Merge pull request 'Fixed Raycasting' (#1) from raycast-debug into main

Reviewed-on: https://git.0x01fe.net/0x01FE/voxel-engine/pulls/1

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

@@ -71,32 +71,56 @@ std::optional<std::pair<glm::ivec3, glm::ivec3>> World::raycast_voxel(glm::vec3
     // Normalize direction to ensure consistent behavior
     direction = glm::normalize(direction);
 
-    std::cout << "[RAYCAST] Start: (" << start.x << ", " << start.y << ", " << start.z << ")" << std::endl;
+    // std::cout << "[RAYCAST] Start: (" << start.x << ", " << start.y << ", " << start.z << ")" << std::endl;
-    std::cout << "[RAYCAST] Direction: (" << direction.x << ", " << direction.y << ", " << direction.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
-    std::cout << "[RAYCAST] Starting voxel: (" << pos.x << ", " << pos.y << ", " << pos.z << ")" << std::endl;
+    // (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 or -1 for each axis)
+    // (+1, -1, or 0 for each axis)
-    glm::ivec3 step_dir = glm::sign(direction);
+    glm::ivec3 step_dir = glm::ivec3(
-    std::cout << "[RAYCAST] Step direction: (" << step_dir.x << ", " << step_dir.y << ", " << step_dir.z << ")" << std::endl;
+        direction.x > 0 ? 1 : (direction.x < 0 ? -1 : 0),
+        direction.y > 0 ? 1 : (direction.y < 0 ? -1 : 0),
+        direction.z > 0 ? 1 : (direction.z < 0 ? -1 : 0)
+    );
+    // std::cout << "[RAYCAST] Step direction: (" << step_dir.x << ", " << step_dir.y << ", " << step_dir.z << ")" << std::endl;
 
-    // How far to step in each axis
+    // Delta: how far along the ray we move for a full voxel step in each axis
-    const float epsilon = 0.0001f;
+    glm::vec3 delta = glm::vec3(
-    glm::vec3 safe_dir = glm::vec3(
+        step_dir.x != 0 ? std::abs(1.0f / direction.x) : FLT_MAX,
-        abs(direction.x) < epsilon ? epsilon : direction.x,
+        step_dir.y != 0 ? std::abs(1.0f / direction.y) : FLT_MAX,
-        abs(direction.y) < epsilon ? epsilon : direction.y,
+        step_dir.z != 0 ? std::abs(1.0f / direction.z) : FLT_MAX
-        abs(direction.z) < epsilon ? epsilon : direction.z
     );
 
-    glm::vec3 delta = glm::abs(1.0f / safe_dir);
+    // Calculate t_max: distance along ray to next voxel boundary for each axis
+    glm::vec3 t_max;
+    glm::vec3 fract = adjusted_start - glm::vec3(pos);
 
-    glm::vec3 fract = start - glm::vec3(pos);
+    // For each axis, calculate distance to the next boundary
-    glm::vec3 t_max = glm::vec3(
+    if (step_dir.x > 0)
-        (step_dir.x > 0 ? (1.0f - fract.x) : fract.x) * delta.x,
+        t_max.x = (1.0f - fract.x) * delta.x;
-        (step_dir.y > 0 ? (1.0f - fract.y) : fract.y) * delta.y,
+    else if (step_dir.x < 0)
-        (step_dir.z > 0 ? (1.0f - fract.z) : fract.z) * delta.z
+        t_max.x = fract.x * delta.x;
-    );
+    else
+        t_max.x = FLT_MAX;
+
+    if (step_dir.y > 0)
+        t_max.y = (1.0f - fract.y) * delta.y;
+    else if (step_dir.y < 0)
+        t_max.y = fract.y * delta.y;
+    else
+        t_max.y = FLT_MAX;
+
+    if (step_dir.z > 0)
+        t_max.z = (1.0f - fract.z) * delta.z;
+    else if (step_dir.z < 0)
+        t_max.z = fract.z * delta.z;
+    else
+        t_max.z = FLT_MAX;
 
     float dist = 0.0f;
     glm::ivec3 last_move = glm::ivec3(0, 0, 0);
@@ -107,11 +131,11 @@ std::optional<std::pair<glm::ivec3, glm::ivec3>> World::raycast_voxel(glm::vec3
     while (dist < max_dist && iterations < max_iterations) {
         iterations++;
 
-        std::cout << "[RAYCAST] Iteration " << iterations << " at voxel (" << pos.x << ", " << pos.y << ", " << pos.z << ")" << std::endl;
+        // std::cout << "[RAYCAST] Iteration " << iterations << " at voxel (" << pos.x << ", " << pos.y << ", " << pos.z << ")" << std::endl;
 
         if (this->get_voxel(pos).has_value()) {
-            std::cout << "[RAYCAST] Hit voxel at (" << pos.x << ", " << pos.y << ", " << pos.z << ") after " << iterations << " iterations" << std::endl;
+            // std::cout << "[RAYCAST] Hit voxel at (" << pos.x << ", " << pos.y << ", " << pos.z << ") after " << iterations << " iterations" << std::endl;
-            std::cout << "[RAYCAST] Returning normal: (" << -last_move.x << ", " << -last_move.y << ", " << -last_move.z << ")" << std::endl;
+            // std::cout << "[RAYCAST] Returning normal: (" << -last_move.x << ", " << -last_move.y << ", " << -last_move.z << ")" << std::endl;
             return std::make_pair(pos, -last_move);
         }
 
