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texture.cpp

@@ -0,0 +1,75 @@
+#include "texture.h"
+
+#include <stdexcept>
+
+#include "stb_image.h"
+
+Texture::Texture(const char* filename) : path(filename)
+{
+    int nrComponents;
+    stbi_set_flip_vertically_on_load(true);
+    unsigned char* bytes = stbi_load(filename, &width, &height, &nrComponents, 4);
+    if (not bytes)
+        throw std::runtime_error("Failed to load texture: " + path);
+
+    pixels.assign(bytes, bytes + (size_t)width * height * 4);
+    stbi_image_free(bytes);
+
+    CreateGLTexture();
+}
+
+Texture::Texture(const unsigned char* encoded, int size, const std::string& name) : path(name)
+{
+    int nrComponents;
+    stbi_set_flip_vertically_on_load(true);
+    unsigned char* bytes = stbi_load_from_memory(encoded, size, &width, &height, &nrComponents, 4);
+    if (not bytes)
+        throw std::runtime_error("Failed to load texture: " + path);
+
+    pixels.assign(bytes, bytes + (size_t)width * height * 4);
+    stbi_image_free(bytes);
+
+    CreateGLTexture();
+}
+
+Texture::Texture(int newWidth, int newHeight) : width(newWidth), height(newHeight)
+{
+    pixels.assign((size_t)width * height * 4, 255);
+    CreateGLTexture();
+}
+
+Texture::Texture(const Texture& source)
+    : path(source.path), width(source.width), height(source.height), pixels(source.pixels)
+{
+    CreateGLTexture();
+}
+
+void Texture::CreateGLTexture()
+{
+    glGenTextures(1, &ID);
+    glBindTexture(GL_TEXTURE_2D, ID);
+
+    // Mipmaps when shrunk, otherwise tiled textures shimmer in the distance
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());
+    glGenerateMipmap(GL_TEXTURE_2D);
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+void Texture::Upload()
+{
+    glBindTexture(GL_TEXTURE_2D, ID);
+    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());
+    glGenerateMipmap(GL_TEXTURE_2D);
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+void Texture::Delete() {
+    glDeleteTextures(1, &ID);
+}