142 lines
3.2 KiB
C++
142 lines
3.2 KiB
C++
// -*-C++-*-
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#version 120
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varying vec3 vertex;
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varying vec3 viewDir;
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uniform float osg_SimulationTime;
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uniform float thrust_collimation;
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uniform float flame_radius_fraction;
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uniform float thrust_density;
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uniform float base_flame_density;
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uniform float shock_frequency;
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uniform float noise_strength;
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uniform float noise_scale;
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uniform float deflection_coeff;
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uniform float random_seed;
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uniform float flame_color_low_r;
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uniform float flame_color_low_g;
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uniform float flame_color_low_b;
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uniform float flame_color_high_r;
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uniform float flame_color_high_g;
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uniform float flame_color_high_b;
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uniform float base_flame_r;
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uniform float base_flame_g;
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uniform float base_flame_b;
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uniform int use_shocks;
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uniform int use_noise;
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float Noise2D(in vec2 coord, in float wavelength);
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const int n_steps = 15;
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float spherical_smoothstep (in vec3 pos)
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{
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float l = length(vec3 (pos.x/2.0, pos.y,pos.z) );
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return 10.0 * thrust_density * base_flame_density * (1.0 - smoothstep(0.5* flame_radius_fraction, flame_radius_fraction, l));
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}
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float thrust_flame (in vec3 pos)
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{
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float noise = 0.0;
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pos.z +=8.0 * deflection_coeff;
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float d_rad = length(pos.yz - vec2 (0.0, deflection_coeff * pos.x * pos.x));
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//float longFade = smoothstep(0.0, 5.0, pos.x) ;
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float longFade = pos.x/5.0;
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float density = 1.0 - longFade;
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float radius = flame_radius_fraction + thrust_collimation * 1.0 * pow((pos.x+0.1),0.5);
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if (d_rad > radius) {return 0.0;}
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if (use_noise ==1)
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{
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noise = Noise2D(vec2(pos.x - osg_SimulationTime * 30.0 + random_seed , d_rad), noise_scale);
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}
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density *= (1.0 - smoothstep(0.125, radius, d_rad)) * (1.0 - noise_strength + noise_strength* noise);
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if (use_shocks == 1)
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{
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float shock = sin(pos.x * 10.0 * shock_frequency);
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density += shock * shock * shock * shock * (1.0 - longFade) * (1.0 - smoothstep(0.25*flame_radius_fraction, 0.5*flame_radius_fraction, d_rad)) * (1.0 - smoothstep(0.0, 1.0, thrust_collimation)) * (1.0 + 0.5 * base_flame_density);
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}
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return 10.0 * thrust_density * density / (radius/0.2);
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}
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void main()
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{
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vec3 vDir = normalize(viewDir);
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float x_E, y_E, z_E;
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if (vDir.x > 0.0) {x_E = 5.0;} else {x_E = 0.0;}
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if (vDir.y > 0.0) {y_E = 1.0;} else {y_E = -1.0;}
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if (vDir.z > 0.0) {z_E = 1.0;} else {z_E = -1.0;}
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float t_x = (x_E - vertex.x) / vDir.x;
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float t_y = (y_E - vertex.y) / vDir.y;
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float t_z = (z_E - vertex.z) / vDir.z;
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float t_min = min(t_x, t_y);
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t_min = min(t_min, t_z);
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float dt = t_min / float(n_steps);
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vec3 step = viewDir * dt;
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vec3 pos = vertex;
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float density1 = 0.0;
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float density2 = 0.0;
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for (int i = 0; i < n_steps; i++)
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{
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pos = pos + step;
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density1 += spherical_smoothstep(pos) * dt;
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density2 += thrust_flame(pos) * dt;
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}
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float density = density1 + density2;
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//density = clamp(density,0.0,1.0);
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density = 1.0 - exp(-density);
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density1 = 1.0 - exp(-density1);
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density2 = 1.0 - exp(-density2);
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vec3 flame_color_low = vec3 (flame_color_low_r, flame_color_low_g, flame_color_low_b);
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vec3 flame_color_high = vec3 (flame_color_high_r, flame_color_high_g, flame_color_high_b);
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vec3 color = mix(flame_color_low, flame_color_high, density2);
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color = mix(color, vec3(base_flame_r, base_flame_g, base_flame_b), density1);
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vec4 finalColor = vec4 (color.rgb, density);
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gl_FragColor = finalColor;
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}
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