Added RaycastGround and ray picking example

examples/Makefile

@@ -203,6 +203,7 @@ EXAMPLES = \
     core_gestures_detection \
     core_3d_mode \
     core_3d_picking \
+    core_3d_raypick \
     core_3d_camera_free \
     core_3d_camera_first_person \
     core_2d_camera \
@@ -320,6 +321,11 @@ core_3d_mode: core_3d_mode.c
 core_3d_picking: core_3d_picking.c
 	$(CC) -o $@$(EXT) $< $(CFLAGS) $(INCLUDES) $(LFLAGS) $(LIBS) -D$(PLATFORM) $(WINFLAGS)
 
+# compile [core] example - 3d ray picking
+core_3d_raypick: core_3d_raypick.c
+	$(CC) -o $@$(EXT) $< $(CFLAGS) $(INCLUDES) $(LFLAGS) $(LIBS) -D$(PLATFORM) $(WINFLAGS)
+
+
 # compile [core] example - 3d camera free
 core_3d_camera_free: core_3d_camera_free.c
 	$(CC) -o $@$(EXT) $< $(CFLAGS) $(INCLUDES) $(LFLAGS) $(LIBS) -D$(PLATFORM) $(WINFLAGS)

examples/core_3d_raypick.c

@@ -0,0 +1,118 @@
+/*******************************************************************************************
+*
+*   raylib [core] example - Ray-Picking in 3d mode, also ground plane
+*
+*   This example has been created using raylib 1.3 (www.raylib.com)
+*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
+*
+*   Copyright (c) 2015 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+int main()
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    int screenWidth = 800;
+    int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [core] example - 3d ray picking");
+
+    // Define the camera to look into our 3d world
+    Camera camera;
+    camera.position = (Vector3){ 10.0f, 10.0f, 10.0f }; // Camera position
+    camera.target = (Vector3){ 0.0f, 0.0f, 0.0f };      // Camera looking at point
+    camera.up = (Vector3){ 0.0f, 1.0f, 0.0f };          // Camera up vector (rotation towards target)
+    camera.fovy = 45.0f;                                // Camera field-of-view Y
+
+    Vector3 cubePosition = { 0.0f, 1.0f, 0.0f };
+    Vector3 cubeSize = { 2.0f, 2.0f, 2.0f };
+    Vector3 groundCursorPos = { 0 };
+    
+    Ray ray;        // Picking line ray
+    
+    bool collision = false;
+    
+    SetCameraMode(camera, CAMERA_FREE); // Set a free camera mode
+
+    SetTargetFPS(60);                   // Set our game to run at 60 frames-per-second
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())        // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        UpdateCamera(&camera);          // Update camera
+        
+        // if (IsMouseButtonPressed(MOUSE_LEFT_BUTTON))
+        // {
+        //     // NOTE: This function is NOT WORKING properly!
+        //     ray = GetMouseRay(GetMousePosition(), camera);
+            
+        //     // Check collision between ray and box
+        //     collision = CheckCollisionRayBox(ray,
+        //                 (BoundingBox){(Vector3){ cubePosition.x - cubeSize.x/2, cubePosition.y - cubeSize.y/2, cubePosition.z - cubeSize.z/2 },
+        //                               (Vector3){ cubePosition.x + cubeSize.x/2, cubePosition.y + cubeSize.y/2, cubePosition.z + cubeSize.z/2 }});
+        // }
+
+        ray = GetMouseRay(GetMousePosition(), camera);
+        RayHitInfo hitinfo = RaycastGroundPlane( ray, 0.0 );
+
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            Begin3dMode(camera);
+
+                if (collision) 
+                {
+                    DrawCube(cubePosition, cubeSize.x, cubeSize.y, cubeSize.z, RED);
+                    DrawCubeWires(cubePosition, cubeSize.x, cubeSize.y, cubeSize.z, MAROON);
+
+                    DrawCubeWires(cubePosition, cubeSize.x + 0.2f, cubeSize.y + 0.2f, cubeSize.z + 0.2f, GREEN);
+                }
+                else
+                {
+                    DrawCube(cubePosition, cubeSize.x, cubeSize.y, cubeSize.z, GRAY);
+                    DrawCubeWires(cubePosition, cubeSize.x, cubeSize.y, cubeSize.z, DARKGRAY);
+                }
+
+                if (hitinfo.hit) {
+
+                    groundCursorPos = hitinfo.hitPosition;
+                    groundCursorPos.y += 0.25; // Offset so the cube rests on the ground
+                    printf("Hit: groundpos %3.2f %3.2f %3.2f\n", 
+                        groundCursorPos.x, groundCursorPos.y, groundCursorPos.z );
+                    DrawCubeWires( groundCursorPos, 0.5, 0.5, 0.5, RED );
+                }
+                
+                DrawRay(ray, MAROON);
+                
+                DrawGrid(10, 1.0f);
+
+            End3dMode();
+            
+            //DrawText("Try selecting the box with mouse!", 240, 10, 20, DARKGRAY);
+            
+            //if(collision) DrawText("BOX SELECTED", (screenWidth - MeasureText("BOX SELECTED", 30)) / 2, screenHeight * 0.1f, 30, GREEN);
+
+            DrawFPS(10, 10);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}

src/raylib.h

@@ -97,6 +97,9 @@
 #define DEG2RAD (PI/180.0f)
 #define RAD2DEG (180.0f/PI)
 
+// A small number
+#define EPSILON 0.000001
+
 // raylib Config Flags
 #define FLAG_FULLSCREEN_MODE    1
 #define FLAG_RESIZABLE_WINDOW   2
@@ -491,6 +494,13 @@ typedef struct Ray {
     Vector3 direction;      // Ray direction
 } Ray;
 
+// Information returned from a raycast
+typedef struct RayHitInfo {
+    bool hit;             // Did the ray hit something?
+    Vector3 hitPosition;  // Position of nearest hit
+    Vector3 hitNormal;    // Surface normal of hit
+} RayHitInfo;
+
 // Wave type, defines audio wave data
 typedef struct Wave {
     unsigned int sampleCount;   // Number of samples
@@ -910,6 +920,11 @@ RLAPI bool CheckCollisionRaySphereEx(Ray ray, Vector3 spherePosition, float sphe
                                      Vector3 *collisionPoint);                                          // Detect collision between ray and sphere, returns collision point
 RLAPI bool CheckCollisionRayBox(Ray ray, BoundingBox box);                                              // Detect collision between ray and box
 
+//------------------------------------------------------------------------------------
+// Ray Casts
+//------------------------------------------------------------------------------------
+RLAPI RayHitInfo RaycastGroundPlane( Ray ray, float groundHeight );
+
 //------------------------------------------------------------------------------------
 // Shaders System Functions (Module: rlgl)
 // NOTE: This functions are useless when using OpenGL 1.1

src/shapes.c

@@ -534,3 +534,23 @@ Rectangle GetCollisionRec(Rectangle rec1, Rectangle rec2)
 
     return retRec;
 }
+
+
+RayHitInfo RaycastGroundPlane( Ray ray, float groundHeight )
+{
+    RayHitInfo result = {0};
+
+    if (fabs(ray.direction.y) > EPSILON)
+    {
+        float t = (ray.position.y - groundHeight) / -ray.direction.y;
+        if (t >= 0.0) {
+        Vector3 camDir = ray.direction;
+        VectorScale( &camDir, t );
+        result.hit = true;
+        result.hitNormal = (Vector3){ 0.0, 1.0, 0.0};
+        result.hitPosition = VectorAdd( ray.position, camDir );
+        }
+    }
+
+    return result;
+}