42 lines
1.8 KiB
Forth
42 lines
1.8 KiB
Forth
|
#version 140
|
||
|
|
|
||
|
|
#define M_PI 3.1415926535897932384626433832795
|
||
|
|
|
||
|
|
// 2D texture (1D texture split by the rows) of color along the object Z axis.
|
||
|
|
uniform sampler2D z_texture;
|
||
|
|
// Scaling from the Z texture rows coordinate to the normalized texture row coordinate.
|
||
|
|
uniform float z_to_texture_row;
|
||
|
|
uniform float z_texture_row_to_normalized;
|
||
|
|
uniform float z_cursor;
|
||
|
|
uniform float z_cursor_band_width;
|
||
|
|
|
||
|
|
// x = tainted, y = specular;
|
||
|
|
in vec2 intensity;
|
||
|
|
|
||
|
|
in float object_z;
|
||
|
|
|
||
|
|
void main()
|
||
|
|
{
|
||
|
|
float object_z_row = z_to_texture_row * object_z;
|
||
|
|
// Index of the row in the texture.
|
||
|
|
float z_texture_row = floor(object_z_row);
|
||
|
|
// Normalized coordinate from 0. to 1.
|
||
|
|
float z_texture_col = object_z_row - z_texture_row;
|
||
|
|
float z_blend = 0.25 * cos(min(M_PI, abs(M_PI * (object_z - z_cursor) * 1.8 / z_cursor_band_width))) + 0.25;
|
||
|
|
// Calculate level of detail from the object Z coordinate.
|
||
|
|
// This makes the slowly sloping surfaces to be shown with high detail (with stripes),
|
||
|
|
// and the vertical surfaces to be shown with low detail (no stripes)
|
||
|
|
float z_in_cells = object_z_row * 190.;
|
||
|
|
// Gradient of Z projected on the screen.
|
||
|
|
float dx_vtc = dFdx(z_in_cells);
|
||
|
|
float dy_vtc = dFdy(z_in_cells);
|
||
|
|
float lod = clamp(0.5 * log2(max(dx_vtc * dx_vtc, dy_vtc * dy_vtc)), 0., 1.);
|
||
|
|
// Sample the Z texture. Texture coordinates are normalized to <0, 1>.
|
||
|
|
vec4 color = vec4(0.25, 0.25, 0.25, 1.0);
|
||
|
|
if (z_texture_row >= 0.0)
|
||
|
|
color = mix(texture2D(z_texture, vec2(z_texture_col, z_texture_row_to_normalized * (z_texture_row + 0.5 )), -10000.),
|
||
|
|
texture2D(z_texture, vec2(z_texture_col, z_texture_row_to_normalized * (z_texture_row * 2. + 1.)), 10000.), lod);
|
||
|
|
// Mix the final color.
|
||
|
|
gl_FragColor = vec4(vec3(intensity.y), 1.0) + intensity.x * mix(color, vec4(1.0, 1.0, 0.0, 1.0), z_blend);
|
||
|
|
}
|