Files
OpenSceneGraph/examples/osgprecipitation/rain.vert
2006-04-11 10:53:46 +00:00

50 lines
1.3 KiB
GLSL

uniform vec3 position;
uniform vec3 dv_i;
uniform vec3 dv_j;
uniform vec3 dv_k;
uniform float inversePeriod;
uniform float startTime;
uniform vec4 particleColour;
uniform float osg_FrameTime;
uniform float osg_DeltaFrameTime;
uniform mat4 previousModelViewMatrix;
varying vec4 colour;
varying vec2 texCoord;
void main(void)
{
const float particleSize = 0.01;
const float particleSize2 = 0.0001;//particleSize*particleSize;
vec3 pos = position + (gl_Vertex.x*dv_i) + (dv_j * gl_Vertex.y);
float offset = gl_Vertex.z;
texCoord = gl_MultiTexCoord0.xy;
vec3 v_previous = pos + dv_k * fract( (osg_FrameTime - startTime)*inversePeriod - offset);
vec3 v_current = v_previous + dv_k * (osg_DeltaFrameTime*inversePeriod);
colour = particleColour;
vec4 v1 = gl_ModelViewMatrix * vec4(v_current,1.0);
vec4 v2 = previousModelViewMatrix * vec4(v_previous,1.0);
vec3 dv = v2.xyz - v1.xyz;
vec2 dv_normalized = normalize(dv.xy);
dv.xy += dv_normalized * particleSize;
vec2 dp = vec2( -dv_normalized.y, dv_normalized.x ) * particleSize;
float area = length(dv.xy)*length(dp);
colour.a = 0.2+(particleSize2)/area;
v1.xyz += dv*texCoord.y;
v1.xy += dp*texCoord.x;
gl_Position = gl_ProjectionMatrix * v1;
}