dolphin-emu/dolphin
1
0
Fork 0
mirror of https://github.com/dolphin-emu/dolphin.git synced 2024-10-06 23:33:34 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Remove AsciiArt shader

Browse Source 
This shader has been rendered nonfunctional due to the removal of the function SampleFontLocation, which was never implemented in VideoCommon. The last reference to SampleFontLocation was located in the OGL video backend. It was removed in this commit: f039149198 (diff-24125a6c968a8aca9cadd977d4b9d68f), where many functions were moved to video common, among other things.

This shader should be removed so it does not confuse users with the error that it causes. Alternatively, it could be rewritten so it is compatible with modern versions of Dolphin. I am not familiar with GLSL, so this is currently beyond my skill set.
This commit is contained in:
G 2020-10-05 21:44:56 -07:00 committed by GitHub
parent dcaf2b9625
commit 62bd79e70d
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 0 additions and 91 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

91
Data/Sys/Shaders/asciiart.glsl
View File

@ -1,91 +0,0 @@
const int char_width = 8;
const int char_height = 13;
const int char_count = 95;
const int char_pixels = char_width*char_height;
const float2 char_dim = float2(char_width, char_height);
const float2 font_scale = float2(1.0/float(char_width)/float(char_count), 1.0/float(char_height));
void main()
{
float2 char_pos = floor(GetCoordinates()*GetResolution()/char_dim);
float2 pixel_offset = floor(GetCoordinates()*GetResolution()) - char_pos*char_dim;
// just a big number
float mindiff = float(char_width*char_height) * 100.0;
float minc = 0.0;
float4 mina = float4(0.0, 0.0, 0.0, 0.0);
float4 minb = float4(0.0, 0.0, 0.0, 0.0);
for (int i=0; i<char_count; i++)
{
float4 ff = float4(0.0, 0.0, 0.0, 0.0);
float4 f = float4(0.0, 0.0, 0.0, 0.0);
float4 ft = float4(0.0, 0.0, 0.0, 0.0);
float4 t = float4(0.0, 0.0, 0.0, 0.0);
float4 tt = float4(0.0, 0.0, 0.0, 0.0);
for (int x=0; x<char_width; x++)
{
for (int y=0; y<char_height; y++)
{
float2 tex_pos = char_pos*char_dim + float2(x,y) + 0.5;
float4 tex = SampleLocation(tex_pos * GetInvResolution());
float2 font_pos = float2(x+i*char_width, y) + 0.5;
float4 font = SampleFontLocation(font_pos * font_scale);
// generates sum of texture and font and their squares
ff += font*font;
f += font;
ft += font*tex;
t += tex;
tt += tex*tex;
}
}
// The next lines are a bit harder, hf :-)
// The idea is to find the perfect char with the perfect background color and the perfect font color.
// As this is an equation with three unknowns, we can't just try all chars and color combinations.
// As criterion how "perfect" the selection is, we compare the "mean squared error" of the resulted colors of all chars.
// So, now the big issue: how to calculate the MSE without knowing the two colors ...
// In the next steps, "a" is the font color, "b" is the background color, "f" is the font value at this pixel, "t" is the texture value
// So the square error of one pixel is:
// e = ( t - a⋅f - b⋅(1-f) ) ^ 2
// In longer:
// e = a^2⋅f^2 - 2⋅a⋅b⋅f^2 + 2⋅a⋅b⋅f - 2⋅a⋅f⋅t + b^2⋅f^2 - 2⋅b^2⋅f + b^2 + 2⋅b⋅f⋅t - 2⋅b⋅t + t^2
// The sum of all errors is: (as shortcut, ff,f,ft,t,tt are now the sums like declared above, sum(1) is the count of pixels)
// sum(e) = a^2⋅ff - 2⋅a^2⋅ff + 2⋅a⋅b⋅f - 2⋅a⋅ft + b^2⋅ff - 2⋅b^2⋅f + b^2⋅sum(1) + 2⋅b⋅ft - 2⋅b⋅t + tt
// To find the minimum, we have to derive this by "a" and "b":
// d/da sum(e) = 2⋅a⋅ff + 2⋅b⋅f - 2⋅b⋅ff - 2⋅ft
// d/db sum(e) = 2⋅a⋅f - 2⋅a⋅ff - 4⋅b⋅f + 2⋅b⋅ff + 2⋅b⋅sum(1) + 2⋅ft - 2⋅t
// So, both equations must be zero at minimum and there is only one solution.
float4 a = (f*ft - ff*t + f*t - ft*float(char_pixels)) / (f*f - ff*float(char_pixels));
float4 b = (f*ft - ff*t) / (f*f - ff*float(char_pixels));
float4 diff = a*a*ff + 2.0*a*b*f - 2.0*a*b*ff - 2.0*a*ft + b*b *(-2.0*f + ff + float(char_pixels)) + 2.0*b*ft - 2.0*b*t + tt;
float diff_f = dot(diff, float4(1.0, 1.0, 1.0, 1.0));
if (diff_f < mindiff)
{
mindiff = diff_f;
minc = float(i);
mina = a;
minb = b;
}
}
float2 font_pos_res = float2(minc * float(char_width), 0.0) + pixel_offset + 0.5;
float4 col = SampleFontLocation(font_pos_res * font_scale);
SetOutput(mina * col + minb * (float4(1.0,1.0,1.0,1.0) - col));
}