stk-code_catmod/data/shaders/IBL.frag

147 lines
4.3 KiB
GLSL

uniform sampler2D ntex;
uniform sampler2D dtex;
uniform sampler2D albedo;
#ifdef GL_ES
layout (location = 0) out vec4 Diff;
layout (location = 1) out vec4 Spec;
#else
out vec4 Diff;
out vec4 Spec;
#endif
#stk_include "utils/decodeNormal.frag"
#stk_include "utils/getPosFromUVDepth.frag"
#stk_include "utils/DiffuseIBL.frag"
#stk_include "utils/SpecularIBL.frag"
float makeLinear(float f, float n, float z)
{
return (2.0f * n) / (f + n - z * (f - n));
}
vec3 CalcViewPositionFromDepth(in vec2 TexCoord)
{
// Combine UV & depth into XY & Z (NDC)
float z = makeLinear(1000.0, 1.0, textureLod(dtex, TexCoord, 0.).x);
vec3 rawPosition = vec3(TexCoord, z);
// Convert from (0, 1) range to (-1, 1)
vec4 ScreenSpacePosition = vec4( rawPosition * 2.0 - 1.0, 1.0);
// Undo Perspective transformation to bring into view space
vec4 ViewPosition = u_inverse_projection_matrix * ScreenSpacePosition;
// Perform perspective divide and return
return ViewPosition.xyz / ViewPosition.w;
}
// Fade out edges of screen buffer tex
// 1 means full render tex, 0 means full IBL tex
float GetEdgeFade(vec2 coords)
{
float gradL = smoothstep(0.0, 0.4, coords.x);
float gradR = 1.0 - smoothstep(0.6, 1.0, coords.x);
float gradT = smoothstep(0.0, 0.4, coords.y);
float gradB = 1.0 - smoothstep(0.6, 1.0, coords.y);
return min(min(gradL, gradR), min(gradT, gradB));
}
vec2 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth)
{
dir *= 0.25f;
for(int i = 0; i < 8; ++i) {
hitCoord += dir;
vec4 projectedCoord = u_projection_matrix * vec4(hitCoord, 1.0);
projectedCoord.xy /= projectedCoord.w;
projectedCoord.xy = projectedCoord.xy * 0.5 + 0.5;
float depth = CalcViewPositionFromDepth(projectedCoord.xy).z;
dDepth = hitCoord.z - depth;
if (dDepth < 0.0)
{
if (projectedCoord.x > 0.0 && projectedCoord.x < 1.0 &&
projectedCoord.y > 0.0 && projectedCoord.y < 1.0)
{
return projectedCoord.xy;
}
else
{
return vec2(0.f);
}
}
}
return vec2(0.f);
}
// Main ===================================================================
void main(void)
{
vec2 uv = gl_FragCoord.xy / u_screen;
vec3 normal = normalize(DecodeNormal(2. * texture(ntex, uv).xy - 1.));
Diff = vec4(0.25 * DiffuseIBL(normal), 1.);
float z = texture(dtex, uv).x;
vec4 xpos = getPosFromUVDepth(vec3(uv, z), u_inverse_projection_matrix);
vec3 eyedir = -normalize(xpos.xyz);
// Extract roughness
float specval = texture(ntex, uv).z;
#ifdef GL_ES
Spec = vec4(.25 * SpecularIBL(normal, eyedir, specval), 1.);
#else
// :::::::: Compute Space Screen Reflection ::::::::::::::::::::::::::::::::::::
// Output color
vec3 outColor;
// Fallback (if the ray can't find an intersection we display the sky)
vec3 fallback = .25 * SpecularIBL(normal, eyedir, specval);
// Only calculate reflections if the reflectivity value is high enough,
// otherwise just use specular IBL
if (specval > 0.5)
{
vec3 View_Pos = CalcViewPositionFromDepth(uv);
// Reflection vector
vec3 reflected = normalize(reflect(eyedir, normal));
// Ray cast
vec3 hitPos = View_Pos.xyz;
float dDepth;
float minRayStep = 50.0f;
vec2 coords = RayCast(reflected * max(minRayStep, -View_Pos.z),
hitPos, dDepth);
if (coords.x == 0.0 && coords.y == 0.0) {
outColor = fallback;
} else {
// FIXME We need to generate mipmap to take into account the gloss map
outColor = textureLod(albedo, coords, 0.f).rgb;
outColor = mix(fallback, outColor, GetEdgeFade(coords));
// TODO temporary measure the lack of mipmapping for RTT albedo
// Implement it in proper way
// Use (specval - 0.5) * 2.0 to bring specval from 0.5-1.0 range to 0.0-1.0 range
outColor = mix(fallback, outColor, (specval - 0.5) * 2.0);
}
}
else
{
outColor = fallback;
}
Spec = vec4(outColor.rgb, 1.0);
#endif
}