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use texelFetch for normal calc
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@ffreyer
ffreyer committed Jan 29, 2023
1 parent aa551be commit 8e79b41
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Showing 3 changed files with 108 additions and 123 deletions.
113 changes: 105 additions & 8 deletions GLMakie/assets/shader/surface.vert
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Expand Up @@ -42,14 +42,111 @@ vec2 grid_pos(Grid2D pos, vec2 uv);
vec2 linear_index(ivec2 dims, int index);
vec2 linear_index(ivec2 dims, int index, vec2 offset);
vec4 linear_texture(sampler2D tex, int index, vec2 offset);
// vec3 getnormal_fast(sampler2D zvalues, ivec2 uv);
vec3 getnormal(Grid2D pos, Nothing xs, Nothing ys, sampler2D zs, vec2 uv);
vec3 getnormal(Nothing pos, sampler2D xs, sampler2D ys, sampler2D zs, vec2 uv);
vec3 getnormal(Nothing pos, sampler1D xs, sampler1D ys, sampler2D zs, vec2 uv);

vec3 getnormal(Grid2D pos, Nothing xs, Nothing ys, sampler2D zs, ivec2 uv);
vec3 getnormal(Nothing pos, sampler2D xs, sampler2D ys, sampler2D zs, ivec2 uv);
vec3 getnormal(Nothing pos, sampler1D xs, sampler1D ys, sampler2D zs, ivec2 uv);


// Normal generation

vec3 getnormal_fast(sampler2D zvalues, ivec2 uv)
{
vec3 a = vec3(0, 0, 0);
vec3 b = vec3(1, 1, 0);
a.z = texelFetch(zvalues, uv, 0).r;
b.z = texelFetch(zvalues, uv + ivec2(1, 1), 0).r;
return normalize(a - b);
}

bool isinbounds(ivec2 uv, ivec2 size)
{
return (uv.x < size.x && uv.y < size.y && uv.x >= 0 && uv.y >= 0);
}

/*
Computes normal at s0 based on four surrounding positions s1 ... s4 and the
respective uv coordinates uv, off1, ..., off4
s2
s1 s0 s3
s4
*/
vec3 normal_from_points(
vec3 s0, vec3 s1, vec3 s2, vec3 s3, vec3 s4,
ivec2 off1, ivec2 off2, ivec2 off3, ivec2 off4, ivec2 size
){
vec3 result = vec3(0,0,0);
// isnan checks should avoid darkening around NaN positions but may not
// work with all systems
if (!isnan(s0.z)) {
bool check1 = isinbounds(off1, size) && !isnan(s1.z);
bool check2 = isinbounds(off2, size) && !isnan(s2.z);
bool check3 = isinbounds(off3, size) && !isnan(s3.z);
bool check4 = isinbounds(off4, size) && !isnan(s4.z);
if (check1 && check2) result += cross(s2-s0, s1-s0);
if (check2 && check3) result += cross(s3-s0, s2-s0);
if (check3 && check4) result += cross(s4-s0, s3-s0);
if (check4 && check1) result += cross(s1-s0, s4-s0);
}
// normal should be zero, but needs to be here, because the dead-code
// elimanation of GLSL is overly enthusiastic
return normalize(result);
}

// Overload for surface(Matrix, Matrix, Matrix)
vec3 getnormal(Nothing pos, sampler2D xs, sampler2D ys, sampler2D zs, ivec2 uv){
vec3 s0, s1, s2, s3, s4;
ivec2 off1 = uv + ivec2(-1, 0);
ivec2 off2 = uv + ivec2(0, 1);
ivec2 off3 = uv + ivec2(1, 0);
ivec2 off4 = uv + ivec2(0, -1);

s0 = vec3(texelFetch(xs, uv, 0).x, texelFetch(ys, uv, 0).x, texelFetch(zs, uv, 0).x);
s1 = vec3(texelFetch(xs, off1, 0).x, texelFetch(ys, off1, 0).x, texelFetch(zs, off1, 0).x);
s2 = vec3(texelFetch(xs, off2, 0).x, texelFetch(ys, off2, 0).x, texelFetch(zs, off2, 0).x);
s3 = vec3(texelFetch(xs, off3, 0).x, texelFetch(ys, off3, 0).x, texelFetch(zs, off3, 0).x);
s4 = vec3(texelFetch(xs, off4, 0).x, texelFetch(ys, off4, 0).x, texelFetch(zs, off4, 0).x);

return normal_from_points(s0, s1, s2, s3, s4, off1, off2, off3, off4, textureSize(zs, 0));
}


