• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.

wagerfield

Members
  • Content count

    1
  • Joined

  • Last visited

Community Reputation

108 Neutral

About wagerfield

  • Rank
    Newbie
  1. Hello Everyone,   I have been working on an area lighting implementation in WebGL similar to this demo:   http://threejs.org/examples/webgldeferred_arealights.html   The above implementation in three.js was ported from the work of ArKano22 over on gamedev.net:   http://www.gamedev.net/topic/552315-glsl-area-light-implementation/   Though these solutions are very impressive, they both have a few limitations. The primary issue with ArKano22's original implementation is that the calculation of the diffuse term does not account for surface normals.   I have been augmenting this solution for some weeks now, working with the improvements by redPlant to address this problem. Currently I have normal calculations incorporated into the solution, BUT the result is also flawed.   Here is a sneak preview of my current implementation:   [attachment=16290:area-lighting-teaser.png]   Introduction   The steps for calculating the diffuse term for each fragment is as follows:   1. Project the vertex onto the plane that the area light sits on, so that the projected vector is coincident with the light's normal/direction. 2. Check that the vertex is on the correct side of the area light plane by comparing the projection vector with the light's normal. 3. Calculate the 2D offset of this projected point on the plane from the light's center/position. 4. Clamp this 2D offset vector so that it sits inside the light's area (defined by its width and height). 5. Derive the 3D world position of the projected and clamped 2D point. This is the nearest point on the area light to the vertex. 6. Perform the usual diffuse calculations that you would for a point light by taking the dot product between the the vertex-to-nearest-point vector (normalised) and the vertex normal.   Problem   The issue with this solution is that the lighting calculations are done from the nearest point and do not account for other points on the lights surface that could be illuminating the fragment even more so. Let me try and explain why…   Consider the following diagram:   [attachment=16291:lighting-problem-1.png]   The area light is both perpendicular to the surface and intersects it. Each of the fragments on the surface will always return a nearest point on the area light where the surface and the light intersect. Since the surface normal and the vertex-to-light vectors are always perpendicular, the dot product between them is zero. Subsequently, the calculation of the diffuse contribution is zero despite there being a large area of light looming over the surface.   Potential Solution   I propose that rather than calculate the light from the nearest point on the area light, we calculate it from a point on the area light that yields the greatest dot product between the vertex-to-light vector (normalised) and the vertex normal. In the diagram above, this would be the purple dot, rather than the blue dot.   Help!   And so, this is where I need your help. In my head, I have a pretty good idea of how this point can be derived, but don't have the mathematical competence to arrive at the solution.   Currently I have the following information available in my fragment shader:   * vertex position * vertex normal (unit vector) * light position, width and height * light normal (unit vector) * light right (unit vector) * light up (unit vector) * projected point from the vertex onto the lights plane (3D) * projected point offset from the lights center (2D) * clamped offset (2D) * world position of this clamped offset – the **nearest point** (3D)   To put all this information into a visual context, I created this diagram (hope it helps):   [attachment=16292:lighting-problem-2.png]   To test my proposal, I need the casting point on the area light – represented by the red dots, so that I can perform the dot product between the vertex-to-casting-point (normalised) and the vertex normal. Again, this should yield the maximum possible contribution value.   Interactive Demo   I have created an interactive sketch over on CodePen that visualises the mathematics that I currently have implemented:   http://codepen.io/wagerfield/pen/ywqCp   [attachment=16293:Screen Shot 2013-06-12 at 16.24.02.png]   The relavent code that you should focus on is line 317.   castingPoint.location is an instance of THREE.Vector3 and is the missing piece of the puzzle. You should also notice that there are 2 values at the lower left of the sketch – these are dynamically updated to display the dot product between the relevant vectors.   Anyway, I hope that some compassionate genius out there can help me solve this!   Many thanks in advance