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fgdata/Shaders/flutter.vert
Vivian Meazza b7960ee919 Add flutter effect for flags etc.
Signed-off-by: Vivian Meazza <vivian.meazza@lineone.net>
2011-10-12 09:43:41 +01:00

79 lines
2.5 KiB
GLSL

// -*-C++-*-
// Shader that uses OpenGL state values to do per-pixel lighting
//
// The only light used is gl_LightSource[0], which is assumed to be
// directional.
//
// Diffuse colors come from the gl_Color, ambient from the material. This is
// equivalent to osg::Material::DIFFUSE.
#define MODE_OFF 0
#define MODE_DIFFUSE 1
#define MODE_AMBIENT_AND_DIFFUSE 2
// The ambient term of the lighting equation that doesn't depend on
// the surface normal is passed in gl_{Front,Back}Color. The alpha
// component is set to 1 for front, 0 for back in order to work around
// bugs with gl_FrontFacing in the fragment shader.
varying vec4 diffuse_term;
varying vec3 normal;
varying float fogCoord;
uniform int colorMode;
uniform float osg_SimulationTime;
uniform float WindSpeed, Offset, AmpFactor;
uniform sampler3D Noise;
void main()
{
// map noise vector
vec4 noisevec = texture3D(Noise, gl_Vertex.xyz);
//waving effect
float tsec = osg_SimulationTime;
vec4 pos = gl_Vertex;
vec4 oldpos = gl_Vertex;
float freq = (10 * WindSpeed) + 10;
pos.y = sin((pos.x * 5.0 + tsec * freq )/5.0) * 0.5 ;
pos.y += sin((pos.z * 5.0 + tsec * freq/2)/5.0) * 0.125 ;
pos.y *= pow(pos.x - Offset, 2.0) * AmpFactor;
gl_Position = gl_ModelViewProjectionMatrix * pos;
vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
normal = gl_NormalMatrix * gl_Normal;
vec4 ambient_color, diffuse_color;
if (colorMode == MODE_DIFFUSE) {
diffuse_color = gl_Color;
ambient_color = gl_FrontMaterial.ambient;
} else if (colorMode == MODE_AMBIENT_AND_DIFFUSE) {
diffuse_color = gl_Color;
ambient_color = gl_Color;
} else {
diffuse_color = gl_FrontMaterial.diffuse;
ambient_color = gl_FrontMaterial.ambient;
}
diffuse_term = diffuse_color * gl_LightSource[0].diffuse;
vec4 ambient_term = ambient_color * gl_LightSource[0].ambient;
// Super hack: if diffuse material alpha is less than 1, assume a
// transparency animation is at work
if (gl_FrontMaterial.diffuse.a < 1.0)
diffuse_term.a = gl_FrontMaterial.diffuse.a;
else
diffuse_term.a = gl_Color.a;
// Another hack for supporting two-sided lighting without using
// gl_FrontFacing in the fragment shader.
gl_FrontColor.rgb = ambient_term.rgb; gl_FrontColor.a = 0.0;
gl_BackColor.rgb = ambient_term.rgb; gl_FrontColor.a = 1.0;
fogCoord = abs(ecPosition.z / ecPosition.w);
}