()
     add_library(title-screen SHARED src/title-screen/title-screen.cpp)
     target_link_libraries(title-screen mods-headers reborn-patch symbols feature compat)
 
+    add_library(skin SHARED src/skin/skin.cpp src/skin/loader.cpp)
+    target_link_libraries(skin mods-headers reborn-patch symbols feature misc textures media-layer-core png12)
+
     add_library(benchmark SHARED src/benchmark/benchmark.cpp)
     target_link_libraries(benchmark mods-headers reborn-patch symbols compat misc media-layer-core)
 endif()
@@ -115,7 +118,7 @@ target_link_libraries(init mods-headers reborn-util compat game-mode misc death
 if(MCPI_SERVER_MODE)
     target_link_libraries(init server)
 else()
-    target_link_libraries(init multiplayer sound camera input sign touch textures atlas title-screen benchmark)
+    target_link_libraries(init multiplayer sound camera input sign touch textures atlas title-screen skin benchmark)
 endif()
 
 ## Install Mods
@@ -123,7 +126,7 @@ set(MODS_TO_INSTALL init compat readdir feature game-mode misc override death op
 if(MCPI_SERVER_MODE)
     list(APPEND MODS_TO_INSTALL server)
 else()
-    list(APPEND MODS_TO_INSTALL multiplayer sound camera input sign touch textures atlas title-screen benchmark)
+    list(APPEND MODS_TO_INSTALL multiplayer sound camera input sign touch textures atlas title-screen skin benchmark)
 endif()
 if(NOT MCPI_HEADLESS_MODE)
     list(APPEND MODS_TO_INSTALL screenshot)

mods/include/mods/init/init.h

@@ -21,6 +21,7 @@ void init_touch();
 void init_textures();
 void init_atlas();
 void init_title_screen();
+void init_skin();
 #endif
 void init_creative();
 void init_game_mode();

mods/include/mods/textures/textures.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <GLES/gl.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void glTexSubImage2D_with_scaling(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLsizei normal_texture_width, GLsizei normal_texture_height, GLenum format, GLenum type, const void *pixels);
+
+#ifdef __cplusplus
+}
+#endif

mods/src/init/init.c

@@ -21,6 +21,7 @@ __attribute__((constructor)) static void init() {
     init_textures();
     init_atlas();
     init_title_screen();
+    init_skin();
 #endif
     init_creative();
     init_game_mode();

mods/src/override/override.c

@@ -27,6 +27,12 @@ HOOK(access, int, (const char *pathname, int mode)) {
 
 // Get Override Path For File (If It Exists)
 char *override_get_path(const char *filename) {
+    // Custom Skin
+    if (starts_with(filename, "data/images/$")) {
+        // Fallback Texture
+        filename = "data/images/mob/char.png";
+    }
+
     // Get MCPI Home Path
     char *home_path = home_get();
     // Get Asset Override Path

mods/src/skin/README.md

@@ -0,0 +1,2 @@
+# ``skin`` Mod
+This mod adds custom skin loading.

