diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d725151..04f283a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -4,9 +4,14 @@ PROJECT(renderer)
 if(NOT CMAKE_BUILD_TYPE)
   set(CMAKE_BUILD_TYPE Release)
 endif()
+
 set(CMAKE_CXX_FLAGS "-Wall -Wextra")
-set(CMAKE_CXX_FLAGS_DEBUG "-g")
 set(CMAKE_CXX_FLAGS_RELEASE "-O3")
+if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+  set(CMAKE_CXX_FLAGS_DEBUG "-gdwarf-4 -g")
+else()
+  set(CMAKE_CXX_FLAGS_DEBUG "-g")
+endif()
 
 file(GLOB_RECURSE CPP_FILES ${CMAKE_CURRENT_SOURCE_DIR} *.cc)
 
diff --git a/src/main.cc b/src/main.cc
index c5c11ab..2568411 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -34,8 +34,8 @@ int main(int argc, char *argv[]) {
   const std::string obj_path{result["obj"].as<std::string>()};
   const std::string diffuse_map_path{result["diffuse_map"].as<std::string>()};
 
-  const int resolution_width = 640;
-  const int resolution_height = 320;
+  const int resolution_width = 1280;
+  const int resolution_height = 720;
   const int far = -100;
   const int near = -1;
   const float fov = 120. / 180. * M_PI;
@@ -146,6 +146,7 @@ int main(int argc, char *argv[]) {
     // to create a named window.
     {
       ImGui::Begin(window_name.c_str()); // Create a window
+      ImGui::SetWindowSize({resolution_width, resolution_height});
 
       // TransformMatrix move2origin{
       //     {1, 0, 0, 0}, {0, 1, 0, -3}, {0, 0, 1, 5.}, {0, 0, 0, 1}};
@@ -162,16 +163,16 @@ int main(int argc, char *argv[]) {
         Point3d offset{0, 0, 0};
         if (ImGui::IsKeyPressed(ImGuiKey_A)) {
           offset.x() -= 1;
-        } else if (ImGui::IsKeyPressed(ImGuiKey_S)) {
-          offset.z() += 1;
         } else if (ImGui::IsKeyPressed(ImGuiKey_D)) {
           offset.x() += 1;
+        } else if (ImGui::IsKeyPressed(ImGuiKey_S)) {
+          offset.z() += 1;
         } else if (ImGui::IsKeyPressed(ImGuiKey_W)) {
           offset.z() -= 1;
         } else if (ImGui::IsKeyPressed(ImGuiKey_E)) {
-          offset.y() += 1;
-        } else if (ImGui::IsKeyPressed(ImGuiKey_Q)) {
           offset.y() -= 1;
+        } else if (ImGui::IsKeyPressed(ImGuiKey_Q)) {
+          offset.y() += 1;
         }
         camera.move(offset);
       }
diff --git a/src/minus_renderer.cc b/src/minus_renderer.cc
index c621e8a..182698d 100644
--- a/src/minus_renderer.cc
+++ b/src/minus_renderer.cc
@@ -130,6 +130,8 @@ void MinusRenderer::view_transform(const TransformMatrix &mtx) {
 
 cv::Mat MinusRenderer::render(const int resolution_width,
                               const int resolution_height) {
+  spdlog::trace("Tick once.");
+
   // 构造 camera space -> screen space 的变换矩阵
   const auto [ss_transform, inv_ss_transform] =
       construct_transform(resolution_width, resolution_height);
diff --git a/src/texture.cc b/src/texture.cc
index 0ac8ad1..74f1922 100644
--- a/src/texture.cc
+++ b/src/texture.cc
@@ -4,6 +4,7 @@
 #include "texture.h"
 #include "spdlog/spdlog.h"
 #include "util/interpolation.h"
+#include <cmath>
 #include <opencv2/highgui/highgui.hpp>
 
 Texture::Texture(const std::filesystem::path &texture_path) {
@@ -20,20 +21,26 @@ Texture::Texture(const std::filesystem::path &texture_path) {
 cv::Vec3b Texture::sample(const Point2d &texture_coordinate) {
   cv::Vec3b res{0, 0, 0};
 
-  const double x = texture_coordinate.x() * texture_.cols - 0.5;
-  const double y = texture_coordinate.y() * texture_.rows - 0.5;
+  double x = texture_coordinate.x() * (texture_.cols - 1);
+  if (x < 0.) {
+    x += texture_.cols;
+  }
+  double y = (1. - texture_coordinate.y()) * (texture_.rows - 1);
+  if (y < 0.) {
+    y = std::fabs(y);
+  }
 
-  const int x_f = x;
-  const int x_c = x + 1.;
+  const int x_f = std::max(0., x);
+  const int x_c = std::min(texture_.cols - 1, static_cast<int>(x + 1.));
   const float t_x = x - x_f;
-  const int y_f = y;
-  const int y_c = y + 1.;
+  const int y_f = std::max(0., y);
+  const int y_c = std::min(texture_.rows - 1, static_cast<int>(y + 1.));
   const float t_y = y - y_f;
 
-  const cv::Vec3b &a = texture_.at<cv::Vec3b>(x_f, y_f);
-  const cv::Vec3b &b = texture_.at<cv::Vec3b>(x_f, y_c);
-  const cv::Vec3b &c = texture_.at<cv::Vec3b>(x_c, y_f);
-  const cv::Vec3b &d = texture_.at<cv::Vec3b>(x_c, y_c);
+  const cv::Vec3b &a = texture_.at<cv::Vec3b>(y_f, x_f);
+  const cv::Vec3b &b = texture_.at<cv::Vec3b>(y_c, x_f);
+  const cv::Vec3b &c = texture_.at<cv::Vec3b>(y_f, x_c);
+  const cv::Vec3b &d = texture_.at<cv::Vec3b>(y_c, x_c);
 
   res = bilerp(t_x, t_y, a, b, c, d);