4
votes
1answer
130 views

PCF shadow shader math causing artifacts

For a while now I used PCSS for my shadow technique of choice until I discovered a type of percentage closer filtering. This method creates really smooth shadows and with hopes of improving ...
0
votes
2answers
107 views

infer half vector length in BRDF

it's my first question on stack. Is it possible to infer length of the half angle vector for specular lighting from N·L and N·V without the whole view and light vectors? I may be completely off-track, ...
2
votes
1answer
129 views

The math behind Variance Shadow Maps - moments

I am not asking how to implement them (that's not particularly difficult), but I'm having a bit of trouble understanding why the moments used in Chebyshev's inequality (indirectly) are equal to the ...
-1
votes
1answer
120 views

Smooth Ramp to zonal harmonics

I have written in blitz3D some code to generate arbitrary 2D lighting lookup textures and I'm looking for a way to compress them. The idea is that they look rather smooth and low frequency, there must ...
3
votes
1answer
116 views

Surface normal to screen angle

I've been struggling to get this working. I simply wish to take a surface normal and convert it to a screen angle. As an example, assuming we're working with the highlighted surface on the sphere ...
-1
votes
3answers
267 views

Directional light and matrix issues

I'm trying to implement basic directional lightning in OpenGL 3.3 by emulating the logic shown in this guide: http://www.arcsynthesis.org/gltut/Illumination/Tutorial%2009.html I do not understand ...
4
votes
2answers
4k views

Basics of drawing in 2d with OpenGL 3 shaders

I am new to OpenGL 3 and graphics programming, and want to create some basic 2d graphics. I have the following scenario of how I might go about drawing a basic (but general) 2d rectangle. I'm not ...
5
votes
1answer
379 views

What is the point of this hard-coded vector when calculating luminance in glow/bloom effects?

I have looked at two different vertex shaders that calculate luminance and both use a "magic" vector that I'm not sure the meaning of the the actual values. For instance: const mediump vec3 ...
7
votes
3answers
2k views

Rotating a vector by another vector in shader

I have a terrain surface with a normal for each point on the terrain. I have a second detail normal map to be applied to the terrain. These normals are in 3-space. The Y value of both normals is ...
2
votes
3answers
3k views

2D shader to draw representation of rotating sphere

I want to display a 3D textured sphere, and then rotate it in one direction. The direction will never change, and the camera will never move. One way is to actually create a spherical mesh, map a ...
7
votes
1answer
2k views

Atmospheric Scattering

I'm trying to implement atmospheric scattering based on Sean O`Neil algorithm that was published in GPU Gems 2. But I have some trouble getting the shader to work. My latest attempts resulted in: ...
1
vote
1answer
376 views

Mandelbrot set not displaying properly

I am trying to render mandelbrot set using glsl. I'm not sure why its not rendering the correct shape. Does the mandelbrot calculation require values to be within a range for the (x,y) [ or (real, ...