@@ -134,7 +158,7 @@ std::optional<std::pair<glm::ivec3, glm::ivec3>> World::raycast_voxel(glm::vec3
         }
     }
 
-    std::cout << "[RAYCAST] No voxel hit after " << iterations << " iterations, dist=" << dist << std::endl;
+    // std::cout << "[RAYCAST] No voxel hit after " << iterations << " iterations, dist=" << dist << std::endl;
     return std::nullopt;
 }
 

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
@@ -35,6 +37,9 @@ bool W_pressed, S_pressed, A_pressed, D_pressed = false;
 glm::mat4 projection = glm::mat4(1.0f);
 Camera camera = Camera(CAMERA_SPEED, glm::vec3(0.0f, 0.0f, 0.0f));
 
+// Targeted block for highlighting
+std::optional<glm::ivec3> targeted_block = std::nullopt;
+
 // Callback function for when the window is resized
 // glfw: whenever the window size changed (by OS or user resize) this callback function executes
 void framebuffer_size_callback(GLFWwindow* window, int width, int height)
@@ -60,7 +65,7 @@ World world;
 void mouse_callback(GLFWwindow * window, double xpos, double ypos)
 {
     float x_offset = xpos - last_x;
-    float y_offset = ypos - last_y;
+    float y_offset = last_y - ypos;  // Inverted Y for typical FPS controls
     last_x = xpos;
     last_y = ypos;
 
@@ -83,7 +88,7 @@ void mouse_callback(GLFWwindow * window, double xpos, double ypos)
 
     glm::vec3 direction;
     direction.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
-    direction.y = -sin(glm::radians(pitch));
+    direction.y = sin(glm::radians(pitch));  // Positive Y is up
     direction.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
     camera.target = glm::normalize(direction);
 }
@@ -93,6 +98,34 @@ 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, 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) {
+            std::cout << "Camera eye: (" << camera.getEyePosition().x << ", " << camera.getEyePosition().y << ", " << camera.getEyePosition().z << ")" << std::endl;
+            std::cout << "Camera target dir: (" << camera.target.x << ", " << camera.target.y << ", " << camera.target.z << ")" << std::endl;
+            std::cout << "Highlighted block: (" << targeted_block.value().x << ", " << targeted_block.value().y << ", " << targeted_block.value().z << ")" << std::endl;
+        }
+        frame_count++;
+    } else {
+        targeted_block = std::nullopt;
+    }
+
     if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
         // if (mouse_lock) {
         //     glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_NORMAL);
@@ -182,10 +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;
@@ -207,10 +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;
@@ -236,7 +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();
@@ -278,10 +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[] = {
@@ -292,12 +325,65 @@ 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);
     glBindVertexArray(0);
 
+    // Setup highlight box (cube outline)
+    unsigned int highlightVAO, highlightVBO, highlightEBO;
+    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[] = {
+        // 8 corners of a cube
+        -0.5f - offset, -0.5f - offset, -0.5f - offset,  // 0
+         0.5f + offset, -0.5f - offset, -0.5f - offset,  // 1
+         0.5f + offset,  0.5f + offset, -0.5f - offset,  // 2
+        -0.5f - offset,  0.5f + offset, -0.5f - offset,  // 3
+        -0.5f - offset, -0.5f - offset,  0.5f + offset,  // 4
+         0.5f + offset, -0.5f - offset,  0.5f + offset,  // 5
+         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
+        0, 1,  1, 2,  2, 3,  3, 0,
+        // Top face
+        4, 5,  5, 6,  6, 7,  7, 4,
+        // 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);
+
+    // Setup debug ray
+    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
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(0);
+    glBindVertexArray(0);
+
     glm::mat4 view;
     double start_time = glfwGetTime();
     double move_time = glfwGetTime();
@@ -400,6 +486,22 @@ int main() {
         // --- Reset polygon mode for next frame (good practice) ---
         glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 
+        // ---- Draw Highlighted Block ----
+        if (targeted_block.has_value()) {
+            shader.use();
+            glm::mat4 model = glm::mat4(1.0f);
+            // Voxels are centered on integer coordinates, so no need to add 0.5
+            model = glm::translate(model, glm::vec3(targeted_block.value()));
+            glm::mat4 mvp = projection * view * model;
+            shader.setMat4("u_mvp", mvp);
+            shader.setVec3("u_Color", glm::vec3(0.0f, 0.0f, 0.0f)); // Black outline
+
+            glLineWidth(2.0f);
+            glBindVertexArray(highlightVAO);
+            glDrawElements(GL_LINES, 24, GL_UNSIGNED_INT, 0); // 24 indices = 12 edges
+            glBindVertexArray(0);
+        }
+
         // ---- Draw Crosshair ----
         glDisable(GL_DEPTH_TEST); // Draw on top of everything
         shader.use();
@@ -425,4 +527,4 @@ int main() {
 
     glfwTerminate(); // Clean up GLFW
     return 0;
-}
+}