63 lines
2.4 KiB
GLSL
63 lines
2.4 KiB
GLSL
// -*-C++-*-
|
|
#version 120
|
|
|
|
varying float fogFactor;
|
|
|
|
float shade = 0.7;
|
|
float cloud_height = 1000.0;
|
|
|
|
void main(void)
|
|
{
|
|
|
|
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
|
|
vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
|
|
vec4 l = gl_ModelViewMatrixInverse * vec4(0.0,0.0,1.0,1.0);
|
|
vec3 u = normalize(ep.xyz - l.xyz);
|
|
|
|
// Find a rotation matrix that rotates 1,0,0 into u. u, r and w are
|
|
// the columns of that matrix.
|
|
vec3 absu = abs(u);
|
|
vec3 r = normalize(vec3(-u.y, u.x, 0));
|
|
vec3 w = cross(u, r);
|
|
|
|
// Do the matrix multiplication by [ u r w pos]. Assume no
|
|
// scaling in the homogeneous component of pos.
|
|
gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
|
|
gl_Position.xyz = gl_Vertex.x * u ;
|
|
gl_Position.xyz += gl_Vertex.y * r * 1.0;
|
|
gl_Position.xyz += gl_Vertex.z * w * 1.0;//0.4;
|
|
//gl_Position.xyz += gl_Vertex.y * r * wScale;
|
|
//gl_Position.xyz += gl_Vertex.z * w * hScale;
|
|
gl_Position.xyz += gl_Color.xyz;
|
|
|
|
gl_Position.z = gl_Position.z * 0.2;
|
|
|
|
// Determine a lighting normal based on the vertex position from the
|
|
// center of the cloud, so that sprite on the opposite side of the cloud to the sun are darker.
|
|
float n = dot(normalize(-gl_LightSource[0].position.xyz),
|
|
normalize(mat3x3(gl_ModelViewMatrix) * (- gl_Position.xyz)));;
|
|
|
|
// Determine the position - used for fog and shading calculations
|
|
vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Position);
|
|
float fogCoord = abs(ecPosition.z);
|
|
float fract = smoothstep(0.0, cloud_height, gl_Position.z + cloud_height);
|
|
|
|
// Final position of the sprite
|
|
gl_Position = gl_ModelViewProjectionMatrix * gl_Position;
|
|
|
|
// Determine the shading of the sprite based on its vertical position and position relative to the sun.
|
|
n = min(smoothstep(-0.5, 0.0, n), fract);
|
|
// Determine the shading based on a mixture from the backlight to the front
|
|
vec4 backlight = gl_LightSource[0].diffuse * shade;
|
|
|
|
gl_FrontColor = mix(backlight, gl_LightSource[0].diffuse, n);
|
|
gl_FrontColor += gl_FrontLightModelProduct.sceneColor;
|
|
|
|
// As we get within 100m of the sprite, it is faded out. Equally at large distances it also fades out.
|
|
gl_FrontColor.a = min(smoothstep(100.0, 300.0, fogCoord), 1 - smoothstep(25000.0, 30000.0, fogCoord));
|
|
gl_BackColor = gl_FrontColor;
|
|
|
|
// Fog doesn't affect clouds as much as other objects.
|
|
fogFactor = exp( -gl_Fog.density * fogCoord * 0.2);
|
|
fogFactor = clamp(fogFactor, 0.0, 1.0);
|
|
}
|