From 324375d6a4199cd16e5aa7d75efba5074bc9eebc Mon Sep 17 00:00:00 2001
From: omar <ocornut@users.noreply.github.com>
Date: Tue, 30 Jul 2024 14:36:26 +0200
Subject: [PATCH] Added LoadTextureFromMemory() for DX11 and DX12 examples.

---
 Image-Loading-and-Displaying-Examples.md | 53 ++++++++++++++++++++++--
 1 file changed, 49 insertions(+), 4 deletions(-)

diff --git a/Image-Loading-and-Displaying-Examples.md b/Image-Loading-and-Displaying-Examples.md
index d45187f..77c0306 100644
--- a/Image-Loading-and-Displaying-Examples.md
+++ b/Image-Loading-and-Displaying-Examples.md
@@ -234,16 +234,17 @@ ImGui::End();
 
 Add at the top of one of your source file:
 ```cpp
+#define _CRT_SECURE_NO_WARNINGS
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
 // Simple helper function to load an image into a DX11 texture with common settings
-bool LoadTextureFromFile(const char* filename, ID3D11ShaderResourceView** out_srv, int* out_width, int* out_height)
+bool LoadTextureFromMemory(const void* data, size_t data_size, ID3D11ShaderResourceView** out_srv, int* out_width, int* out_height)
 {
     // Load from disk into a raw RGBA buffer
     int image_width = 0;
     int image_height = 0;
-    unsigned char* image_data = stbi_load(filename, &image_width, &image_height, NULL, 4);
+    unsigned char* image_data = stbi_load_from_memory((const unsigned char*)data, (int)data_size, &image_width, &image_height, NULL, 4);
     if (image_data == NULL)
         return false;
 
@@ -283,6 +284,24 @@ bool LoadTextureFromFile(const char* filename, ID3D11ShaderResourceView** out_sr
 
     return true;
 }
+
+// Open and read a file, then forward to LoadTextureFromMemory()
+bool LoadTextureFromFile(const char* file_name, ID3D11ShaderResourceView** out_srv, int* out_width, int* out_height)
+{
+    FILE* f = fopen(file_name, "rb");
+    if (f == NULL)
+        return false;
+    fseek(f, 0, SEEK_END);
+    size_t file_size = (size_t)ftell(f);
+    if (file_size == -1)
+        return false;
+    fseek(f, 0, SEEK_SET);
+    void* file_data = IM_ALLOC(file_size);
+    fread(file_data, 1, file_size, f);
+    bool ret = LoadTextureFromMemory(file_data, file_size, out_srv, out_width, out_height);
+    IM_FREE(file_data);
+    return ret;
+}
 ```
 
 At initialization time, load our texture:
@@ -328,17 +347,18 @@ If you want to use this code to load more than one texture (and don't have your
 
 The actual implementation itself is as follows - firstly, at the top of one of your source files add:
 ```cpp
+#define _CRT_SECURE_NO_WARNINGS
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
 // Simple helper function to load an image into a DX12 texture with common settings
 // Returns true on success, with the SRV CPU handle having an SRV for the newly-created texture placed in it (srv_cpu_handle must be a handle in a valid descriptor heap)
-bool LoadTextureFromFile(const char* filename, ID3D12Device* d3d_device, D3D12_CPU_DESCRIPTOR_HANDLE srv_cpu_handle, ID3D12Resource** out_tex_resource, int* out_width, int* out_height)
+bool LoadTextureFromMemory(const void* data, size_t data_size, ID3D12Device* d3d_device, D3D12_CPU_DESCRIPTOR_HANDLE srv_cpu_handle, ID3D12Resource** out_tex_resource, int* out_width, int* out_height)
 {
     // Load from disk into a raw RGBA buffer
     int image_width = 0;
     int image_height = 0;
-    unsigned char* image_data = stbi_load(filename, &image_width, &image_height, NULL, 4);
+    unsigned char* image_data = stbi_load_from_memory((const unsigned char*)data, (int)data_size, &image_width, &image_height, NULL, 4);
     if (image_data == NULL)
         return false;
 
@@ -489,6 +509,30 @@ bool LoadTextureFromFile(const char* filename, ID3D12Device* d3d_device, D3D12_C
 
     return true;
 }
+
+// Open and read a file, then forward to LoadTextureFromMemory()
+bool LoadTextureFromFile(const char* file_name, ID3D12Device* d3d_device, D3D12_CPU_DESCRIPTOR_HANDLE srv_cpu_handle, ID3D12Resource** out_tex_resource, int* out_width, int* out_height)
+{
+    FILE* f = fopen(file_name, "rb");
+    if (f == NULL)
+        return false;
+    fseek(f, 0, SEEK_END);
+    size_t file_size = (size_t)ftell(f);
+    if (file_size == -1)
+        return false;
+    fseek(f, 0, SEEK_SET);
+    void* file_data = IM_ALLOC(file_size);
+    fread(file_data, 1, file_size, f);
+    bool ret = LoadTextureFromMemory(file_data, file_size, d3d_device, srv_cpu_handle, out_tex_resource, out_width, out_height);
+    IM_FREE(file_data);
+    return ret;
+}
+
+void DestroyTexture(ID3D12Resource** tex_resources)
+{
+    (*tex_resources)->Release();
+    *tex_resources = NULL;
+}
 ```
 
 Then at initialization time, load our texture:
@@ -882,6 +926,7 @@ RemoveTexture(&my_texture);
 
 If instead of loading from a file you would like to load from memory, you can call `stbi_load_from_memory()` instead of `stbi_load()`. 
 All `LoadTextureFromFile()` function could be reworked to call `LoadTextureFromMemory()` which contains most of the code.
+See our implementation of `LoadTextureFromFile()` for DX11 and DX12 examples.
 
 ##### [Return to Index](#index)