Downscale

include/ReTexture/Texture.h

@@ -19,6 +19,8 @@ namespace ReTexture {
         std::vector<unsigned char> pixelData;
         explicit Texture(const std::string& file);
         Texture(const std::string& file, const TextureFlag& flags);
+        Texture(const std::vector<unsigned char>& pixel_data, TextureFormat format, unsigned int width, unsigned int height);
+        Texture downscale(unsigned int rhs);
         [[nodiscard]] unsigned int getWidth() const;
         [[nodiscard]] unsigned int getHeight() const;
         TextureFormat getTextureFormat();

include/ReTexture/flags.h

@@ -2,8 +2,9 @@
 
 namespace ReTexture {
     enum TextureFlag {
-        INVERT_Y = 0,
-        INVERT_X = 1,
+        NONE = 0,
+        INVERT_Y = 1,
+        INVERT_X = 2,
     };
 
     inline TextureFlag operator|(TextureFlag a, TextureFlag b) {

src/Texture.cpp

@@ -1,9 +1,10 @@
 #include <fstream>
 #include <algorithm>
 #include <ReTexture/Texture.h>
-
 #define STB_IMAGE_IMPLEMENTATION
 #include <stb_image.h>
+#define STB_IMAGE_RESIZE_IMPLEMENTATION
+#include <stb_image_resize2.h>
 
 namespace ReTexture {
 
@@ -19,6 +20,15 @@ namespace ReTexture {
         *this = Texture(file, {});
     }
 
+    Texture::Texture(const std::vector<unsigned char>& pixel_data, TextureFormat format, unsigned int width, unsigned int height) {
+        pixelData = pixel_data;
+        this->width = width;
+        this->height = height;
+        this->format = format;
+        this->flags = TextureFlag::NONE;
+    }
+
+
     void Texture::load(const std::string &file) {
         std::ifstream ifStream(file, std::ios::in | std::ios::binary);
         unsigned char bmpFileHeader[14];
@@ -117,4 +127,18 @@ namespace ReTexture {
     TextureFlag Texture::getFlags() {
         return flags;
     }
+
+    Texture Texture::downscale(unsigned int rhs) {
+        std::vector<unsigned char> result;
+
+        if (format == TextureFormat::RGB)
+            result.resize((width / rhs) * (height / rhs) * 3),
+            stbir_resize_uint8_linear(pixelData.data(), width, height, 0, result.data(), (width / rhs), (height / rhs), 0, stbir_pixel_layout::STBIR_RGB);
+
+        else if (format == TextureFormat::RGBA)
+            result.resize((width / rhs) * (height / rhs) * 4),
+            stbir_resize_uint8_linear(pixelData.data(), width, height, 0, result.data(), (width / rhs), (height / rhs), 0, stbir_pixel_layout::STBIR_RGBA);
+
+        return Texture(result, format, (width / rhs), (height / rhs));
+    }
 }