planar shadow matrix and plane b value

Posted by DevExcite on Game Development See other posts from Game Development or by DevExcite
Published on 2011-11-18T10:09:00Z Indexed on 2011/11/18 10:22 UTC
Read the original article Hit count: 474

Filed under:

directx

|

shadows

I implemented planar shadows with the function D3DXMatrixShadow.

As you know, we need plane and light factor to calculate a shadow matrix.

The problem is that when I set the plane as D3DXPLANE p(0, -1, 0, 0.1f), the shadows by directional light are correctly rendered, but the shadows by point light are not rendered.

However, if I use D3DXPLANE p(0, 1, 0, 0.1f), the situation is reversed, shadows by directional light are not drawn, the shadows by point light are ok.

I cannot understand why it happens. Is it normal or am i missing something? Please explain to me why this happens.

Thanks in advance.

© Game Development or respective owner

Related posts about directx

Compatibility between DirectX 9 and DirectX 10 shaders

as seen on Game Development - Search for 'Game Development'
I am a beginner to game development and as I am used to programming in C# I decided to go for XNA. I've been playing around with it for a while and now I am learning the basics of HLSL shaders, I have noticed in the MSDN documentation that there have been some syntax changes in HLSL between DirectX… >>> More
DirectX 9 or DirectX 10 for starters ??

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to do projects to make my resume more appealing to game companies. So I am going to start buying books. But I don't know rather to read DirectX 9 or 10 api books to start off with. DirectX10 is great, but it seems the industry is moving slow to 10. so should I use 9 or go with 10 ?? >>> More
book "Programming Role Playing Games with DirectX 2nd edition" and newer DirectX api

as seen on Stack Overflow - Search for 'Stack Overflow'
I got the book "Programming Role Playing Games with DirectX 2nd edition" and I notice there are things in the book that are now considered deprecated. There is a whole Section on DirectPlay. And as much as I would like to avoid this section, I am afraid it might screw up the entire engine he is trying… >>> More
Need help transforming DirectX 9 skybox hlsl shader to DirectX 11

as seen on Game Development - Search for 'Game Development'
I am in the middle of implementing a skybox to my game. I have been following this tutorial http://rbwhitaker.wikidot.com/skyboxes-2. I am using MonoGame as a framework and in order to support both Windows and Windows 8 metro I need to compile the shader with pixel and vertex shader 4. compile vs_4_0_level_9_1 compile… >>> More
load directx xfile in xaml/wpf

as seen on Stack Overflow - Search for 'Stack Overflow'
How can I load a .x file in xaml/wpf? >>> More

Related posts about shadows

planar shadow matrix and plane b value

as seen on Game Development - Search for 'Game Development'
I implemented planar shadows with the function D3DXMatrixShadow. As you know, we need plane and light factor to calculate a shadow matrix. The problem is that when I set the plane as D3DXPLANE p(0, -1, 0, 0.1f), the shadows by directional light are correctly rendered, but the shadows by point light… >>> More
XNA Masking Mayhem

as seen on Game Development - Search for 'Game Development'
I'd like to start by mentioning that I'm just an amateur programmer of the past 2 years with no formal training and know very little about maximizing the potential of graphics hardware. I can write shaders and manipulate a multi-layered drawing environment, but I've basically stuck to minimalist pixel… >>> More
Shadow Mapping and Transparent Quads

as seen on Game Development - Search for 'Game Development'
Shadow mapping uses the depth buffer to calculate where shadows should be drawn. My problem is that I'd like some semi transparent textured quads to cast shadows - for example billboarded trees. As the depth value will be set across all of the quad and not just the visible parts it will cast a quad… >>> More
Rendering shadow sprites in cocos2d-x

as seen on Game Development - Search for 'Game Development'
I am writing a 2D game with cocos2d-x. I want to put a "shadow" sprite on a background sprite using the equation: MAX(0, Cd*1 - Cs*S) where Cd is the destination color (that is, a background pixel), Cs is the source color (the shadow pixel) , S is the scale factor (between 0 and 1). The MAX()… >>> More
Shadow-mapping xna

as seen on Game Development - Search for 'Game Development'
I've been trying to implement shadows in my game and I've been following quite a few tutorials online, mainly Riemers, but I'm always getting the same 2 errors when I'm drawing my models and setting the parameters from the effect file. The errors are: This method does not accept null for this… >>> More