Added world to screen conversion

- Added function WorldToScreen(...).
- Added world to screen example.
- Review GetMouseRay() comment.
- Removed deprecated lighting functions from raylib header.

src/core.c

@@ -791,7 +791,7 @@ int StorageLoadValue(int position)
     return value;
 }
 
-// Gives the ray trace from mouse position
+// Returns a ray trace from mouse position
 //http://www.songho.ca/opengl/gl_transform.html
 //http://www.songho.ca/opengl/gl_matrix.html
 //http://www.sjbaker.org/steve/omniv/matrices_can_be_your_friends.html
@@ -857,6 +857,34 @@ Ray GetMouseRay(Vector2 mousePosition, Camera camera)
     return ray;
 }
 
+// Returns the screen space position from a 3d world space position
+Vector2 WorldToScreen(Vector3 position, Camera camera)
+{    
+    // Calculate projection matrix (from perspective instead of frustum
+    Matrix matProj = MatrixPerspective(45.0f, (float)((float)GetScreenWidth() / (float)GetScreenHeight()), 0.01f, 1000.0f);
+    
+    // Calculate view matrix from camera look at (and transpose it)
+    Matrix matView = MatrixLookAt(camera.position, camera.target, camera.up);
+    MatrixTranspose(&matView);
+    
+    // Convert world position vector to quaternion
+    Quaternion worldPos = { position.x, position.y, position.z, 1.0f };
+    
+    // Transform world position to view
+    QuaternionTransform(&worldPos, matView);
+    
+    // Transform result to projection (clip space position)
+    QuaternionTransform(&worldPos, matProj);
+    
+    // Calculate normalized device coordinates (inverted y)
+    Vector3 ndcPos = { worldPos.x / worldPos.w, -worldPos.y / worldPos.w, worldPos.z / worldPos.z };
+    
+    // Calculate 2d screen position vector
+    Vector2 screenPosition = { (ndcPos.x + 1.0f) / 2.0f * GetScreenWidth(), (ndcPos.y + 1.0f) / 2.0f * GetScreenHeight() };
+    
+    return screenPosition;
+}
+
 //----------------------------------------------------------------------------------
 // Module Functions Definition - Input (Keyboard, Mouse, Gamepad) Functions
 //----------------------------------------------------------------------------------

src/raylib.h

@@ -527,7 +527,8 @@ void EndDrawing(void);                                      // End canvas drawin
 void Begin3dMode(Camera cam);                               // Initializes 3D mode for drawing (Camera setup)
 void End3dMode(void);                                       // Ends 3D mode and returns to default 2D orthographic mode
 
-Ray GetMouseRay(Vector2 mousePosition, Camera camera);      // TODO: Returns a ray trace from mouse position
+Ray GetMouseRay(Vector2 mousePosition, Camera camera);      // Returns a ray trace from mouse position
+Vector2 WorldToScreen(Vector3 position, Camera camera);     // Returns the screen space position from a 3d world space position
 
 void SetTargetFPS(int fps);                                 // Set target FPS (maximum)
 float GetFPS(void);                                         // Returns current FPS
@@ -786,26 +787,6 @@ void SetShaderMap(Shader *shader, int mapLocation, Texture2D texture, int textur
 
 void SetBlendMode(int mode);                                        // Set blending mode (alpha, additive, multiplied)
 
-//----------------------------------------------------------------------------------
-// Lighting System Functions (engine-module: lighting)
-// NOTE: light and material structs uses float pointers instead of vectors to be compatible with SetShaderValue()
-//----------------------------------------------------------------------------------
-// Lights functions
-void SetLightPosition(Light *light, Vector3 position);                  // Set light position converting position vector to float pointer
-void SetLightRotation(Light *light, Vector3 rotation);                  // Set light rotation converting rotation vector to float pointer
-void SetLightIntensity(Light *light, float intensity);                  // Set light intensity value 
-void SetLightAmbientColor(Light *light, Vector3 color);                 // Set light ambient color value (it will be multiplied by material ambient color)
-void SetLightDiffuseColor(Light *light, Vector3 color);                 // Set light diffuse color (light color)
-void SetLightSpecularColor(Light *light, Vector3 color);                // Set light specular color (it will be multiplied by material specular color)
-void SetLightSpecIntensity(Light *light, float specIntensity);          // Set light specular intensity (specular color scalar multiplier)
-
-// Materials functions
-void SetMaterialAmbientColor(Material *material, Vector3 color);        // Set material ambient color value (it will be multiplied by light ambient color)
-void SetMaterialDiffuseColor(Material *material, Vector3 color);        // Set material diffuse color (material color, should use DrawModel() tint parameter)
-void SetMaterialSpecularColor(Material *material, Vector3 color);       // Set material specular color (it will be multiplied by light specular color)
-void SetMaterialGlossiness(Material *material, float glossiness);       // Set material glossiness value (recommended values: 0 - 100)
-void SetMaterialNormalDepth(Material *material, float depth);           // Set normal map depth (B component from RGB type map scalar multiplier)
-
 //----------------------------------------------------------------------------------
 // Physics System Functions (engine-module: physics)
 //----------------------------------------------------------------------------------