mods/src/skin/loader.cpp

@@ -0,0 +1,162 @@
+#include <pthread.h>
+#include <vector>
+
+#include <libreborn/libreborn.h>
+#include <symbols/minecraft.h>
+
+#include <png.h>
+#include <GLES/gl.h>
+
+#include <mods/misc/misc.h>
+#include <mods/textures/textures.h>
+#include "skin-internal.h"
+
+// Constants
+#define SKIN_WIDTH 64
+#define SKIN_HEIGHT 32
+
+// Loading Pending Skins
+struct pending_skin {
+    int32_t texture_id;
+    char *data;
+};
+static std::vector<pending_skin> &get_pending_skins() {
+    static std::vector<pending_skin> pending_skins;
+    return pending_skins;
+}
+static pthread_mutex_t pending_skins_lock = PTHREAD_MUTEX_INITIALIZER;
+static void read_from_png(png_structp pngPtr, png_bytep data, png_size_t length) {
+    char **src = (char **) png_get_io_ptr(pngPtr);
+    memcpy(data, *src, length);
+    *src += length;
+}
+static void load_pending_skins(__attribute__((unused)) unsigned char *minecraft) {
+    // Lock
+    pthread_mutex_lock(&pending_skins_lock);
+
+    // Loop
+    for (pending_skin &skin : get_pending_skins()) {
+        // Init LibPNG
+        png_structp pngPtr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+        if (!pngPtr) {
+            continue;
+        }
+        png_infop infoPtr = png_create_info_struct(pngPtr);
+        if (!infoPtr) {
+            png_destroy_read_struct(&pngPtr, NULL, NULL);
+            continue;
+        }
+
+        // Read PNG Info
+        char *cursor = skin.data;
+        png_set_read_fn(pngPtr, (png_voidp) &cursor, read_from_png);
+        png_read_info(pngPtr, infoPtr);
+        int width = png_get_image_width(pngPtr, infoPtr);
+        int height = png_get_image_height(pngPtr, infoPtr);
+        if (png_get_color_type(pngPtr, infoPtr) != PNG_COLOR_TYPE_RGBA) {
+            continue;
+        }
+        if (width != SKIN_WIDTH || height != SKIN_HEIGHT) {
+            continue;
+        }
+        int pixelSize = 4;
+
+        // Read Image
+        png_bytep *rowPtrs = new png_bytep[height];
+        unsigned char *data = new unsigned char[pixelSize * width * height];
+        int rowStrideBytes = pixelSize * width;
+        for (int i = 0; i < height; i++) {
+            rowPtrs[i] = (png_bytep) &data[i * rowStrideBytes];
+        }
+        png_read_image(pngPtr, rowPtrs);
+
+        // Load Texture
+        GLint last_texture;
+        glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+        glBindTexture(GL_TEXTURE_2D, skin.texture_id);
+        glTexSubImage2D_with_scaling(GL_TEXTURE_2D, 0, 0, 0, width, height, SKIN_WIDTH, SKIN_HEIGHT, GL_RGBA, GL_UNSIGNED_BYTE, data);
+        glBindTexture(GL_TEXTURE_2D, last_texture);
+
+        // Free
+        delete[] data;
+        png_destroy_read_struct(&pngPtr, &infoPtr, (png_infopp) 0);
+        delete[] rowPtrs;
+    }
+
+    // Free
+    for (pending_skin &skin : get_pending_skins()) {
+        free(skin.data);
+    }
+
+    // Clear
+    get_pending_skins().clear();
+
+    // Unlock
+    pthread_mutex_unlock(&pending_skins_lock);
+}
+
+// Skin Loader
+struct loader_data {
+    int32_t texture_id;
+    std::string name;
+};
+static void *loader_thread(void *user_data) {
+    // Loader Data
+    loader_data *data = (loader_data *) user_data;
+
+    // Download
+    std::string url = std::string(MCPI_SKIN_SERVER) + '/' + data->name + ".png";
+    int return_code;
+    const char *command[] = {"wget", "-O", "-", url.c_str(), NULL};
+    char *output = run_command(command, &return_code);
+
+    // Check Success
+    if (output != NULL && is_exit_status_success(return_code)) {
+        // Success
+        DEBUG("Downloaded Skin: %s", data->name.c_str());
+
+        // Add To Pending Skins
+        pending_skin skin;
+        skin.texture_id = data->texture_id;
+        skin.data = output;
+        pthread_mutex_lock(&pending_skins_lock);
+        get_pending_skins().push_back(skin);
+        pthread_mutex_unlock(&pending_skins_lock);
+    } else {
+        // Failure
+        WARN("Failed To Download Skin: %s", data->name.c_str());
+        free(output);
+    }
+
+    // Free
+    delete data;
+    return NULL;
+}
+
+// Intercept Texture Creation
+static int32_t Textures_assignTexture_injection(unsigned char *textures, std::string const& name, unsigned char *data) {
+    // Call Original Method
+    int32_t id = (*Textures_assignTexture)(textures, name, data);
+
+    // Load Skin
+    if (starts_with(name.c_str(), "$")) {
+        loader_data *user_data = new loader_data;
+        user_data->name = name.substr(1);
+        DEBUG("Loading Skin: %s", user_data->name.c_str());
+        user_data->texture_id = id;
+        // Start Thread
+        pthread_t thread;
+        pthread_create(&thread, NULL, loader_thread, (void *) user_data);
+    }
+
+    // Return
+    return id;
+}
+
+// Init
+void _init_skin_loader() {
+    // Intercept Texture Creation
+    overwrite_calls((void *) Textures_assignTexture, (void *) Textures_assignTexture_injection);
+    // Pending Skins
+    misc_run_on_tick(load_pending_skins);
+}

