Fixed raycasting

README.md

@@ -35,3 +35,9 @@ Different voxel types are now supported in the data structures and passed to the
 When placing a block, the program now raycasts to place where the camera is looking.
 
 ![a place of brown dirt with word Hi built out of stone.](.attachments/raycasting_test.png)
+
+### 0.6.1 : Raycast Bug Fixes - 11/17/25
+
+It took me a couple of days to fix the ray casting. I forgot that my mesh is offset by 0.5, so 3/4 raycasts looked at least a block off of what the camera was looking at.
+
+![Hello, written in blocks on a dirt plane](.attachments/fixed-raycast.png)

run.ps1

@@ -0,0 +1 @@
+.\build\Debug\VoxelEngine.exe

src/World.cpp

@@ -74,7 +74,11 @@ std::optional<std::pair<glm::ivec3, glm::ivec3>> World::raycast_voxel(glm::vec3
     // std::cout << "[RAYCAST] Start: (" << start.x << ", " << start.y << ", " << start.z << ")" << std::endl;
     // std::cout << "[RAYCAST] Direction: (" << direction.x << ", " << direction.y << ", " << direction.z << ")" << std::endl;
 
-    glm::ivec3 pos = glm::ivec3(std::floor(start.x), std::floor(start.y), std::floor(start.z));
+    // Adjust start position to account for voxels being centered at integer + 0.5
+    // (voxel at pos (0,0,0) occupies space from (-0.5,-0.5,-0.5) to (0.5,0.5,0.5))
+    glm::vec3 adjusted_start = start + glm::vec3(0.5f, 0.5f, 0.5f);
+    
+    glm::ivec3 pos = glm::ivec3(std::floor(adjusted_start.x), std::floor(adjusted_start.y), std::floor(adjusted_start.z));
     // std::cout << "[RAYCAST] Starting voxel: (" << pos.x << ", " << pos.y << ", " << pos.z << ")" << std::endl;
 
     // (+1, -1, or 0 for each axis)
@@ -94,7 +98,7 @@ std::optional<std::pair<glm::ivec3, glm::ivec3>> World::raycast_voxel(glm::vec3
 
     // Calculate t_max: distance along ray to next voxel boundary for each axis
     glm::vec3 t_max;
-    glm::vec3 fract = start - glm::vec3(pos);
+    glm::vec3 fract = adjusted_start - glm::vec3(pos);
 
     // For each axis, calculate distance to the next boundary
     if (step_dir.x > 0)

src/main.cpp

@@ -13,6 +13,8 @@
 unsigned int SCR_WIDTH = 1920;
 unsigned int SCR_HEIGHT = 1080;
 
+const int EDIT_RANGE = 5;
+
 // Jump
 const float JUMP_COOLDOWN = 0.0f;
 const float JUMP_POWER = 10.0f; // Initial Jump Speed
@@ -96,12 +98,22 @@ void processInput(GLFWwindow *window)
 {
     float current_time = glfwGetTime();
 