// Overload for (range, range, Matrix) surface plots
// Though this is only called by surface(Matrix)
vec2 grid_pos(Grid2D position, ivec2 uv, ivec2 size);

vec3 getnormal(Grid2D pos, Nothing xs, Nothing ys, sampler2D zs, ivec2 uv){
vec3 s0, s1, s2, s3, s4;
ivec2 off1 = uv + ivec2(-1, 0);
ivec2 off2 = uv + ivec2(0, 1);
ivec2 off3 = uv + ivec2(1, 0);
ivec2 off4 = uv + ivec2(0, -1);
ivec2 size = textureSize(zs, 0);

s0 = vec3(grid_pos(pos, uv, size).xy, texelFetch(zs, uv, 0).x);
s1 = vec3(grid_pos(pos, off1, size).xy, texelFetch(zs, off1, 0).x);
s2 = vec3(grid_pos(pos, off2, size).xy, texelFetch(zs, off2, 0).x);
s3 = vec3(grid_pos(pos, off3, size).xy, texelFetch(zs, off3, 0).x);
s4 = vec3(grid_pos(pos, off4, size).xy, texelFetch(zs, off4, 0).x);

return normal_from_points(s0, s1, s2, s3, s4, off1, off2, off3, off4, size);
}


// Overload for surface(Vector, Vector, Matrix)
// Makie converts almost everything to this
vec3 getnormal(Nothing pos, sampler1D xs, sampler1D ys, sampler2D zs, ivec2 uv){
vec3 s0, s1, s2, s3, s4;
ivec2 off1 = uv + ivec2(-1, 0);
ivec2 off2 = uv + ivec2(0, 1);
ivec2 off3 = uv + ivec2(1, 0);
ivec2 off4 = uv + ivec2(0, -1);

s0 = vec3(texelFetch(xs, uv.x, 0).x, texelFetch(ys, uv.y, 0).x, texelFetch(zs, uv, 0).x);
s1 = vec3(texelFetch(xs, off1.x, 0).x, texelFetch(ys, off1.y, 0).x, texelFetch(zs, off1, 0).x);
s2 = vec3(texelFetch(xs, off2.x, 0).x, texelFetch(ys, off2.y, 0).x, texelFetch(zs, off2, 0).x);
s3 = vec3(texelFetch(xs, off3.x, 0).x, texelFetch(ys, off3.y, 0).x, texelFetch(zs, off3, 0).x);
s4 = vec3(texelFetch(xs, off4.x, 0).x, texelFetch(ys, off4.y, 0).x, texelFetch(zs, off4, 0).x);

return normal_from_points(s0, s1, s2, s3, s4, off1, off2, off3, off4, textureSize(zs, 0));
}

uniform uint objectid;
uniform vec2 uv_scale;
Expand Down
116 changes: 2 additions & 114 deletions GLMakie/assets/shader/util.vert
View file
Expand Up @@ -31,8 +31,8 @@ vec2 grid_pos(Grid2D position, vec2 uv){

vec2 grid_pos(Grid2D position, ivec2 uv, ivec2 size){
return vec2(
(1 - uv.x / (size.x - 1)) * position.start[0] + uv.x / (size.x - 1) * position.stop[0],
(1 - uv.y / (size.y - 1)) * position.start[1] + uv.y / (size.y - 1) * position.stop[1]
(1.0 - (uv.x + 0.5) / size.x) * position.start[0] + (uv.x + 0.5) / size.x * position.stop[0],
(1.0 - (uv.y + 0.5) / size.y) * position.start[1] + (uv.y + 0.5) / size.y * position.stop[1]
);
}

Expand Down Expand Up @@ -243,118 +243,6 @@ void render(vec4 position_world, vec3 normal, mat4 view, mat4 projection, vec3 l
o_view_pos = view_pos.xyz / view_pos.w;
}

//
vec3 getnormal_fast(sampler2D zvalues, ivec2 uv)
{
vec3 a = vec3(0, 0, 0);
vec3 b = vec3(1, 1, 0);
a.z = texelFetch(zvalues, uv, 0).r;
b.z = texelFetch(zvalues, uv + ivec2(1, 1), 0).r;
return normalize(a - b);
}

bool isinbounds(vec2 uv)
{
return (uv.x <= 1.0 && uv.y <= 1.0 && uv.x >= 0.0 && uv.y >= 0.0);
}


/*
Computes normal at s0 based on four surrounding positions s1 ... s4 and the
respective uv coordinates uv, off1, ..., off4
s2
s1 s0 s3
s4
*/
vec3 normal_from_points(
vec3 s0, vec3 s1, vec3 s2, vec3 s3, vec3 s4,
vec2 uv, vec2 off1, vec2 off2, vec2 off3, vec2 off4
){
vec3 result = vec3(0,0,0);
// isnan checks should avoid darkening around NaN positions but may not
// work with all systems
if (!isnan(s0.z)) {
bool check1 = isinbounds(off1) && !isnan(s1.z);
bool check2 = isinbounds(off2) && !isnan(s2.z);
bool check3 = isinbounds(off3) && !isnan(s3.z);
bool check4 = isinbounds(off4) && !isnan(s4.z);
if (check1 && check2) result += cross(s2-s0, s1-s0);
if (check2 && check3) result += cross(s3-s0, s2-s0);
if (check3 && check4) result += cross(s4-s0, s3-s0);
if (check4 && check1) result += cross(s1-s0, s4-s0);
}
// normal should be zero, but needs to be here, because the dead-code
// elimanation of GLSL is overly enthusiastic
return normalize(result);
}