mods/src/skin/skin-internal.h

@@ -0,0 +1,3 @@
+#pragma once
+
+__attribute__((visibility("internal"))) void _init_skin_loader();

mods/src/skin/skin.cpp

@@ -0,0 +1,94 @@
+#include <libreborn/libreborn.h>
+#include <symbols/minecraft.h>
+
+#include <mods/init/init.h>
+
+#include "skin-internal.h"
+
+// Base64 Encode (https://gist.github.com/tomykaira/f0fd86b6c73063283afe550bc5d77594)
+static std::string base64_encode(const std::string data) {
+    static constexpr char encoding_table[] = {
+        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+        'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+        'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
+        'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+        'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
+        'w', 'x', 'y', 'z', '0', '1', '2', '3',
+        '4', '5', '6', '7', '8', '9', '+', '/'
+    };
+
+    size_t in_len = data.size();
+    size_t out_len = 4 * ((in_len + 2) / 3);
+    std::string ret(out_len, '\0');
+    size_t i;
+    char *p = const_cast<char*>(ret.c_str());
+
+    for (i = 0; i < in_len - 2; i += 3) {
+        *p++ = encoding_table[(data[i] >> 2) & 0x3f];
+        *p++ = encoding_table[((data[i] & 0x3) << 4) | ((int) (data[i + 1] & 0xf0) >> 4)];
+        *p++ = encoding_table[((data[i + 1] & 0xf) << 2) | ((int) (data[i + 2] & 0xc0) >> 6)];
+        *p++ = encoding_table[data[i + 2] & 0x3f];
+    }
+    if (i < in_len) {
+        *p++ = encoding_table[(data[i] >> 2) & 0x3f];
+        if (i == (in_len - 1)) {
+            *p++ = encoding_table[((data[i] & 0x3) << 4)];
+            *p++ = '=';
+        }
+        else {
+            *p++ = encoding_table[((data[i] & 0x3) << 4) | ((int) (data[i + 1] & 0xf0) >> 4)];
+            *p++ = encoding_table[((data[i + 1] & 0xf) << 2)];
+        }
+        *p++ = '=';
+    }
+
+    return ret;
+}
+
+// Change Texture For Player Entities
+static void Player_username_assign_injection(std::string *target, std::string *username) {
+    // Call Original Method
+    *target = *username;
+
+    // Get Player
+    unsigned char *player = ((unsigned char *) target) - Player_username_property_offset;
+    // Get Texture
+    std::string *texture = (std::string *) (player + Mob_texture_property_offset);
+
+    // Set Texture
+    *texture = '$' + base64_encode(*username);
+}
+static void Player_username_assign_injection_2(std::string *target, const char *username) {
+    std::string username_str = username;
+    Player_username_assign_injection(target, &username_str);
+}
+
+// Change Texture For HUD
+static int32_t Textures_loadAndBindTexture_injection(unsigned char *textures, __attribute__((unused)) std::string const& name) {
+    // Change Texture
+    static std::string new_texture;
+    if (new_texture.length() == 0) {
+        std::string username = base64_encode(*default_username);
+        new_texture = '$' + username;
+    }
+
+    // Call Original Method
+    return (*Textures_loadAndBindTexture)(textures, new_texture);
+}
+
+// Init
+void init_skin() {
+    // LocalPlayer
+    overwrite_call((void *) 0x44c28, (void *) Player_username_assign_injection);
+    // RemotePlayer
+    overwrite_call((void *) 0x6ce58, (void *) Player_username_assign_injection_2);
+    // ServerPlayer
+    overwrite_call((void *) 0x7639c, (void *) Player_username_assign_injection_2);
+
+    // HUD
+    overwrite_call((void *) 0x4c6d0, (void *) Textures_loadAndBindTexture_injection);
+
+    // Loader
+    _init_skin_loader();
+}

