stbi_load() return NULL and "PNG not supported: unknown PNG chunk type" error occurred, when load android internal storage file path

Purpose

I am making an Android application with vulkan. I saved bitmap in "texture.png" file in the device internal storage. I want to show this image with vulkan. Then I need to pass image data to c++ somehow.

Try

I tried below process:

pass the image file path to c++
load file data from path with stbi_load() (OSS stb_image.h)

Error

But stbi_load() return NULL and stb_error message is "PNG not supported: unknown PNG chunk type".

How to fix to load image in android internal storage file?

code

outlet of my code.

// create file path (kotlin)
val filePath: String = File(context.filesDir, "texture.png").path

// load image file (c++)

#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

void loadImage(const std::string filePath) {// same as ↑ filePath

    int width, height, channels;
    auto* pImage = stbi_load(filePath.c_str(), &width, &height, &channels, 0);

    if (pImage == nullptr) {
        return;// I'm here.
    }
    // (some successive process)
}

Solution

I found the alternative to pass image data to c++.

before

I tried and give up this.

filePath->stbi_load()->iamge data(unsigned char*)

after

It is working very well. I can show the file image with vulkan now.

bitmap->AndroidBitmap_getInfo()->iamge data(unsigned char*).

code outlet


JNIEXPORT void JNICALL
Java_com_example_yourproject_NativeAPI_loadBitmap(JNIEnv* env, jobject thiz, jobject bitmap) {
    AndroidBitmapInfo androidBitmapInfo;
    AndroidBitmap_getInfo(env, bitmap, &androidBitmapInfo);
    void* pixels;// image data.
    AndroidBitmap_lockPixels(env, bitmap, &pixels);
    AndroidBitmap_unlockPixels(env, bitmap);
    
    ・
    ・
    ・
    // For example, copy image data to vulkan image memory.
    void* p;
    vkMapMemory(device, imageMemory, 0, VK_WHOLE_SIZE, 0, &p);
    memcpy(p, pixels, width * height * sizeof(uint32_t));
    vkUnmapMemory(device, imageMemory);
}

Don't forget to link jnigraphics in CMakeList.txt!