// Overload for surface(Matrix, Matrix, Matrix)
vec3 getnormal(Nothing pos, sampler2D xs, sampler2D ys, sampler2D zs, vec2 uv){
// The +1e-6 fixes precision errors at the edge
float du = 1.0 / textureSize(zs,0).x + 1e-6;
float dv = 1.0 / textureSize(zs,0).y + 1e-6;

vec3 s0, s1, s2, s3, s4;
vec2 off1 = uv + vec2(-du, 0);
vec2 off2 = uv + vec2(0, dv);
vec2 off3 = uv + vec2(du, 0);
vec2 off4 = uv + vec2(0, -dv);

s0 = vec3(texture(xs, uv).x, texture(ys, uv).x, texture(zs, uv).x);
s1 = vec3(texture(xs, off1).x, texture(ys, off1).x, texture(zs, off1).x);
s2 = vec3(texture(xs, off2).x, texture(ys, off2).x, texture(zs, off2).x);
s3 = vec3(texture(xs, off3).x, texture(ys, off3).x, texture(zs, off3).x);
s4 = vec3(texture(xs, off4).x, texture(ys, off4).x, texture(zs, off4).x);

return normal_from_points(s0, s1, s2, s3, s4, uv, off1, off2, off3, off4);
}


// Overload for (range, range, Matrix) surface plots
// Though this is only called by surface(Matrix)
vec3 getnormal(Grid2D pos, Nothing xs, Nothing ys, sampler2D zs, vec2 uv){
// The +1e-6 fixes precision errors at the edge
float du = 1.0 / textureSize(zs,0).x + 1e-6;
float dv = 1.0 / textureSize(zs,0).y + 1e-6;

vec3 s0, s1, s2, s3, s4;
vec2 off1 = uv + vec2(-du, 0);
vec2 off2 = uv + vec2(0, dv);
vec2 off3 = uv + vec2(du, 0);
vec2 off4 = uv + vec2(0, -dv);

s0 = vec3(grid_pos(pos, uv).xy, texture(zs, uv).x);
s1 = vec3(grid_pos(pos, off1).xy, texture(zs, off1).x);
s2 = vec3(grid_pos(pos, off2).xy, texture(zs, off2).x);
s3 = vec3(grid_pos(pos, off3).xy, texture(zs, off3).x);
s4 = vec3(grid_pos(pos, off4).xy, texture(zs, off4).x);

return normal_from_points(s0, s1, s2, s3, s4, uv, off1, off2, off3, off4);
}


// Overload for surface(Vector, Vector, Matrix)
// Makie converts almost everything to this
vec3 getnormal(Nothing pos, sampler1D xs, sampler1D ys, sampler2D zs, vec2 uv){
// The +1e-6 fixes precision errors at the edge
float du = 1.0 / textureSize(zs,0).x + 1e-6;
float dv = 1.0 / textureSize(zs,0).y + 1e-6;

vec3 s0, s1, s2, s3, s4;
vec2 off1 = uv + vec2(-du, 0);
vec2 off2 = uv + vec2(0, dv);
vec2 off3 = uv + vec2(du, 0);
vec2 off4 = uv + vec2(0, -dv);

s0 = vec3(texture(xs, uv.x).x, texture(ys, uv.y).x, texture(zs, uv).x);
s1 = vec3(texture(xs, off1.x).x, texture(ys, off1.y).x, texture(zs, off1).x);
s2 = vec3(texture(xs, off2.x).x, texture(ys, off2.y).x, texture(zs, off2).x);
s3 = vec3(texture(xs, off3.x).x, texture(ys, off3.y).x, texture(zs, off3).x);
s4 = vec3(texture(xs, off4.x).x, texture(ys, off4.y).x, texture(zs, off4).x);

return normal_from_points(s0, s1, s2, s3, s4, uv, off1, off2, off3, off4);
}

uniform vec4 highclip;
uniform vec4 lowclip;
Expand Down
2 changes: 1 addition & 1 deletion GLMakie/src/glshaders/surface.jl
View file
Expand Up @@ -6,7 +6,7 @@ end
function normal_calc(x::Bool, invert_normals::Bool = false)
i = invert_normals ? "-" : ""
if x
return "$(i)getnormal(position, position_x, position_y, position_z, index01);"
return "$(i)getnormal(position, position_x, position_y, position_z, index2D);"
else
return "vec3(0, 0, $(i)1);"
end
Expand Down

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