Working on the night mode

src/render/ShadowMap.cpp

@@ -133,6 +133,29 @@ namespace ZL {
         lightSpaceMatrix = lightProjectionMatrix * lightViewMatrix;
     }
 
+    static Eigen::Matrix4f perspective(float fovY, float aspect, float zNear, float zFar) {
+        float t = std::tan(fovY * 0.5f);
+        Eigen::Matrix4f m = Eigen::Matrix4f::Zero();
+        m(0, 0) = 1.0f / (aspect * t);
+        m(1, 1) = 1.0f / t;
+        m(2, 2) = -(zFar + zNear) / (zFar - zNear);
+        m(2, 3) = -(2.0f * zFar * zNear) / (zFar - zNear);
+        m(3, 2) = -1.0f;
+        return m;
+    }
+
+    void ShadowMap::updateSpotlightMatrix(const Eigen::Vector3f& lightPos,
+                                          const Eigen::Vector3f& lightDir,
+                                          float fovY, float nearZ, float farZ) {
+        Eigen::Vector3f d = lightDir.normalized();
+        Eigen::Vector3f up(0.f, 1.f, 0.f);
+        if (std::abs(d.dot(up)) > 0.99f)
+            up = Eigen::Vector3f(1.f, 0.f, 0.f);
+        lightViewMatrix       = lookAt(lightPos, lightPos + d, up);
+        lightProjectionMatrix = perspective(fovY, 1.0f, nearZ, farZ);
+        lightSpaceMatrix      = lightProjectionMatrix * lightViewMatrix;
+    }
+
     void ShadowMap::bind() {
         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
         glViewport(0, 0, resolution, resolution);