+    if (glfwGetKey(window, GLFW_KEY_P) == GLFW_PRESS) {
+        glm::vec3 eye = camera.getEyePosition();
+        glm::mat4 view = camera.getView();
+        glm::vec3 forward = -glm::vec3(view[0][2], view[1][2], view[2][2]); // Extract forward from view matrix
+
+        std::cout << "Camera target (from pitch/yaw): (" << camera.target.x << ", " << camera.target.y << ", " << camera.target.z << ")" << std::endl;
+        std::cout << "Camera forward (from view matrix): (" << forward.x << ", " << forward.y << ", " << forward.z << ")" << std::endl;
+        std::cout << "Match: " << (glm::length(camera.target - forward) < 0.01f ? "YES" : "NO") << std::endl;
+    }
+
     // Update targeted block every frame for highlight
     std::optional<std::pair<glm::ivec3, glm::ivec3>> raycast_result =
-        world.raycast_voxel(camera.getEyePosition(), camera.target, 5);
+        world.raycast_voxel(camera.getEyePosition(), camera.target, EDIT_RANGE);
     if (raycast_result.has_value()) {
         targeted_block = raycast_result.value().first;
-        
+
         // Debug: print occasionally
         static int frame_count = 0;
         if (frame_count % 60 == 0) {
@@ -203,10 +215,10 @@ void processInput(GLFWwindow *window)
         std::cout << "\n=== LEFT CLICK (PLACE) ===" << std::endl;
         std::cout << "Camera eye pos: (" << camera.getEyePosition().x << ", " << camera.getEyePosition().y << ", " << camera.getEyePosition().z << ")" << std::endl;
         std::cout << "Camera target: (" << camera.target.x << ", " << camera.target.y << ", " << camera.target.z << ")" << std::endl;
-        
+
         std::optional<std::pair<glm::ivec3, glm::ivec3>> raycast_result =
-            world.raycast_voxel(camera.getEyePosition(), camera.target, 3);
+            world.raycast_voxel(camera.getEyePosition(), camera.target, EDIT_RANGE);
-        
+
         if (raycast_result.has_value()) {
             auto [target_block, normal] = raycast_result.value();
             std::cout << "Hit block at: (" << target_block.x << ", " << target_block.y << ", " << target_block.z << ")" << std::endl;
@@ -228,10 +240,10 @@ void processInput(GLFWwindow *window)
         std::cout << "\n=== RIGHT CLICK (REMOVE) ===" << std::endl;
         std::cout << "Camera eye pos: (" << camera.getEyePosition().x << ", " << camera.getEyePosition().y << ", " << camera.getEyePosition().z << ")" << std::endl;
         std::cout << "Camera target: (" << camera.target.x << ", " << camera.target.y << ", " << camera.target.z << ")" << std::endl;
-        
+
         std::optional<std::pair<glm::ivec3, glm::ivec3>> raycast_result =
-            world.raycast_voxel(camera.getEyePosition(), camera.target, 3);
+            world.raycast_voxel(camera.getEyePosition(), camera.target, EDIT_RANGE);
-        
+
         if (raycast_result.has_value()) {
             auto [target_block, normal] = raycast_result.value();
             std::cout << "Hit block at: (" << target_block.x << ", " << target_block.y << ", " << target_block.z << ")" << std::endl;
@@ -257,7 +269,7 @@ int main() {
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
     // 2. --- Create a Window ---
-    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "Voxel Engine 0.6.0", NULL, NULL);
+    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "Voxel Engine 0.6.1", NULL, NULL);
     if (window == NULL) {
         std::cerr << "Failed to create GLFW window" << std::endl;
         glfwTerminate();
@@ -299,10 +311,10 @@ int main() {
     unsigned int crosshairVAO, crosshairVBO;
     glGenVertexArrays(1, &crosshairVAO);
     glGenBuffers(1, &crosshairVBO);
-    
+
     glBindVertexArray(crosshairVAO);
     glBindBuffer(GL_ARRAY_BUFFER, crosshairVBO);
-    
+
     // Crosshair vertices in NDC (Normalized Device Coordinates: -1 to 1)
     float crosshairSize = 0.02f; // Size in NDC
     float crosshairVertices[] = {
@@ -313,7 +325,7 @@ int main() {
          0.0f, -crosshairSize, 0.0f,
          0.0f,  crosshairSize, 0.0f
     };
-    
+
     glBufferData(GL_ARRAY_BUFFER, sizeof(crosshairVertices), crosshairVertices, GL_STATIC_DRAW);
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
     glEnableVertexAttribArray(0);
@@ -324,10 +336,10 @@ int main() {
     glGenVertexArrays(1, &highlightVAO);
     glGenBuffers(1, &highlightVBO);
     glGenBuffers(1, &highlightEBO);
-    
+
     glBindVertexArray(highlightVAO);
     glBindBuffer(GL_ARRAY_BUFFER, highlightVBO);
-    
+
     // Cube outline vertices (slightly larger than 1 unit cube for visibility)
     float offset = 0.001f; // Slight offset to prevent z-fighting
     float highlightVertices[] = {
@@ -341,7 +353,7 @@ int main() {
          0.5f + offset,  0.5f + offset,  0.5f + offset,  // 6
         -0.5f - offset,  0.5f + offset,  0.5f + offset   // 7
     };
-    
+
     // Indices for the 12 edges of the cube
     unsigned int highlightIndices[] = {
         // Bottom face
@@ -351,11 +363,11 @@ int main() {
         // Vertical edges
         0, 4,  1, 5,  2, 6,  3, 7
     };
-    
+
     glBufferData(GL_ARRAY_BUFFER, sizeof(highlightVertices), highlightVertices, GL_STATIC_DRAW);
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
     glEnableVertexAttribArray(0);
-    
+
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, highlightEBO);
     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(highlightIndices), highlightIndices, GL_STATIC_DRAW);
     glBindVertexArray(0);
@@ -364,7 +376,7 @@ int main() {
     unsigned int debugRayVAO, debugRayVBO;
     glGenVertexArrays(1, &debugRayVAO);
     glGenBuffers(1, &debugRayVBO);
-    
+
     glBindVertexArray(debugRayVAO);
     glBindBuffer(GL_ARRAY_BUFFER, debugRayVBO);
     glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6, nullptr, GL_DYNAMIC_DRAW); // 2 points * 3 coords
@@ -490,39 +502,6 @@ int main() {
             glBindVertexArray(0);
         }
 
-        // ---- Draw Debug Ray ----
-        {
-            shader.use();
-            glm::vec3 ray_start = camera.getEyePosition();
-            
-            static bool printed_debug = false;
-            
-            // Draw multiple small cubes along the ray path to make it visible
-            for (int i = 1; i <= 10; i++) {
-                float distance = i * 0.5f;
-                glm::vec3 point = ray_start + camera.target * distance;
-                
-                if (!printed_debug && i == 1) {
-                    std::cout << "\n[DEBUG RAY]" << std::endl;
-                    std::cout << "Ray start: (" << ray_start.x << ", " << ray_start.y << ", " << ray_start.z << ")" << std::endl;
-                    std::cout << "Ray direction: (" << camera.target.x << ", " << camera.target.y << ", " << camera.target.z << ")" << std::endl;
-                    std::cout << "First marker at: (" << point.x << ", " << point.y << ", " << point.z << ")" << std::endl;
-                    printed_debug = true;
-                }
-                
-                glm::mat4 model = glm::mat4(1.0f);
-                model = glm::translate(model, point);
-                model = glm::scale(model, glm::vec3(0.1f)); // Small marker
-                glm::mat4 mvp = projection * view * model;
-                shader.setMat4("u_mvp", mvp);
-                shader.setVec3("u_Color", glm::vec3(1.0f, 0.0f, 0.0f)); // Red markers
-                
-                glBindVertexArray(highlightVAO);
-                glDrawElements(GL_LINES, 24, GL_UNSIGNED_INT, 0);
-                glBindVertexArray(0);
-            }
-        }
-
         // ---- Draw Crosshair ----
         glDisable(GL_DEPTH_TEST); // Draw on top of everything
         shader.use();
@@ -548,4 +527,4 @@ int main() {
 
     glfwTerminate(); // Clean up GLFW
     return 0;
-}
+}