Cascaded shadow map splits

Johan Jons · 2014-04-02T16:34:45

Hello, I'm tinkering with cascaded shadow maps and I have an issue when it comes to shadows between splits. The below picture shows it: http://s23.postimg.org/ngwk5gnff/image.png From the camera position to the edge of the shadow is the first split, and then from the end of the shadow starts the other split... the problem is the aliens shadow is in both splits. The alien is not inside the bounding box of the second split and thus the shadow abruptly stops. That is my theory anyway... and ideas? Heres my lighting pass shader FYI (directional light source, deferred renderering): #version 430 layout(std140) uniform; const float DEPTH_BIAS = 0.00005; uniform UnifDirLight { mat4 mVPMatrix[4]; // the bias * crop * projection* view matrices for the directional light float mSplitDistance[4]; // far distance for each split in camera space vec4 mLightColor; vec4 mLightDir; vec4 mGamma; vec2 mScreenSize; } UnifDirLightPass; layout (binding = 2) uniform sampler2D unifPositionTexture; layout (binding = 3) uniform sampler2D unifNormalTexture; layout (binding = 4) uniform sampler2D unifDiffuseTexture; layout (binding = 6) uniform sampler2DArrayShadow unifShadowTexture; out vec4 fragColor; void main() { vec2 texcoord = gl_FragCoord.xy / UnifDirLightPass.mScreenSize; vec3 worldPos = texture(unifPositionTexture, texcoord).xyz; // stored world position; in world space vec3 normal = normalize(texture(unifNormalTexture, texcoord).xyz); vec3 diffuse = texture(unifDiffuseTexture, texcoord).xyz; int index = 3; if (worldPos.z > UnifDirLightPass.mSplitDistance[0]) // this is problematic when looking anywhere except straight the negative Z axis... any ideas on better comparison? index = 0; else if (worldPos.z > UnifDirLightPass.mSplitDistance[1]) index = 1; else if (worldPos.z > UnifDirLightPass.mSplitDistance[2]) index = 2; vec4 projCoords = UnifDirLightPass.mVPMatrix[index] * vec4(worldPos, 1.0); projCoords.w = projCoords.z - DEPTH_BIAS; projCoords.z = float(index); float visibilty = texture(unifShadowTexture, projCoords); float angleNormal = clamp(dot(normal, UnifDirLightPass.mLightDir.xyz), 0, 1); fragColor = vec4(diffuse, 1.0) * visibilty * angleNormal * UnifDirLightPass.mLightColor; }

Graphics and GPU Programming Programming

Started by KaiserJohan March 28, 2014 10:53 PM

11 comments, last by KaiserJohan 10 years ago

NumberXaero

2,625

March 31, 2014 10:23 PM

What if you were to use the view space pos in this line instead of the world

vec4 projCoords = UnifDirLightPass.mVPMatrix[index] * vec4(worldPos, 1.0);

and incorporate the invMainView into the lights matrix?

TheChubu

9,484

April 01, 2014 01:59 AM

I don't know GLSL 4xx quite well, what is this line here trying to do?

layout(std140) uniform;

You declare the layout of an uniform... but without the uniform?

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KaiserJohan

2,320

Author

April 02, 2014 04:34 PM

What if you were to use the view space pos in this line instead of the world

vec4 projCoords = UnifDirLightPass.mVPMatrix[index] * vec4(worldPos, 1.0);

and incorporate the invMainView into the lights matrix?

I tried, I guess they cancel each other out; the result is the same as using the world position directly.

I don't know GLSL 4xx quite well, what is this line here trying to do?

layout(std140) uniform;

You declare the layout of an uniform... but without the uniform?

Yeah that was a bug; wierd that it compiled, fixed it but it didn't have any effect on the rest of the code :)

Cascaded shadow map splits

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