mods/src/textures/textures.cpp

@@ -9,6 +9,7 @@
 
 #include <mods/misc/misc.h>
 #include <mods/feature/feature.h>
+#include <mods/textures/textures.h>
 #include <mods/init/init.h>
 
 // Animated Water
@@ -124,7 +125,7 @@ static void *scale_texture(const unsigned char *src, GLsizei old_width, GLsizei
 }
 
 // Scale Animated Textures
-static void Textures_tick_glTexSubImage2D_injection(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void *pixels) {
+void glTexSubImage2D_with_scaling(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLsizei normal_texture_width, GLsizei normal_texture_height, GLenum format, GLenum type, const void *pixels) {
     // Get Current Texture Size
     GLint current_texture;
     glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
@@ -133,8 +134,8 @@ static void Textures_tick_glTexSubImage2D_injection(GLenum target, GLint level,
     get_texture_size(current_texture, &texture_width, &texture_height);
 
     // Calculate Factor
-    float width_factor = ((float) texture_width) / 256.0f;
-    float height_factor = ((float) texture_height) / 256.0f;
+    float width_factor = ((float) texture_width) / ((float) normal_texture_width);
+    float height_factor = ((float) texture_height) / ((float) normal_texture_height);
 
     // Only Scale If Needed
     if (width_factor == 1.0f && height_factor == 1.0f) {
@@ -161,6 +162,9 @@ static void Textures_tick_glTexSubImage2D_injection(GLenum target, GLint level,
         free(new_pixels);
     }
 }
+static void Textures_tick_glTexSubImage2D_injection(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void *pixels) {
+    glTexSubImage2D_with_scaling(target, level, xoffset, yoffset, width, height, 256, 256, format, type, pixels);
+}
 
 // Init
 void init_textures() {

symbols/include/symbols/minecraft.h

@@ -443,6 +443,7 @@ typedef void (*Mob_die_t)(unsigned char *entity, unsigned char *cause);
 static uint32_t Mob_die_vtable_offset = 0x130;
 
 static uint32_t Mob_health_property_offset = 0xec; // int32_t
+static uint32_t Mob_texture_property_offset = 0xb54; // std::string
 
 // PathfinderMob
 
@@ -1051,9 +1052,12 @@ static OptionsPane_unknown_toggle_creating_function_t OptionsPane_unknown_toggle
 
 // Textures
 
-typedef void (*Textures_loadAndBindTexture_t)(unsigned char *textures, std::string const& name);
+typedef int32_t (*Textures_loadAndBindTexture_t)(unsigned char *textures, std::string const& name);
 static Textures_loadAndBindTexture_t Textures_loadAndBindTexture = (Textures_loadAndBindTexture_t) 0x539cc;
 
+typedef int32_t (*Textures_assignTexture_t)(unsigned char *textures, std::string const& name, unsigned char *data);
+static Textures_assignTexture_t Textures_assignTexture = (Textures_assignTexture_t) 0x5354c;
+
 // Recipes
 
 typedef void (*Recipes_addShapelessRecipe_t)(unsigned char *recipes, ItemInstance const& result, std::vector<Recipes_Type> const& ingredients);