1 files changed, 78 insertions, 0 deletions
diff --git a/src/core/texture.c b/src/core/texture.c
index 7104bfb..1b70e4b 100644
--- a/src/core/texture.c
+++ b/src/core/texture.c
@@ -1,3 +1,81 @@
 #include "texture.h"
+#define STB_IMAGE_IMPLEMENTATION
+#include "../lib/stb_image.h"
+#include <stdio.h>
 
+static void texture_abgr2argb(Texture* tex) {
+	ssr_assert(tex);
+	int width = tex->width, height = tex->height;
+	Color* pixels = tex->pixels;
+	for (int i = 0; i < width * height; ++i) {
+		uint r = (pixels[i] & 0xff) << 16;
+		uint g = ((pixels[i] >> 8) & 0xff) << 8;
+		uint b = ((pixels[i] >> 16) & 0xff);
+		uint a = ((pixels[i] >> 24) & 0xff) << 24;
+		pixels[i] = r | g | b | a;
+	}
+}
 
+Texture* texture_loadfromfile(const char* path) {
+	ssr_assert(path);
+	FILE* file = fopen(path, "rb");
+	ssr_assert(file);
+	fseek(file, 0, SEEK_END);
+	int size = ftell(file);
+	fseek(file, 0, SEEK_SET);
+	char* buffer = ssrM_newvector(char, size);
+	ssr_assert(buffer);
+	int l = fread(buffer, 1, size, file);
+	if ( l!= size) {
+		free(buffer);
+		fclose(file);
+		return NULL;
+	}
+	fclose(file);
+	int width, height;
+	Color* pixels = (Color*)stbi_load_from_memory((unsigned char*)buffer, size, &width, &height, NULL, STBI_rgb_alpha);
+	ssrM_free(buffer);
+	if (!pixels) return NULL;
+	Texture* texture = ssrM_new(Texture);
+	texture->width = width; texture->height = height;
+	texture->pixels = pixels;
+	texture_abgr2argb(texture);
+	return texture;
+}
+
+static Color32 sampling(Texture* tex, WrapMode wrap_mode, int x, int y) {
+	Color32 color; 
+	if (wrap_mode == WRAPMODE_CLAMP) { /*clamp*/
+		x = clamp(x, 0, tex->width - 1);
+		y = clamp(y, 0, tex->height - 1);
+	}	else { /*repeat*/
+		x = x % tex->width; 
+		y = y % tex->height;
+	}
+	color_tocolor32(tex->pixels[x + y * tex->width], &color);
+	return color;
+}
+
+Color32 texture_sampling(Texture* tex, FilterMode filter_mode, WrapMode wrap_mode, float x01, float y01) {
+	ssr_assert(tex);
+	int x = x01 * tex->width, y = (1 - y01) * tex->height; /*map to texture coordinate*/
+	if (filter_mode == FILTERMODE_POINT) {
+		return sampling(tex, wrap_mode, x, y);
+	}
+	else if (filter_mode == FILTERMODE_BILINEAR) {
+		int x_min = floor(x), y_min = floor(y);
+		int x_max = ceil(x), y_max = ceil(y);
+		static Color32 tl, tr, bl, br, t, b, out;
+		tl = sampling(tex, wrap_mode, x_min, y_min);
+		tr = sampling(tex, wrap_mode, x_max, y_min);
+		bl = sampling(tex, wrap_mode, x_min, y_max);
+		br = sampling(tex, wrap_mode, x_max, y_max);
+		vec4_lerp(&tl, &tr, x - x_min, &t);
+		vec4_lerp(&bl, &br, x - x_min, &b);
+		vec4_lerp(&t, &b, y - y_min, &out);
+		return out;
+	}
+	else if (filter_mode == FILTERMODE_TRILINEAR) {
+		/*TODO*/
+	}
+}